Effects of Modification on Properties of Wood Flour/PBAT Biocomposites

Wood flour (WF)-reinforced poly (butylene adipate-co-terephthalate) (PBAT) composites were successfully fabricated by injection-molding process after being mixed using an extruder. The effects of fiber modifications, including mercerization, acetylation, as well as coupling agent treatment on the properties of WF/PBAT composites, were studied. The results indicated that all the modifications increased the mechanical properties (e.g., tensile strength, tensile modulus, flexural strength, flexural modulus, elongation at break, and Charpy impact strength) of the composites. After modification, all the composites showed better interfacial bonding, hydrophobicity, and thermal properties compared to the untreated fiber composites; meanwhile, the moisture absorption test showed that all the modified fiber composites exhibited a much lower saturated water absorption rate than untreated ones. WF modification by addition of a coupling agent could improve the properties most obviously, except for the tensile strength, elongation at break, and saturated water absorption rate. By this modification, the tensile modulus, flexural strength, flexural modulus, impact strength, onset temperature during thermal degradation, degree of crystallinity, and water contact angle of the composite were 313.47 MPa, 20.55 MPa, 830.79 MPa, 16.01 kJ/cm², 367.71 °C, 17.10%, and 101.8°, all increased from those of untreated composites by 17.95%, 30.73%, 87.52%, 35.79%, 61.49%, 25.67 °C, 89.16%, and 6.6°, respectively.