Rice Straw/Thermoplastic Composite: Effect of Filler Loading, Polymer Type and Moisture Absorption on the Performance

Abstract

ABSTRAT: Thermoplastic composites made with 45, 60 and 75% of rice straw as filler and two types of thermoplastics, virgin polyethylene (PE) and polypropylene (PP) were evaluated. The final boards were made with and without maleic anhydride modified polypropylene (MAPP) at 2% of the total weight of each specimen. The flexural and tensile strengths were measured for dry composites and also measured after 24 h of water immersion of the composites (wet condition). By increasing the filler content, the flexural and tensile strengths and also the density of the specimens decreased. The type of matrix (PE or PP) did not affect significantly the flexural strength, but PP led to higher values of tensile strength for low fiber loadings (45% and 60%). Coupling agents increased the flexural and tensile strength. After water immersion, modulus of elasticity and modulus of rupture were decreased, while tensile strength was less influenced. COMPÓSITO TERMOPLÁSTICO/PALHA DE ARROZ: EFEITO DA CARGA DE ENCHIMENTO, TIPO DE POLÍMERO E ABSORÇÃO DE UMIDADE NO DESEMPENHORESUMO: Foram avaliados compósitos termoplásticos feitos com 45, 60 e 75% de palha de arroz como material de enchimento e dois tipos de termoplásticos, polietileno virgem (PE) e polipropileno (PP). As placas finais foram feitas com e sem polipropileno modificado com anidrido maleico (MAPP) a 2% do peso total de cada amostra. As resistências à flexão e à tração foram medidas para compósitos secos e também medidas após 24 h de imersão em água dos compósitos (condição úmida). Ao aumentar o teor de enchimento, as resistências à flexão e à tração e também a densidade dos matérias diminuíram. O tipo de matriz (PE ou PP) não afetou significativamente a resistência à flexão, mas o PP levou os maiores valores de resistência à tração para baixas cargas de fibras (45% e 60%). Os agentes de acoplamento aumentaram a resistência à flexão e à tração. Após a imersão em água, o módulo de elasticidade e o módulo de ruptura diminuíram, enquanto que a resistência à tração foi menos influenciada.

Impacts of gamma irradiation on the properties of hardwood composite based on rice straw and recycled polystyrene foam wastes

“…Therefore, it can be claimed that moisture is not a problem for irradiated HWC composites, under consideration, because the lignocellulosic fillers, post irradiation, may be totally encapsulated into the polymer matrix. In this case, polymers would protect the fibers because they are hydrophobic .…”

Effects of mold sealing and fiber volume fraction on properties of rice straw/unsaturated polyester biocomposites

“…5). This was because these systems had an insufficient amount of matrix to fill in and cover all fibers [24,25]. Generally, the porosity in solid materials is highly related to a decline in their mechanical properties [26][27][28].…”

Particle Size Effect on Mechanical and Physical Properties of Rice Straw Epoxy Resin Particleboard

“…Rice straw & urea formaldehyde 0.62 [8] Rice straw & urea formaldehyde 0.79 [24] Rice straw & polyethylene 0.90 [17] Rice straw & polypropylene 0.88 [17] Rice straw & polypropylene 0.56 [23] Rice straw & epoxy resin (20 mesh of rice straw) 0.48 [16] Rice straw & epoxy resin (60 mesh of rice straw) 0.87 This study…”

“…The previous study conducted by Mohammadi et al indicated that the type of matrix and fiber loading influenced the flexural and tensile strengths of the composite [17]. Besides the matrix, particle size may also affect the physical and mechanical properties of the particleboard [18].…”

“…% of rice straw is 0.823 g/cm 3 obtained at 60 mesh particle size. Fonio husk and gum Arabic resin 0.08 [26] Wood -bamboo and polyurethane resin 0.17 [27] Rice straw -polypropylene 1.05 [17] Rice straw & epoxy resin (50 mesh of rice straw) 0.60 This study…”