聚氨酯涂料人工加速老化行为的研究

通过热氧老化、人工加速气候老化、耐水性能测试等方法,对聚氨酯涂膜人工加速老化性能进行了初步研究。并对其老化前后的力学性能进行了分析与讨论,并通过扫描电子显微镜对其表面形貌的变化做出了理论分析。结果表明,涂膜在水中浸泡2周内不会有明显的力学性能下降,并保持良好的表观装饰性;但经长时间(3周以上)水的作用,涂层力学性能会大幅下降,表面也会产生裂纹和起泡。SEM分析表明老化后涂膜表面产生了许多孔穴,随老化时间增加逐渐向涂膜内部发展,孔隙率逐渐增大,最终贯穿整个涂层。

Study on the artificially-accelerated aging behavior of PU coating

The aging behavior of polyurethane coating through thermal oxidation,ultraviolet exposure and soaking in the water was studied.The mechanical properties were tested and the morphologies of these coatings were determined by means of Scanning Electron Microscopy.The results show that mechanical properties and surface toughness maintained well in 2 weeks in water.But after 3 weeks in water,mechanical properties of the coatings were reduced a lot and some flaws were found on the surface.The micrographs,which were obtained by Scanning Electron Microscopy,show that a lot of cavities in coatings appeared after aging process,and also when the aging time was prolonged,the cavity rate increased,and it penetrated the whole coating finally.