低介电损耗氟化丙烯酸聚氨酯疏水材料的制备

Preparation of Hydrophobic Fluoroacrylate Polyurethane Films with Low Dielectric Lossfla

摘要: 以甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)、丙烯酸(AA)、甲基丙烯酸十二氟庚酯(G-04)以及丙烯酸-?-羟丙酯为原料，采用溶液自由基聚合工艺，合成不同氟含量和不同羟基含量的氟化丙烯酸树脂，与六亚甲基二异氰酸酯三聚体(N3390，HDI三聚体)交联制备氟化丙烯酸聚氨酯。对聚氨酯薄膜的透光性、疏水性和介电性能进行检测，并与市售的FEVE型氟化树脂(ZY-1)以及丙烯酸型氟化树脂(SGK-5701)的交联产物进行性能对比研究。结果表明，氟化丙烯酸型聚氨酯相较市售氟化树脂交联聚氨酯具有更低的疏水角、疏水稳定性和更低的介电常数和介电损耗值：可见光区透光率 > 90%；调整共聚物中氟单体含量，可使聚氨酯膜的疏水角 < 98°，吸水率 < 0.5%；氟单体的含量大于22 wt.%时，膜介电常数(ε) < 2.5，介电损耗(tanδ) < 0.01。可望作为雷达罩体表面的高透过、低张力和低介电损耗疏水材料。

Abstract: Fluoroacrylate copolymers with different fluoroacrylate monomer content and hydroxyl monomer content are synthesized by free-radical solution polymerization. The comonomers are composed of methyl methacrylate (MMA), butyl acrylate (BA), acrylic acid (AA), 2-hydroxypropyl acrylate (2-HPA) and dode-cafluoroheptyl methacrylate (G-04). Fluoroacrylate polyurethane (FPU) is prepared by curing the copolymers with HDI (hexamethylene diisocyanate) trimer. The hydrophobicity, dielectric properties, and transparency of FPU films are investigated. The comparative investigation is carried out with polyurethane obtained by re-acting with commercial resin of ZY-1 and SGK-5701. The results indicated that fluoroacrylate polyurethane possess a lower contact angle(CA), excellent hydrophobic stability，lower dielectric constant and dielectric loss. And the transmittance is higher in the whole visible wavelength range ( > 90%) than the FPU prepared by commercial resin. The FPU film exhibits excellent hydrophobicity(CA > 98°) and hydrophobic stability with a lower water absorption ( < 0.5%) by adjusting the fluoroacrylate monomer content. The dielectric con-stant and dielectric loss of the film is less than 2.5 and 0.01, respectively when the fluoroacrylate monomer content higher than 22 wt.%. The FPU may be used as the hydrophobic materials coated on the surface of radome according to their outstanding properties such as higher optical transmittance, lower surface energy and lower dielectric loss.