Superior dispersion led excellent performance of wood-plastic composites via solid-state shear milling process

Abstract

Wood-plastic composites as a kind of lightweight and green biomaterials are attracting great interest from academia and industry. However, challenges for effective wood flour (WF) dispersion in wood-plastic composites have hindered the desired property enhancements and limits their wider applications. This study reported an effective method to produce linear low-density polyethylene (LLDPE)/WF composite with superior WF dispersion via solid-state shear milling (S3M) for the first time. Such well-dispersed WF results in a significant enhancement in processability and shows a decrease of viscosity from 8021 Pa s to 3893 Pa s, which is closer to that of neat LLDPE (2286 Pa s) at shear rates of 100−1. The S3M processed composites also show a 26.5% increase and maximum tensile strength reached 31.1 MPa. In addition to the excellent mechanical performance, the water absorption of composites was as low as 0.22% after 840 h immersion, which is lower than most reported data. Moreover, the S3M processed composites exhibit a significant increase in LLDPE crystallinity and a dramatic 66 °C increase in maximum weight loss rate temperature in air. This work was conducted without any surface modification or use of compatibilizer, this new method will have potential applications in producing excellent performance wood-plastic composites in the industrial process.