高强高韧聚甲醛粉末静电喷涂涂层的制备与性能研究

Preparation and properties of high-strength and high-toughness polyoxymethylene coatings through electrostatic powder spraying

针对不同平均粒径聚甲醛(POM)粉末制得的静电喷涂涂层性能开展了对比研究,确定了应用于静电喷涂用POM粉末的最佳平均粒径应小于100μm。采用聚丙烯(PP)和聚氨酯(TPU)粉末对纯POM涂层进行增韧改性,以提高其抗冲击性能;对复合涂层进行了厚度、硬度、厚度、冲击强度、耐化学溶剂性、微观形貌以及耐磨等性能进行了考察。结果表明,所有复合涂层均具有良好的外观和耐酸耐碱耐盐性,厚度较为均一,涂层表面光滑,无缩孔橘皮及开裂现象,附着力等级均为1级以上,符合实际应用标准,具有一定的力学性能和优异的耐摩擦性能,摩擦系数最低可达0.261。当PP和TPU粉末添加量分别为3%、15%时,其复合涂层的冲击强度分别为4.42、5.12 N·m,复合涂层的抗冲击性能改善效果显著,可满足其在相关领域的应用要求。

In this work,an intensive investigation was carried out to determine an optimal mean particle size of less than 100 μm for the powder electrostatic spraying process of polyoxymethylene(POM) powders through comparing the performance of powder coatings made from POM powders with different average particle sizes.Polypropylene and polyurethane were then incorporated to pure POM powders to improve the impact resistance of POM powder coatings.The performance of the resultant composite coating samples were evaluated by characterizing their thickness,hardness,thickness,impact strength,chemical resistance,morphology,and wear resistance.The results indicated that all of the coating samples exhibited good appearance,acid and alkali resistance,and salt resistance together with a uniform thickness and a smooth surface.There was no shrinkage orange peel and cracking phenomena.Their adhesion grades reached above grade 1 and their friction coefficients were as low as 0.261.All of these can meet the requirement of application standards for good mechanical properties and excellent friction resistance.Moreover,the composite coatings obtained impact strength of 4.42 and 5.12 N·m when 3 wt% PP and 15 wt% TPU were incorporated,respectively.With such a modification,the impact resistance of the composite coatings was greatly improved to meet the requirement for practical applications in the specific areas.