Synthesis of Poly-(poly(ethylene glycol) methyl ether methacrylate-co-vinylphosphonic acid) and its Cement-Dispersing Ability

摘要

Polyethylene glycol (PEG)-comb branched polyphosphonate copolymer was prepared to study the effect of complete replacing the carboxylic acid groups in PEG polycarboxylate copolymer by phosphonic acid groups on the cement dispersion property. The purpose of the present study was to determine if the phosphonate group renders less so-called "cement sensitivity" sometimes observed with the carboxylate polymers. A series of phosphonate and carboxylate comb-polymers were synthesized and their dispersion ability was examined by the mini slump method using four commercially available normal portland cements (CEM I) with differences mainly in water-soluble alkali and clinker composition. Although the polyphosphonate comb-polymer exhibited comparable dispersing ability to the polycarboxylate counterpart, the phosphonate substitution did not reduce the cement sensitivity.