高压电缆绝缘低密度聚乙烯交联过程中级数和自催化反应的逆向调控  

Reverse Regulation of Order and Autocatalysis Reactions During the Cross-Linking Process of Low-Density Polyethylene Used in High-Voltage Cable Insulation

作　　者：李加才 尚恺 司志成 王诗航[1] 李盛涛[1] Li Jiacai;Shang Kai;Si Zhicheng;Wang Shihang;Li Shengtao(State Key Laboratory of Electrical Insulation and Power Equipment,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]电工材料电气绝缘全国重点实验室(西安交通大学),西安710049

出　　处：《电工技术学报》2024年第1期13-22,共10页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金重点支持项目-智能电网联合基金项目(U2066204);国家电网有限公司总部管理科技项目(SGSNKY00KJJS2100283)资助。

摘　　要：在保证交联度的前提下提升耐焦烧性能是进一步发展国产高压电缆低密度聚乙烯绝缘料的关键之一。焦烧和交联度本质上是交联反应及其结果的反映,该文基于高分子化学流变学和凝胶理论,提出了绝缘料耐焦烧性能的定量表征方法,结合实验分析和交联反应动力学模型,首次全面探讨了交联反应与焦烧和交联度的关联机理,提出了提升耐焦烧性能并保证交联度的优化策略。研究发现,低密度聚乙烯交联过程中有级数反应和自催化反应,低温下级数反应的级数越低,越有利于延缓交联反应,增加凝胶时间,提高耐焦烧性能;而高温下自催化反应的级数越高,越有利于加速交联反应,提高交联度。单一添加剂只能同向改变级数反应和自催化反应的级数,复合添加剂的协同作用则能逆向改变级数反应和自催化反应的级数,从而实现了在保证交联度的前提下提升绝缘料的耐焦烧性能。该研究为推进高压电缆低密度聚乙烯绝缘料国产化提供了重要理论支撑。Extruded cross-linked polyethylene(XLPE)insulating materials with excellent thermal,mechanical and electrical properties have been widely used in high-voltage cable insulation.The insulating materials are composed of low-density polyethylene(LDPE)by introducing cross-linking agent(dicumyl peroxide,DCP)and antioxidants.During the continuous extrusion process,the increase of local temperature causes the decomposition of DCP in advance,which results in the phenomenon of pre-cross-linking and even scorch in the melt.However,scorch will not only reduce the extrusion quality of insulating materials,but also threaten the electrical performance of XLPE.Scorch and cross-linking degree are essentially the reflection of the cross-linking reaction and its results.Under the premise of ensuring the cross-linking degree,improving the anti-scorch performance is one of the most important factors to promote the further development of domestic LDPE insulating materials used in high-voltage cables.Herein,the correlation mechanism between cross-linking reactions with anti-scorch properties and cross-linking degree of insulating materials used for high-voltage cables was discussed.Firstly,a quantitative characterization method for the anti-scorch properties of insulating materials was proposed based on macromolecular chemorheology and gel theory.Moreover,insulating materials adding with different antioxidants were prepared.The correlation mechanism between cross-linking reactions with anti-scorch properties and cross-linking degree of insulating materials was established by experimental analysis and reaction kinetic method.Finally,the regulation strategies of order and autocatalysis reactions to improve the anti-scorch performance under the premise of ensuring the cross-linking degree were discussed by employing the compound antioxidants.The following conclusions can be drawn.Firstly,a quantitative characterization method for the anti-scorch performance of insulating materials is proposed,and this method can accurately obtain the char

关 键 词：低密度聚乙烯 级数反应 自催化反应 焦烧 交联度 

分 类 号：TM215[一般工业技术—材料科学与工程]