Mechanical composites and biodegragability of green composites based on biodegradable polyesters and lyocell fabric

Green composites composed of regenerated cellulose (lyocell) fabric and biodegradable polyesters [poly(3-hydroxybutyrate-co-3-hydroxyvarelate) (PHBV), poly(butylene succinate) (PBS), and poly(lactic acid) (PLA)] were prepared by compression-molding method. The tensile moduli and strength of all the biodegradable polyester/ lyocell composites increased with increasing fiber content. When the obtained PLA/lyocell composites were annealed at 100degreesC for 3 h the tensile strength and moduli were lowered despite the increase of degree of crystallization of the PLA component. The SEM observation of the composites revealed that the surface of the annealed composite has many cracks caused by the shrinkage of the PLA adhered to lyocell fabric. Multilayered PLA/lyocell laminate composites showed considerably higher Izod impact strength than PLA. As a result of the soil viral test, although the order of higher weight loss for the single substance was lyocell > PHBV > PBS > PLA, the biodegradability of the green composites did not reflect the order of a single substance because of the structural defect of the composite. (C) 2004 Wiley Periodicals, Inc.