关键词: 聚酰胺, 霉菌, 化学反应, 颜色变化, 失效机理

Abstract: This article focuses on polyamide materials T1 and B1， and uses two types of fungi to conduct anti mold tests on them. It conducts in-depth exploration and research on the failure mechanism during the co cultivation process of fungi and polyamide. Through infrared spectroscopy analysis， it was found that mold growth can absorb oxygen from the outside， which can cause the methylene on the polyamide molecular chain to break and react with it to form carbonyl groups， causing changes in the internal structure of the molecule. Through UV spectroscopy and nuclear magnetic resonance analysis， it can be seen that due to the presence of highly reactive methylene structures on the internal molecular chains of polyamide， the color of polyamide and mold will change during the co cultivation process. It will react with the outside world to generate methylene free radicals， further react with oxygen to generate hydrogen peroxide， and then isomerize to generate carbonyl groups. The carbonyl groups then combine with other active groups to produce carbonyl imines. As a result， the conjugated chains on the polyamide molecular chains will increase， and the maximum absorption wavelength will be seen in the visible light region， which is macroscopically manifested as the color change of the polyamide material. Thermogravimetric analysis shows that fungi can obtain nutrients from the surface of polyamide for reproduction， and the surface structure will undergo significant damage and changes. Mechanical performance tests have shown that mold can cause a decrease in the tensile， bending， and impact properties of polyamide materials， and the two types of mold can cause different degrees of attenuation.

Key words: polyamide, mold, chemical reaction, color change, failure mechanism