Enhanced strength and foamability of high-density polyethylene prepared by pressure-induced flow and low-temperature crosslinking

We report a high-performance high-density polyethylene (HDPE) with significantly enhanced mechanical strength by means of pressure-induced flow (PIF) and low-temperature crosslinking treatment. The tensile and flexural strengths increased from 23.5 and 36.2 MPa, up to 74.8 and 78.6 MPa, respectively. This was achieved by the elongated and flattened 'brick-and-mud' like crystal structure of HDPE occurred during PIF, and an adequate crosslinking network that was formed in the amorphous region beneath the melting point. Furthermore, high strength foams of this material could also be produced under supercritical CO₂ batch foaming in solid-state.