Novel comb copolymer and process for the preparation thereof

Abstract

A comb polymer of which the backbone is 2-acrylamido-2-methylpropanesulfonic acid, onto which poly(N-alkylacrylamide) or poly(N,N-dialkylacrylamide) lateral segments are grafted; process for the preparation thereof comprising: a step (a) of reacting a compound of formula (II) with a compound of formula (III), in a (tert-butanol)-water mixture, so as to obtain a poly(N-alkylacrylamide) or poly(N,N-dialkylacrylamide) telomere of formula (I); a step (c) of reacting, in tert-butanol, the telomer of formula (I) obtained in step (a), with an acid chloride of formula (IV) so as to obtain a solution of the macromonomer of formula (V); a step (e) of copolymerising, in tert-butanol, the macromonomer of formula (V) resulting from step (c), with the ammonium salt of 2-acrylamido-2-methylpropanesulfonic acid and, if desired, a step (f) of purifying the comb polymer obtained in step (e).

1 . A process for the preparation of a comb copolymer, the backbone of which is of the 2-acrylamido-2-methylpropanesulfonic acid type, to which poly(N-alkylacrylamide) or poly(N,N-dialkylacrylamide) side segments are grafted, characterized in that it comprises the following successive stages:
 a stage (a) of reaction of a compound of formula (II):
   CH 2 ═C(R 2 )—C(═O)—N(R 3 )(R 4 )   (II)
 
   
       in which R 2  represents a hydrogen atom or a methyl group, R 3  represents a hydrogen atom or a linear or branched alkyl radical comprising from 1 to 4 carbon atoms and R 4 , which is identical to or different from R 3 , represents a linear or branched alkyl radical comprising from 1 to 4 carbon atoms, with a chain-limiting compound of formula (III):
   Z—R 1 —NH 2    (III)
 
 
       in which R 1  represents a divalent radical comprising from 1 to 4 carbon atoms and Z represents a functional group capable of acting as radical transfer agent, in the presence of a polymerization initiator, in a tert-butanol/water mixture, in order to obtain a poly(N-alkylacrylamide) or poly(N,N-dialkylacrylamide) telomer of formula (I):
   H 2 N—R 1 —Z—{CH 2 —C(R 2 )[C(═O)N(R 3 )(R 4 )]—} n —H   (I)
 
 
       in which n represents an integer greater than or equal to 2 and less than or equal to 100 and Z represents a functional group capable of acting as radical transfer agent; optionally
 a stage (b) of isolation and/or of drying of said telomer of formula (I) obtained in stage (a); 
 a stage (c) of reaction in tert-butanol of the telomer of formula (I) obtained in stage (a) or optionally in stage (b) with an acid chloride of formula (IV):
   CH 2 ═C(R 5 )—C(═O)—Cl   (IV)
 
 
 
       in which R 5  represents a hydrogen atom or a methyl radical, in a (IV)/(III) molar ratio of less than or equal to 10 and greater than or equal to 1, while maintaining the pH of the reaction medium at a value of between 8 and 10, in order to obtain a solution of the macromonomer of formula (V):
   CH 2 ═C(R 5 )—C(═O)NH—R 1 —Z—{CH 2 —C(R 2 )[C(═O)N(R 3 )(R 4 )]—} n —H   (V)
 
 
       optionally
 a stage (d) of isolation and/or of drying of said macromonomer of formula (V) obtained in stage (c); 
 a stage (e) of copolymerization in tert-butanol of the macromonomer of formula (V) resulting from stage (c) or from stage (d) with the ammonium salt of 2-acrylamido-2-methylpropanesulfonic acid and, if desired; 
 a stage (f) of purification of the comb copolymer obtained in stage (e). 
 
     
     
         2 . The process as defined in  claim 1 , for which, in the formula (II), R 2  and R 3  each represent a hydrogen atom and R 4  represents an isopropyl radical. 
     
     
         3 . A comb copolymer, the backbone of which is of the 2-acrylamido-2-methylpropanesulfonic acid type, to which poly(N-alkylacrylamide) or poly(N,N-dialkylacrylamide) side segments are grafted, said side segments being chosen from the following side segments:
 poly(N-methylmethacrylamide) side segments,   poly(N-ethylmethacrylamide) side segments,   poly(N-propylmethacrylamide) side segments,   poly(N-isopropylmethacrylamide) side segments,   poly[N-(2-hydroxyethyl)methacrylamide] side segments,   poly(N,N-dimethylmethacrylamide) side segments,   poly(N,N-diethylmethacrylamide) side segments,   poly(N-methylacrylamide) side segments,   poly(N-ethylacrylamide) side segments,   poly(N-propylacrylamide) side segments,   poly(N-isopropylacrylamide) side segments,   poly[N-(2-hydroxyethyl) acrylamide] side segments,   poly(N,N-dimethylacrylamide) side segments and   poly(N,N-diethylacrylamide) side segments.   
     
     
         4 . The comb copolymer as defined in  claim 3 , in which said side segments are chosen from the following side segments:
 poly(N-isopropylacrylamide) side segments,   poly[N-(2-hydroxyethyl)acrylamide] side segments,   poly(N,N-dimethylacrylamide) side segments and   poly(N,N-diethylacrylamide) side segments.