聚酰胺材料霉致失效机理研究

Exploration on the mechanism of failure caused by mold in polyamide materials

针对聚酰胺材料T1和B1,选用两种霉菌分别对其进行防霉测试,对霉菌与聚酰胺共培养过程中的失效机理开展了深入探索和研究。结果表明,霉菌生长会从外界吸收氧气,这会导致聚酰胺分子链上的亚甲基断裂,并与之发生反应生成羰基,使分子内部结构发生改变;由于聚酰胺内部分子链上存在反应活性较高的亚甲基结构,导致聚酰胺和霉菌在共培养过程中会发生颜色上的改变,会与外界反应生成亚甲基自由基,进一步与氧气产生化学反应生成氢过氧化物,然后通过异构化生成羰基,羰基再与其他活性基团结合产生羰亚胺,这样聚酰胺分子链上的共轭链就会增加,在可见光区就会看到最大吸收波长,宏观上表现为聚酰胺材料变色;霉菌会从聚酰胺表面获得营养物质从而进行繁殖,表面结构会发生明显的破坏和改变;力学性能测试表明,霉菌会导致聚酰胺材料的拉伸、弯曲以及冲击性能发生衰减下降,且两种霉菌致衰减下降幅度不一样。

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.