Modification of Polymers by Perfluoroalkylation and Radiation Exposure Characteristics of the Modified Polymers

Abstract

Perfluoroalkyl (R_f) groups could be directly introduced into some phenyl groups of poly(α-methylstyrene) (Pα-MeSt) or poly(phenyl methacrylate) (PPhMA) without fission of the polymer chains by treating these polymers with (perfluoroalkyl)phenyliodonium triflates (FITS) at 75∼80°C in presence of pyridine using a mixture of chloroform and acetonitrile as a solvent. R, groups introduced into the polymers were C₂F₅, i-C₃F₇, n-C₄F₉ or n-C₆F₁₃ groups (Table 2 and 3). The yields (1O∼36%) were, varied depending on the polymers, R_f groups and the reaction conditions.
The electron beam exposu re experiment of the R_f-Pα-MeSt revealed that the electron beam exposure increased the molecular weight of the R_f-Pα-MeSt(negative type) in contrast to Pα-MeSt which was degraded(possitive type) (Fig.4). On the other hand, deep UV irradiation to R_f-Pα-MeSt resulted in the fission of the polymer chains (Fig.5). The R., PPhMA was also a negative type polymer toward the electron beam (Fig.6). It was suggested that reactive species in such crosslinking reactions were α, α-difluorobenzyl radicals [C4].