Synthetic method for the preparation of rheological modifying polymers and the use thereof

A terpolymer resulting from aqueous polymerization of a mixture of:

• monomer A, having a water-soluble monoethylenically unsaturated group consisting of R1—(C—C)—(C═O)—N—(R3)—R4 wherein R1 is H;
• R3 is H;
• and
• R4 is H;
• monomer B, having a monoethylenically unsaturated monomer capable of forming hydrophobically associative bonds in aqueous medium and amenable to aqueous polymerization conditions consisting of R1—(C═C)—(C—O)—N—(R6)—R7 wherein R1 is H;
• R6 is A-methoxyisobutyl,
• R7 is H;
• and
• monomer C, having an ionic water-soluble monoethylenically unsaturated group, said monomer C consisting of R3—(C—C)—(C—O)—N—(R10)—R11 wherein R3 is H;
• R10 is sodium salt of 2-methylpropane-1-sulfonic acid;
• R11 is H;
• and
• an iniferter initiated with light selected from the group comprising R1′-(C—S)—S—Z1 or R2′—S—(C═S)—S—Z2 wherein:
• R1′ is selected from the group consisting of:
• methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, iso-butoxy, t-butoxy, benzyl, phenyl, N-methylaniline,
• Z1 is selected from the group consisting of:
• propanoic acid, propanoate, phenylpropane-2-yl, cyanomethyl, cyanopropan-2-yl,
• R2′ is selected from the group consisting of:
• is a linear or branched alkyl chain having a carbon length between C1-C12, benzyl, phenyl, isobutyronitrile, propanoate, propanoic acid, benzyl isobutyrate, 2-(pyridin-2-yldisulfanyl) ethyl propionate,
• Z2 is selected from the group consisting of:
• propanoate, propanoic acid, methyl, ethyl, propyl, butyl, pentyl, hexyl, phenyl, benzyl, benzyl isobutyrate, polyethyleneglcoylated 2-cyanopropanoic acid.