改性聚乙烯泡沫材料介电性能与力学性能

Dielectric and Mechanical Properties of Modified Polyethylene Foams

以硼硅酸盐空心玻璃微球(BSH)为介电填料,乙烯-醋酸乙烯酯共聚物(EVA)为改性树脂,采用偶氮二甲酰胺(AC)发泡方法制备了改性聚乙烯(PE)泡沫材料,研究了复合材料的形貌结构及其介电性能与力学性能。研究结果表明,BSH能够有效地降低PE的介电常数,同时对泡沫材料的孔结构与介电性能具有显著影响,在1 kHz频率下,PE/BSH的介电常数降低至2.25,PE/BSH-f的介电常数增加至2.36;利用EVA含量对材料相结构的影响,可以调控泡沫材料的孔结构与介电性能,并且EVA含量较高的复合材料的介电常数也较高,但是介电损耗有所下降;EVA和BSH能够显著改善泡沫材料的拉伸性能,与纯PE泡沫材料相比,PE7/EVA3/BSH-f和PE5/EVA5/BSH-f的拉伸强度分别提高了173%和944%。二者复合使用对泡沫材料的拉伸强度的提高具有协同作用。

Polyethylene(PE)foams modified with borosilicate hollow glass microsphere(BSH)as dielectric filler and ethylene vinyl acetate copolymer(EVA)as modified resin were prepared by foaming with azodicarbonamide(AC).The morphological structure,dielectric and mechanical properties of the composite were studied.As a result,BSH had notable effects on the pore structure and dielectric properties of PE foams,which was beneficial to decrease the dielectric constant of PE.At 1 kHz,the dielectric constant of PE/BSH decreased to 2.25 and that of PE/BSH-f increased to 2.36;The phase structure of PE/EVA blends,as well as the pore structure of modified foams,showed dependence on the content of EVA.The foams with higher EVA content showed slightly higher dielectric constant and lower dielectric loss.EVA and BSH could significantly improve the tensile properties of foams.The tensile strength of PE7/EVA3/BSH-f and PE5/EVA5/BSH-f increased by 173%and 944%respectively compared with that of pure PE foams.The synergistic effect of EVA and BSH was revealed on the tensile strength of the modified foams.