多巴胺改性聚苯硫脲与聚偏氟乙烯共混复合材料的制备与性能

Preparation and properties of polyphenylthiourea-poly(vinylidene fluoride)composites modified by dopamine

聚苯硫脲(ArPTU)是一种新型高击穿、低损耗的材料,为提高其储能密度,在与聚偏氟乙烯(PVDF)共混的过程中,如何提高其溶解性,降低界面问题,成为研究热点之一。利用多巴胺(DA)对其进行改性可以有效地改善其与PVDF的界面问题。采用溶液流延热压的方法制备出不同共混比的多巴胺改性聚苯硫脲共混聚偏氟乙烯(DA/ArPTU-PVDF)复合薄膜。并采用X射线衍射仪、扫描电子显微镜、核磁共振、凝胶渗透色谱、阻抗分析仪等对其进行表征。结果表明:当DA/ArPTU-PVDF中DA/ArPTU质量分数为10wt%~15wt%时,PVDF的β晶型相对含量显著增加,这是其介电性能增加的主要原因之一;100Hz时,介电常数最大可以达到10.3(10wt%DA/ArPTU),同时介电损耗降低,最低达到了0.008(25wt%DA/ArPTU)。复合材料的储能密度也有明显提高,最大可以达3.0J/cm3(10wt%DA/ArPTU),相对于纯PVDF提高了63.3%。此外,复合材料的击穿特性相比于纯PVDF具有很大的提高,最大可达556.4MV/m(15wt%DA/ArPTU)。而且,改性后的复合材料力学性能也有了很大的提高。最大断裂伸长率可以达到196.7%(5wt%DA/ArPTU),展现出了柔性高击穿储能材料的潜力。

Polyphenylthiourea(ArPTU)is a new type of high breakdown,low loss material.In order to improve its energy storage density,ArPTU can be blended with poly(vinylidene fluoride)(PVDF).The problem that how to improve its solubility and reduce the interface during blending with PVDF has become one of the research hotspots.Modification with dopamine(DA)can effectively improve its interface with PVDF.DA modified ArPTU-PVDF(DA/ArPTU-PVDF)composite films with different blending ratios were prepared by solution casting hot pressing method and characterized by X-ray diffractometry,scanning electron microscopy,nuclear magnetic resonance,gel permeation chromatography and impedance analyzer.The results show that when the mass fraction of DA/ArPTU is 10 wt%-15 wt%,the relative content ofβcrystal form of PVDF increases remarkably,which is one of the main reasons for the increase of dielectric properties.At 100 Hz,the dielectric constant can be the largest.It reaches10.3(10 wt%DA/ArPTU),while the dielectric loss decreases,and the minimum reaches 0.008(25 wt%DA/ArPTU).The energy storage density of the composite material also increases significantly,up to 3.0 J/cm3(10 wt%DA/ArPTU),which is 63.3%higher than that of the pure PVDF.In addition,the breakdown characteristics of the composites are greatly improved compared to the pure PVDF,up to 556.4 MV/m(15 wt%DA/ArPTU).Moreover,the mechanical properties of the modified composites have also been greatly improved.The maximum elongation at break can reach 196.7%(5 wt%DA/ArPTU),showing the potential of flexible high breakdown energy storage materials.