多壁碳纳米管改性氰酸酯树脂体系的研究

针对环氧树脂(DGEBA)／双酚A型氰酸酯树脂(BADCy)体系,采用多壁碳纳米管(MWNTs)对其增韧改性,制备了MWNTs/ DGEBA／BADCy复合材料。利用透射电子显微镜(TEM)观察MWNTs在树脂中的分散情况,研究了MWNTs的用量对复合材料性能的影响,借助凝胶时间和扫描电子显微镜(SEM)对碳纳米管增强氰酸酯树脂的机理进行初步的探讨。研究表明:当碳纳米管的质量分数为1％时,复合材料的力学性能达到最佳,弯曲强度和冲击强度分别提高约15％和8％。     

双马来酰亚胺改性氰酸酯树脂及其复合材料

制备了一种新型的双马来酰亚胺改性氰酸酯树脂以提高这类树脂的耐热性,力学性能及成型工艺性。对合成的树脂作了流变分析,对其玻纤复合材料进行了力学性能测试和热失重分析,结果表明,当双马树脂达到改性氰酸酯树脂的质量分数的37.5%时,新型改性氰酸酯树脂的5%热失重温度为432℃。改性氰酸酯基复合材料在常温条件下的拉伸强度为492.4 MPa,弯曲强度为526.3 MPa。在200℃时改性氰酸酯基复合材料的拉伸强度为357.3 MPa,弯曲强度为292.7 MPa。该树脂具有良好的加工性,耐热性,力学性能及高温力学保持性。     

双马来酰亚胺改性氰酸酯树脂及其复合材料

制备了一种新型的双马来酰亚胺改性氰酸酯树脂以提高这类树脂的耐热性,力学性能及成型工艺性。通过流变分析和热失重分析对合成的树脂进行了研究,对其玻纤复合材料力学性能进行了测试。结果表明,当双马树脂达到改性氰酸酯树脂的质量分数的37.5%时,树脂的5%热失重温度为415℃,复合材料常温下的拉伸强度为438.8MPa,弯曲强度为657.3MPa,断裂伸长率为9.2%;200℃下的数据分别为310.5MPa,307.4MPa,12.5%。该树脂具有良好的加工性,优异的耐热性和力学性能。     

新型双马来酰亚胺改性氰酸酯树脂及其复合材料

采用双马来酰亚胺封端的硫醚酰亚胺低聚物对氰酸酯树脂进行了改性(SBMI),通过红外光谱对改性树脂(SBT)的结构作了表征,通过流变分析,热失重分析研究了其粘度特性及耐热性,并对其玻纤复合材料的力学性能进行了测试。结果表明,当SBMI质量分数为氰酸酯树脂的的37.5%时,SBT树脂的5%热失重温度为415℃,其复合材料在常温下的拉伸强度为438.8 MPa,弯曲强度为657.3 MPa,断裂伸长率为9.2%;200℃时拉伸强度为310.5 MPa,弯曲强度为307.4 MPa,断裂伸长率为12.5%。该树脂具有良好的加工性,耐热性和力学性能。     

改性氰酸酯基复合材料力学和透波性能研究

利用低介电改性剂对氰酸酯树脂进行改性,制备了石英纤维/改性氰酸酯树脂复合材料,利用SEM表征了树脂及其复合材料的断面,并对改性氰酸酯树脂的耐热性能、力学性能、复合材料的力学性能及透波性能进行了研究。结果表明,改性氰酸酯树脂的玻璃化转变温度达到200℃以上,树脂拉伸破坏表现为韧性断裂,拉伸强度、弯曲强度和压缩强度分别在27MPa、69MPa和148MPa以上;改性氰酸酯树脂和纤维的界面结合良好,复合材料的拉伸强度、弯曲强度和压缩强度分别达到447MPa、461MPa和259MPa以上;在0.5~18GHz范围内,介电常数为3.1~3.3,4mm试样的S21小于-1.6d B。     

液体端羧基丁腈橡胶改性氰酸酯／玻璃纤维复合材料的性能研究

用液体端羧基丁腈橡胶(CTBN)对氰酸酯树脂(CE)进行了增韧改性,通过树脂体系的凝胶时间曲线和DSC曲线确定了体系的固化工艺,并制备了玻璃纤维(GF)增强复合材料。CTBN改性后的CE树脂及复合材料具有良好的力学性能,其中固化树脂的弯曲强度和冲击强度分别提高了34.6%和48%,复合材料的弯曲强度和冲击强度分别提高了11.4%和21.3%,这来源于CTBN对氰酸酯树脂的增韧作用及与GF良好的粘接性能。     

纤维缠绕CEm基复合材料力学性能研究

为使氰酸酯(Cyanate ester,CE)树脂适合纤维缠绕工艺,对氰酸酯树脂进行了改性.改性的目的是在不降低纯氰酸酯基复合材料耐热性能的前提下,使氰酸酯树脂适合纤维缠绕.用TG/DTA研究了氰酸酯树脂改性前(略为CE)及其改性后(略为CEm)的复合材料热分解温度;用复合材料单向板研究了CErm基复合材料的力学性能,并与目前应用量大面广的环氧基复合材料的力学性能进行了比较.研究结果表明:改性后的氰酸酯基复合材料不仅可以充分发挥CE基复合材料具有的耐高温优势,而且能充分发挥复合材料0°方向的力学性能.     

pCBT/MWNTs/CFF复合材料的制备及力学性能研究

以环状对苯二甲酸丁二醇酯(CBT)为原料,采用双螺杆挤出机反应挤出与热压复合法制备了碳纳米管/聚环状对苯二甲酸丁二醇酯/碳纤维织物(MWNTs/pCBT/CFF)复合材料,研究了酸化处理前后MWNTs的加入对CBT开环聚合的影响,以及MWNTs对pCBT基体及pCBT/CFF复合材料力学性能的影响。结果表明:MWNTs的加入降低了CBT的聚合速率,增大了pCBT树脂的低黏度加工窗口;酸化处理后的MWNTs对pCBT基体具有更加明显的增强增韧效果,并有助于改善pCBT基体与CFF的界面结合力,显著提高了pCBT/CFF复合材料的力学性能;加入酸化处理后的MWNTs质量分数1%,得到的MWNTs/pCBT/CFF复合材料的层间剪切强度和弯曲强度分别较pCBT/CFF复合材料提高了17.7%和32.7%。     

二乙烯三胺改性碳纳米管对环氧树脂纳米复合材料力学性能影响研究

采用二乙烯三胺(DETA)对碳纳米管(MWNTs)进行改性,并用X射线衍射(XRD)和傅里叶变换红外光谱(FTIR)对其进行表征。发现DETA被有效地包覆在MWNTs表面。并将改性前后的MWNTs与环氧树脂进行复合,采用浇铸成型法制备了MWNTs/环氧树脂纳米复合材料,测试其力学性能,并采用透射电镜(TEM)研究其分散性,扫描电镜(SEM)对其断口进行了分析研究。结果表明,少量的改性MWNTs可以使复合材料的力学性能提高,具有明显的增韧作用。当MWNTs的含量为0.6%时,纳米复合材料的冲击强度与纯环氧体系相比,提高幅度达400%以上,弯曲强度和弯曲模量的提高幅度均达到了100%以上。     

一种改性氰酸酯树脂性能的研究

采用自制改性剂改性双酚A型氰酸酯树脂,制备了一种适合常规180℃固化工艺的改性氰酸酯树脂,可用于热熔法制备预浸料。对改性氰酸酯树脂的工艺性、力学性能、耐热性能和微观形貌等进行了研究,结果表明制备的树脂具有良好的工艺性,无需进行高温后固化处理即可得到力学性能和耐热性能较为优异的固化物,可广泛用于航空、航天、电子等领域高性能复合材料的制备。     

纳米SiO2对聚苯醚树脂/氰酸酯复合材料性能的影响

以聚苯醚树脂(PPO)改性BCE(双酚A型氰酸酯)作为复合材料的基体树脂,以硅烷偶联剂(KH-560)处理过的纳米二氧化硅(nano-SiO2)作为改性剂,制备出nano-SiO2/PPO/BCE复合材料.结果表明:适量的nano-SiO2既可同时提高PPO/BCE体系的韧性和强度,又可改善其介电性能和吸湿性能;当w(...     

CE/EP/CF复合材料的湿热性能研究

采用溶液预浸渍法分别制备了两种碳纤维(CF)增强环氧树脂(EP)改性氰酸酯树脂(CE)(CE/EP/CF)复合材料,研究了该复合材料的吸湿行为及湿热环境对其力学性能和微观结构的影响。结果表明,CE/EP基体具有比EP更小的吸湿能力;湿热环境对CE/EP/CF复合材料的纵向拉伸强度影响不大,但对其层间剪切强度的影响较为显著。     

甲基笼型倍半硅氧烷/CE杂化复合材料的力学性能

以甲基笼型倍半硅氧烷(POSS)作为氰酸酯树脂(CE)的改性剂,制备出一种POSS/CE杂化复合材料。研究了杂化复合材料中POSS用量对CE结构及力学性能的影响,同时采用红外光谱(FT-IR)法对不同POSS/CE体系的反应性进行了研究。结果表明:POSS的加入对CE的反应性影响不大,有利于POSS/CE杂化体系固化工艺的制定;当杂化体系中w(POSS)=5%时,材料的冲击强度(9.7 kJ/m2)相对最大(提高了49%),弯曲强度(90 MPa)也相对较高,说明适量的POSS对CE具有明显的增韧、增强作用。     

BADCy/MMA半互穿网络的制备及性能表征

在加热熔融的氰酸酯树脂(BADCy)中加入甲基丙烯酸甲酯(MMA)单体(同步合成法)或MMA预聚体(异步合成法)并引发使其发生本体聚合,制备了具有半互穿聚合物网络结构的氰酸酯树脂/聚甲基丙烯酸甲酯(BADCy/MMA-SIPN),通过力学性能测试,红外及DSC分析研究了MMA含量对体系力学性能和热性能的影响。结果表明,互穿网絡的形成使氰酸酯树脂体系的力学性能和耐热性能都有较大的提高,冲击强度、弯曲强度及玻璃化温度分别提高了97.8%、58.6%和65℃。     

Synthesis and characterization of bis(4‐cyanato 3,5‐dimethylphenyl) naphthyl methane/epoxy/glass fiber composites

Bis(4‐cyanato 3,5‐dimethylphenyl) naphthylmethane was prepared by treating CNBr with bis(4‐hydroxy 3,5‐dimethylphenyl) naphthylmethane in the presence of triethylamine at −5 to 5°C. The dicyanate was characterized by FT‐IR and NMR techniques. The prepared dicyanate was blended with commercial epoxy resin in different ratios and cured at 120°C for 1 hr, 180°C for 1 hr, and post cured at 220°C for 1 hr using diamino diphenyl methane (DDM) as curing agent. Castings of neat resin and blends were prepared and characterized by FT‐IR technique. The morphology of the blends was evaluated by SEM analysis. The composite laminates were also fabricated from the same composition using glass fiber. The mechanical properties like tensile strength, flexural strength, and fracture toughness were measured as per ASTMD 3039, D 790, and D 5528, respectively. The tensile strength increased with increase in cyanate content (3, 6, and 9%) from 322 to 355 MPa. The fracture toughness values also increased from 0.7671 kJ/m² for neat epoxy resin to 0.8615 kJ/m² for 9% cyanate ester epoxy modified system. The thermal properties were also studied. The 10% weight loss temperature of pure epoxy is 358°C and it increased to 398°C with incorporation of cyanate ester resin. The incorporation of cyanate ester up to 9% loading level does not affect the T_g to a very great extent. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

二烯丙基双酚A催化改性酚醛型氰酸酯树脂的催化固化

研究了二烯丙基双酚A（DBA）催化改性酚醛型氰酸酯树脂（cy-5）,通过差示扫描量热法（DSC）、热重分析（TG）、冲击性能和动态热机械分析（DMA）测试,分析了改性树脂的热性能和力学性能。研究表明：DBA对cy-5有催化和增韧的双重作用,当DBA的添加量为5%（质量分数）时,催化效果最为明显,含10% DBA的改性树脂固化物的冲击强度达到7.41 kJ/m2,改性树脂固化物的玻璃化转变温度（Tg）和储能模量（E'）均有所降低,但幅度不大。     

Resin transfer molding (RTM) with toughened cyanate ester resin systems

This investigation explored the feasibility of recently developed toughened cyanate ester networks as candidate materials for high performance composite matrix applications. The resin investigated was a bisphenol-A cyanate ester toughened with hydroxy functionalized phenolphthalein based amorphous poly(arylene ether sulfone). A series of four toughened cyanate ester resins were generated by varying the concentration and the molecular weight of the toughener. The thermoplastic modified toughened networks exhibited improvement in the fracture toughness over the base cyanate ester networks without significant reductions in mechanical properties or glass transition temperature. Carbon fabric composite panels were manufactured by liquid molding processes (resin transfer molding and resin film infusion) with the untoughened and toughened cyanate ester resin systems. The panels were subjected to physical, impact damage, and fracture toughness tests. The results of physical testing indicate consistently uniform quality, and the maximum void content was found to be less than 2%. The toughened cyanate ester composites exhibited significantly improved impact damage resistance and tolerance compared with hot-melt epoxy systems. A marked increase in the mode II composite fracture toughness was observed with an increase in the concentration and the molecular weight of the toughener.     

Environmental effects on thermoplastic and elastomer toughened cyanate ester composite systems

The effects of temperature and moisture on thermal and mechanical properties of high‐temperature cyanate ester composite materials were investigated. A resin transfer molding process was used to impregnate glass fiber fabrics with matrices that underwent thermoplastic or elastomeric toughness modifications. The elastomer‐modified material obtained the highest mode I fracture toughness values primarily because the toughener did not phase separate. Extended exposure to 200°C, however, deteriorated initial toughness improvements regardless of the modifier utilized. Although the thermal stability was increased by using thermoplastic modifiers in comparison to the elastomer‐modified material, the degradation was mainly governed by the cyanate ester network. Gaseous degradation products caused delaminations and therefore reduced strength when the materials were exposed to 200°C for 1000 h. Also, upon immersion in water at 95°C, the matrices absorbed up to 3.3 wt % more than previous values reported in the literature. Fiber/matrix interfacial phenomena were responsible for this behavior because fiber/matrix adhesion also was reduced drastically as shown by the strong reduction in flexural strength. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 556–567, 2000     

POSS/CE杂化复合材料的制备与介电性能研究

为制备介电常数(ε)低、介电损耗因子(tanδ)小的集成电路板用树脂基体,以笼型倍半硅氧烷(POSS)对双酚A型氰酸酯(CE)树脂进行改性,制备出一种POSS/CE无机-有机杂化复合材料。着重探讨了POSS用量和后处理工艺等对POSS/CE树脂体系介电性能的影响。结果表明:当w(POSS)=2%(相对于CE单体质量而言)、后处理工艺为240℃/3 h时,改性体系的介电性能相对最好,其测试频率为60 MHz时的ε(为2.9)和tanδ(为0.004 5)分别比纯CE树脂降低了9.4%和35.7%;该改性体系的表观活化能为51.9 kJ/mol。