偏氟乙烯/三氟乙烯铁电共聚物的非晶介电弛豫

DIELECTRIC RELAXATION OF NONCRYSTALLINE REGIONS IN THE FERROELECTRIC COPOLYMERS OF VINYLIDENE FLUORIDE/TRIFLUOROETHYLENE

用溶液成膜、液氮淬火、熔融慢冷和热处理4种方法制得不同结晶度的VDF/TrFE共聚物试样。在已改进的介电弛豫谱仪(精度由原来的1％提高到2‰)上测得复数介电常数。从结晶度为20％的淬火试样室温以下的介电频率谱中发现了非晶介电弛豫,并由此得到了玻璃化温度与共聚物组分含量的关系。

The films of copolymers of vinylidene fluoride with trifluoroethylene (VDF/TrFE) with different crystallinity were prepared by four methods, i. e. , as-cast, quenching in liquid nitro-gen, slow-cooling and annealing at 140℃. The complex dielectric constants were measured using an improved dielectric relaxation spectrometer whose precision increased to 2‰ from the original 1%. The dielectric relaxation of noncrystalline regions was found in accordance with the dielectric frequency spectra of quenched sample that the crystallinity was 20% below room temperature. Thereby, the relationship between the glass transition temperature and the component of copolymers was got.