Herein, the effects of ungrafted acrylic acid (AA) monomers in graft copolymers on electrical properties were investigated. Linear low-density polyethylene-grafted AA (LLDPE-g-AA) was synthesized by preirradiation and melt-extrusion grafting. Then, LLDPE/LLDPE-g-AA and LLDPE/u-LLDPE-g-AA blends were prepared based on purified LLDPE-g-AA and untreated LLDPE-g-AA, respectively. The rheological, thermal, and electrical properties of blends were studied and compared. The results showed that the suppression of space charges mainly resulted from grafted polyacrylic acid (PAA) branches. Ungrafted AA monomers in blends had no apparent effects on space charge distribution but featured positive influence on the DC breakdown strength within the concentration range of this study. The dielectric strength for different accelerated migration periods showed that as ungrafted AA monomers migrated from the blends, the influence of ungrafted AA monomers on the dielectric strength weakened, and PAA branches played a dominant role in the enhancement of dielectric strength.

中文翻译：

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接枝共聚物中未接枝单体对聚乙烯电绝缘性能的影响

在此，研究了接枝共聚物中未接枝的丙烯酸（AA）单体对电性能的影响。通过预辐照和熔融挤出接枝合成了线性低密度聚乙烯接枝的AA（LLDPE- g -AA）。然后，LLDPE / LLDPE-克-AA和LLDPE / U-LLDPE-克-AA共混物根据制备纯化的LLDPE-克-AA和未处理LLDPE-克-AA。研究并比较了混合物的流变，热和电性能。结果表明，空间电荷的抑制主要是由接枝的聚丙烯酸（PAA）支链引起的。共混物中的未接枝AA单体对空间电荷分布没有明显影响，但在本研究的浓度范围内对DC击穿强度具有积极影响。不同加速迁移时间的介电强度表明，当未接枝的AA单体从共混物中迁移出来时，未接枝的AA单体对介电强度的影响减弱，PAA支链在介电强度的增强中起主要作用。