POSS改性EPDM耐烧蚀复合材料的制备及性能  

Preparation and properties of POSS modified EPDM ablative composites

作　　者：刘昊东 聂晶 朱光明[1] 侯晓 LIU Haodong;NIE Jing;ZHU Guangming;HOU Xiao(Department of Applied Chemistry,Northwestern Polytechnical University,Xi’an 710129,China;Academy of Aerospace Solid Propulsion Technology,Xi’an 710025,China)

机构地区：[1]西北工业大学理学院应用化学系,西安710129 [2]中国航天科技集团有限公司第四研究院,西安710025

出　　处：《固体火箭技术》2019年第6期717-723,共7页Journal of Solid Rocket Technology

摘　　要：由于高性能推进剂的广泛应用,导致固体火箭发动机燃烧室内的燃烧温度与工作压强不断升高,因此研制出性能更加优异的隔热层迫在眉睫。以三元乙丙橡胶(EPDM)为基体,气相纳米SiO2为补强填料,首次引入八甲基丙烯酰氧基丙基POSS(MA-POSS),经由过氧化物引发双键之间的自由基聚合反应,制备了POSS改性EPDM耐烧蚀复合材料。研究了MA-POSS与气相纳米SiO2的添加量对隔热材料的交联度、力学性能、热稳定性、耐烧蚀性能的影响。在POSS与气相纳米SiO2协同作用下,改性后的材料各项性能均有所提升。结果表明,当气相纳米SiO2含量为40份、MA-POSS为5份时,凝胶含量高达92.61%,拉伸强度为12.02 MPa;MA-POSS含量为3份时,复合材料的线性烧蚀率和质量烧蚀率最低,分别为0.296 mm/s和0.100 g/s。The high demands of nanocomposite rocket ablative materials for thermal protection system in space vehicles applications has resulted in extensive developments in cost-effective heat-shielding materials.Wide applications of high-performance propellants leads to rising temperature and working pressure in solid rocket motor combustion chambers,which have paved the way for the enhancement of ablative heat-shielding materials.Here the properties of heat-shielding nanocomposites,based on ethylene propylene diene monomer(EPDM)copolymer additionally modified with fumed nano-silica and functional octa-methacryloyloxypropyl polyhedral oligomeric silsesquioxane(MA-POSS),were examined.Cross-linking percentages with respect to gel contents have been achieved with a certain method of refluxing toluene in a soxhlet extractor.The mechanical properties were characterized by tensile strengths and elongations at break.Thermal stability was demonstrated from TG analysis in the temperature range up to 800℃from room temperature.The ablation characteristics in terms of liner ablation rates and mass ablation rates were investigated by using an oxyacetylene flame torch equipment in accordance with national standard GJB323A-96,which simulates the conditions of solid rocket motor combustion chambers.The surface topographies of ablated samples were observed by means of SEM.The results shows that maximum gel content of 92.61%and tensile strength of 12.02 MPa are achieved for EPDM with 40 phr of SiO2 and 5 phr of MA-POSS.The lowest linear and mass ablation rates are as low as 0.296 mm/s and 0.100 g/s respectively by using 3 phr of POSS.

关 键 词：隔热材料 三元乙丙橡胶 笼形倍半硅氧烷 耐烧蚀性 热稳定性 

分 类 号：V250.4[一般工业技术—材料科学与工程]