Rice hull biocomposites, part 2: Effect of the resin composition on the properties of the composite

Abstract

A free radical thermoset resin consisting of a copolymer of conjugated linseed oil (CLO) or conjugated soybean oil (CSO), n-butyl methacrylate (BMA), divinylbenzene (DVB), and maleic anhydride (MA) has been reinforced with rice hulls. Composites containing 70 wt % of the filler were compression molded, the conjugated oil content in the resin was kept constant at 50 wt %, and the relative amounts of BMA, DVB, and MA were varied to afford composites with different resin compositions. Tensile tests, DMA, thermogravimetric analysis, and Soxhlet extraction of the different composites prepared have been used to establish the relationship between resin composition and the properties of the composites. Overall, the mechanical properties tend to improve when MA is introduced into the resin. Scanning electron microscopy of selected samples showed a better filler-resin interaction for MA-containing composites and samples prepared from CLO exhibit better properties than those prepared from CSO.

Soybean and linseed oil‐based composites reinforced with wood flour and wood fibers

“…These results support the idea that a higher number of carbon–carbon double bonds in the oil (linseed oil has on average 6.0 carbon–carbon double bonds per triglyceride, while soybean oil only possesses 4.5 carbon–carbon double bonds per triglyceride) gives a more crosslinked and stronger material. A similar trend has been observed and recently published by us for soybean and linseed oil‐based rice hull composites 33. As for the Young's modulus of the CSO‐ and CLO‐based composites compared here (entries 2 and 5, Table III), the values measured fall within the standard deviation of the method used and therefore cannot be considered statistically different.…”

“…The presence of ligno‐cellulosic filler particles minimizes shrinkage of the resin and only minimal microcracks have been detected by scanning electron microscopy (SEM) of soybean hull composites 30. Recent results from the study of natural filler‐reinforced composites in the Larock group suggested that maleic anhydride (MA) can serve as a good filler‐resin compatibilizer and help improve the stress transfer from the matrix to the reinforcement, resulting in an overall increase of the mechanical properties 32, 33…”

“…26 More recently, in an attempt to improve the mechanical properties of the aforementioned bio-based polymers, the Larock group has used inorganic 27,28 and natural fillers as reinforcements for the preparation of ''green'' composites. [29][30][31][32][33] The natural fillerreinforced composites contain up to 85 wt % of biobased materials, including the resin and the filler. [29][30][31][32][33] In the preparation of such materials, it has been demonstrated that free radical initiators are quite effective in crosslinking the carbon-carbon double bonds in the oils and the other monomers used.…”

“…[29][30][31][32][33] The natural fillerreinforced composites contain up to 85 wt % of biobased materials, including the resin and the filler. [29][30][31][32][33] In the preparation of such materials, it has been demonstrated that free radical initiators are quite effective in crosslinking the carbon-carbon double bonds in the oils and the other monomers used. The presence of ligno-cellulosic filler particles minimizes shrinkage of the resin and only minimal microcracks have been detected by scanning electron microscopy (SEM) of soybean hull composites.…”

Progress of Polymers from Renewable Resources: Furans, Vegetable Oils, and Polysaccharides

“…91,92 In addition, the free radical polymerization of conjugated soybean or linseed oil, divinylbenzene, and n-butyl methacrylate produced thermosets used as matrixes for biocomposites reinforced with soy hull, 93 corn stover, 94 and rice hulls. 95,96 Maleic anhydride was added to serve as an additional comonomer to prepare biocomposites reinforced with wood Chem. Rev.…”