Acoustic, tomographic, and morphological properties of bismaleimide-modified PLA green composites

Abstract

The effect of N′-(o-phenylene)dimalemide and 2,2′ dithiobis(benzothiazole) on the speed of sound, sound attenuation and loss factor, 3-D microstructure, fiber dispersion, and morphology of wood pulp-reinforced PLA composites produced by hot press was investigated. Analysis of the chemical composition and fiber length of the wood pulp fibers provided information about the mechanism of adhesion and crystallinity of the modified composites. It was found that the modified composites have quite similar sound attenuation values, whereas the 3-D tomography analysis suggests the creation of a closely compact, cross-linked microstructure with improved fiber dispersion at higher processing temperature. The occurrence of a uniform, single-phase morphology suggests good compatibility between N′-(o-phenylene)dimalemide and 2,2′ dithiobis(benzothiazole) to PLA. Fourier transform–infrared (FT–IR) spectrometry suggests the creation of a new bond involving scission of the N′-(o-phenylene)dimalemide molecule to PLA and/or wood pulp. XRD analysis showed that the largest increase in the crystallinity occurred in the modified PLA blends.