摘要
在保持β-半水石膏（β-H）试件吸水性能的基础上,提高β-H试件的机械强度是石膏模具行业亟待解决的难题之一。以部分水解的聚醋酸乙烯酯（PHPVAc）为添加剂,考察了不同水解度的PHPVAc对β-H试件抗折强度、抗压强度和吸水率的影响,并初步探讨了PHPVAc对β-H水化进程的影响。研究发现,水解度为65%~99%的PHPVAc均能提高β-H试件的机械强度,但其吸水率有所降低。当PHPVAc的水解度为91%~99%时,可使β-H试件的抗折、抗压强度提高7%~8%,吸水率降低2%~3%;水解度为78%的PHPVAc（PHPVAc78）可使β-H试件在吸水率少量降低的同时,最大幅度地提高β-H试件的抗折强度和抗压强度;PHPVAc78掺量为0.05wt%的β-H试件的抗折、抗压强度分别较未添加大分子的石膏试件者提高了26%和4%,吸水率仅降低2%。此外,PHPVAc改性β-H的水化度和电导率实验的结果表明,PHPVAc可以加速β-H的水化进程。
h is urgent to improve mechanical strength of hardened gypsum pieces made from 15-calcium sulfate hemihydrate （β-H） in the case of keeping water absorption. In this study, partial hydrolyzed polyvinyl acetate （PHPVAc） was employed as additive to investigate the effect on the mechanical strength and water absorption. Then, the hydration of β-H with PHPVAc was discussed preliminarily. It was found that all the PHPVAc with the hydrolysis degree of 65%-99% could enhance the mechanical strength of the hardened pieces but weaken the water absorption. PHPVAc with the hydrolysis degree of 91%-99% made the bending strength and compressive strength increased 7%-8% and the water absorption decreased 2%-3%. The PHPVAc with the hydrolysis degree of 78% （PHPVAc78） contributes to increasing the bending strength and compressive strength of hardened gypsum piece maximumly with acceptable loss of water absorption. PHPVAc78 gave, respectively, 26% and 4% increases in the bending strength and compressive strength, while 2% decreases in the water absorption at the optimum dosage of 0.05wt%. In addition, the influence of PHPVAc78 on hydration degree and the conductivity of 15-H was determined. It was found that PHPVAc78 could accelerate the hydration of β-H.
出处
《硅酸盐通报》
CAS
CSCD
北大核心
2015年第6期1664-1669,共6页
Bulletin of the Chinese Ceramic Society
基金
"十二五"国家科技支撑计划资助项目(2011BAE30B02
2014BAE03B00)
关键词
聚醋酸乙烯酯
部分水解
模具石膏
机械强度
吸水率
poly （ vinyl acetate）
partial hydrolyzed
gypsum
mechanical strength
water absorption
