Structure insight into the interfacial effect of fiber-low density polyethylene composites by the combination of experiment and finite element simulation

Good interfacial adhesion is one of the key factors to ensure the excellent performance of composite materials. However, the interfacial effect of fiber-polymer composites remain incompletely understood. Herein, a self-designed mold was used to prepare UHMWPE (Ultra-high molecular weight polyethylene)-fiber/LDPE (Low density polyethylene)-matrix (LU) and PET (polyethylene terephthalate)-fiber/LDPE-matrix composite materials (LP). The interfacial bonding effect was explored by the interfacial shear strength (IFSS), and the interfacial structure and failure mechanism during the fiber pull-out process were analyzed by the combination of experiment and finite element simulation. The results show that the IFSS of LU (3.59 MPa) is 3 times greater than that of LP (1.18 MPa), giving rise to a higher tensile strength. Moreover, Raman mapping and DSC results suggest that UHMWPE-fiber act as nucleation sites to improve the orientation and crystallization of LDPE molecular chains, generating an obvious interfacial transition zone between UHMWPE-fiber and LDPE, while no obvious interfacial transition zone is found between PET-fiber and LDPE. These findings will be expected to give some guidelines for the design and manufacturing high-performance fiber-polymer composites.