THE ANHYDRIDE CONTENT OF SOME COMMERCIAL PP-G-MA - FTIR AND TITRATION

A set of anhydride-grafted polypropylenes was collected from various c ompanies. They were studied in light of our recent results on polyprop ylene melt grafted with maleic anhydride.(1) This work confirmed that an important decrease of the anhydride content is recorded on heating or washing, due to the elimination of free, ungrafted products, respec tively, by sublimation of maleic anhydride and by polymaleic anhydride solubilization. The deconvolution of the infrared spectra of washed a nhydride-grafted polypropylenes (PP-g-MA) revealed two types of grafte d anhydride: succinic anhydride form and polymaleic anhydride form. Al l in all, four forms of anhydride functions were detected: two grafted and two free, each being either on monomeric or polymeric forms. Neve rtheless, one PP-g-MA (Hercoprime) can be distinguished by its very hi gh grafting level. This polymer is therefore discussed in more detail. Finally, all the present results are discussed with regard to the pri ncipal applications of the PP-g-MA as a blend compatiblizer or as an a dhesion promoter. (C) 1996 John Wiley & Sons, Inc.