Radiation grafting of various water-soluble monomers on ultra-high molecular weight polyethylene powder. Part III: Preparation of compression moulded films, and water-uptake and morphological studies

Abstract

Compression moulded films were obtained from PAA, PMAA, PAAm, PNDAAm and PVP radiation grafted ultrahigh molecular weight polyethylene (UHMWPE) powders. Mechanical properties and water-uptake of PVP and PNDAAm grafted UHMWPE were found to be distinctly better than PAA, PMAA and PAAm ones. The former group showed almost complete melting and flow during compression moulding compared with the latter group. Hence, the mechanical properties of this group were found to be better than the others. Important parameters affecting the film formation appeared as H-bonding ability and also the compatibility between grafting polymer and UHMWPE. Per cent water-uptake of films increase with the grafting level and approaches 30% at most for all types of films except PMAA one. High per cent water-uptake results of PAA and PAAm cases should be taken cautiously due to incomplete flowing during compression in film preparation. SEM analysis revealed incomplete melting and flow for the case of PAA, PMAA and PAAm-co-UHMWPE resulting in pores and holes in the final films while homogeneous films were obtained for the case of PVP and PNDAAm.