液氧环境用改性氰酸酯树脂体系的制备与性能研究

发布时间：2018-03-18 06:43

本文选题：氰酸酯树脂　切入点：增韧改性　出处：《哈尔滨工业大学》2017年博士论文　论文类型：学位论文

【摘要】：为了满足于新一代可重复使用航天器(RLV)推进系统燃料贮箱(液氧)的减重设计要求,液氧贮箱用材料逐步采用树脂基碳纤维复合材料(CFRP)取代原有的金属材料,而CFRP中树脂基体与液氧相容性是CFRP能否应用在液氧环境中的关键因素,要求树脂基体具有良好的低温力学强度,热稳定性、优阻燃性和优异的液氧相容性。现今通用的环氧树脂因其结构缺陷,液氧相容性较差,无法满足液氧环境使用要求。近年来出现的双酚A型氰酸酯树脂(CE)由于固化物具有独特的三嗪结构,因而具有优异的耐温性、较好的抗氧化性,并且其工艺性优异,具备用于制备CFRP液氧贮箱材料的潜质,但是其低温韧性差、阻燃性不足,需要改性应用。目前关于改性后的氰酸酯树脂在低温液氧环境下应用的研究工作尚未深入开展。针对上述问题,本文采用了氰酸酯树脂为主体,通过引入不同改性组分的方式,制备了两种改性氰酸酯树脂体系及其CFRP,研究了其树脂结构组成与力学性能、液氧相容性、阻燃性等性能的关系,并分析CFRP界面失效机理。本文采用低粘度环氧树脂(EP)和高性能耐温塑料(PES-C)共增韧改性双酚A型氰酸酯树脂(CE),合成了改性CYEP氰酸酯树脂。研究结果表明,EP和PES-C能促进CE自聚反应,提高CE树脂的低温(-196℃)韧性,但是对CE树脂的热稳定性有一定影响。18wt%的EP和6wt%的PES-C共混合加入到CE中制备得到的CYEP matrix(CYEP6)兼具良好的低温韧性、工艺性、耐热性和粘接稳定性等综合性能。-196℃下,CYEP matrix的冲击韧性比纯CE树脂提高了近200%,而模量下降仅为约6%,其经过15次冷热循环交变(-196℃~50℃)后表面无裂纹。CYEP matrix经177℃/4h+200℃/2h固化后,单体转化率95%,80℃树脂黏度仅为734 cp,并维持4h工艺黏度无明显变化。CYEP matrix粘接双马树脂基CFRP剪切试样,在空气中经200℃/1000h老化后,剪切强度保持率大于80%,然而CYEP matrix阻燃测试为V1级,需进一步改进阻燃性。本文自制了含苯醚键双马树脂(BMPB)和耐高温活性稀释剂(DABDGE)加入到CYEP matrix树脂,制备了具有阻燃性的改性氰酸酯树脂(CEBM)。实验结果表明,BMPB中加入5wt%的DABDGE后,体系的黏度明显降低,而IDT温度下降不足10%。7wt%的BMPB改性CYEP matrix,得到了阻燃性提和低温韧性均较优异的CEBM7(CEBM matrix)基体,但过多的BMPB加入体系的冲击韧性和工艺黏性变差。在-196℃下,CEBM matrix冲击韧性CYEP matrix树脂的提高了20%,30次冷热循环后冲击强度保持率大于85%。CEBM matrix的阻燃性达到V0级别,具有自熄性,其工艺黏性和贮存稳定性与CYEP matrix树脂相当。本文对合成的CYEP树脂和CEBM树脂的(液)氧相容性及失效机理进行分析。研究结果表明,BMPB的含量和环氧基团的含量是影响基体树脂与液氧相容性的关键因素,尤其是BMPB与CE共聚形成的氮双杂环结构对基体的(液)氧相容性提升有明显效果。BMPB的含量超过5wt%时,其氧增重的起始温度提高近40℃,IRS值下降到4%以下,相反,当环氧树脂含量超过15wt%,其IRS值急速增加;不同的基体树脂中,分散相粒子的微观形貌和氧增重量不受热氧老化过程影响,但是在液氧冲击过程中,相界面明显展示出氧不相容。CEBM matrix液氧连续浸泡30天后,基体力学强度保持率80%。采用动态接触角测试和微滴脱粘法测试等方法对不同基体与碳纤维界面性能进行了评价。结果表明,基体树脂的低黏度和增大极性在有利于提高其与碳纤维浸润性。提高基体自身强度、增加纤维表面粗糙程度和浸润性,能提高基体与纤维的界面剪切强度(IFSS)和断裂韧性Gdc。在Tg±50℃成形温度范围内,成形温度温度每升高10℃,IFSS值提高约3%。基体树脂中DABDGE稀释剂的加入有利于基体和纤维的界面过渡层的形成,分散应力并阻止裂纹扩展,其中CEBM基体与纤维表面形成约200nm的界面过渡层。考察了两种基体碳纤维复合材料的宏观力学性能和液氧相容性。研究结果表明,CEBM matrix基复材具有优异的低温力学强度,层间剪切强度(ILSS)为102.5MPa(-196℃),轴向拉伸强度可达2602MPa(-196℃)。树脂中增韧材料的过多加入对复合材料的整体性能提高不明显。CEBM matrix基层合板试样经过40次冷热循环后,复材表面无明显的微裂纹产生。复合材料试样表面缺陷是影响其液氧浸泡失效的关键因素,其浸泡后的IRS值比无缺陷试样的IRS值大5倍。
[Abstract]:In order to satisfy the new generation of reusable spacecraft propulsion system (RLV) fuel tank (LOX) designed to lose weight, liquid oxygen tank material gradually using resin based carbon fiber composite (CFRP) to replace the original metal materials, and CFRP resin matrix and the LOX compatibility is the key factor of whether the application of CFRP in the oxygen environment, requirements of resin matrix with low temperature strength, good thermal stability, excellent flame retardancy and excellent compatibility. The general liquid epoxy resin because of its structural defects, oxygen poor compatibility, can not meet the environmental requirements of LOX. Bisphenol A cyanate ester resin (CE) emerged in recent years. The cured product has three triazine unique structure, which has excellent heat resistance, good oxidation resistance, and its technology is excellent, have used for the preparation of CFRP liquid oxygen tank material potential, but its toughness in low temperature Flame retardant, lack of need modification application. Current research on the modification of cyanate ester resin was used in cryogenic liquid oxygen environment has not been carried out. Aiming at the above problems, this paper adopts the cyanate ester resin as the main body, through the introduction of different modified components, preparation of two kinds of modified cyanate ester the resin system and CFRP, to study the structure of resin composition and mechanical properties, oxygen compatibility, flame retardant properties of the relationship, and analyze the failure mechanism of CFRP interface. This paper adopts low viscosity epoxy resin (EP) and the performance of high temperature resistant plastic (PES-C) Co toughening modification of bisphenol A cyanate ester resin (CE) CYEP, modified cyanate ester resin was synthesized. The results showed that EP and PES-C can promote the self polymerization of CE, improve the CE resin at low temperature (-196 DEG C) toughness, but the thermal stability of CE resin has certain influence on.18wt% EP and 6wt% PES-C were mixed into CE The prepared CYEP matrix (CYEP6) with low temperature toughness, good processability, comprehensive performance of heat resistance and adhesive stability of.-196 DEG C, the impact toughness of CYEP matrix was nearly 200% higher than that of pure CE resin, and the modulus decreased only about 6%, after the 15 thermal cycles (alternating -196 ~50 DEG C) after the surface crack of.CYEP matrix by 177 DEG /4h+200 DEG /2h after curing, the monomer conversion rate of 95%, 80 C resin viscosity is 734 CP, and the maintenance of 4H process viscosity did not change significantly in.CYEP based CFRP matrix bismaleimide resin adhesive shear specimens, aging in the air by 200 DEG /1000h, the shear strength retention rate is greater than 80%, while the CYEP matrix flame test for V1 class, need to be further improved. This paper made a flame retardant containing benzene ether bismaleimide resin (BMPB) and high temperature reactive diluent (DABDGE) into CYEP matrix resin, preparation of cyanate ester resin modified with flame retardancy (CEBM ). The experimental results show that adding 5wt% DABDGE in BMPB, the viscosity of the system decreased significantly, while the IDT temperature drops less than 10%.7wt% BMPB CYEP matrix has been modified, flame retardant and low temperature toughness were provided excellent CEBM7 (CEBM matrix) matrix, but too much BMPB into the system of impact toughness and the process of viscous variation. At -196 DEG C, CEBM matrix CYEP matrix resin impact toughness increased by 20% after 30 thermal cycles, the impact strength retention rate is greater than the 85%.CEBM matrix flame retardant reached V0 level, self extinguishing, its viscosity and storage stability of a process with CYEP matrix resin. The synthesis of CYEP resin and CEBM resin (liquid) oxygen compatibility and failure mechanism were analyzed. The results show that the content of BMPB and epoxy groups is the effect of matrix resin and liquid oxygen compatible key factors, especially BMPB and CE copolymer formed by nitrogen Double heterocyclic structure on the matrix (liquid) oxygen compatibility enhancing effect of.BMPB content was more than 5wt%, the increase of the initial temperature oxygen increase the weight of nearly 40 degrees, the IRS value dropped to below 4%, on the contrary, when the content of epoxy resin is more than 15wt%, the IRS value increased rapidly; the matrix resin in different. The morphology of dispersed phase particles and oxygen increasing weight is not the process of aging effect, but in the liquid oxygen in the process of impact, showing obvious phase interface is not compatible with.CEBM matrix oxygen oxygen continuously for 30 days, the mechanical strength retention rate of 80%. by dynamic contact angle test and micro droplet debonding method testing method for different matrix and the interface properties of carbon fiber were evaluated. The results show that the low viscosity resin and increase in polarity can improve the wettability of carbon fiber and matrix. To improve its strength and increase the fiber surface roughness and wettability, can raise the The interfacial shear strength and fiber (IFSS) and fracture toughness of Gdc. in Tg + - 50 DEG forming temperature range, forming temperature increasing the temperature of 10 DEG C, the IFSS value increased to form about 3%. matrix resin DABDGE diluent adding interfacial transition layer to matrix and fiber, disperse stress and prevent crack propagation. The interface transition layer about 200nm is formed on the surface of CEBM matrix and fiber. The effects of two kinds of macro mechanical properties and oxygen matrix carbon fiber composite material compatibility. The results show that the CEBM matrix composite material with low temperature and excellent mechanical strength, interlaminar shear strength (ILSS) to 102.5MPa (-196 C), axial tension the strength can reach 2602MPa (-196 C). Too much to join the whole performance of the composite material increased.CEBM matrix laminates subjected to 40 thermal cycles after toughening material, resin, composite surface without producing obvious micro cracks The surface defect of the composite specimen is the key factor affecting the liquid oxygen immersion failure. The IRS value after immersion is 5 times larger than the IRS value of the non defect sample.

【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TQ320.1

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