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PVC在生产中会因为温度升高而降解,通常添加热稳定剂来抑制PVC的降解。在碱性条件下,用柠檬酸和硝酸镧所制备碱式柠檬酸镧作为PVC热稳定剂。用红外光谱、元素分析以及差热分析仪对产物进行表征。通过刚果红实验和变色性能测试对PVC进行稳定性测试。结果显示,185℃条件下碱式柠檬酸镧对PVC的热稳定时间达到57 min,有较好的长期抗变色能力。为了改善其对PVC的初期抗变色能力,引入硬脂酸锌和季戊四醇,制备复合稳定剂。复合稳定剂对PVC的热稳定能力得到提高,且对PVC的初期着色有了较大的改善。碱式柠檬酸镧在提高镧含量的基础上增加了活性羟基,从而使其对PVC降解起到抑制作用。
PVC in production due to temperature degradation and degradation, usually adding heat stabilizer to inhibit the degradation of PVC. Under alkaline conditions, lanthanum basic citrate, prepared from citric acid and lanthanum nitrate, is used as the PVC heat stabilizer. The product was characterized by FTIR, elemental analysis and differential thermal analysis. The PVC was tested for stability by the Congo red test and the discoloration performance test. The results show that the thermal stability of lanthanum basic citrate reaches to 57 min at 185 ℃, which has good long-term anti-discoloration ability. In order to improve its initial resistance to discoloration of PVC, zinc stearate and pentaerythritol were introduced to prepare a composite stabilizer. The thermal stability of composite stabilizer to PVC is improved, and the initial coloring of PVC has been greatly improved. Basic lanthanum citrate increases the active hydroxyl group on the basis of increasing the content of lanthanum, thereby inhibiting the degradation of PVC.