On the chemical modifications of poly(maleic anhydride‐co‐isobutene) by means of hydrolysis, ammoniation or aminations

Abstract Ring‐opening reactions of maleic anhydride ( 1 )/isobutene ( 2 ) copolymer ( M̄ w = 2,76 · 10 5 g/mol), carried out by the use of: NaOH solution (hydrolysis); NH 3 ; NH(CH 3 ) 2 ; N(CH 3 ) 3 ; NH(C 2 H 5 ) 2 and H 2 N(CH 2 CH 2 NH) 2 CH 2 CH 2 NH 2 (TETA), resp., yielded water‐soluble products, with the exception of the TETA‐modified copolymer. The degrees of conversion α were found to be in the range between 87 to 100%, with the exception of the N(CH 3 ) 3 ‐reacted copolymer where α = 41,6%. As a result of the conversion reactions, the weight‐average molecular weights M̄ w dropped significantly, by 30% in the case of hydrolysis, and by 40% in the cases of ammoniation or amination, despite the mild conditions which were employed. Based on nitrogen contents found analytically, as well as on 13 C NMR spectra, it was concluded that under the given conditions the reactions using ammonia or amines do not proceed beyond the half‐amidation step. 13 C NMR investigations on products of both the ammoniation and amination reactions indicate a directing influence produced by the CH 3 groups of the isobutene unit. As a result, only those carbonyl groups remote from the pendant substitutents are prone to an attack which causes amidation.