Submitted to: Journal of Environment and Polymers
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/14/2010
Publication Date: 6/16/2010
Citation: Corradini, E., Imam, S.H., Agnelli, J.A., Mattoso, L.H. 2009. Effect of Coconut, Sisal and Jute Fibers on the Properties of Starch/Gluten/Glycerol Matrix. Journal of Environment and Polymers. 17:1-9. Interpretive Summary: Plant derived polymers such as starch and gluten have good properties and blend well in the presence of plasticizer glycerol to yield useful plastic composites. However, commodity chemicals are becoming increasingly expensive as their usefulness is being realized in a variety of other applications. Several cellulosic ffibers derived from unconventional and cheaper sources were investigated for blending with starch/gluten and glycerol as a reinforcement additive and a filler material. This approach worked well as blends yielded stronger composites and also loweed the overall cost of the plastic composites. Cellulosic fibers used here are produced in abundance and their use in composites could provide new use for this material in engineered products.
Technical Abstract: Coconut, sisal and jute fibers were added as reinforcement materials in a biodegradable polymer matrix comprised of starch/gluten/glycerol. The content of fibers used in the composites varied from 5% to 30% by weight of the total polymers (starch and gluten). Materials were processed in a Haake torque rheometer (1200C, 50 rpm) for 6 min. The mixtures obtained were molded by heat compression and further characterized. Addition of lignocellulosic fibers in the matrix decreased the water absorption at equilibrium. The diffusion coefficient decreased sharply around 5% fiber concentration, and further fiber additions caused only small variations. The thermogravimetric (TG) analysis revealed improved thermal stability of matrix upon addition of fibers. The Young’s modulus and ultimate tensile strength increased with fiber content in the matrix. The storage modulus increased with increasing fiber content, whereas t and curves decreased, confirming the reinforcing effect of the fibers. Morphology of the composites analyzed under the scanning electron microscope (SEM) exhibited good interfacial adhesion between the matrix and the added fibers. Matrix degraded rapidly in compost, and addition of increased amounts of coconut fiber in the matrix caused a slowdown the biodegradability of the matrix.