High-performance polylactic acid composites reinforced by artificially cultured diatom frustules

Polylactic acid (PLA) is a promising biodegradable polyester, however, the brittle nature of PLA restricts its applications. In this study, PLA is reinforced by artificially cultured diatom frustules (DFs) to prepare high-performance and biodegradable polymer composites via melt blending. Interpenetrating structure can be observed between DFs and PLA by scanning electron microscope (SEM) due to the porous nature of diatom. Both X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analysis reveal that well-dispersed DFs can act as a nucleating agent to increase the crystallinity of the alpha-crystal in PLA, but decrease its cold crystallization temperature (T-cc). Tensile tests show that both strength and ductility of PLA can be enhanced simultaneously by incorporation of a few percent of DFs. Dynamic mechanical analysis (DMA) indicates that DFs can increase the storage modulus and maintain the glass transition temperature of PLA. Our study illustrates the promise of utilizing artificially cultured diatom frustules as biomass-based reinforcing fillers for preparing high-performance fully-biodegraded polymeric materials for green and sustainable applications. (c) 2020 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).