受阻酚抗氧剂对交联聚乙烯绝缘料交联流变特性的影响

Effect of Hindered Phenol Antioxidants on Cross-linking Rheological Properties of Cross-linked Polyethylene Insulation Material

交联聚乙烯(XLPE)绝缘料的交联流变特性可以反映绝缘料挤出过程中的过早交联现象和加工性能。绝缘料中的受阻酚抗氧剂不仅可以抑制挤出过程中的热氧化和降解,还可以有效地捕获自由基来抑制交联反应,从而改善聚乙烯熔体的加工性能。通过制备不同受阻酚抗氧剂种类和不同含量的绝缘料,测试140℃下剪切作用中绝缘料的扭矩与温度的变化,研究绝缘料的交联流变特性,并表征了绝缘料的交联度和交联副产物含量。结果表明:绝缘料抑制过早交联的能力越差,产生的凝胶越多,平衡扭矩越大。受阻酚抗氧剂可以抑制过早交联反应,相比于抗氧剂的分子量和空间位阻,单位质量的羟基数目与抑制过早交联的能力关系更为密切。

The cross-linking rheological properties of the cross-linked polyethylene(XLPE)insulation material can reflect the premature cross-linking phenomenon and processing performance during the extrusion process.The hindered phenol antioxidant in the insulation material can not only inhibit the thermal oxidation and degradation during extrusion process,but also effectively capture free radicals to inhibit the cross-linking reaction,thereby improving the processing performance of the polyethylene melt.In this paper,insulation materials with different types and contents of hindered phenol antioxidants were prepared,the changes in the torque and temperature of the insulation material under shear at 140℃were tested,the cross-linking rheological properties of insulating materials were studied,and the cross-linking degree and cross-linking by-products content of the insulating materials were characterized.The results show that the worse the ability of the insulating material to inhibit premature crosslinking,the more gel is produced,and the greater the equilibrium torque.The hindered phenol antioxidant can inhibit the premature cross-linking reaction,compared with the molecular weight and steric hindrance of hindered phenol antioxidant,the number of hydroxyl groups per unit mass is more closely related to the ability to inhibit premature crosslinking.