氯偏共聚物在水泥浆中的降解与稳定

Degradation and Stabilization of Vinylidenechloride-Vinylchloride Copolymer in Cement Paste

研究了氯偏乳液在水泥砂浆碱性条件下的降解与稳定 .结果发现 ,试样中的游离氯离子含量随聚灰比而增加 .聚合物的降解在最初几天比较快 ,氯离子释放量达到聚合物质量的 2 %～ 5% .随后 ,降解在很长的时间内缓慢进行 ,持续时间至少 1～ 2a .通过氯偏聚合物中偏氯乙烯单元含量的估算 ,可知该聚合物可能释放氯离子的最大数量约为聚合物质量的 1 0 % .因此 ,使用氯偏乳液作为水泥砂浆改性剂时 ,必须考虑其降解的影响 .使用二月桂酸二丁基锡、环氧大豆油和亚磷酸三苯酯作为稳定剂 ,可以对氯偏乳液起到一定的稳定作用 .但是有必要继续开发更好的稳定剂 ,并提高稳定剂与聚合物的混合均匀性 .

By determining the free chloride content in the samples, the degradation and stabilization of vinylidenechloride-vinylchloride copolymer latex (PVDC) in cement paste were studied. The test results showed that PVDC degrades rapidly in first several days, the released chloride reaches 2% [similar to] 5% (mass fraction) of the polymer. Then the degradation rate decreases and continues to 1 [similar to] 2 years. Through the measurement of amount of vinylidenechloride in copolymer, the maximum release of chloride in copolymer can be evalulated. With 1% dilauryldibutyltin, 0.5% epoxidized soybean oil and 0.5 % triphenylphosphite the copolymer can be stabilized in some extent. However for better alkali stability of PVDC, more research works are needed to search for better stabilizer and better technique for mix.