采用可变纤维增强反应注射成型技术制备了长玻纤/聚氨酯泡沫复合材料, 运用正交试验方法研究了工艺参数对其冲击性能的影响, 对试样冲击断口进行了观察, 分析了复合材料微观缺陷产生的原因, 对成型工艺参数进行了优化。结果表明: 纤维含量、混合料温、在模时间和物料配比均对复合材料的冲击强度有显著影响, 模具温度和纤维长度对冲击强度影响均不显著; 纤维长度一定时, 随着纤维含量的增加, 复合材料的冲击强度先增加后降低; 当纤维质量分数达到30%, 长度大于25 mm时, 复合材料的冲击强度不稳定, 容易产生纤维团聚、空泡变大、贫脂等缺陷; 冲击性能最佳的工艺参数为纤维质量分数25%、纤维长度25 mm、模具温度45 ℃、混合料温50 ℃、在模时间12 min、A料与B质量比1∶1.80。

Long glass fiber(GF)/polyurethane(PU) foam composites were prepared by variable fiber reinforced reaction injection molding. The influences of process parameters on the impact property of the composite were studied by orthogonal experiments, and the impact fracture morphology of specimens was observed to analyze the causes for microscopic defects forming in the composite. And process parameters were optimized. The results show that fiber content, mixture temperature, molding time, mass ratio of material A to B had a significant effect on the impact strength, while mold temperature and fiber length had little effect. When the fiber length was constant, the impact strength of composites increased firstly and then decreased with the increase of fiber content. When the fiber mass content was 30wt.% and the fiber length was greater than 25 mm, the impact strength of composites was unstable and fiber aggregation, large vacuoles, lean burn and other defects happened easily in the composites. The best molding process parameters were the fiber content 25%, fiber length 25 mm, mold temperature 45 ℃, mixture temperature 50 ℃, molding time 12 min, mass ratio of material A to B 1∶1.80.