Comodification of Polyethylene With EVA and Fibrous Wollastonite for Improved Thermal Cycling Crack Resistance

Polyethylene (PE) is widely used as a general-purpose plastic; however, its application in harsh environments is limited by poor resistance to thermal cycling crack resistance. In this study, a dual-modification strategy was developed to improve the thermal cycling crack resistance of PE by incorporating fibrous wollastonite (FW) and ethylene-vinyl acetate copolymer (EVA). FW acts as a rigid reinforcing phase that restricts polymer-chain mobility and helps suppress crack initiation. EVA serves as a flexible toughening phase and promotes energy dissipation during deformation. The combination of FW and EVA delays crack propagation and improves the crack resistance of PE. The combined use of FW and EVA produces a synergistic effect involving physical crack blocking and energy dissipation, thereby delaying crack propagation. Consequently, the modified PE demonstrates substantially enhanced resistance to thermal cycling cracking. The PE coating samples maintained structural integrity after cyclic exposure between −40°C and 60°C for 100 h. In addition, the tensile strength increased to 14.94 MPa, representing a 39% improvement compared with pristine PE (10.73 MPa). The combined FW-EVA system effectively improves PE's thermal cycling crack resistance, offering a feasible strategy for its high-demand applications.