SWELLING-ASSISTED MODIFICATION OF POLY(ETHYLENE-TEREPHTHALATE) BY METHACRYLIC-ACID

When a poly(ethylene terephthalate), PET, film is heated in an aqueous solution of methacrylic acid in the presence of hydrogen peroxide as an initiator, it is found that the weight of the film is increased. Th e amount of methacrylic acid that may be added onto the film is depend ent upon the concentration of the monomer, the initiator, and the temp erature at which the reaction occurs. Pretreatment of the film with 1, 1,2,2,tetrachloroethane causes swelling and the amount of add-on is in creased as the swelling level increases. Methacrylic-acid-modified PET films hydrolyze at room temperature in aqueous sodium hydroxide; the rate of hydrolysis is dependent upon the amount of add-on and the conc entration of the base. This procedure leads to a chemically induced bl end of polymethacrylic acid and poly(ethylene terephthalate), and graf ting of the monomer onto the polymer film does not occur. (C) 1995 Joh n Wiley and Sons, Inc.