稳定剂对PVC辐射变色性能影响的研究

采用^60Coγ射线对聚氯乙烯（Polyvinyl chloride，PVC）／稳定剂复合体系进行辐照。研究了不同稳定剂对PVC辐射变色．陛能的影响；并采用紫外光谱仪（Ultraviolet spectrometer，UV）和傅立叶变换红外光谱仪（Fouriertransform infrared spectrometer，FT—IR）对其结构进行了表征。结果表明，硬脂酸钙（Calcium stearate，CaSt），硬脂酸锌（Zinc stearate，ZnSt）复合稳定剂、环氧大豆油、亚磷酸酯和光稳定剂的加入可提高PVC耐辐射变色性能。亚磷酸酯的加入可提高PVC的耐辐射氧化性能。在相同吸收剂量下，添加硬脂酸钙／硬脂酸锌复合稳定剂的PVC具有优异的耐辐射变色性能。在吸收剂量为30kGy时，CaSt：Znst为4：1的PVC黄变指数变化率为8．3％。PVC经辐照后主要形成3至4个共轭双键的不饱和酮或共轭烯烃结构。

Study on the effect of stabilizers on discoloring of PVC by irradiation

Composites of polyvinyl chloride (PVC) filled with stabilizers was irradiated by ~(60)Co γ-ray. The effect of different stabilizers on the radiation-induced discoloring of PVC was investigated and the structures of irradiated PVC were characterized by ultraviolet spectrum (UV) and Fourrier transfer infrared spectrum (FT-IR). It shows that the stabilizers including calcium stearate / zinc stearate, epoxidised oil, phosphite and photostabilizer can improve the property of resistance to radiation-induced discoloring of PVC, and phosphite can improve the property of resistance to radiation-induced oxidation of PVC. Among the stabilizers, formulations with calcium stearate/zinc stearate show high transparency and excellent property of resistance to radiation at same absorbed dose. Change rate of yellow in-dex of formulation (calcium stearate: zinc stearate=2:1) has been determined to be 8.3% at the absorbed dose of 30 kGy. It has been found that the structures of PVC with numbers of conjugated double bond or α, β-unsaturated ketone are formed after irradiation by γ-rays.