Effect of zone drawing accompanied with crosslinking on the structure and properties of ultrahigh molecular weight polyethylene gel film

To enhance the thermal properties of ultrahigh molecular weight (UHMW) (viscosity-average molecular weight of 6 × 10⁶) polyethylene (PE) gel film, this was crosslinked by dicumyl peroxide (DCP) during a high-temperature zone drawing, which is effective to orient film. Through a series of experiments, it turned out that crosslinking actualized by an optimum amount of DCP and high-temperature zone drawing technique caused significant changes in the structure and properties of UHMW PE gel film. That is, crosslinking increased storage modulus of UHMW PE gel film at 25°C, resulting in improving thermal properties of the film. On the contrary, the crosslinking effect played a hindering role in raising the draw ratio of UHMW PE gel film. Maximum storage modulus of 165 GPa at 25°C could be obtained at the draw ratio of 324 of uncrosslinked homo-PE gel film. In the case of crosslinked PE gel film, the highest storage modulus at 25°C reached 65 GPa at maximum draw ratio of 150. Crosslinked film exhibited high modulus, even at 190°C, to some extent, while uncrosslinked homo-PE gel film was molten completely at 150°C.