高硅氧纤维增强聚四氟乙烯复合材料的制备与性能

Preparation and Properties of High Silica Fiber Reinforced PTFE Composites

采用模压成型工艺制备了高硅氧纤维增强聚四氟乙烯复合材料(GF/PTFE),研究了纤维含量、热处理温度、成型压力以及成型温度对复合材料的影响。研究结果表明,当纤维含量为40%,即树脂含量为60%时,复合材料具有良好的性能。热处理温度过低或过高会造成预浸料中杂质发生滞留或碳化,导致复合材料介电常数和损耗偏高,选择热处理温度为260℃~280℃。成型压力升高会降低GF/PTFE复合材料孔隙率,提高压缩强度和介电常数。压力过大会造成PTFE颗粒剧烈变形,布层相对滑移发生撕裂,压缩强度下降,GF/PTFE复合材料最佳成型压力为10 MPa。成型温度在320℃~380℃时,随着成型温度升高,GF/PTFE复合材料力学性能升高,但当温度超过380℃会加速树脂的分解,分解生成气体造成复合材料内部出现孔隙和微缺陷,降低复合材料力学性能。所以,GF/PTFE复合材料成型温度选择380℃为最佳。

High silica fiber-reinforced polytetrafluoroethylene composites (GF/PTFE) were prepared by compression molding, and the effects of fiber content, heat treatment temperature, molding pressure and molding temperature on the composites were studied. The results of the study show that the composites have good properties when the fiber content is 40%, that is, the resin content is 60%. If the heat treatment temperature is too low or too high, impurities in the prepreg will be retained or carbonized, resulting in high dielectric constant and loss of the composites. The heat treatment temperature is selected to be 260˚C~280˚C. Increasing the molding pressure reduces the porosity of GF/PTFE composites and increases the compressive strength and dielectric constant. Excessive pressure will cause the PTFE particles to deform violently, the relative slip of the cloth layer will tear, and the compressive strength will decrease. The optimal molding pressure of GF/PTFE composite material is 10 MPa. When the molding temperature is 320˚C~380˚C, the mechanical properties of GF/PTFE composites increase with the increase of molding temperature. However, when the temperature exceeds 380˚C, the decomposition of the matrix resin is accelerated, and the gas generated by the decomposition produces more micro-defects and pores in the material, which reduces the strength of the composite material. Therefore, 380˚C is the best choice for the molding temperature of GF/PTFE composites.