月桂酸镧基蒙脱土的制备及其对聚氯乙烯热稳定性的影响

利用层状硅酸盐改善聚氯乙烯的热稳定性已成为一种经济有效的新途径。本文以钠基蒙脱土(Na-MMT)、月桂酸钠(SDD)和氯化镧为原料,通过沉淀吸附法制备了月桂酸镧基蒙脱土(La-OMMT)。红外光谱和X线衍射分析表明,长链有机酸进入蒙脱土层间并使层间距增大至3.36 nm;将La-OMMT加入PVC树脂制备纳米复合材料,热重分析表明,La-OMMT对PVC有显著的热稳定作用,当添加量为3%(wt)时,PVC的起始分解温度提高至32.42℃;刚果红实验发现,随着蒙脱土中镧含量的增加,PVC的热稳定时间延长,当添加量为5%(wt)时,热稳定时间达到46.99 min,较纯PVC提高了15倍以上,明显优于目前商用的季铵盐类有机化蒙脱土。这表明:本研究制得的月桂酸镧基蒙脱土在PVC的加工应用中具有更优越的适用性。

Preparation of Lanthanum Organic Montmorillonite to Enhance the Thermal Stability of Polyvinyl Chloride

In recent years, using layered silicate to enhance the thermal stability of PVC has become a cost-effective method. In this paper, Na-MMT was modified with sodium laurate and lanthanum chloride by precipitation-adsorption method to preparation of effectively intercalated and thermally stable lauric acid lanthanum montmorillonite（La-OMMT）. Fourier transform infrared（FTIR） spectroscopy and X-ray diffraction（XRD） indicated that the anionic surfactant resided in the interlayer spaces and expanded the basal spacing to 3.36 nm. The nanoeomposites prepared by incorporation of OMMT to PVC resin. Thermogravimetrie analysis results showed that La-OMMT could significantly enhance the thermal stability of PVC, when the addition amount of 5 %（wt）, the onset degradation temperature can be increased up to 32.42 ℃. Congo red results suggested that the thermal stable efficiency was affected by the La content.When the addition amount of 5 %（wt）, thermal stability time of PVC can achieve to 46.99 rain. Comparing with pure PVC, it increased over 15 times which was better than the Na-MMT modified with quaternary ammonium salt. In summary, La-OMMT exhibited superior applicability in the processing of PVC.