Pyrolysis-GC-MS reveals important differences in hydrolytic degradation process of wood flour and rice bran filled polylactide composites

Pyrolysis-GC-MS of polylactide (PLA) biocomposites before and after hydrolytic degradation revealed prominent differences in the hydrolytic degradation process of rice bran and wood flour filled biocomposites. The water uptake and mass loss for polylactide/wood flour composites were similar to that of plain PLA. Pyrolysis-GC-MS, however, showed that on prolonged ageing the hydrolysis of PLA led to increased wood flour concentration in the remaining biocomposite matrices. In contrast, the polylactide/rice bran composites exhibited larger water uptake and higher mass loss. Pyrolysis-GC-MS and FTIR analysis proved that the higher mass loss was caused by migration of rice bran from the composites. The type of natural filler could thus greatly influence the degradation process and/or the stability of the materials in aqueous or humid environments.