Preparation of metallocene polyethylene films with tunable onset heat‐sealing temperatures through a structured processing strategy

Abstract Due to its excellent thermodynamic properties, metallocene polyethylene has been widely used in the inner layer of multilayer films to increase the heat‐sealing strength and reduce the initial heat‐sealing temperature. In this study, polyolefin elastomer (POE), ethylene‐vinyl acetate copolymer (EVA), and metallocene polyethylene (mPE) were blended to create POE/EVA/mPE films using the cast film extrusion processes. Subsequently, the effects of varying mass fractions of POE and EVA were investigated on the morphology, crystal structure, heat‐sealing properties, and mechanical properties of the mPE films. The results indicated that the addition of POE and EVA significantly enhanced the tensile strength and elongation at break of the films. POE and EVA formed a characteristic island structure within the mPE matrix, and EVA effectively improved compatibility between POE and mPE. Increased compatibility between POE, EVA, and mPE led to a lower onset heat‐sealing temperature of the films. The compatibility and crystallinity of POE, EVA, and mPE were controlled through a structural processing strategy, enabling the gradient regulation of the film's initial heat‐sealing temperature. Highlights POE, EVA, and mPE films were blended with varying mass fractions. POE and EVA improved the tensile strength and elongation of mPE films. EVA enhanced compatibility between POE and mPE. Heat‐sealing temperature was controlled by adjusting the POE/EVA ratio.