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A macromer, methoxypolyethylene glycol acrylate(MPEGAA), was synthesized by direct esterification using methoxypolyethylene glycol(MPEG-1200) and acrylic acid(AA) as the main materials. MPEGAA was then used to prepare a polyacrylic acid superplasticizer modified with 2-acrylamido-2- methylpropane sulfonic acid(AMPS). A single-factor test was performed to investigate the effects of the molar ratio of acid to alcohol(n(AA)/n(MPEG)), inhibitor amount, catalyst amount, temperature, and time of esterification on the synthesis of MPEGAA. The experimental results showed that the optimal esterification conditions were as follows: n(AA)/n(MPEG), 3.5:1; amount of hydroquinone(as an inhibitor), 1.2%; amount of para-toluenesulfonic acid(as a catalyst), 5.5%; reaction temperature, 95 ℃; and reaction time, 6 h. The AMPS- modified polyacrylic acid superplasticizer prepared under the optimal esterification conditions enabled the achievement and maintenance of high cement dispersibility. At an admixture amount of 0.15%, the cement paste fluidity was initially as high as 300 mm, and then decreased to 315 mm after 1 h and to 290 mm after 2 h.
A macromer, methoxypolyethylene glycol acrylate (MPEGAA), was synthesized by direct esterification using methoxypolyethylene glycol (MPEG-1200) and acrylic acid (AA) as the main materials. MPEGAA was then used to prepare a polyacrylic acid superplasticizer modified with 2-acrylamido- A single-factor test was performed to investigate the effects of the molar ratio of acid to alcohol (n (AA) / n (MPEG)), inhibitor amount, catalyst amount, temperature, and time of esterification on the synthesis of MPEGAA. The experimental results showed that the optimal esterification conditions were as follows: n (AA) / n (MPEG), 3.5: 1; amount of hydroquinone (as an inhibitor), 1.2%; amount of para The reaction temperature, 95 ° C .; and reaction time, 6 h. The AMPS-modified polyacrylic acid superplasticizer prepared under the optimal esterification conditions enabled the achievement and maintenance of high cement dispersibility. Atan admixt ure amount of 0.15%, the cement paste fluid was initially as high as 300 mm, and then decreased to 315 mm after 1 h and to 290 mm after 2 h.