Mechanical Properties of Ultra-High Molecular Weight Polyethylene Irradiated with Gamma Rays

摘要

With the goal of enhancing the creep resistance of ultra-high molecular weight polyethylene(UHMWPE),we performed gamma irradiation and post-irradiation annealing at a low temperature,and investigated the crystalline structures and mechanical properties of the samples.Electron spin resonance spectra reveal that most of the residual radicals are stabilized by annealing at 100 deg C for 72 h under vacuum.Both the melting temperature and crystallinity increase after increasing the dose and by post-irradiation annealing.When irradiated with the same dose,the quenched sample having a higher amorphous fraction exhibits a lower swell ratio than does the slow-cooled sample.The measured tensile properties correlate well to the crystalline structure of the irradiated and annealed samples.For enhancing creep resistance,high crystallinity appears to be more critical than a high degree of crosslinking.