聚氨酯-有机硅杂化耐烧蚀隔热涂料的制备及其性能研究

Preparation and Performance Study of Polyurethane Organosilicon Hybrid Ablative and Thermal Insulation Coatings

为研制高速飞行器外壳体用轻量化耐烧蚀隔热涂料,以苯基三乙氧基硅烷、甲基三乙氧基硅烷、硅溶胶、自制多支化聚氨酯预聚物为主要原料,采用溶胶-凝胶法制备了聚氨酯-有机硅杂化树脂,并复配改性陶瓷微珠、云母粉、滑石粉和助剂制备耐烧蚀隔热涂料。测试了聚氨酯-有机硅杂化树脂的相对分子质量分布和羟值,用热重分析仪和扫描电镜表征了聚氨酯-有机硅杂化树脂的结构;研究了多支化聚氨酯预聚物用量、颜基比、改性陶瓷微珠用量、固化工艺对涂层性能的影响。结果表明:多支化聚氨酯预聚物占甲组分质量30%时,聚氨酯-有机硅杂化树脂综合性能最优;颜基比为0.6、改性陶瓷微珠用量占颜填料质量15%时,涂层的拉伸强度为5.0 MPa,断裂伸长率为41%,密度为0.71 g/cm^(3),导热系数为0.15 W/(m·K),涂层具有良好的隔热性能及耐烧蚀性能,同时可室温和高温固化,具有广泛的适用性。

In order to develop lightweight ablative and thermal insulation coatings for the outer shell of high-speed aircraft,polyurethane organic silicon hybrid resin was prepared by the sol-gel method using phenyltriethoxysilane,methyltriethoxysilane,silica sol and self-made polybranched polyurethane prepolymer as main raw materials,and the ablative and thermal insulation coatings was prepared by compounding modified ceramic beads,mica powder,talc powder and additives.The relative molecular weight distribution and hydroxyl value of silicone hybrid resin were tested,and the structure of the polyurethane silicone hybrid resin was characterized by thermogravimetric analysis and scanning electron microscopy;the effects of dosage of multi branched polyurethane prepolymer,pigment/binder ratio,dosage of modified ceramic microbeads and curing process on the coating performance were studied.The results showed that the comprehensive performance of polyurethane organic silicon hybrid resin was optimal when multi branched polyurethane prepolymer accounted for 30%of the mass of resin component alpha;when pigment/binder ratio was 0.6 and the amount of modified ceramic microbeads accounts for 15%of color filler mass,the tensile strength of the coating was 5 MPa,the elongation at break was 41%,the density was 0.71 g/cm^(3),the thermal conductivity was 0.15 W(/m·K),and the coating had good thermal insulation and ablative resistance;at the same time,the coating could meet the requirements of room temperature and high temperature curing with a wide range of applicability.