Use of an epoxidized oil‐based resin as matrix in vegetable fibers‐reinforced composites

Abstract

Hemp fibers were used as natural reinforcement in composites of thermosetting vegetal oil based resin. Boards with fibers content from 0 to 65 vol % were produced by hot pressing. The mechanical properties were investigated with flexural testing. The effect of effect has been observed on both modulus and strength, indicating a good fiber-matrix interfacial adhesion, which was confirmed by means of scanning electron microscopy observations. Dynamic mechanical analysis also showed an important reinforcement effect in the polymer rubbery region, where at 180°C the storage modulus increased from 17 MPa for the neat resin to 850 MPa for 65 vol % fiber content composites. It also revealed an glass transition temperature decrease when fiber amount in the composite increased. Additional experiments based on differential scanning calorimetry show a weakly accelerated cure when fibers content increases, which usually lead to a lower T g . But, this phenomenon alone cannot explain the observed T g change. Contact angle on hemp evolution with time for the resin components show that anhydride is totally absorbed after a few seconds, whereas contact angle of epoxydized oil decreases slowly. This indicates probably a preferential anhydride absorption that leads to a lower amount of anhydride in the matrix and as a consequence to a reduced T g .

Cationically cured natural oil‐based green composites: Effect of the natural oil and the agricultural fiber

“…Most researchers have used acrylated or methacrylated epoxidized soybean oil, vegetable oil monoglyceride maleates, or epoxidized vegetable oils to produce biobased resins and have reinforced these materials with various lignocellulosic fibers, generally, hemp, flax, or kenaf. [4][5][6][7][8][9][10][11][12] Research on the preparation of green composites from unfunctionalized natural oils has either taken advantage of the double bonds already present in the oil to produce thermosetting resins or made use of the hydroxyl groups present in castor oil to produce polyurethanes, which have been reinforced with natural fibers. 13,14 The green composites produced in our group have used a range of agricultural fibers to strengthen biobased resins prepared by the free-radical copolymerization of conjugated vegetable oils through the carbon-carbon double bonds present in the triglyceride.…”

Selected biotrends in development of epoxy resins and their composites

“…In the case of natural fibres used as a fillers in epoxy composites, special research attention has been focused on flax [57-66], hemp [67][68][69][70][71][72], jute [73][74][75][76], sisal [77,78], kenaf [79,80] and bamboo [81,82] fibres. Some research has also been conducted using banana [83], sugar palm [84], date palm [85,86] and piassava [87] fibres.…”

Monocotyledons in Particleboard Production: Adhesives, Additives, and Surface Modification of Reed Canary Grass

“…Epoxy resins are used with lignocellulose raw material as matrix-building components consisting sometimes of epoxidised plant oils in fibre-reinforced composites. Examples are composites with hemp, jute, sisal, flax, coir, and ramie fibres Boquillon 2006;Gassan and Bledzki 1999;Rong et al 2001;Sgriccia et al 2008). The idea with these composites is to replace glass fibres with natural fibres (Wambua et al 2003).…”