| abstract |
Methods are described that include elongating, e.g., by stretching and/or compressing, a polymeric material, such as an ultra-high molecular weight polyolefin (e.g., an ultra-high molecular weight polyethylene (UHMWPE)), below, or above a melt temperature of the polymeric material to disentangle polymeric chains of the polymeric material. The disentangled materials provided can be effectively and efficiently crosslinked, e.g., by using ionizing radiation (e.g., generated by a gamma radiation source and/or an electron beam source). Parts formed from the crosslinked polymeric materials have, e.g., high wear resistance, enhanced stiffness, as reflected in flexural and tensile moduli, a high level of fatigue and crack propagation resistance, and enhanced creep resistance. Some of the crosslinked polymeric materials have a low coefficient of friction. Prior to elongating, it can be desirable to slightly crosslink the polymeric material to impart shape memory into the polymeric material. |