水滑石对PVC的热稳定特性与机理  

Characteristics and Mechanism of Heat Stabilization of Hydrotalcite on PVC

作　　者：毛芳[1] 吴茂英[1] 赖文华[1] 

机构地区：[1]广东工业大学轻工化工学院,广东广州510006

出　　处：《塑料》2010年第6期84-88,16,共6页Plastics

基　　金：科技部科技型中小企业技术创新基金项目(08C26213600946)

摘　　要：研究水滑石(HT)对PVC的热稳定特性,结果表明:1)HT是一种长期型热稳定剂,热稳定效能显著优于硬脂酸钙,与硬脂酸锌(ZnSt2)、β-二酮(β-DK)和环氧大豆油(ESBO)并用存在明显的协同效应,但与多元醇发生对抗作用;2)以HT/ZnSt2/ESBO和HT/ZnSt2/ESBO/β-DK稳定的PVC的受热变色呈现明显的突变特征,即初期阶段变色非常缓慢,而后突然显著加速。HT的独特热稳定特性可解释如下:HT首先主要以层间CO32-,然后再以层板Mg、Al氢氧化物中和HCl,以层间CO32-中和HCl的转化产物Cl-型HT不会置换主效热稳定剂中的Zn2+而导致其消耗,因此PVC在受热的初期变色非常缓慢,一旦层间CO23-消耗殆尽,接下来以层板Mg、Al氢氧化物中和HCl生成的MgCl2、AlCl3则会置换主效热稳定剂中Zn2+,因此PVC变色加快。The heat stabilizing characteristics of hydrotalcite （HT） on PVC were studied and the mechanism was discussed. It was shown that HT was a long-term type heat stabilizer with the heat stabilizing efficiency markedly higher than calcium stearate,and showed synergitic effect with β-diketone （β-DK） and epoxidized soybean oil （ESBO） , but antagonic effect with polyols. And the heat diacoloration of PVC stabilized with HT/ZnStJESBO and HT/ZnSt2/ESBO/β-DK showed obvious mutation characteristics. The discoloration was very slow at early stage, then suddenly accelerate significantly. The unique heat stabilizing characteristics of HT could be explained as follows, HT neutralized HCI first mainly with its interlayer＇s CO3 2- ,and then with Mg and Al hydroxide layers;the Cl- type HT produced by neutralization of HCl with the interlayer＇s CO3 2- could not replace Zn 2＋ in the primaray heat stabilizer and cause the consumption of the primaray heat stabilizer, therefore,the heat discoloration of PVC was very slow at early stage, but once the interlayer＇ s CO3 2- was depleted, because MgCl2 and AlCl3 then produced by neutralization of HCl with the Mg and Al hydroxide layers could replace Zn2＋ in the primaray heat stabilizer and caused the consumption of the primaray heat stabilizer, the heat discoloration of PVC suddenly accelerated significantly.

关 键 词：水滑石 聚氯乙烯 热稳定剂 热稳定特性 热稳定机理 

分 类 号：TQ325.3[化学工程—合成树脂塑料工业]