钛酸铜钙/含氟聚合物基复合薄膜的制备、表面和介电性能

Preparation, surface and dielectric properties of copper calcium titanate/ fluoro-containing polymer composite films

  • 摘要: 为了提高含氟聚合物的介电性能,本文采用碘转移细乳液聚合合成了由全氟己基乙基丙烯酸酯-丙烯酸十八酯无规共聚物链段和甲基丙烯酸缩水甘油酯-丙烯酸甲酯无规共聚物链段构成的嵌段共聚物乳液,并与钛酸铜钙(CCTO)复合制得复合薄膜,采用凝胶渗透色谱、红外、扫描电镜和宽频介电阻抗谱等表征了共聚物、复合薄膜的结构和性能。结果表明,复合薄膜具有由富聚合物和富CCTO层组成的双层结构,6vol% CCTO的复合薄膜在100 Hz时的介电常数为32,同时具有较好的表面疏水疏油性能(水和正十六烷接触角分别为107.5°和57.2°)。进一步采用含氟硅烷偶联剂改性CCTO制备复合薄膜,在改性CCTO含量为6vol%时,复合薄膜在100 Hz下的介电常数提升至85,这归因于“氟-氟”相互作用带来的相界面作用的改善。以上结果为低频高介电常数复合材料的设计提供了一种新的思路。

     

    Abstract: In order to improve dielectric properties of fluoropolymers, a emulsion based on a block copolymer composed of perfluorohexylethyl acrylate-stearyl acrylate random copolymer segment and glycidyl methacrylate-methyl acrylate random copolymer segment was synthesized by iodine transfer miniemulsion polymerization process, and compounded with copper calcium titanate (CCTO) to prepare composite films. The structure and properties of the copolymer and composite films were characterized by GPC, IR, SEM and dielectric impedance spectrometer. Results show that the composite films exhibit a bi-layer structure composed of a CCTO-riched layer and a polymer-riched layer. The composite film with 6 vol% CCTO exhibits a dielectric constant of 34 at 100 Hz, and good surface hydrophobic and oleophobic properties (static contact angles of water and n-hexadecane are 107.5° and 57.2°, respectively). The dielectric constant of the composite films at 100 Hz is increased to 85 when 6 vol% of CCTO surface modified with fluorinated-silane coupling agent is used. This is attributed to the improvement of the phase interface action caused by the "fluorine-fluorine" interaction. The above results provide a new idea for the design of high-dielectric constant composites at low-frequencies.

     

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