Radiation grafting of hydrophilic monomers onto poly(4‐methylpentene‐1), II. Grafting of long chain monomers and physical properties of the grafted films

Radiation grafting of 2‐hydroxyethyl methacrylate (HEMA) and methoxytetraethyleneglycol methacrylate (M4G) on low crystallinity poly(4‐methylpentene‐1) (TPX) has been investigated. Grafting yield increased with increasing pre‐irradiation dose, grafting temperature, and monomer concentration. Grafting rate depends on length of molecular chain in the monomers and decreases with increasing chain length. The grafting yields of electron beam irradiated samples were higher than those of γ‐irradiated ones because of higher radical concentration. Tensile strength of the grafted film in the dried state increased and the elongation at break decreased with increasing degree of grafting. On the other hand, in the wet state, the tensile strength and elongation at break decreased with increasing the degree of grafting due to the lack of hydrogen bonds between the grafted chains caused by increased water absorption.