Crystal structure and mechanical properties of UHMWPE-g-PMA fiber prepared by radiation grafting

Methyl acrylate (MA) monomer was grafted onto ultra-high molecular weight polyethylene (UHMWPE) fibers by γ-ray pre-irradiation induced graft polymerization. The grafting of MA on UHMWPE fiber was confirmed by thermogravimetric analysis and Fourier-transform infrared spectroscopy. The degree of grafting (DG) increased with an increase in absorbed dose and reached a significantly high value (approximately 200%) at 100 kGy. Scanning electron microscopy analysis revealed that the surface of the UHMWPE-g-PMA fibers was covered by the MA grafting layer and became rough. The monoclinic crystalline and orientated intermediate phases were disordered by the grafting chains such that degree of orientation declined gradually with increasing DG. The tensile strength of UHMWPE-g-PMA fiber decreased with increasing dose but was independent of DG, whereas the fiber modulus declined with DG. UHMWPE-g-PMA fiber that possesses desirable mechanical properties could be obtained at a dose of less than 10 kGy. - Highlights: ► Methyl acrylate was grafted on UHMWPE fiber by radiation graft polymerization. ► High dose led to an increase in grafting yield and reaction rate. ► Grafting chains disordered the monoclinic crystalline and intermediate phase. ► Tensile strength of modified fiber decreased with an increase in dose. ► Modulus of modified fiber decreased with an increase in grafting yield