热氧老化对碳纤维双马树脂基复合材料性能的影响

采用三点弯曲测试方法,研究热氧老化对碳纤维双马树脂基复合材料弯曲性能的影响,分析复合材料的失重行为以及不同老化时间下的弯曲性能、断口形貌、动态力学性能和红外谱图。结果表明:随着老化时间的增加,老化温度为100℃时的质量损失率逐渐趋于平稳,180℃时的质量损失率逐渐增加。老化温度为100℃时,只是物理老化,没有新物质的生成;而老化温度为180℃时,发生了化学老化,产生了热老化效应和氧化反应,引起了基体性能和界面性能的退化。热氧老化对复合材料弯曲强度的影响要大于对弯曲模量的影响。     

KH-SiO2/PES/BMI-F51复合材料的介电性能

采用3-缩水甘油醚氧基丙基三甲氧基硅烷(KH-560)修饰纳米二氧化硅(nano-SiO2)获得改性纳米二氧化硅(KH-SiO2)。以酚醛环氧树脂(F51)和双马来酰亚胺(BMI)作为基体,添加4%(质量分数,下同)聚醚砜(PES)和不同含量(0.5%~2.5%)的KH-SiO2,制备KH-SiO2/PES/BMI-F51多相复合材料。红外光谱(FT-IR)、扫描电镜(SEM)和透射电镜结果表明:纳米SiO2表面修饰效果良好,纳米粒子团聚倾向减弱,粒径减小,比表面积增大。介电性能测试结果表明:随着KH-SiO2掺杂量的增加,材料的介电常数先降低后升高,介电损耗没有明显变化,体积电阻率和击穿强度先升高后降低。当KH-SiO2掺杂量为1.5%时,10Hz下介电常数和介电损耗角正切分别为4.55和0.0029,体积电阻率和击穿强度分别为1.74×10^14Ω·m和29.11kV/mm,比树脂基体提高了68.9%和35.9%。     

具有双峰反应特性的高韧性双马来酰亚胺树脂固化动力学和TTT图

以全动态DSC扫描实验为基础,结合半经验的唯象模型获得了基于唯象模型的具有双峰反应特性的高韧性双马来酰亚胺5429树脂的固化动力学参数,建立相应的唯象动力学模型。以5429树脂在180℃条件下,恒温不同时间的DSC实验数据为基础,利用DiBenedetto方程研究等温条件下固化度与加热时间的关系并得到玻璃化转变温度与固化时间的关系表达式,并采用凝胶盘法得到5429树脂不同温度下的凝胶时间,建立了凝胶时的固化度和玻璃化转变温度之间的函数关系,在此基础上绘制了TTT图,从TTT图中得到的5429树脂的最优固化工艺曲线与其标准固化工艺曲线一致。     

聚醚醚酮和烯丙基化合物改性双马来酰亚胺复合材料微观结构及力学性能

采用浓H₂SO₄氧化聚醚醚酮（PEEK）得到磺化聚醚醚酮（SPEEK）,以3,3'-二烯丙基双酚A （BBA）、双酚A双烯丙基醚（BBE）为活性稀释剂、SPEEK为改性剂、双马来酰亚胺（BMI）树脂为基体,浇注成型制备SPEEK/BBA-BBE-BMI复合材料,同时研究了SPEEK的改性效果及复合材料微观形貌与力学性能。结果表明：SPEEK改性效果较好,在FTIR中存在明显的磺酸基团特征峰,SEM和能谱分析表明,SPEEK微观形貌变化明显,硫元素含量较高;SPEEK/BBA-BBE-BMI复合材料的微观形貌显示,SPEEK在基体中呈现直径为2 μm左右的多孔状两相结构,且分散均匀,此多孔结构改善了复合材料的断裂形貌,由脆性断裂转变为韧性断裂,当断裂纹遇到SPEEK组分时受阻而出现不规则发散,此变化会赋予复合材料更加优异的性能。力学性能测试结果显示,当SPEEK含量为5wt%时,SPEEK/BBA-BBE-BMI复合材料的弯曲强度和冲击强度达到最佳,分别为147.93 MPa和15.74 kJ/mm²,分别比基体提高了49.47%和66.21%。     

含硼烯丙基树脂改性BMI树脂

采用 同主链结构的含硼烯丙基树脂改性双马来酰亚胺（ＢＭＩ）树脂，并对其预聚工艺、反应性、固化树脂力学性能、耐烧蚀性能及玻璃布层压性能进行了研究。     

双马来酰亚胺树脂改性研究进展

对双马来酰亚胺树脂(BMI)增韧改性方法,包括橡胶、芳香聚酯、热塑性树脂共混法,氰酸酯共固法,二胺加成扩链法、烯丙基化合物共聚法、长链型BMI合成法等,对BMI的工艺性及自熄阻燃性等方面的改进研究进展加以综述,并对其它改性方法进行了介绍。     

耐热200℃双马改性环氧结构胶膜的研究

研制了一种双马改性环氧结构胶膜,探讨了主要组份对胶粘剂胶接性能的影响,考核了胶粘剂的耐热、耐老化等综合性能。该胶不但对金属之间具有良好的粘接强度,而且对双马树脂基复合材料具有良好的粘接性能。用扫描电镜(SEM)观测固化产物断裂面的微观形态为均相增韧结构;通过示差扫描量热法(DSC)测定该胶的热变形温度为211℃,用热重分析法(TG)测定该胶固化物明显热失重温度为378℃。热力学分析试验表明该胶可以在200℃下长期工作,提高了国内环氧类型膜状胶粘剂的耐温等级。     

Bismaleimide modified bis propargyl ether bisphenol A resin: Synthesis,cure, and thermal properties

Bis propargyl ether bisphenol A (PBPA) was synthesized and blended with 4,4′‐bismaleimide diphenyl methane (BDM) at different molar ratios. The cure behavior of the blend resins was measured by DSC and FTIR spectra. The results indicated that the onset cure temperatures of the blend resins were about 20–30°C lower than that of pure PBPA, and the cure exothermic enthalpy of the resins also significantly reduced from 1320 (PBPA) to 493 J/g (PBPA–BDM (1.0:2.0)). The thermal stabilities and dynamic mechanical properties of the cured resins were characterized by TGA and DMA, respectively. The thermal stability of the resins improved markedly with the increase in BDM content, and the glass transition temperature increased from 306°C for PBPA–BDM (1.0:0.5) to 358°C for PBPA–BDM (1.0:2.0). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3610–3615, 2006     

Study on properties of low dielectric loss resin matrix

Allyl phenyl compounds, allyl epoxy resins, and epoxy acrylate resins are adapted to copolymerize with bismaleimide (BMI) resins and to modify mechanical properties and processing properties. Reaction activity, physical properties, mechanical properties, dielectric properties, and thermal stability were investigated. Impact strength and flexural strength of modified BMI resin are increased about twice and 42% than that of pure BMI resin, respectively. Fracture elongation is from 1.6 to 2.3%. The fracture surfaces of the broken specimens are examined by scanning electron microscopy (SEM). As a result, modified BMI resins put up typical toughness rupture. The modified BMI resins possess excellent dielectric properties, and dielectric constant and dielectric loss almost hold the line with increasing epoxy concentration. When the test frequency scope is from 1 to 20 GHz, the dielectric constant and dielectric loss of modified BMI resins is 3.05–3.12 and 0.0089–0.012, respectively. The modified BMI resins still possess fine properties after hydrothermal aging. After 100 h in boiling water, the reservation ratios of both the impact strength and flexural strength of modified system exceeded 90%, and the water absorption and heat distortion temperature (HDT) is 2.6% and 235°C, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 315–319, 2006     

Copolymers derived from bismaleimide oligomer with active solvent

An oligomer from 4, 4′‐bis(maleimido)diphenyl methane and methylenedianiline were dissolved in active solvent N,N‐dimethyl acrylamide in a solid content up to 50–70%; the solution was poured in a sheet‐shaped module and irradiated by ⁶⁰Co with the dose from 20 to 350 kGy at room temperature. The polymerized sheet was postcured at 180°C to obtain a transparent red‐orange sheet with tensile strength above 100 MPa. The glass transition temperature before and after postcuring was around 100°C and 150–180°C, respectively. Styrene was used along with DMAA to decrease the water absorption for the copolymers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2879–2882, 2004