Radiation grafting of hydrophilic monomers onto poly(4‐methylpentene‐1), I. Grafting of acrylic acid

Radiation grafting of acrylic acid (AAc) onto poly(4‐methylpentene‐1) (TPX) with different crystallinity has been investigated under various conditions. Free radicals formed by pre‐irradiation of TPX in vacuum were more stable than those in the presence of air and might initiate the grafting reaction if come in contact with the AAc. Grafting yields increased with increasing preirradiation dose, grafting temperature, and concentration of AAc. Lower crystalline TPX (24%) showed a higher initial grafting rate compared with higher crystalline one. The distribution of grafting was observed by X‐ray microanalyzer. The grafting reaction proceeded gradually with time from the surface of the film to the inner part. In high crystalline TPX (34%) the grafting distribution in the final stage depended on the film thickness, while in lower crystalline TPX it was homogeneous regardless the film thickness.