Interfacial control and dispersion characteristics of polylactic acid fiber/pulp fiber composites

Abstract To solve the problem of the dispersibility of pulp fiber in polylactic acid (PLA)/pulp fiber composites, PLA fiber instead of PLA beads and pulp fiber were used for initial physical mixing, and then internal mixer‐melting was conducted. The dispersion of pulp fiber in PLA was improved compared with conventional composite preparation protocols. After the pulp fiber was treated with a silane coupling agent, the compatibility of the composite and the transparency of the material were also improved. When the pulp fiber content reached 30%, the mechanical properties and heat resistance of the composite were optimal: tensile fracture strength of 56.52 MPa, and thermal deformation temperature increase of 5°C. Rheological studies indicate that when the pulp fiber content reached 10%, the system exhibited a PLA‐pulp fiber network. When the pulp fiber content was ≥20%, the system exhibited a PLA–PLA and pulp fiber–pulp fiber dual‐network structure. Highlights The dispersion of filler in the matrix was improved by blending fiber with fiber. There was rheological percolation upon filling the pulp fiber in the PLA matrix. The coupling agent facilitated reactive compatibilization and PLA chain extension.