Fracture Behaviour of Thermoplastic Modified Epoxy Resins

This work has shown that the addition of polyetherimide (PEI) can significantly increase the toughness of highly cross-linked epoxy resins, whilst retaining a high T_g and modulus. These combined properties indicate the potential of PEI modified epoxy resins for use as matrices for advanced composite materials. In terms of G_IC, addition of 20wt% PEI raised the toughness by a factor of eight. Evidence from SEM fracture surfaces suggests that the toughening mechanism operating in bulk PEI modified epoxy resin is ductile drawing of the PEI. Carbon fibre composites based on 30wt% PEI modified epoxy resin matrices show considerable improvement in toughness at low and high strain rates when compared with CFRP possessing unmodified or 20wt% modified PEI content epoxy resins.     

CTBN增韧环氧树脂微孔发泡研究

研究了液体端羧基丁腈橡胶(CTBN)增韧高分子量环氧树脂(EP,牌号CYD–014U)的超临界二氧化碳(SC–CO_2)微孔发泡及其泡孔结构,通过差示扫描量热(DSC)、动态热力学分析(DMA)和扫描电子显微镜(SEM)分别研究了不同含量CTBN共混体系的热性能、动态模量、断面形貌和不同发泡条件下的泡孔结构。研究发现,当CTBN含量从0%增加到30%时,EP/CTBN体系的玻璃化转变温度持续下降,其DSC测试结果从98.44℃下降至81.89℃。SEM观察断面和气体传质发现,CTBN含量增加基体塑化,出现两相结构,体系气体吸附量增加,解吸附速率加快。CTBN含量为10%~15%时,经60℃/12 MPa/72 h气体饱和以及110℃发泡10~15 s,泡孔尺寸为1~2μm,泡孔密度为5.60×10~(10)~6.28×10~(10)个/cm~3;随着发泡时间增加,泡孔经历成核、生长、聚并三个阶段,泡孔尺寸增加,泡孔密度先增后降。     

橡胶增韧环氧树脂低温韧性的研究

以低分子量聚酰胺(PA300)为固化剂,以液体端羧基丁腈橡胶(CTBN)为增韧剂增韧改性双酚A型环氧树脂,考察了橡胶增韧剂、固化剂、稀释剂和无机填料对环氧树脂低温韧性的影响。通过对增韧体系应力应变特性和动态力学性能的研究表明,该体系具有优异的低温韧性。     

用改性环氧胶黏剂粘接硫化丁腈橡胶

以端异氰酸基聚氨酯预聚体改性环氧树脂和双氰胺为主要原料制备了一种单组分耐热环氧树脂胶黏剂,该胶可以对表面未处理的丁腈橡胶进行粘接。文中考察了增韧剂种类、增韧剂用量对粘接强度的影响,同时考察了促进剂种类和用量对凝胶时间和贮存期的影响。实验结果表明,该胶黏剂对丁腈橡胶的粘接强度好,具有较好耐热性和较长贮存期。     

端羧基液体丁腈橡胶增韧环氧树脂研究

制备了由端羧基液体丁腈橡胶（cTBN）增韧环氧树脂（ER）于室温下固化的双组分胶黏剂。研究了CTBN与ER配比、甲组分处理温度及其保温时间对胶黏剂剪切强度的影响并用扫描电子显微镜（SEM）观察了其微观形态。实验结果表明CTBN：ER=8：1、甲组分于200℃下反应2．5h时,胶黏剂剪切强度可以达到25．34MPa,耐介质性能良好。同时SEM测试结果表明端羧基液体丁腈橡胶对ER增韧作用明显,为提高环氧树脂的粘接性和韧性提供了技术依据。     

无溶剂聚酯改性环氧涂料的研制

本试验研究的无溶剂聚酯改性环氧涂料既能满足重防腐工程的需要,同时减少VOC的排放,施工容易达到设计要求。试验结果表明,无溶剂聚酯改性环氧树脂及其涂料的各项指标可以达到很高的防腐标准,合成的含羧基低分子量聚酯树脂与环氧树脂比例在2∶(3~5)范围内综合性能良好,同时涂膜韧性、弹性突出,适合在温变大、干湿变化大等恶劣环境下进行防腐涂装,由于该涂料能达到施工、成膜后均不含低分子添加物,适用于对密闭空间有空气质量要求的场所的涂装,具有很好的应用前景和市场需求。     

聚氨酯改性环氧胶粘剂的研究

聚氨酯预聚体通过催化剂与环氧树脂接枝反应合成了蒙氨酯改性环氧树脂。该树脂在改性胺和催化剂作用下，具有良好的施工性能和较高的强度，对极性基材和非极性PE材料具有良好的粘接性能。     

改性环氧酯树脂的研制

采用价格便宜、原料易得、贮存稳定性好的豆油酸与环氧树脂酯化,并拼用210松香改性酚醛树脂进行改性,制得改性环氧酯树脂。讨论了210松香改性酚醛树脂添加量对环氧酯树脂,以及用其配制色漆漆膜性能的影响。     

改性环氧树脂制备复合材料层间断裂韧性的实验研究

采用纳米SiO2对环氧树脂改性并通过RTM工艺制成碳/环氧复合材料,观察纳米粒子在复合材料中的分布情况,测试复合材料的层间断裂韧性并用显微镜观察断裂面形貌.结果表明,纳米粒子在复合材料厚度方向和沿预裂纹的面内方向均没有明显的过滤性,改性后的碳/环氧复合材料的层间断裂韧性比改性前提高45％,断裂面更粗糙,纳米SiO2对环氧树脂的增韧效果良好.     

DDM/EP/CTBN增韧BMI耐高温胶合成工艺研究

以N,N-′4,4′-二氨基二苯甲烷型双马来酰亚胺(BM I)、环氧树脂(EP)、4,4′-二氨基二苯甲烷(DDM)为主要原料,合成了2种以BM I为基体的耐高温胶粘剂,分析了DDM、EP用量对胶粘剂性能的影响。采用差示扫描量热、红外光谱、热重分析表征了产物的反应程度、结构和热稳定性。结果表明,2种工艺都采用mBM I∶mEP∶mDDM=1∶1∶0.85时综合性能最优,在相同的固化条件下,共熔型体系耐高温实验强度(30.07 MPa)优于预聚型体系(27.33 MPa),但耐温冲击实验强度(29.83 MPa)不如后者(31.58 MPa)。     

丁腈橡胶增韧环氧树脂的性能研究

采用固体丁腈橡胶（NBR）对环氧树脂（EP）进行增韧改性,并对改性后的树脂性能进行了表征。结果显示环氧树脂的韧性随着丁腈橡胶含量的提高而提高,在15%时达到最好。固化剂的用量会对树脂的力学性能有影响,90%是最佳用量。无机填料的加入对树脂的冲击强度和拉伸强度有较大幅度的提高。     

弹性体改性环氧树脂的新进展

本文就丁腈橡胶,丙烯酸酯橡胶,聚氨酯,聚硅氧烷等弹性体改性环氧树脂的研究在近些年取得的进展进行概述。     

环氧改性丙烯酸乳液涂料的研制

采用三元复合乳化剂体系和核壳乳液聚合工艺,制得环氧树脂改性的苯丙乳液。研究了乳化剂、反应温度、环氧树脂的用量、三乙烯四胺固化剂对环氧改性苯丙乳液综合性能的影响,确定了适宜的反应条件和配方。     

Thermal and dielectric properties of epoxy/DDS/CTBN adhesive modified by cardanol-based benzoxazine

Cardanol-based benzoxazine (Bz-C) was introduced to a ternary resin system to substitute carboxyl-terminated butadiene–acrylonitrile (CTBN) partially and improve the thermal and dielectric properties of the diglycidyl ether of bisphenol-A (epoxy)/4,4′-diaminodiphenylsulfone (DDS)/CTBN adhesive resin system. The effect of Bz-C on the curing behavior of blends was studied, and factors that affect the thermal, mechanical, and dielectric properties were discussed systematically. Results show that reactions between Ep, DDS, and Bz-C decrease the curing temperature of the quaternary blends and increase the cross-linking densities of the network, leading to higher glass-transition temperature and enhanced mechanical properties. The flexibility of the copolymer films was maintained by the introduction of the aliphatic side chain of Bz-C. Substitution of Bz-C for some group of CTBN in the cross-linked network resulted in decreased dielectric constant and dielectric loss in the copolymer films.     

环氧改性有机硅树脂的制备及其性能研究

采用化学方法制备了环氧改性有机硅树脂。通过红外分析表明,环氧树脂与有机硅树脂发生了化学反应。研究发现：环氧改性有机硅树脂的水接触角、瓦均有变化,微观形态仍呈均相结构。研究还发现：随环氧树脂用量增大,改性有机硅树脂微观结构的粗糙度提高,水接触角增大。     

The Curing Behavior and Adhesion Strength of the Epoxidized Natural Rubber Modified Epoxy/Dicyandiamide System

The curing properties and adhesive strengths of the epoxidized natural rubber (ENR, 25 mole percent epoxidation) modified epoxy systems are studied with differential thermal calorimetry (DSC), scanning electron microscopy (SEM), and lap shear strength (LSS) measurement. The results of DSC analyses indicate that the curing exotherm, the curing rate, the reaction order, and the glass transition temperature of the epoxy system are affected by the presence of reactive ENR. From SEM micrographs, it is obtained that a second spherical rubber phase is formed during cure and the particle size of the rubber phase is increased by increasing the curing temperature and the ENR content. The changes of the volume fraction of the rubber phase and the T_g of the cured systems indicate that the mutual dissolution between epoxy resin and ENR happens and which changes with the curing temperature and the ENR content. The LSS of adhesive joints prepared with the ENR modified adhesives are all lower than those of the unmodified epoxy system, and decrease with increasing the amount of ENR added because of the limited compatibility of the ENR with the epoxy matrix.     

CTBN与ATBN改性环氧胶粘剂的研究

将端羧基丁腈橡胶(CTBN)接枝上环氧官能团进行改性,将改性后的CTBN添加到环氧胶粘剂的A组分中;将端氨基丁腈橡胶(ATBN)以不同的比例加入到环氧胶粘剂的固化剂即B组分中。考查胶粘剂的剪切、剥离强度和玻璃化转变温度以及2组分的配比对胶粘剂性能的影响。结果表明,将改性后的CTBN橡胶与ATBN配合使用比单独使用其中一种的综合性能更好,2者在A、B组分中分别占12质量份数左右时其增韧效果最显著。     

Structure and properties of CE/CTBN/EP blends: II. Effect of EP on the mechanical properties and thermostability of the CE/CTBN system

Carboxyl‐terminated butadiene‐acrylonitrile rubber (CTBN) has often been used to improve the toughness of cyanate ester (CE) resin while sacrificing modulus and thermostability. In this paper, the addition of the appropriate amount of epoxy resin (EP) to the CE/CTBN system is shown to not only increase the modulus and thermostability of the blend, but also improve the toughness. The values of impact strength showed a maximum for the CE/CTBN/EP 100/5/5 blend. The temperature of 10 % weight loss (T₁₀) improves from 376 °C for CE/CTBN 100/5 to 407 °C for the CE/CTBN/EP 100/5/2.5 blend. It is proposed that addition of the appropriate amount of EP can decrease the mobility and increase the stability of CTBN via the reaction between the terminal carboxyl group of CTBN and the hydroxyl group of EP. But a very high EP concentration will decrease the crosslinking density of CE, consequently reducing the mechanical properties and thermostability of the blends. Copyright © 2004 Society of Chemical Industry     

有机硅改性环氧树脂的合成与性能

热熔法制备了系列聚甲基苯基硅氧烷(PMPS)改性环氧树脂,通过环氧值、红外光谱(IR)和凝胶色谱(GPC)分析表明,有机硅接枝到了环氧树脂上,且环氧基保持不变。探讨了改性方法、有机硅含量对改性树脂固化体系的微观形态、韧性及耐热性的影响。实验表明,当m(E-20)∶m(DC-3074)=7∶3时,化学改性树脂固化体系的韧性和耐热性能明显提高,玻璃化转变温度(Tg)为88.33℃,质量损失50%时的热分解温度(Td)为487.80℃,分别比物理改性环氧树脂提高了52.63℃和36.75℃,同时此改性树脂固化物还具有优良的涂膜性能。     

改性环氧树脂在防腐涂料中的应用思路

综述了改性环氧树脂在防腐涂料中的应用及高性能化的方向。