不同混合比例微胶囊对水性漆涂层耐老化及自修复性能的影响

Effects of different proportions of mixed microcapsules on aging resistance and self-healing properties of waterborne coatings

含有密胺稻壳粉包覆虫胶微胶囊的水性漆涂层在受到机械损伤和老化影响后,对其表面产生的微裂纹有一定的自修复能力,但单一的壁材材料使得微胶囊破裂时所需应力阈值较小。为了延长水性漆涂层自修复性能的有效时间,将不同壁材配比的微胶囊进行混合,加入以椴木为基材的水性漆涂层中,探究其对涂层基本性能、自修复性能及耐老化性能的影响。本研究将微观形貌较好的3种密胺稻壳粉包覆虫胶微胶囊,区别是稻壳粉含量(质量分数)分别为2.8%,5.5%和8.0%,采用3种比例进行混合。以最佳的添加量(质量分数)6.0%和最佳涂覆工艺“底漆3遍、面漆2遍、微胶囊加在底漆中”制备涂层进行测试。结果表明,含有混合型微胶囊的漆膜在光学性能方面仍可以保持最佳状态。耐老化测试表明,添加“稻壳粉含量2.8%+稻壳粉含量5.5%+稻壳粉含量8.0%”混合型微胶囊的水性漆涂层具有更为长效的耐老化性能。划痕试验正面验证了混合微胶囊可以一定程度上延长修复时间、缩小裂纹尺寸及抑制裂纹扩大速度。对混合型微胶囊的比例进行探究,可以为涂层自修复效果的优化提供新的思路,也可以为木基自修复涂层的发展提供技术基础。

The waterborne coatings containing melamine/rice husk powder coated shellac microcapsules perform well on self-healing ability,which can repair the microcracks on its surface without artificial intervention after being damaged by mechanical forces,high temperature,and/or ultraviolet.However,the stress threshold which causes the microcapsules to rupture is limited because of its single cell wall structure.In order to prolong the effective time of self-healing performance of waterborne coatings,the microcapsules with different wall component ratios were mixed and added to the waterborne coatings based on basswood(Tilia cordata)to explore their effects on the basic properties,the self-healing performance,and the aging resistance of the coatings.In this study,three kinds of microcapsules with good micro morphology,which contain 2.8%,5.5%,and 8.0%of rice husk powder in wall materials were mixed according to three different proportions.The coatings were prepared and tested under the conditions of the best addition amount of 6.0%and the best coating process of“three coats of primer,two coats of finish,and microcapsules added in the primer”.The results showed that the film containing the mixed microcapsules can achieve excellent optical properties.The coating containing mixed microcapsules with“rice husk powder content of 2.8%+rice husk powder content of 5.5%+rice husk powder content of 8.0%”demonstrated the best optical properties among all samples.The aging resistance tests showed that the waterborne coating containing mixed types of microcapsules with“rice husk powder content of 2.8%+rice husk powder content of 5.5%+rice husk powder content of 8.0%”produced a marked effect on the aging resistance for longer durations.The scratch tests positively verified that the mixed microcapsules could prolong the repair time,reduce the crack size,and inhibit the crack growth rate.By studying the proportion of mixed microcapsules,it can provide not only new ideas for the optimization of self-healing effect,but also a technical basis for the development of self-healing coating on wooden surface.