SynopsisFive to six million molecular weight polyacrylamide and polymethacrylamides of comparable post-alkaline hydrolysis viscosities were imidized by dissolution and heating in 6N HC1. After alkaline hydrolysis, the imidized polymers demonstrated significantly better retention of viscosity to 2% NaCl than did similar partially hydrolyzed polymers. Viscosities in 0.01% NaCl and resistance to shear were not markedly affected by this modification. It is assumed that this improved performance in brine is the result of chain stiffening due to intrachain imide rings.
SynopsisDue to the high chain transfer to monomer, the homopolymerization of methacrylamide yields polymers of extremely low molecular weight. On partial alkaline hydrolysis, the viscosities of these polymers in aqueous solution are much inferior to those of partially hydrolyzed polyacrylamide (HPAM). However, polymethacrylamides prepared by room temperature, persulfate-initiated polymerization in the presence of small amounts of N,N'-methylenebisacrylamide demonstrate posthydrolysis reduced viscosities in 0.01% NaCl comparable to typical commercial HPAM materials.
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