Preparation of single poly(lactic acid) composites

An approach for making poly(lactic acid) (PLA) single‐polymer composites (SPCs) on the basis of PLA's slowly crystallizing characteristics was investigated. As a slowly crystallizing polymer, PLA can be processed with standard polymer processing techniques into end‐use products with varied crystallinities, from amorphous films to highly crystalline fibers. In this study, amorphous PLA sheets and crystalline PLA fibers/fabrics were laminated and compression‐molded to form an SPC at a processing temperature substantially lower than PLA's melting temperature. The effects of the major process conditions on the performance of the SPC were studied. The processing temperature played a profound role in affecting the fiber–matrix bonding properties. As the processing temperature increased, a drastic improvement in the interfacial bonding occurred at a temperature of around 135°C, which indicated the lower boundary of the process window. The compression‐molded SPC exhibited enhanced mechanical properties; particularly, the tearing strength of the fabric‐reinforced SPC was almost an order higher than that of the nonreinforced PLA. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008