Tailoring flexible interphases in bamboo fiber-reinforced linear low-density polyethylene composites

Abstract

Traditional modifiers with low-molecular-weight often result in a rigid interface between reinforcing fibers and matrix. This study built a flexible interphase for a linear low-density polyethylene and bamboo fiber (LLDPE/BF) composite by synthesizing a silane-based flexible macromolecular modifier (γ-APS-PAEE). FTIR analysis indicated that γ-APS-PAEE bridged BF and LLDPE by chemical bonding and good inter-molecular compatibility. Scanning electron microscope (SEM) showed the shear fracture behavior of BF pulled from the LLDPE matrix. The flexible interface was detailly analyzed. Compared with the traditional vinyltriethoxysilane and γ-aminopropyltriethoxysilane modifications, the new flexible interphase contributed simultaneous strengthening and toughening to the LLDPE/BF composite (70:30 mass fraction), resulting in increases of 20.63%-36.12% in tensile strength, 46.33%-78.97% in impact toughness, 24.59%-72.52% in fracture elongation, and 104.62% in fracture work. By introducing γ-APS-PAEE, a strong and tough LLDPE/BF composite was developed, which was comparable to high-density polyethylene based wood-plastic composite. This would benefit to reuse the recycled LLDPE.