聚丙烯酸-甲基丙烯磺酸钠对建筑石膏性能研究

The Property Research of Acrylic Acid-co-Sodium Methallyl Sulfonate for Building Gypsum

摘要:

通过自由基聚合制备了五种聚丙烯酸-甲基丙烯磺酸钠共聚物(PC-1~PC-5)，并探讨其对建筑石膏性能的影响，并以梳状聚羧酸(PC)和萘系(FDN)为对照。发现，当掺量为0.3%时： PC-4(n丙烯酸:n甲基丙烯磺酸钠=6:1)的减水率最高，为22%；经时损失持续时间PC-4最长，达70min；掺PC-4试块2h吸水率最低，为16%，比空白低11.5%；掺PC-4的试块抗折、抗压强度分别提高30%，31%；掺PC-4软化系数最大，达0.36，比空白高0.1。SEM发现PC-4的掺入使建筑石膏水化晶型由针状变成片状。通过IR确定PC-4主要官能团。综上，线性共聚物PC-4对建筑石膏的适应性较好。

Abstract:

Five kinds of acrylic acid-co-sodium methallyl sulfonate(PC-1~5) were synthesized by free radical polymerization, and these copolymers′ influences on building gypsum system were studied, and compared with comb-like polycarboxylate-type(PC) and FDN. The results indicated that when the dosage was 0.3%: PC-4(nacrylic acid:nsodium methallyl sulfonate = 6:1) was the best copolymer on water-reducing rate, achieved 22%, and the longest slump retain，reached 70 min, and the lowest water absorption rate at 2h, achieved 16%, 11.5% lower than the blank, and the bending and compressive strength enhanced 30%, 31% respectively, and the highest softening coefficient, achieved 0.36, 0.1 higher than the blank. It was found that building gypsum hydration crystal form from needle turned to flake when added PC-4. The major functional groups of PC-4 was determined by IR. This shows that the adaptability of linear copolymer PC-4 on building gypsum system was fine.