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  • 1.
    Baghaei, Behnaz
    et al.
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Berglin, Lena
    University of Borås, Swedish School of Textiles.
    Ramamoorthy, Sunil Kumar
    University of Borås, School of Engineering.
    Hemp/PLA Co-Wrapped Hybrid Yarns For Structured Thermoplastic Composites2013Conference paper (Refereed)
    Abstract [en]

    In recent years, natural fibre-reinforced polymer composites have been attracting attention from the viewpoint of reducing the impact on the natural environment. Currently, the use of thermoplastic resins in composites is clearly of higher potential than the use of thermoset. There are many thermoplastic polymers derived from renewable raw materials, which are also biodegradable. Polylactic acid (PLA) is one such candidate, and it shows rather good properties that are suitable for applications that do not require long-term durability or elevated mechanical performance at higher temperatures. In order to make their possible use in many technical applications more attractive, the mechanical properties of the PLA can be enhanced by using reinforcements. Hemp fibres can be considered to be a good choice for reinforcing polymer composites, due to their high stiffness, strength, and aspect ratio. Highly ordered textile reinforcements, such as interlaced woven fabrics and unidirectional fabrics made from natural-fibre yarns, perform considerably better than random non-woven mats in natural-fibre composites. At present, the commercially available plant-fibre yarns are not intended for structural composites, but for textiles, which have entirely different demands on the yarns. Thus, work is needed to tailor-make the best plant-fibre yarn for reinforcement of composites. This also includes investigation of the possibility of combining plant-fibre yarns with the matrix polymer in fibre form into one hybrid yarn (a composite preform), and how to do it (twisting or blending). It is well known that fibres provide the highest strength and stiffness when they are continuous and aligned in the direction of the applied load. Natural fibres are naturally discontinuous and conventional spun staple yarns tend to be highly twisted, which leads to fibre misalignment and poor resin wet-out. The structured natural-fibre composites reported so far are based on twisted yarns produced by long-established conventional spinning methods, mainly ring spinning. In this paper, we report our work on improving the orientation of hemp fibres in composites by using our recent development of co-wrapped yarn structures. This novel co-wrapped yarn consists of low twist and very fine hemp yarns next to PLA filaments in the core part, which are wrapped by PLA filaments. By varying the composition of hybrid yarn, it is possible to vary the hemp fibre content from 10 to 45 wt %. An exciting recent advancement has been a new family of aligned natural-fibre reinforcements, which has overcome these issues by using low twist yarns. We also report the influence of fibre content and wrap density (number of wraps per unit length) on the properties of composites. Before compression moulding, multilayer 0/90 bidirectional hybrid yarn prepregs were prepared by winding the hybrid yarn around a steel rectangular frame. We investigated the mechanical and thermo-mechanical properties of hemp-reinforced PLA composites. Compared to neat PLA, the tensile and flexural modulus and the strength of the PLA-hemp composites were significantly higher as a result of the increased fibre content. Impact strength of the composites decreased initially up to 10 wt % fibre loading, but even higher fibre loading caused an improvement in impact strength. From the DMTA results, it is evident that incorporation of the fibres gives a considerable increase in storage modulus and a decrease in tan δ values. These results show the reinforcing effect of hemp on PLA matrix. From the general trend in the results obtained, it can be affirmed that co-wrapped hybrid yarn with lower wrapping density leads to lower mechanical properties in the composite. The study performed with DSC revealed that the glass transition temperature and the crystalline melting point of PLA were not affected significantly after reinforcement with hemp. The crystallisation temperature of the hemp-reinforced PLA composites decreased compared to pure PLA, which indicates that the hemp fibres hinder the migration and diffusion of PLA molecular chains to the surface of the nucleus in the composites. No noteworthy differences in calorimetric data from DSC for composites were observed between the hybrid yarn preforms with different wrapping density. Future work will concentrate on efforts to evaluate the biodegradability of these developing and promising composites.

  • 2.
    Bakare, Fatimat O.
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Ramamoorthy, Sunil Kumar
    University of Borås, Faculty of Textiles, Engineering and Business.
    Åkesson, Dan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Thermomechanical properties of bio-based composites made from a lactic acid thermoset resin and flax and flax/basalt fibre reinforcements2016In: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 83, p. 176-184Article in journal (Refereed)
    Abstract [en]

    Low viscosity thermoset bio-based resin was synthesised from lactic acid, allyl alcohol and pentaerythritol. The resin was impregnated into cellulosic fibre reinforcement from flax and basalt and then compression moulded at elevated temperature to produce thermoset composites. The mechanical properties of composites were characterised by flexural, tensile and Charpy impact testing whereas the thermal properties were analysed by dynamic mechanical thermal analysis (DMTA) and thermogravimetric analysis (TGA). The results showed a decrease in mechanical properties with increase in fibre load after 40 wt.% for the neat flax composite due to insufficient fibre wetting and an increase in mechanical properties with increase fibre load up to 60 wt.% for the flax/basalt composite. The results of the ageing test showed that the mechanical properties of the composites deteriorate with ageing; however, the flax/basalt composite had better mechanical properties after ageing than the flax composite before ageing.

  • 3.
    Kumar Ramamoorthy, Sunil
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Kuzhanthaivelu, Gauthaman
    Bohlén, Martin
    Research Institutes of Sweden.
    Åkesson, Dan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Waste Management Option for Bioplastics Alongside Conventional Plastics2019In: IRC 2019 International Research Conference Proceedings, 2019Conference paper (Refereed)
    Abstract [en]

    Bioplastics can be defined as polymers derived partly or completely from biomass. Bioplastics can be biodegradable such as polylactic acid (PLA) and polyhydroxyalkonoates (PHA); or non-biodegradable (biobased polyethylene (bio-PE), polypropylene (bio-PP), polyethylene terephthalate (bio-PET)). The usage of such bioplastics is expected to increase in the future due to new found interest in sustainable materials. At the same time, these plastics become a new type of waste in the recycling stream. Most countries do not have separate bioplastics collection for it to be recycled or composted. After a brief introduction of bioplastics such as PLA in UK, these plastics are once again replaced by conventional plastics by many establishments due to lack of commercial composting. Recycling companies fear the contamination of conventional plastic in the recycling stream and they said they would have to invest in expensive new equipment to separate bioplastics and recycle it separately. Bioplastics are seen as a threat to the recycling industry as bioplastics may degrade during the mechanical recycling process and the properties of the recycled plastics are seriously impacted. This project studies what happens when bioplastics contaminate conventional plastics.

    Three commonly used conventional plastics were selected for this study: polyethylene (PE), polypropylene (PP) and polyethylene terephthalate (PET). In order to simulate contamination, two biopolymers, either polyhydroxyalkanoate (PHA) or thermoplastic starch (TPS) were blended with the conventional polymers. The amount of bioplastics in conventional plastics was either 1% or 5%. The blended plastics were processed again to see the effect of degradation. Mechanical, thermal and morphological properties of these plastics were characterized.

     

    The results from contamination showed that the tensile strength and the modulus of PE was almost unaffected whereas the elongation is clearly reduced indicating the increase in brittleness of the plastic. Generally, it can be said that PP is slightly more sensitive to the contamination than PE. This can be explained by the fact that the melting point of PP is higher than for PE and as a consequence, the biopolymer will degrade more quickly. However, the reduction of the tensile properties for PP is relatively modest. It is also important to notice that when plastics are recovered, there will always be a contamination that will reduce the material properties. The reduction of the tensile properties is not necessary larger than if a non-biodegradable polymer would have contaminated PE or PP. The Charpy impact strength is generally a more sensitive test method towards contamination. Again, PE is relatively unaffected by the contamination but for PP there is a relatively large reduction of the impact properties already at 1% contamination.

    PET is polyester and it is by its very nature more sensitive to degradation than PE and PP. PET also have a much higher melting point than PE and PP and as a consequence the biopolymer will quickly degrade at the processing temperature of PET. As for the tensile strength, PET can tolerate 1% contamination without any reduction of the tensile strength. However, when the impact strength is examined, it is clear that already at 1% contamination, there is a strong reduction of the properties. It can also be seen that presence of TPS is more detrimental to PET than PHA is. This can be explained by the fact that TPS contain reactive hydroxyl groups that can react with the ester bond of PET. This will in other words lead to degradation of PET.

    The thermal properties show the change in the crystallinity. As a general conclusion, it can be said that the plastics become less crystalline when contaminated. The blends were also characterized by SEM. Biphasic morphology can be seen as the two polymers are not truly blendable which also contributes to reduced mechanical properties. Recycling of the contaminated polymer shows an increase in crystallinity. This means that when the polymers are processed, polymer degradation occur causing the polymer chains to gradually become shorter which will enhance the crystallization process.

    The study shows that PE is relatively robust againt contamination, while polypropylene (PP) is somewhat more sensitive and polyethylene terephthalate (PET) can be quite sensitive towards contamination.

  • 4.
    Kumar Ramamoorthy, Sunil
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Periyasamy, Aravin Prince
    Technical University Liberec, Liberec, Czech Republic.
    Lavate, Saatish Siddappa
    DKTE’s Textile Engineering Institute, Ichalkaranji, India.
    Eco-friendly Denim Processing2018In: Handbook of Ecomaterials / [ed] Leticia Myriam Torres Martínez, Springer Publishing Company, 2018Chapter in book (Refereed)
    Abstract [en]

    The denim sector is booming worldwide, because of the spread of denim culture. All over the world it has brought with it a trend of fast-changing fashion. Denim washing has emerged as one of the important production routes toward meeting the fast-changing demands of the fashion market. There are huge ecological concerns, as this sector is enormous. Approximately 1500 gallons of water is needed to produce 1.5 pounds of cotton to make one pair of jeans. If this continues, soon it will pose a serious problem to drinking water supplies. It is therefore important to study the environmental impact of denim and find alternative processes. This chapter starts by describing the different types of denim washing techniques. In addition, it discusses the environmental impact of denim dry and wet washing techniques, and the importance of environmentally friendly washing techniques. It also describes the latest denim finishing technologies, comparing their impacts on the environment with those of the classic techniques. Further, the environmental aspects of auxiliaries and washing chemicals are reviewed, followed by a discussion of garment washing and finishing processes.

  • 5.
    Kumar Ramamoorthy, Sunil
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Periyasamy, Aravin Prince
    Technical University of Liberec, Liberec, Czech Republic.
    Rwawiire, Samson
    Busitema University, Tororo, Uganda.
    Zhao, Yan
    Soochow University, Suzhou, People’s Republic of China.
    Sustainable Wastewater Treatment Methods for Textile Industry2018In: Sustainable Innovations in Apparel Production / [ed] Subramanian Senthilkannan Muthu, Singapore: Springer Publishing Company, 2018Chapter in book (Refereed)
    Abstract [en]

    All over the world, environmental considerations are now becoming vital factors during the selection of consumer goods which include textiles. According to the World Bank, 20% of water pollution globally is caused by textile processing, which means that these industries produce vast amounts of wastewater. Generally, these effluents contain high levels of suspended solids (SS), phosphates, dyes, salts, organo-pesticides, non-biodegradable organics, and heavy metals. Increase in water scarcity and environmental regulations has led to textile industries to seek for sustainable wastewater treatment methods which help to reduce their water footprint as well as reduce their operational costs. Therefore, sustainable wastewater treatment could be the best choice for the textile industries with respect to the current issues. So, it is important to discuss and champion awareness mechanisms which help to reduce the current issues with respect to the textile wastewater. Therefore, this chapter intends to discuss the various sustainable wastewater treatments, namely granular activated carbon (GAC), electrocoagulation (EC), ultrasonic treatment, an advanced oxidation process (AOP), ozonation, membrane biological reactor (MBR), and sequencing batch reactor (SBR).

  • 6.
    Kumar Ramamoorthy, Sunil
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Alagar, Ragunathan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Akhtar, Naeem
    University of Borås, Faculty of Textiles, Engineering and Business.
    End of life textiles as reinforcements in biocomposites2017In: Journal of polymers and the environment, ISSN 1566-2543, E-ISSN 1572-8919, p. -12Article in journal (Refereed)
    Abstract [en]

    A number of attempts have been made to recycle cotton/polyester blend woven fabrics after use; however, most of these fabrics are disposed of in landfills. Major part of these blend fabrics are not recycled due to complexity of the fibre arrangement and cannot be separated economically. This study shows that these discarded woven fabrics could be directly used as reinforcements in composites without fibre separation. Uniform alignment in the woven fabric provided consistent properties to the composites. The fabrics were reinforced by soybean-based-bioresins to produce biocomposites. The composites were analysed for mechanical, thermal, viscoelastic and morphological properties. Porosity and wettability of the composites were also evaluated. Results demonstrate that the tensile strength and modulus of over 100 and 10 MPa, respectively, can be obtained without any fibre treatment. Furthermore, impact strength over 70 kJ/m2 was obtained without any chemical treatment on fibres. The porosity of the composites produced was less than 9 vol%. Additionally, the fabrics were treated with alkali in order to improve the fibre–matrix interface and the composite properties were studied. From the economical perspective, these composites can be produced at a low cost as the major component is available for free or low cost.

  • 7.
    Kumar Ramamoorthy, Sunil
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Rajan, Rathish
    Tampere University of Technology.
    Rainosalo, Egidija
    Centria University of Applied Sciences.
    Thomas, Selvin
    Yanbu Industrial College and Advanced Materials Laboratory.
    Zavasnik, Janez
    Jožef Stefan Institute.
    Vuorinen, Jyrki
    Tampere University of Technology.
    Mechanical, thermal, and burning properties of viscose fabric composites: Influence of epoxy resin modification2018In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 135, no 36Article in journal (Refereed)
    Abstract [en]

    The influence of epoxy resin modification by 3-aminopropyltriethoxysilane (APTES) on various properties of warp knitted viscose fabric is reported in this study. Dynamic mechanical, impact resistance, flexural, thermal properties, and burning behavior of the epoxy/viscose fabric composites are studied with respect to varying content of silane coupling agent. The results obtained forAPTES-modified epoxy resin based composites reinforced with unmodified viscose fabric composites are compared to unmodified epoxy resin based composites reinforced with APTES-modified viscose fabric. The dynamic mechanical behavior of the APTES-modified resin based composites indicates improved interfacial adhesion. The composites prepared from modified epoxy resin exhibited a twofold increase in impact resistance. The improved adhesion between the fiber and modified resin was also visible from the scanning electron microscope analysis of the impact fracture surface. There was less influence of resin modification on the flexural properties of the composites. The 5% APTES modification induced early degradation of composites compared to all other compo-sites. The burning rate of all the composites under study is rated to be satisfactory for use in automotive interior applications.

  • 8.
    Kumar Ramamoorthy, Sunil
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Åkesson, Dan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Rajan, Rathish
    Tampere University.
    Periyasamy, Aravin Prince
    Technical University of Liberec.
    Mechanical performance of biofibers and their corresponding composites2019In: Mechanical and Physical Testing of Biocomposites, Fibre-Reinforced Composites and Hybrid Composites / [ed] Mohammad Jawaid, Mohamed Thariq, Naheed Saba, Woodhead Publishing Limited, 2019Chapter in book (Refereed)
    Abstract [en]

    This chapter focuses on mechanical performance of biofibers such as flax, hemp, and sisal and their effect on mechanical performance when they are reinforced in thermoset and thermoplastic polymers. The aim of this chapter is to present an overview of the mechanical characterization of the biofibers and their corresponding composites. The mechanical characterization includes tensile, flexural, impact, compressive, shear, toughness, hardness, brittleness, ductility, creep, fatigue, and dynamic mechanical analyses. Detailed studies of each test have been widely reported and an overview is important to relate the studies. Studies pertaining to the topics are cited. The most common materials used in biocomposites are biofibers (also called natural fibers) and petroleum-based polymers such polypropylene. The use of renewable materials in biocomposites has increased in the past couple of decades owing to extensive research on cellulosic fibers and biopolymers based on starch or vegetable oil. Today, research is focused on reinforcing natural fibers in petroleum-based polymers. However, the emphasis is shifting toward the amount of renewable materials in biocomposites, which has led to the use of biopolymers instead of petroleum-based polymers in composites. The mechanical properties of some renewable resource-based composites are comparable to commercially available nonrenewable composites.

    Several plant biofibers have been reinforced in thermoplastics or thermosets to manufacture biocomposites because of their specific properties. The Young's modulus of commonly used biofibers such as hemp and flax could be over 50 GPa and therefore they could be good alternatives to glass fibers in several applications. The good mechanical properties of these biofibers influence the composites' mechanical performance when reinforced in polymers. It is important to understand the mechanical performance of these biofibers and biocomposites in a working environment. A detailed discussion about the mechanical performance of commonly used biofibers and composites is provided in this chapter.

  • 9. Lindström, Katarina
    et al.
    Ramamoorthy, Sunil Kumar
    University of Borås, School of Engineering.
    Persson, Anders
    University of Borås, Swedish School of Textiles.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Reuse of Waste Textiles For Composite Production2013Conference paper (Refereed)
    Abstract [en]

    Large amounts of cotton/PET textiles are wasted every year due to economically unfeasible separation of cotton and PET from waste textiles. These waste textiles were reused to form composites for technical applications and their properties were studied in this project. The waste textile, bed linen, used in this project comes from local hospital. The aim of this study is to produce composites from cotton/PET waste textiles and characterize by mechanical and thermal analysis. The effect of orientation of the fibers was studied and the processing parameters such as temperature, pressure and time of compression were optimized.

  • 10.
    Persson, Nils-Krister
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Baghaei, Behnaz
    University of Borås, Faculty of Textiles, Engineering and Business.
    Bashir, Tariq
    University of Borås, Faculty of Textiles, Engineering and Business.
    Brorström, Björn
    University of Borås, Faculty of Textiles, Engineering and Business.
    Hedegård, Lars
    University of Borås, Faculty of Textiles, Engineering and Business.
    Carlson Ingdahl, Tina
    University of Borås, Faculty of Textiles, Engineering and Business.
    Larsson, Jonas
    University of Borås, Faculty of Textiles, Engineering and Business.
    Lindberg, Ulla
    University of Borås, Faculty of Textiles, Engineering and Business.
    Löfström, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Oudhuis, Margaretha
    University of Borås, Faculty of Textiles, Engineering and Business.
    Pal, Rudrajeet
    University of Borås, Faculty of Textiles, Engineering and Business.
    Pettersson, Anita
    University of Borås, Faculty of Textiles, Engineering and Business.
    Påhlsson, Birgitta
    University of Borås, Faculty of Textiles, Engineering and Business.
    Kumar Ramamoorthy, Sunil
    University of Borås, Faculty of Textiles, Engineering and Business.
    Richards, Tobias
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Worbin, Linda
    University of Borås, Faculty of Textiles, Engineering and Business.
    Åkesson, Dan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Re: en ny samhällssektor spirar2016Report (Other academic)
    Abstract [sv]

    Resurser och hållbarhet är nära förknippade. Hållbarhet innebär att hushålla med resurser - materiella, miljömässiga och mänskliga. Och hushållning är per definition kärnan i ekonomi. Man börjar alltmer se framväxten av en hel arsenal av verktyg och förhållnings- och angreppssätt för att bygga hållbarhet. Detta förenas av ett synsätt att det som hitintills setts  om avfall och värdelöst, och rent utav besvärligt att ta hand om, nu blir en värdefull resurs. Det glömda och gömda kommer åter. Faktum är att många ord och begrepp kring detta börjar på just åter- eller re- . Internationellt talar man om Redesign, Recycling, Remake, Recycle, Recraft, Reuse, Recreate, Reclaim, Reduce, Repair, Refashion.

    Vad är då allt detta? Ja, vill man dra det långt, är det inte mindre än framväxten av ett nyvunnet sätt att tänka, ja av en ny samhällssektor, en bransch och en industri,  sammanbundet av filosofin att återanvändningen, spillminskningen, vidarebruket, efterlivet anses som viktiga faktorer för ett miljömedvetet samhälle. Re: blir paraplytermen för detta. I denna antologi av forskare från skilda discipliner vid Högskolan i Borås lyfts ett antal av dessa begrepp inom Re: fram.

  • 11.
    Rajan, Rathish
    et al.
    Tampere University of Technology.
    Rainosalo, Egidija
    Centria University of Applied Sciences.
    Thomas, Selvin
    Royal Commission Yanbu Colleges and Institutes.
    Kumar Ramamoorthy, Sunil
    University of Borås, Faculty of Textiles, Engineering and Business.
    Vuorinen, Jyrki
    Tampere University of Technology.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Zavasnik, Janez
    Jožef Stefan Institute.
    Modification of epoxy resin by silane-coupling agent to improve tensile properties of viscose fabric composites2018In: Polymer Bulletin, ISSN 0170-0839, E-ISSN 1436-2449, Vol. 75, no 1, p. 167-195Article in journal (Refereed)
    Abstract [en]

    The modification of epoxy resin by 3-aminopropyltriethoxysilane (APTES) to improve the tensile properties of warp knitted viscose fabric composites is reported in this study. The study evaluates the efficiency of modification methods adopted to modify the epoxy resin and the influence of the resin modification on various properties of the cured castings. The influence of matrix resin modification on the tensile properties of viscose fabric composite is compared to those prepared from chemically modified fibre. The efficiency of the modification was determined through titration method to determine the epoxide content of epoxy resin, viscosity measurement and FTIR. The effect of APTES modification on various properties of cured castings is studied through differential scanning calorimeter, contact angle measurement and tensile testing. The addition of APTES into the epoxy resin decreased the epoxide content in the resin as evident from the titration method. The tensile strength of cured castings decreased after the resin modification. The tensile strength and elongation at break of the viscose fabric composites prepared from modified resin, increased up to 14 and 41%, respectively. The improved adhesion of APTES-modified epoxy resin to the viscose fibre is confirmed from SEM analysis of tensile fracture surface.

  • 12.
    Ramamoorthy, S. K.
    et al.
    University of Borås, School of Engineering.
    Di, Q.
    Adekunle, K.
    University of Borås, School of Engineering.
    Skrifvars, M.
    University of Borås, School of Engineering.
    Effect of water absorption on mechanical properties of soybean oil thermosets reinforced with natural fibers2012In: Journal of reinforced plastics and composites (Print), ISSN 0731-6844, E-ISSN 1530-7964, Vol. 31, no 18, p. 1191-1200Article in journal (Refereed)
    Abstract [en]

    Natural fiber composites are known to absorb more water than glass fiber reinforced composites. In this study, hybrid natural fiber composites were prepared by combining different fiber reinforcements, and both the water absorption and the mechanical properties were studied. Compression molding technique was used to manufacture composite laminates from a bio-based resin (acrylated epoxidized soybean oil) and natural fibers: non-woven and woven jute, non-woven regenerated cellulose mat (Lyocell and viscose), and woven glass fiber. The composite laminates were cured at 160–170 C and 40 bar, with a fiber content of 40 wt%. We investigated effect of pretreatment of regenerated cellulose fiber using 4% NaOH solution. The gravimetric water absorption was tested by exposure to water for 10 days. Specimens were cut from composites with laser-cutting technique according to ISO standards, and tested for tensile, flexural, and impact strength. To determine the influence of water absorption on the mechanical properties, specimens were immersed in distilled water for 10 days before testing. As a reference, dry specimens were tested. The results showed that water absorption was reduced by producing hybrid composites with jute fibers, glass fiber, and Lyocell fiber. The tensile, flexural, and impact properties were improved by inclusion of glass fiber and Lyocell in the composite. The tensile and flexural properties of natural fiber reinforced composites were mostly affected by the influence of water, but this was improved considerably by hybridization with glass and Lyocell fibers. The viscoelastic properties of the manufactured composites and hybrid composites were studied using dynamic mechanical thermal analysis.

  • 13.
    Ramamoorthy, Sunil Kumar
    University of Borås, Faculty of Textiles, Engineering and Business.
    Properties and performance of regenerated cellulose thermoset biocomposites2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Biocomposites have been developed to address the sustainability issues of nonrenewableresource based materials. These composites are often produced by reinforcing natural fibres in petroleum based thermoset resins or thermoplastic polymers. Thermoplastic polymers from renewable resources are commercially available, whereas thermoset resins are predominantly derived from crude oil resources. Cellulose fibres have significant importance and potential for polymer reinforcement in lightweight composites. Natural fibres are chemically diverse and their properties vary largely which makes it difficult for them to be used in several applications. The natural fibre based products are limited by their characteristic odour emissions. These issues of natural fibres can be addressed by partly manmade fibres i.e. regenerated cellulose fibre which with little or no compromise in the environmental benefits of the natural fibres can be produced from biomass origin. Natural fibres and their composites have been observed and researched closely for many decades. Study of regenerated cellulose fibres and their composites is, on the other hand, relatively new. Regenerated cellulose fibres are prospective reinforcing material in the composite field due to their even quality and high purity. These fibres have good mechanical properties and also address the odour emission issue of the natural fibres. The development of biocomposites from regenerated cellulose fibre and thermoset resin synthesized from renewable resources has therefore been viewed with considerable interest.

    This thesis describes the development of biocomposites from regenerated cellulose fibres (lyocell and viscose) and thermoset resins synthesized from renewable resources (soybean oil and lactic acid). The performance and the properties of the composites were evaluated. Chemical surface treatments, alkali and silane, were performed on the fibres in order to improve the performance of the composites. Hybrid composites were also produced by mixing of two types of reinforcement in order to complement one type of fibre with other. The developed composites were evaluated through mechanical, thermal, viscoelastic and morphological properties among others. The results showed that the regenerated cellulose fibre thermoset biocomposites have reasonably good properties. Fibres before and after treatment were studied in detail. The silane treatment on these fibres improved the mechanical properties of the composites as the silane molecules act as a link between the fibre and resin which gives the molecular continuity across the interface region of the composite.

  • 14.
    Ramamoorthy, Sunil Kumar
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Bakare, Fatimat
    University of Borås, Faculty of Textiles, Engineering and Business.
    Herrmann, Rene
    Arcada University of Applied Science.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Performance of biocomposites from surface modified regenerated cellulose fibers and lactic acid thermoset bioresin2015In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882XArticle in journal (Refereed)
    Abstract [en]

    The effect of surface treatments, silane and alkali, on regenerated cellulose fibers was studied by using the treated fibers as reinforcement in lactic acid thermoset bioresin. The surface treatments were performed to improve the physico–chemical interactions at the fiber–matrix interface. Tensile, flexural and impact tests were used as indicator of the improvement of the interfacial strength. Furthermore, thermal conductivity, viscoelasticity measurements as well as microscopy images were made to characterize the fiber surface treatments and the effect on adhesion to the matrix. The results showed that silane treatment improved the mechanical properties of the composites as the silane molecule acts as link between the cellulose fiber and the resin (the fiber bonds with siloxane bridge while the resin bonds with organofunctional group of the bi-functional silane molecule) which gives molecular continuity in the interphase of the composite. Porosity volume decreased significantly on silane treatment due to improved interface and interlocking between fiber and matrix. Decrease in water absorption and increase in contact angle confirmed the change in the hydrophilicity of the composites. The storage modulus increased when the reinforcements were treated with silane whereas the damping intensity decreased for the same composites indicating a better adhesion between fiber and matrix on silane treatment. Thermogravimetric analysis indicated that the thermal stability of the reinforcement altered after treatments. The resin curing was followed using differential scanning calorimetry and the necessity for post-curing was recommended. Finite element analysis was used to predict the thermal behavior of the composites and a non-destructive resonance analysis was performed to ratify the modulus obtained from tensile testing. The changes were also seen on composites reinforced with alkali treated fiber. Microscopy images confirmed the good adhesion between the silane treated fibers and the resin at the interface.

  • 15.
    Ramamoorthy, Sunil Kumar
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Bakare, Fatimat Oluwatoyin
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Mechanical and thermal properties of the textile bio-composites: measurement and prediction2015In: , 2015Conference paper (Refereed)
  • 16.
    Ramamoorthy, Sunil Kumar
    et al.
    University of Borås, School of Engineering.
    Di, Qin
    Adekunle, Kayode
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Can the Outdoor Properties Of Natural Fiber Reinforced Bio-Based Composites Be Improved?2012Conference paper (Refereed)
    Abstract [en]

    Natural fiber composites are known to absorb more moisture than glass or carbon fiber reinforced composites. The hybrid natural fiber composites prepared in this study have relatively less moisture absorption than natural fiber composites. The composite laminates were manufactured by compression molding technique. A bio‐based resin known as acrylated epoxidized soybean oil (AESO) was used as a matrix, while jute fiber, regenerated cellulose fiber (Lyocell and viscose) and glass fiber were used as reinforcements. The composite laminates were prepared at temperature between 160‐170°C and pressure of 40 bar with natural fiber reinforcement between 30‐60 wt% of the fiber. Specimens were cut from the laminates with a laser cutting machine according to standard. The effect of pretreatment of natural fiber and regenerated cellulose fiber using 4% NaOH solution was investigated and discussed. The amount of water absorbed by the composites was determined by soaking the specimens in distilled water for 10 days. To see the influence of water absorption on mechanical properties of the composites, specimens were immersed in distilled water for 10 days before testing. Dry specimens were also tested for reference. Charpy Impact testing was performed on the composite laminates in order to calculate the energy absorbed by specimen during fracture. Water absorption behavior of the natural fiber composites was reduced by manufacturing hybrid composites with glass and Lyocell fibers. Tensile, flexural and impact properties of the natural fiber reinforced composites were improved by the inclusion of glass or Lyocell fiber. Tensile and flexural properties of natural fiber reinforced composites were affected largely by the influence of water and it could be improved by hybridization. Viscoelastic properties of the composites and hybrid composites were studied by dynamic mechanical thermal analysis.

  • 17.
    Ramamoorthy, Sunil Kumar
    et al.
    University of Borås, School of Engineering.
    Di, Qin
    Adekunle, Kayode
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Processing Of Non-Woven Lyocell Fabric And Mechanical Properties Of Non-Woven Fiber Reinforced Bio-Based Composites2012Conference paper (Refereed)
    Abstract [en]

    Non‐woven Lyocell mats were made from the fibers by carding and needling process at Swerea IVF, Mölndal, Sweden. The carding was done first in order to align the clumps of fibers. And then needle punching was done to obtain compact and entangled fiber mat. The composites were made by compression molding technique at temperature between 160‐170°C and pressure of 40 bar with non‐woven Lyocell, jute and viscose fiber reinforcements. The hybrid bio‐based composites were produced in this study to improve the mechanical properties of the composites. Bio‐based thermoset resin known as acrylated epoxidized soybean oil (AESO) was used as matrix in the composites. Laser cutting technique was adopted to cut specimens from laminates according to standard. The dimensional stability of the composites was determined by soaking the composite specimens in water for 10 days. Tensile and flexural properties of the composites were determined before and after water uptake. Hybridizing the jute fiber with glass and Lyocell fibers reduced the water uptake. Mechanical properties of the non‐woven fiber reinforced composites were studied by tensile, flexural, impact tests. Viscoelastic properties were studied using dynamic mechanical thermal analysis (DMTA). Tensile, flexural and impact properties of natural fiber composites were improved by hybridizing with Lyocell fiber.

  • 18.
    Ramamoorthy, Sunil Kumar
    et al.
    University of Borås, School of Engineering.
    Kundu, Chanchal Kumar
    Adekunle, Kayode
    University of Borås, School of Engineering.
    Bashir, Tariq
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Biocomposites From Regenerated Cellulose Textile Fibers And Bio-Based Thermoset Matrix For Automotive Applications2013Conference paper (Refereed)
    Abstract [en]

    Biocomposites were produced from regenerated cellulose fiber reinforcement and soybean based bio-matrix. Mechanical, thermal, viscoelastic and morphological results show the good potential of these composites to be used as structural materials in automotive industries. This article focuses on manufacturing and testing of these composites for engineering materials. Regenerated cellulose fibers such as Lyocell and viscose were reinforced in soybean based thermoset matrix to produce composites by compression molding. Hybrid composites were produced by mixing both these fibers at known ratio and the total fiber content in composite was between 40 and 60 weight %. In general, Lyocell based composites showed better tensile properties than viscose based composites. Composites consisting 60 weight % Lyocell and rest with matrix had tensile strength of 135 MPa and tensile modulus of 17 GPa. These composites also showed good flexural properties; flexural strength of 127 Mpa and flexural modulus of 7 GPa. Dynamic mechanical thermal analysis showed that these composites had good viscoelastic properties. Viscose based composites had better percentage elongation during tensile test. These composites also showed relatively good impact and viscoelastic properties. Scanning electron microscope images showed that the composites had good fiber-matrix adhesion. Several efforts are made to produce sustainable biomaterials to replace synthetic materials due to inherent properties like renewable, biodegradable and low density. Biocomposites play significant role in sustainable materials which has already found applications in automotive and construction industries. Many researchers produced biocomposites from natural fiber and bio-based/synthetic matrix and it had found several applications. There are several disadvantages of using natural fiber in composites; quality variation, place dependent, plant maturity, harvesting method, high water absorption etc. These composites also give odor which has to be avoided in indoor automotive applications. These natural fibers can be replaced with lignocelluloses, agro mass and biomass to develop biocomposites as they are from natural origin. Lyocell and viscose are manmade regenerated cellulose fibers which is from natural origin has excellent properties. These fibers can be used as reinforcements to produce biocomposites which can overcome most of the above listed disadvantages of natural fibers. Many composites were made from natural fiber reinforcement and petroleum based synthetic matrix. Researchers have been finding ways to get matrix out of natural resources like soybean and linseed on chemical modifications. This article is focused on producing and testing sustainable material with regenerated cellulose and soybean based bio-matrix for automotive applications.

  • 19.
    Ramamoorthy, Sunil Kumar
    et al.
    University of Borås, School of Engineering.
    Kundu, Chanchal Kumar
    Adekunle, Kayode
    University of Borås, School of Engineering.
    Bashir, Tariq
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Characterization Of Wood Based Fiber Reinforced Bio-Composites2013Conference paper (Refereed)
    Abstract [en]

    Natural fiber composites have got more focus in recent times due to their intrinsic properties such as lightweight, biodegradable, low cost etc. Several researchers have made bio-composites out of many natural fibers such as jute, flax, sisal. These composites have large market in Europe and North America where it is used in automobile and construction industry. A lot of research has been done to improve the properties such as surface modification of fiber, manufacturing hybrid composites. However, the natural fibers are dissimilar and vary largely due to many factors such as variety, harvest, maturity, climate etc. Apart from technical drawbacks, these fibers grow only in certain countries such as India and China. High demand raised the price of these fibers which increases the product price as well. Wood-based fibers such as Lyocell and Viscose was used to make composites in order to make less variation in products, decrease the dependency of natural fibers, promoting locally available fibers and encourage forest products as value-added products. Lyocell and viscose fibers have relatively less variation and high quality. Bio-composites were made by reinforcing wood-based fibers in soybean based thermoset matrix. Hybrid composites were prepared by mixing two different wood-based fibers in known ratio. The fiber content in the composites was between 40 and 60 weight%. Mechanical properties were characterized by tensile, flexural and impact tests. Lyocell and viscose based composites had better mechanical properties than jute fiber composites. Alkali treatment of Lyocell fibers improved the mechanical properties of the composites. The behaviour of wood-based fiber composites were studied under wet environment as well. In wet environment, the mechanical properties of wood-based fiber composites were superior to jute fiber composites. Lyocell based composites had tensile strength of 135 MPa and tensile modulus of 17 GPa. The composites had flexural strength of 127 MPa and flexural modulus of 7 GPa. Better percentage elongation was obtained when viscose fiber was reinforced in matrix. Viscose composites had better impact strength and viscoelastic properties. The change in properties in two different wood-based fibers (Lyocell and viscose) lies in the morphology of the fiber itself. Hybrid composites were produced and the effect of hybridization was clear in most of the cases. The properties were able to be tailored by making hybrid composites, by changing the amount of each fiber in the composites. The results (tensile and flexural) were competitive and fulfil the requirements of these composites to be used in several applications including automotive headliners, car door panel, construction door frame etc. The forest products such as wood fibers could be used in composites to produce environmentally friendly products and promote forest industry. Wood-based fibers such as Lyocell and Viscose was used to make composites in order to make less variation in products, decrease the dependency of natural fibers, promoting locally available fibers and encourage forest products. Bio-composites were made by reinforcing wood-based fibers in soybean based thermoset matrix. Hybrid composites were prepared by mixing two different wood-based fibers in known ratio. Mechanical properties were characterized by tensile, flexural and impact tests. Lyocell and viscose based composites had better mechanical properties than jute fiber composites. Alkali treatment of Lyocell fibers improved the mechanical properties of the composites. The behaviour of wood-based fiber composites were studied under wet environment as well. In wet environment, the mechanical properties of wood-based fiber composites were superior to jute fiber composites. Lyocell based composites had tensile strength of 135 MPa and tensile modulus of 17 GPa. The composites had flexural strength of 127 MPa and flexural modulus of 7 GPa. Viscose composites had better impact strength and viscoelastic properties. The result fulfils the requirements of these composites to be used in several applications including automotive headliners, car door panel etc. The forest products could be used in composites to produce environmentally friendly products and promote forest industry.

  • 20.
    Ramamoorthy, Sunil Kumar
    et al.
    University of Borås, School of Engineering.
    Kundu, Chanchal Kumar
    Adekunle, Kayode
    University of Borås, School of Engineering.
    Bashir, Tariq
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Properties of green composites with regenerated cellulose fiber and soybean-based thermoset for technical applications2014In: Journal of reinforced plastics and composites (Print), ISSN 0731-6844, E-ISSN 1530-7964, Vol. 33, no 2, p. 193-201Article in journal (Refereed)
    Abstract [en]

    Composites were developed by reinforcing available non-woven Lyocell and viscose in acrylated epoxidized soybean oil (AESO). Compression molding was used to make composites with 40–60 wt% fiber content. The fiber content comprises only Lyocell or viscose fiber, or mixture of these fibers in known ratio. Hybrid composites were made by a mixture of both the fibers in known ratio and it affects the properties. The effect of hybridization was evident in most tests which gives us an opportunity to tailor the properties according to requirement. Lyocell fiber reinforced composites with 60 wt% fiber content had a tensile strength and modulus of about 135 MPa and 17 GPa, respectively. Dynamic mechanical analysis showed that the Lyocell fiber reinforced composites had good viscoelastic properties. The viscose fiber reinforced composites had the high percentage elongation and also showed relatively good impact strength and flexural modulus. Good fiber-matrix adhesion reflected in mechanical properties. SEM images were made to see the fiber-matrix compatibility.

  • 21.
    Ramamoorthy, Sunil Kumar
    et al.
    University of Borås, School of Engineering.
    Kundu, Chanchal Kumar
    Adekunle, Kayode
    University of Borås, School of Engineering.
    Bashir, Tariq
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Regenerated Cellulose Fiber Reinforced Composites2013Conference paper (Refereed)
    Abstract [en]

    Wood pulp based regenerated cellulose fibers like Lyocell and viscose which are from natural origin have high and even quality; used to develop superior composites with good properties. In this project, Lyocell and viscose fibers were reinforced in chemically modified soybean based bio-matrix, acrylated epoxidized soybean oil (AESO) by compression molding technique. The composites are characterized for mechanical performance by tensile, flexural and impact tests, viscoelastic performance by dynamical mechanical thermal analysis (DMTA) and morphological analysis by scanning electron microscopy (SEM). In general, Lyocell composites had better tensile and flexural properties than viscose based composites. The same goes with elastic and viscous response of the composites. Hybrid composites were formed by fiber blending; on addition of Lyocell to viscose based composites improved the properties. The amount of Lyocell and viscose fibers used determined the properties of hybrid composites and the possibility of tailoring properties for specific application was seen. Hybrid composites showed better impact strength. Morphological analysis showed that the viscose composites had small fiber pull out whereas Lyocell composites had few pores. Hybrid composite analysis showed that they had uneven spreading of matrix; delamination occurred on constant heating and cooling. To overcome the above mentioned issue and to reduce the water absorption, surface modification of the fiber was done by alkali treatment and silane treatment. The effect of treatment is done through swelling, water absorption and morphological analysis tests. The properties could be increased on proper modification of the fibers. The results show the good potential of these composites to be used in automotives and construction industries.

  • 22.
    Ramamoorthy, Sunil Kumar
    et al.
    University of Borås, School of Engineering.
    Kundu, Chanchal Kumar
    Baghaei, Behnaz
    University of Borås, School of Engineering.
    Adekunle, Kayode
    University of Borås, School of Engineering.
    Bashir, Tariq
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Green Composites Based On Regenerated Cellulose Textile Fibers For Structural Composites2013Conference paper (Refereed)
    Abstract [en]

    Composites were manufactured from regenerated cellulose and biobased matrix by compression molding. The reinforcing materials used were Lyocell and viscose, while the matrix used was chemically modified soybean oil. Hybrid composites were prepared by mixing both the fibers. The total fiber content in the composites was between 40-60 weight %. Lyocell based composites had better tensile properties than viscose based composites; composites consisting 60 weight % Lyocell impregnated with matrix had tensile strength of 135 MPa and tensile modulus of 17 GPa. These composites also showed better flexural properties; flexural strength of 127 MPa and flexural modulus of 7 GPa. Dynamic mechanical thermal analysis results showed that these composites had good viscoelastic properties. Viscose based composites had better percentage elongation; these composites also showed relatively good impact and viscoelastic properties. Hybrid composites showed good mechanical and viscoelastic properties. Scanning electron microscope images showed that the composites had good fiber-matrix adhesion.

  • 23.
    Ramamoorthy, Sunil Kumar
    et al.
    University of Borås, School of Engineering.
    Persson, Anders
    University of Borås, Swedish School of Textiles.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Reusing Textile Waste As Reinforcements In Composites2014In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 131, no 17, p. 1-16Article in journal (Refereed)
    Abstract [en]

    Polyester (PET) has wide applications in textile industries as textile fiber and its share continues to grow. Substantial quantities of cotton/polyester blend fabrics are disposed every year due to technical challenges, which pose a big environmental and waste-dumping problem. The aim of this study is to evaluate the potential of discarded cotton/PET fabrics as raw materials for composites. If their inherent reinforcement properties can be used in composites, an ecological footprint issue can be solved. In this study, we investigate three concepts for reuse of cotton/PET fabrics for composites: compression molding above the Tm of PETs, use of a matrix derived from renewable soybean oil, use of thermoplastic copolyester/polyester bi-component fibers as matrix. All three concepts have been explored to make them available for wider applications. The effects of processing parameters such as compression temperature, time and pressure are considered in all three cases. The third concept gives the most appealing properties, which combine good tensile properties with toughness; more than four times better tensile strength than the first concept; and 2.2 times better than the second concept.

  • 24.
    Ramamoorthy, Sunil Kumar
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    BIOCOMPOSITES FROM SURFACE MODIFIED REGENERATED CELLULOSE FIBERS AND LACTIC ACID THERMOSET BIORESIN2016Conference paper (Refereed)
    Abstract [en]

    Abstract:

    Thermoset bioresin was synthesized from lactic acid and glycerol, and the resin was characterized for it to be used in composite applications. On the other hand, regenerated cellulose fibers were surface treated to improve the physico–chemical interactions at the fiber–matrix interface. The effect of surface treatments, silane and alkali, on regenerated cellulose fibers was studied by using the treated fibers as reinforcement in lactic acid thermoset bioresin. Mechanical tests were used as indicator of the improvement of the interfacial strength. Fiber surface treatments and the effect on adhesion to the matrix were characterized using microscopy images and thermal conductivity. Mechanical properties of the composites showed an increase when treated with silane as the bi-functional silane molecule acts as link between the regenerated cellulose fiber and the bioresin.

    Porosity volume decreased significantly on silane treatment due to improved interface and interlocking between fiber and matrix. Decrease in water absorption and increase in contact angle confirmed the change in the hydrophilicity of the composites. The storage modulus increased when the reinforcements were treated with silane whereas the damping intensity decreased for the same composites indicating a better adhesion between fiber and matrix on silane treatment. Thermogravimetric analysis indicated that the thermal stability of the reinforcement altered after treatments. The resin curing was followed using differential scanning calorimetry and the necessity for post-curing was recommended. Finite element analysis was used to predict the thermal behavior of the composites and a non-destructive resonance analysis was performed to ratify the modulus obtained from tensile testing. The changes were also seen on composites reinforced with alkali treated fiber. Microscopy images confirmed the good adhesion between the silane treated fibers and the resin at the interface.

  • 25.
    Ramamoorthy, Sunil Kumar
    et al.
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Thermoset Biocomposites From Cellulose-Based Fibers And Triglyceride Plant Oil: Properties And Improvement By Chemical Treatments2014Conference paper (Refereed)
  • 26.
    Ramamoorthy, Sunil Kumar
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Persson, Anders
    University of Borås, Faculty of Textiles, Engineering and Business.
    A Review of Natural Fibers Used in Biocomposites: Plant, Animal and Regenerated Cellulose Fibers2015In: Polymer Reviews, ISSN 1558-3724, Vol. 55, no 1, p. 107-162Article in journal (Refereed)
    Abstract [en]

    Natural fibers today are a popular choice for applications in composite manufacturing. Based on the sustainability benefits, biofibers such as plant fibers are replacing synthetic fibers in composites. These fibers are used to manufacture several biocomposites. The chemical composition and properties of each of the fibers changes, which demands the detailed comparison of these fibers. The reinforcement potential of natural fibers and their properties have been described in numerous papers. Today, high performance biocomposites are produced from several years of research. Plant fibers, particularly bast and leaf, find applications in automotive industries. While most of the other fibers are explored in lab scales they have not yet found large-scale commercial applications. It is necessary to also consider other fibers such as ones made from seed (coir) and animals (chicken feather) as they are secondary or made from waste products. Few plant fibers such as bast fibers are often reviewed briefly but other plant and animal fibers are not discussed in detail. This review paper discusses all the six types of plant fibers such as bast, leaf, seed, straw, grass, and wood, together with animal fibers and regenerated cellulose fibers. Additionally, the review considers developments dealing with natural fibers and their composites. The fiber source, extraction, availability, type, composition, and mechanical properties are discussed. The advantages and disadvantages of using each biofiber are discussed. Three fabric architectures such as nonwoven, woven and knitted have been briefly discussed. Finally, the paper presents the overview of the results from the composites made from each fiber with suitable references for in-depth studies.

  • 27.
    Ramamoorthy, Sunil Kumar
    et al.
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Rissanen, Marja
    Effect of alkali and silane surface treatments on regenerated cellulose fibre type (Lyocell) intended for composites2014In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 22, no 1Article in journal (Refereed)
    Abstract [en]

    Cellulose fibres have significant importance and potential for polymer reinforcement. It is essential to modify the surface of the fibre to obtain good fibre-matrix interface. Surface treatments can increase surface roughness of the fibre, change its chemical composition and introduce new moieties that can effectively interlock with the matrix, resulting in good mechanical properties in the composites. This is mainly due to improved fibre-matrix adhesion. The treatments may also reduce the water absorption rate by converting part of the hydroxyl groups on the fibre surface into other functional groups. Chemical modification of the surface of a regenerated cellulose fibre of the Lyocell type was carried out by alkali and silane treatments, which significantly changed the properties of the Lyocell fibres. Three parameters were considered when the fibre surface treatment was done: concentration (2–15 wt%), temperature (25 and 50 C) and time (30 min–72 h). Fourier transform infrared spectroscopy and Raman spectroscopy were used for chemical analysis and qualitative analysis of the cellulose crystallinity due to the surface treatments; subsequently, mechanical strength of the fibres was tested by tensile testing. Weight loss, moisture regain and swelling measurements were taken before and after treatments, which showed the obvious changes in fibre properties on treatment. Heat capacity of the fibres was measured for untreated and treated fibres, and thermal degradation of fibres was examined to see the stability of fibres at elevated temperatures. Wettability and surface energies were measured using dynamic contact angle method in three wetting mediums. Scanning electron microscopy was used to study the morphological properties of the fibres.

  • 28.
    Ramamoorthy, Sunil Kumar
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Åkesson, Dan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Baghaei, Behnaz
    University of Borås, Faculty of Textiles, Engineering and Business.
    Preparation and Characterization of Biobased Thermoset Polymers from Renewable Resources and Their Use in Composites2017In: Handbook of Composites from Renewable Materials, Physico-Chemical and Mechanical Characterization / [ed] Vijay Kumar Thakur, Manju Kumari Thakur, Michael R. Kessler, Hoboken, New Jersey, USA: John Wiley & Sons, 2017, p. 425-457Chapter in book (Refereed)
    Abstract [en]

    This chapter focuses on physicochemical and mechanical characterization of compositesmade from renewable materials. Most common renewable materials used in composites arenatural fibers and polymers based on starch or vegetable oil. The extent of using renewablematerials in biocomposites has increased during the past decade due to extensive research oncellulosic fibers and biobased polymers. Earlier, the research was focused on using the naturalfibers as reinforcement in crude oil-based polymers such as polypropylene. Later, the emphasisshifted to increase the amount of renewable components in the biocomposites which led tothe introductionof biobased resins in the composites. The properties of some biocompositesare today comparable to the properties for commercially available nonrenewable composites.Several plant biofibers have been used as reinforcement in biobased thermoplastics or thermosetsto manufacture biocomposites. Material characterization is important to understand theperformance of these composites under specific environment. Detailed discussion about themechanical and physicochemical characterization is provided in this chapter. Physicochemicalcharacterization includes chemical composition, density, viscosity, molecular weight, meltingtemperature, crystallinity,morphology, wettability, surface tension, water binding capacity,electricalconductivity, flammability, thermal stability, and swelling. Mechanical characterizationincludes tensile, flexural, impact, compressive, shear, toughness, hardness, brittleness, ductility,creep, fatigue, and dynamic mechanical analysis.

  • 29.
    Skrifvars, Mikael
    et al.
    University of Borås, School of Engineering.
    Baghaei, Behnaz
    University of Borås, School of Engineering.
    Kumar Ramamoorthy, Sunil
    University of Borås, School of Engineering.
    Berglin, Lena
    University of Borås, Swedish School of Textiles.
    Development of hybrid natural fibre reinforcements for structural composites: Concepts and opportunities2013Conference paper (Refereed)
  • 30.
    Skrifvars, Mikael
    et al.
    University of Borås, School of Engineering.
    Baghaei, Behnaz
    University of Borås, School of Engineering.
    Kumar Ramamoorthy, Sunil
    University of Borås, School of Engineering.
    Rajan, Rathish
    Berglin, Lena
    University of Borås, Swedish School of Textiles.
    Regenerated cellulose fibres for structural composites2014Conference paper (Other academic)
  • 31.
    Skrifvars, Mikael
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Baghaei, Behnaz
    University of Borås, Faculty of Textiles, Engineering and Business.
    Rissanen, Marja
    Tampere University of Technology.
    Ramamoorthy, Sunil Kumar
    University of Borås, Faculty of Textiles, Engineering and Business.
    Mechanical and thermal characterization of compression moulded polylactic acid natural fiber composites reinforced with hemp and Lyocell fibers2014In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 131, no 15Article in journal (Refereed)
  • 32.
    Skrifvars, Mikael
    et al.
    University of Borås, School of Engineering.
    Ramamoorthy, Sunil Kumar
    University of Borås, School of Engineering.
    Baghaei, Behnaz
    University of Borås, School of Engineering.
    Development Of Regenerated Cellulose Reinforcements And Their Use In Structural Composites For Automotive Applications2013Conference paper (Refereed)
    Abstract [en]

    There is need for the bio‐based materials which could fully or partly replace the synthetic materials in automotive components. Several studies have been suggested to incorporate natural fiber based materials into automotives, and regenerated cellulose fibers could have a great potential several automotive applications. In the paper we will describe ongoing research where we study non‐woven viscose and Lyocell as well as uniaxial continuous viscose filament reinforcements for the use in structural composites. Hybrid reinforcements based on regenerated cellulose fibers and glass fibers have also been studied, with the intention to optimize the reinforcement durability. The uniaxial viscose filament reinforcements were prepared by a winding technique, and we have also combined the viscose filament with continuous hemp yarns as well as different thermoplastic yarns. Both thermoset and thermoplastic composites were then produced by compression moulding with a pressure of 40 bar and at the temperature between 160‐170°C for 5 minutes. The resulting composites have been characterized regarding mechanical and thermal properties.

1 - 32 of 32
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