Thermal and Mechanical Properties of Bleached Pulp-filled Poly(Lactic Acid) Composites Fabricated with an Internal Mixing Process


  • Yanan She College of Materials Science and Engineering, Nanjing Forestry University
  • Xinwu Xu College of Materials Science and Engineering, Nanjing Forestry University


Poly(lactic acid), Biocomposite, Pulp fiber, Internal mixing


Bioderived poly(lactic acid) (PLA) is a promising alternative for fossil-based polymers, but its poor hydrophilicity, high brittleness, and low heat-resistance are problems for its utilization. In this work, bleached softwood kraft pulp (BSKP) fiber was adopted to modify PLA with MAPP as the coupling agent, with BSKP accounting for 10 wt% to 50 wt%. Internal mixing (IM) was applied to mix the PLA/fiber blend instead of screw grinding. The thermal and mechanical properties of the composites were assessed. The IM process was proven qualified for its effective dispersion of BSKP fibers in the PLA matrix. At a fiber loading of 50 wt%, IM-processed composites acquired satisfactory tensile strength (50.49 MPa, slightly higher than PLA) and Young's modulus (2.56 GPa, 45.8% higher than PLA). The pulp fillers matched PLA matrix well for the characteristic temperatures in thermal decomposition. The BSKP/PLA composites were thermally strengthened by pulp fibers characterized by higher content of residues. The fibers improved the interfacial crystallinity of PLA in the composites (i.e., from 5.22% to 11.86%). The increased crystallinity resulted in enhanced stiffness or weaker damping performance of the composites. In conclusion, natural plant fibers are a feasible option to modify PLA for extended applications.






Research Article or Brief Communication