A random copolymer comprises ethylene units which preferably forms a polyethylene chain and 0.001 to 10 mol% of ester units which are ethylenically α,β-unsaturated acid esters represented by the formula (1) or (II):
wherein R1 is H or -CH3 and R2 is a halogenated, preferably fluorinated C1-15 alkyl group;
wherein R3 is H or -CH3 and n = 0 or 1; optionally up to 10 mol% of a modifying comonomer may be present.
Production is by catalytic radical polymerisation of the monomers or by grafting the ester unit onto a polymer or copolymer of ethylene.
The copolymer may be blended with other polymers, may be crosslinked, and is extruded into wire or cable coatings or molded into sheets, films, or laminates.
The copolymer has excellent dielectric breakdown characteristics, such as electricity treeing or water treeing pro- party, and is useful as insulation for high-voltage cables.
无规共聚物由
乙烯单元和 0.001 至 10 摩尔%的酯单元组成,
乙烯单元最好是形成聚
乙烯链的
乙烯单元,酯单元是
乙烯基 α,β-不饱和酸酯,由式 (1) 或 (II) 表示:
其中 R1 是 H 或-
CH3,R2 是卤化的,最好是
氟化的 C1-15 烷基;
其中 R3 是 H 或- ,n = 0 或 1;可选择含有高达 10 摩尔%的改性共聚单体。
生产方法是单体的催化自由基聚合或将酯单元接枝到
乙烯的聚合物或共聚物上。
共聚物可与其他聚合物混合,也可交联,挤压成电线或电缆涂层,或模压成薄片、薄膜或层压板。
这种共聚物具有优异的介电击穿特性,例如电击穿或
水击穿特性,可用作高压电缆的绝缘材料。