设法提高电介质材料的介电性能和击穿特性，进而改善PVDF基的电介质脉冲电容器储能性能，对于促进其在军事和民用领域的应用具有重要意义。偏氟乙烯-六氟丙烯共聚物（P(VDF-HFP)）是一类综合性能优良的电介质材料。为了进一步提高其介电性能，文章首先通过溶液流延法制得P(VDF-HFP)薄膜，在不同温度和时间下对其进行退火处理，以考察后处理对P(VDF-HFP)晶体结构及介电性能的影响。采用X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）和示差扫描量热分析（DSC）对样品的晶体结构、结晶度和电活性β相含量进行表征，并对薄膜的介电性能进行测试。结果表明，退火处理可有效提高P(VDF-HFP)共聚物的β相含量，在120℃下退火12 h，体系的β相含量可高达92.1%，对应的介电常数可达15.3（100 Hz），较原始薄膜提高45%，同时样品介电损耗可降至0.019。%It is of significant importance to improve the dielectric property and the electric breakdown performance of polymer dielectric materials for their successful applications in the impulse capacitors as they are related with the large energy density and the high cycle efficiency, which are desirable for applications in various military and civil domains. As a type of polymer dielectric materials, the vinylidene fluoride-hexafluoropropylene copolymer (P(VDF-HFP)) enjoys excellent comprehensive properties. However, its dielectric property remains to be improved. In this paper, the P(VDF-HFP) films are first made through a solution-casting process, and then isothermally annealed under serially changing temperatures and times. The crystal form, the crystallinity and theβ-phase content of the resulting films are characterized with the X-ray diffraction (XRD), the Fourier transformed infrared (FTIR) spectroscopy and the differential scanning calorimetry (DSC), respectively, and the dielectric properties of the films are assessed to see the effects of annealing. It is indicated that the relative fraction of theβ-phase in the P(VDF-HFP) films can be effectively improved simply by annealing under adequate temperatures and times, with considerably enhanced dielectric performance. Upon being annealed at 120℃ for 12 h, the P(VDF-HFP) film is found to have the highest proportion of theβ-phase up to 92.1%, with a high dielectric constant of 15.3 (100 Hz, 45% higher than the original film) and low dielectric loss of 0.019.
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