Structure and performance of Poly(vinyl alcohol)/wood powder composite prepared by thermal processing and solid state shear milling technology

In this study, the Poly(vinyl alcohol)(PVA)/wood powder composite was prepared through combining the novel technologies of solid-state shear milling (S3M) and thermal processing of PVA, which provided a large-scale and non-solvent way to efficiently utilize the abundant biomass materials. The results showed that S3M can significantly promote pulverization, dispersion, mechanical activation, and interfacial compatibility of the components, endowing the materials with better processability and mechanical performances. The XRD and FTIR results showed that with the increasing of milling cycles, the hydrogen bonds of PVA molecules were partially destroyed, leading to the formation of looser crystalline structure and lower crystalline degree, while the hydrogen bonding between PVA and wood powder was strengthened. Combining with thermal processing technology of PVA, the composite treated by S3M had a good processability and mechanical properties. DSC curves revealed that the melting temperature of PVA/wood powder (70 wt/30 wt) composite decreased to 123 °C, providing a quite wide thermal processing window for composite. High-pressure Capillary rheology analysis showed that the shear viscosity of the composite decreased with the increasing milling cycles. Finally, the composites exhibited significant improvements in mechanical properties. The tensile strength increased from 16.6 MPa to 22.5 MPa, and the elongation at break increased from 32.0% to 120.5%, respectively.