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为开发一种满足航空环境要求的新型环氧胶衣,首先,研究了不同分子量、不同含量的聚乙二醇(PEG)改性环氧胶衣在室温下的冲击韧性及冲击断面形貌;然后,采用一种简单温度冲击试样模型,着重研究了PEG改性环氧胶衣在温度冲击(-50℃/30min+90℃/30min)下的开裂性能,并通过分析热膨胀及储能模量等的变化趋势对其进行了验证。结果表明:5wt%PEG-1000改性环氧胶衣的冲击强度比未改性环氧胶衣的提高了31.8%,达到最高值4.97kJ·m~(-2);PEG-1000和PEG~(-2)000改性环氧胶衣的冲击断面呈现出更明显的塑性变形形貌,胶衣的冲击韧性得到提高;15wt%PEG-400改性环氧胶衣在温度冲击下的宏观初始开裂性能达到最佳,平均初始开裂需要进行10.4次循环;改性环氧胶衣的耐开裂扩散性能基本上随着PEG分子量和含量的增加而提高,但裂纹宽度也会随PEG分子量的增加而扩大。
In order to develop a new type of epoxy gel coat to meet the requirements of the aviation environment, the impact toughness and impact cross section morphology of polyethylene glycol (PEG) modified epoxy gel coat with different molecular weight and different contents at room temperature were studied. Then, using a simple temperature impact specimen model, the cracking behavior of PEG-modified epoxy gel coat under temperature shock (-50 ℃ / 30min + 90 ℃ / 30min) was studied emphatically. By analyzing the thermal expansion and energy storage mode Volume and other changes in the trend of its validation. The results showed that the impact strength of 5% PEG-1000 modified epoxy gel coat was 31.8% higher than that of unmodified epoxy gel coat, reaching the highest value of 4.97 kJ · m -2. (-2) 000 modified epoxy gel coat shows a more obvious plastic deformation morphology, the impact toughness of gel coat is improved; 15wt% PEG-400 modified epoxy gel coat under macro-initial impact of temperature The cracking performance is best, and the average initial cracking requires 10.4 cycles. The crack resistance of modified epoxy gel coat basically increases with the increase of PEG molecular weight and content, but the crack width also increases with the increase of PEG molecular weight expand.