Hao Xiangping, Yang Kexin, Zhang Dawei, Lu Lin
National Materials Corrosion and Protection Data Center, Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China.
BRI Southeast Asia Network for Corrosion and Protection (MOE), Shunde Innovation School, University of Science and Technology Beijing, Foshan 528399, China.
Polymers (Basel). 2023 Jan 9;15(2):328. doi: 10.3390/polym15020328.
Two different fungi, Talaromyces funiculosus (T. funiculosus) and Phanerochaete chrysosporium (P. chrysosporium), were collected from the Xishuangbanna atmospheric corrosion site and incubated on a polyurethane (PU) coating at 30 °C for two weeks under 95% relative humidity (RH). The biodegrading effects of these fungi on the coating failure were investigated from aspects of metabolism and electrochemistry. The results showed that T. funiculosus contributed more to the degradation of the PU coating failure than P. chrysosporium, and two factors played dominant roles. First, the weight of the T. funiculosus mycelium was nearly 3 times more than that of P. chrysosporium, indicating there was more substrate mycelium of T. funiculosus deep into the coatings to get more nutrition in atmospheric during colonization. Second, T. funiculosus secreted carboxylic acids, such as citric, propanoic, succinic, and tartaric acids, and accelerated the hydrolysis of the ester and urethane bonds in the PU coatings. As a result, the mycelium of T. funiculosus readily penetrated the interface of the coating and substrate resulting in a rapid proliferation. Thus, the |Z|0.01Hz value of the coating decreased to 5.1 × 104 Ω·cm2 after 14 days of colonization by T. funiculosus while the value remained at 7.2 × 107 Ω·cm2 after colonization by P. chrysosporium. These insights suggest that the biodegradation process in simulated atmospheric environments would provide theoretical guidance and directions for the design of antifungal PU coatings.
从西双版纳大气腐蚀现场采集了两种不同的真菌，即绳状篮状菌（Talaromyces funiculosus，T. funiculosus）和黄孢原毛平革菌（Phanerochaete chrysosporium，P. chrysosporium），并在30℃、相对湿度95%的条件下于聚氨酯（PU）涂层上培养两周。从代谢和电化学方面研究了这些真菌对涂层失效的生物降解作用。结果表明，绳状篮状菌对PU涂层失效的降解作用比黄孢原毛平革菌更大，有两个因素起主导作用。第一，绳状篮状菌的菌丝体重量几乎是黄孢原毛平革菌的3倍，这表明在定殖过程中，绳状篮状菌有更多的底物菌丝体深入涂层，以在大气中获取更多营养。第二，绳状篮状菌分泌柠檬酸、丙酸、琥珀酸和酒石酸等羧酸，并加速PU涂层中酯键和聚氨酯键的水解。结果，绳状篮状菌的菌丝体很容易穿透涂层与基材的界面，导致快速增殖。因此，在绳状篮状菌定殖14天后，涂层的|Z|0.01Hz值降至5.1×104Ω·cm2，而在黄孢原毛平革菌定殖后该值保持在7.2×107Ω·cm2。这些见解表明，模拟大气环境中的生物降解过程将为抗真菌PU涂层的设计提供理论指导和方向。
