2,4-二羟基二苯甲酮镧对PVC热稳定性能的影响

Effect of Lanthanum 2,4-dihydroxybenzophenone on Thermal Stability of PVC

通过2,4-二羟基二苯甲酮(BP)与稀土镧离子配位,合成了2,4-二羟基二苯甲酮镧(LBP)。用元素分析、红外分析、热分析等对配合物进行了表征。同时用刚果红试纸法和高温热老化箱,探讨了配合物以及配合物与硬脂酸锌(ZnSt_(2))、硬脂酸钙(CaSt_(2))、季戊四醇(PE)复配对PVC热稳定性能的影响。结果表明:2,4-二羟基二苯甲酮镧的分子式为:La_(2)(C_(13)H_(8)O_(3))_(3)·5H_(2)O。当配合物单独添加到PVC中时,热稳定性能一般,但当以m(LBP)∶m(ZnSt_(2))∶m(PE)=2∶1∶2进行复配后,热稳定时间长达81 min,并且抗变色效果最好。由热稳定机理研究得出,2,4-二羟基二苯甲酮镧可以与PVC受热分解出的氯化氢反应,生成LaCl_(3),降低氯化氢对PVC的催化降解,进而增强PVC的热稳定性能。

2,4-dihydroxybenzophenone lanthanum(LBP)was synthesized by the coordination of 2,4-dihydroxy⁃benzophenone(BP)with lanthanum ion.The complex was characterized by elemental analysis,infrared analysis and thermal analysis.At the same time,Congo red test paper method and high temperature thermal aging cham⁃ber were used to study the effect of complexes and their combination with zinc stearate(ZnSt_(2)),calcium stea⁃rate(CaSt_(2))and pentaerythritol(PE)on the thermal stability of PVC.The results showed that the molecular for⁃mula of 2,4-dihydroxybenzophenone lanthanum is La_(2)(C_(13)H_(8)O_(3))_(3)·5H_(2)O.When the complex was added to PVC alone,the thermal stability was general,but when m(LBP)∶m(ZnSt_(2))∶m(PE)=2∶1∶2,the thermal stability time was 81 min,and the anti-tarnishing effect was the best.According to the mechanism of thermal stability,lantha⁃num 2,4-dihydroxybenzophenone can react with hydrogen chloride decomposed from PVC to form LaCl_(3),which can reduce the catalytic degradation of PVC by hydrogen chloride and enhance the thermal stability of PVC.