混杂纤维增强酚醛热固性注塑料的研究

Hybrid Fiber Reinforced Thermoset Phenolics for Injection Molding

采用短切混杂纤维增强酚醛热固性注塑料成型汽车电器零件换向器，提高了换向器耐光轴过盈配合时受到的最大应力。在扫描电镜下观察换向器断口分析及其破裂方式。结果表明混杂纤维中由于有机纤维对主裂纹的发展有阻碍作用，延缓了主裂纹的增长速度，使其它裂纹在制件失效前有更多的发展。因此拔出的纤维长度增加，吸收的能量增多，材料的冲击强度，弯曲强度相应提高。

Commutators of automobile engines in Shanghai Santana are still made by mold pressing. Injection molding is a much more efficient way to make them, but commutators made by injection molding cannot stand the stress exerted by the smooth axis in 17 μm surplus coordination. We get a contract to solve this problem. After years of experiments, we developed a kind of short hybrid fiber reinforced thermoset phenolics for injection molding to make the automobile commutators. Table 1 gives the performance data of the hybrid fiber reinforced thermoset phenolics for injection molding, and that of the glass fiber reinforced material. Fig.1 shows the variation of the shock strength (curve 1) and bending strength (curve 2) with the percentage of organic fibers in the material. Fig.3a shows the broken section of a commutator made from glass fiber reinforced materials under scanning electron microscope (SEM), Fig.3b shows that of a commutator made from hybrid fiber reinforced materials. A series of tests by Shanghai Santana show that commutators made from hybrid fiber reinforced materials can meet all of their requirements. To our best knowledge, there is no such reports in the open literatures.