【作者】 耿东兵；

【导师】 曾黎明；

【作者基本信息】 武汉理工大学 ， 材料学， 2007， 博士

【摘要】 热固性聚酰亚胺（PI）是一类性能优异的先进复合材料树脂基体,纤维增强聚酰亚胺复合材料由于在强度、模量、热稳定性、电性能等方面的突出优点,而逐渐成为航空航天领域不可替代的材料。随着航空航天技术的发展,飞行速度和机动、突防功能的不断提高,对这类材料提出了更多、更高的要求。为了满足航空航天领域高速飞行对高温结构轻量化、功能一体化的需求,本着将聚酰亚胺功能化和实用化的指导思想,本论文采用分子设计方法,提出了在分子结构中同时引入溴元素的和醚键结构的新思路,合成了新型溴化含醚结构的BMI型聚酰亚胺树脂体系（BPI）,并以其作为技术平台,开展了有关耐高温结构及透波复合材料的研究,主要的内容和结论如下:1、采用一步法合成了系列BPI树脂,并详细探讨了合成工艺对树脂合成的影响。利用红外、核磁、GC-MS、GPC等方法对BPI树脂体系进行了表征和分析,采用DMA和TGA手段评价了BPI树脂的热性能。结果表明,采用的合成工艺可以制得不同分子量、热性能优异的BPI树脂。2、采用流变、DSC等手段,利用Arrhenius、Kissinger等模型的分析方法,建立了BPI树脂固化反应动力学方程:da/dt=3.617×10⁷exp（-11202/T）（1-a）^0.913;获得了BPI树脂流变模型:η_t=5.05×10^-3exp[（4086.9/T）+exp（13.68-7904.96/T）t];确定了BPI树脂固化工艺:190℃/1h+240～260℃/1h+270～290℃/2h。3、研究了碳纤维/BPI结构复合材料的耐热性、力学性能以及热物理性能。结果表明:T-300/BPI复合材料经后处理后Tg高达425℃,并在室温下具有良好的基本力学性能,其短梁剪切与纵向弯曲的强度分别为103 MPa与1590 MPa;在300℃下,短梁剪切与纵向弯曲的强度保持率分别为53.7%与69.7%,同时,弯曲模量保持率更是高达95%,表明T300/BPI复合材料具有优良的耐高温力学性能,可在300℃下作为高温结构复合材料使用;4、研究了石英布/BPI透波复合材料（Qz/BPI）的耐热性、力学性能以及介电性能。Qz/BPI复合材料室温下具有良好的基本力学性能,压缩强度与弯曲强度在250℃下分别为221 MPa与401 MPa,保持率分别为67%与80%;而在300℃下,弯曲强度保持率更是高达66%,表明Qz/BPI复合材料具有优良的耐高温力学性能;Qz/BPI复合材料室温下具有良好的电绝缘性能和介电性能,其表面电阻率和体积电阻率分别在7.2～8.3×10¹⁴Ω和8.1～9.1×10¹⁵Ωcm之间;材料的介电常数ε为3.54～3.55,介电损耗Tanδ为8×10^-3;Qz/BPI-30在9.8GHz、室温～350℃下的介电常数基本保持稳定,介电损耗在300℃内基本保持不变,可望在300℃下作为高温透波复合材料使用;5、为了进一步改善BPI树脂的加工性能,通过分子设计,合成了一种适用于电子束固化（EB）成型工艺的新型聚酰亚胺树脂（EBBPI）,研究了活性稀释剂、辐敏交联剂、辐照剂量等对树脂热性能的影响,结果表明:EBBPI可实现电子束固化,固化树脂的Tg为243℃,具有一定使用价值。更多还原

【Abstract】 Thermosetting polyimide（PI）composites have been playing a very important role in aerospace and aviation industry due to their outstanding combination properties,such as excellent mechanical properties,thermal stabilities and electronic properties at elevated temperature.However,there is still a need to develop the integration ability that would meet the thermal lightweight and multifunction requirements.The main goal of this work was to develop thermal stability of PI composite that would contribute to reducing the overall weight of a vehicle by eliminating or reducing the thermal protection required to protect the internal structural elements of the vehicle.The molecule design method was used to introducing bromine and ether into structure to improve potential thermal-oxidation degradation,dielectric performance and processability in this paper.Main contents and conclusions of this dissertation are as follows:1、A serial novel PI resin（BPI）including of bromine and ether linkage were synthesized by using 1,3-benzenediol（DB）,N-（2,4,6-tribromophenyl）maleimide and N,N’-bismaleimido-4,4’-diphenylmethane（BDM）.The best conditions of synthesizing resins were found.Their resins were characterized by FTIR,NMR, GC-MS,GPC,DMA,TGA et al.The results indicated that BPI exhibit excellent thermal stability with the glass transition temperature（Tg）up to 327℃and less than 5 wt%weight loss at 400℃.2、Rheological behavior of BPI resin was systemic studied.A rheological model based on Dual-Arrhenius equation wasη_t=5.05×10^-3exp[（4086.9/T）+exp （13.68-7904.96/T）t],The ideal temperature of processing window for the BPI composite was about 160℃;The cure kinetics of BPI resin was analyzed by DSC, The activation energy E of the BPI system is 93.14 kJ/mol,and the order of reaction n and the dynamic equation of the BPI are 0.913 and dct/dt = 3.617×10⁷ exp（-11202/T）（1-α）^0.913,respectively;Finally,the curing cycle for the BPI system was ascertained to be 190℃/1h+240～260℃/1h+270～290℃/2h.3、The graphite-reinforced BPI composite laminates（C/BPI）were made by autoclave techniques with the optimal cure processes and its properties were tested. The laminates of C/BPI exhibited high storage modulus and glass transition temperature（Tg）up to 425℃.The mechanical properties of C/BPI composite exhibit outstanding mechanical properties at room temperature and elevated temperature as high as 300℃.Compared with the room temperature,the retained rate of bending strength,bending modulus and shear strength were about 69.7%,95%and 53.7%.4、The quartz-reinforced composite laminates（Qz/BPI）were also made by autoclave techniques with the optimal cure processes,and its properties were tested subsequently.The laminates of Qz/BPI exhibited high storage modulus and glass transition temperature up to 330℃.The mechanical properties of Qz/BPI composite exhibit outstanding mechanical properties at room temperature and elevated temperature as high as 300℃.Compared with the room temperature,the retained rate of bending strength were about 66%.Qz/BPI composite also had excellent dielectric performance.The dielectric constant（ε）and loss tangent（Tanδ）were 3.54～3.55 and 8～9×10^-3at room temperature in the frequency of lKHz～20GHz,No significant changes were observe at elevated temperature up to 350℃.It was revealed that the Qz/BPI composite might be the candidate for broadband wavelength application.5、The molecule design method was used to synthesize the electron beam curing PI resin（EBBPI）by using BPI,trimethylolpropane trimethacrylate（TMPTMA）and N-Vinyl-2-pyrrolidone（NVP）.Their resins were characterized by FTIR,DMA,et al. Experimental results indicate that EBBPI systems could be cured by EB with a Tg of 243℃.Furthermore,the curing reaction mechanism of the EBBPI system was discussed.更多还原