NOVEL METHOD FOR PREPARING HEAT-THICKENING POLYMERS AND NOVEL COMB COPOLYMERS

摘要

Method for preparing a comb copolymer, includes sequentially: (a) reacting a compound of formula (II): CH2═C(R2)—C(═O)—N(R3)(R4) (II), with a chain-limiting compound of formula (IIIa): HS—R1—NH2 (IIIa) or of formula (IIIb): HS—R1—C(═O)—OH (IIIb), to obtain a poly(N-alkyl acrylamide) or poly(N,N-dialkyl acrylamide) telomer, of formula (Ia): H2N—R1—S—{CH2—C(R2)[C(═O)N(R3)(R4)]-}n-H (Ia) or of formula (Ib): HO—C(═O)—R1—S—{CH2—C(R2)[C(⊚O)N(R3)(R4)]-}n-H (Ib) formula (IIIa) or (IIIb) where n represents a whole number≧2 and≰100; (b) isolating and/or drying the obtained telomer; (c) reacting the telomer of formula (Ia) or of formula (Ib) in tert-butanol with glycidyl methacrylate (IV) to obtain a solution of the macromonomer of formula (Va): CH2═C(R5)-C(═O)—NH—R1—Z—{CH2—C(R2)[C(═O)N(R3)(R4)]-}n-H (Va) or of formula (Vb); CH2═C(R5)-C(═O)—O—(C═O)-R1—Z—{CH2—C(R2)[C(═O)N(R3) (R4)]-}n-H (Vb); (d) isolating and/or drying the obtained telomer; (e) copolymerizing the macromonomer of formula (Va) or of formula (Vb) in tert-butanol with the ammonium salt of 2-acrylamido-2-methyl-propanesulphonic acid, and, if applicable, with the optional monomer or monomers in the desired molar proportions.