通过硅烷偶联剂3-氨丙基三乙氧基硅烷(KH550)改性聚氨酯(PU)/Al-Sm2O3复合涂层,从功能特性和力学性能角度系统研究了改性前后涂层自然老化性能的变化规律. 结果表明,改性后PU/Al-Sm2O3复合涂层的红外发射率对自然老化的稳定性得到明显增强,在同等条件下改性后的涂层发射率要明显低于未改性的涂层发射率. 改性后涂层表面的Sm2O3颗粒分散更加均匀,对近红外光的吸收强度有所增强,从而使改性后涂层对1.06 μm近红外光的反射率要明显低于未改性涂层. 改性前后涂层的硬度对自然老化具有良好的稳定性,其硬度可保持在3 H;未改性涂层的附着力和耐冲击强度受自然老化影响明显,但改性后涂层的附着力和耐冲击强度得到明显加强,经自然老化4个月后仍然可保持在1级和50 kg·cm.
Polyurethane(PU)/Al-Sm2O3 composite coatings were modified by silane coupling agent 3-aminopropyltriethoxysilane(KH550).The variation of natural aging property before and after modification was systematically investigated from the perspectives of functional properties and mechanical properties.The results indicate that the stability of infrared emissivity of PU/Al-Sm2O3 composite coatings for natural aging is significantly enhanced after KH550 modification.The infrared emission of modified coatings is significantly lower than that of unmodified coatings under the same conditions.The dispersion of Sm2O3 particles on the coatings′ surface is more uniform after modified by KH550.The near-infrared light absorption intensity has increased, and this leads to a 1.06 μm near-infrared reflectivity of modified coatings, which is significantly lower than that of unmodified coatings.The coatings′ hardness has good stability for natural aging before and after modification.The hardness can maintain for 3 H.The adhesion strength and impact strength of the unmodified coatings are significantly affected by natural aging, but it can be significantly strengthened after KH550 modification to maintained at 1 grade and 50 kg·cm after natural aging for 4 months, respectively.