聚氨酯丙烯酸酯结构对光固化涂层防腐性能的影响

The Influence of Structure of the Polyurethane Acrylates on the Anticorrosive Performance of UV-Curing Coatings

低聚物树脂作为光固化涂料的主要成膜组分,其结构直接影响着涂层的化学结构。研究其化学结构与光固化涂层防腐性能之间的关系具有重要的意义。本文通过二异氰酸酯和聚醚二醇扩链后再用丙烯酸羟乙酯封端合成了一系列不同化学结构的聚氨酯丙烯酸酯树脂。通过增质量法和失质量法研究了聚氨酯丙烯酸酯的化学结构对涂层吸水率的影响,通过电化学阻抗谱和耐中性盐雾研究了涂层的耐腐蚀性能。研究发现:聚氨酯丙烯酸酯分子链中醚键含量越高,涂层吸水率越高,防腐性能越差;通过在醚键附近引入疏水性的甲基能够降低涂层的吸水率,从而提高涂层的防腐性能;此外,相比于醚键结构,软段为酯键结构时涂层的吸水率更低,防腐性能更高;相比于直链硬段结构,含有环状硬段结构的聚氨酯丙烯酸酯光固化涂层吸水率更低,防腐性能更好。

Oligomer resins are the main film-forming component of UV-curing coatings,and its structure has a direct impact on the chemical structure of the coatings. Therefore,it is a great significance to study the relationship between the chemical structure of the oligomer resin and the anticorrosive properties of the prepared UV-curing coatings. In this paper,a series of polyurethane acrylate with different chemical structures were synthesized via the reaction of diisocyanate and polyether glycol and then capped with hydroxyethyl acrylate. The influences of chemical structure of the polyurethane acrylates on the water absorption of the UV-curing coatings were studied by weight gain and weight loss method,and the corrosion resistance of the coatings were studied by electrochemical impedance spectroscopy and neutral salt spray test. IT was found that the more ether bonds in the molecular chain of polyurethane acrylate,the higher water absorption of the UV-curing coatings,and the worse their anticorrosion performance was. The water absorption of the UV-curing coatings could be reduced by introducing methyl group near the ether bond in polyurethane acrylate,and the anticorrosion performance of the UV-curing coatings were also improved accordingly. In addition,when thesoft segment had an ester bond structure,the water absorption rate of the coating was lowerthan that of the coatings with ether bond soft segment and the corrosion resistance was higher.The polyurethane acrylate UV-cured coatings containing the cyclic hydrocarbon hard segmentstructures provided lower water absorption and higher corrosion resistance than thosecontaining linear hydrocarbon hard segment structures.