环氧基苯基硅油改性环氧绝缘胶

上海交通大学化学与化工学院采用环氧基苯基硅油（PEPDMS）作为环氧树脂的增韧剂,与环氧树脂相容性良好,改变了传统有机硅聚合物对环氧树脂相容性差的不足。试验结果表明,PEPDMS对环氧树脂具有明显的增韧增强效果,且对环氧树脂的耐热性和电性能影响甚微。以F-44酚醛环氧树脂、E-51环氧树脂、E-20环氧树脂、PEPDMS（平均分子质量Mn约3000,用量10％）、甲基六氢苯酐等,制得了改性环氧树脂绝缘胶黏剂。 13．8kJ／m。,比     

丁腈羟聚氨酯增韧环氧树脂研究

环氧树脂与甲苯二异氰酸酯(TDI)反应生成预聚物,再加入丁腈羟与TDI的预聚物,用芳香族伯胺固化,可以得到增韧的环氧树脂。本文研究了固化剂用量,丁腈羟用量对粘接性能的影响及这种增韧环氧树脂的玻璃化转变,动态力学性能和电性能,并对反应机理进行了初步探讨。实验结果表明:丁腈羟预聚物对环氧树脂有明显增韧效果,是一种良好的环氧树脂改性剂。     

环氧丁羟增韧环氧树脂应用研究

采用环氧化端羟基聚丁二烯(EHTPB,简称环氧丁羟)作为环氧树脂固化体系的增韧剂,研究了不同EHTPB质量分数对固化体系力学性能、热性能和电性能的影响。结果表明:随EHTPB质量分数的增加,EHTPB增韧环氧树脂灌封胶的冲击强度呈现先增加后减小的趋势;EHTPB质量分数为10%时增韧环氧树脂灌封胶的冲击强度较佳,增韧性能较好。     

端羟基丁二烯-丙烯腈液体橡胶增韧环氧树脂的研究

环氧树脂与甲苯二异氰酸酯(TDI)反应生成预聚物,再加入端羟基丁二烯-丙烯腈共聚物(丁腈羟)与TDI的预聚物,用芳香族伯胺固化,可以得到增韧的环氧树脂。研究了固化剂用量及丁腈羟用量对粘接性能的影响及这种增韧环氧树脂的玻璃化转变、动态力学性能和电性能,并对反应机理进行了初步探讨。实验结果表明,丁腈羟预聚物是一种良好的环氧树脂改性剂。     

环氧化SBSVP对增韧环氧树脂性能的影响

利用甲酸和过氧化氢对吡啶基官能化的SBS(SBSVP)进行环氧化改性,制备了不同环氧化程度的环氧化SBSVP(ESBSVP)。将ESBSVP用于增韧环氧树脂,研究了不同环氧化程度的ESBSVP对环氧树脂增韧效果的影响。结果表明,ESBSVP与环氧树脂具有良好的相容性,加入ESBSVP后,环氧树脂体系的抗冲击强度增大、弯曲强度降低,玻璃化转变温度略有增加。ESBSVP的环氧化结构对增韧效果有较大的影响,使用胺类作固化剂时,弹性体中环氧基团含量越多,抗冲击强度的增加幅度越大,弯曲强度的降低幅度越小,环氧树脂体系的玻璃化转变温度增加也越明显。使用胺类作固化剂时,环氧基团对于提高体系交联密度、增加体系玻璃化转变温度的贡献较大,ESBSVP中的环氧基团含量越多,增韧效果越明显。     

CTBN-704-环氧体系的初步研究

前言ST-791结构胶系双酚A型环氧树脂,采用端羧基液体聚丁二烯丙烯腈共聚物(CTBN)增韧和改性咪唑为固化剂,具有强度高、韧性好、热变形温度高、介电性能好的结构胶粘剂.有关采用CTBN增韧环氧树脂,国外报道很多,并已有总结性文献,国内七十年代也有报道,但本体系国内外都未有公开的报导.本文主要对影响此胶性能的一些因素及其物性进行一些初步研究.     

环氧树脂/蒙脱土纳米复合材料性能研究进展

综述了环氧树脂/蒙脱土纳米复合材料在力学、热学、介电性能、阻隔性能等方面的研究进展。归纳总结了裂纹与银纹相互转化增强增韧机理、裂纹钉铆机理、基体剪切屈服增韧机理等几种蒙脱土增韧环氧树脂机理,并对环氧树脂/蒙脱土纳米复合材料的发展前景作了展望。     

液体羧端基丁腈橡胶增韧环氧树脂的韧性与微观相态

本文采用断裂能的测定作为评价CTBN增韧环氧树脂韧性的主要方法,用透射电子显微镜观察增韧环氧树脂的微观相态,研究了CTBN的丙烯腈含量、分子量和固化剂对增韧环氧树脂的韧性和微观相态的影响。并从相容性和相分离的角度讨论了这些影响的原因。     

芳纶纤维/环氧树脂预浸料界面相容性的方法探究

预浸料要求树脂基体和增强纤维具有良好的匹配性,为了提高芳纶纤维/环氧树脂预浸料的界面相容性,本文从芳纶纤维表面改性及增韧技术两个方面进行综述,讨论了芳纶纤维物理改性和化学改性方法的优缺点,分析了界面增韧及环氧树脂基体的不同增韧途径,重点介绍了聚氨酯/环氧树脂互穿网络体系.认为芳纶纤维的偶联剂表面处理和聚氨酯增韧环氧树脂相结合,是提高芳纶纤维/环氧树脂预浸料层间剪切强度的的可行途径.     

热致型液晶增韧环氧树脂的研究进展

利用热致型液晶化合物对环氧树脂进行增韧改性,固化体系既融合了液晶的有序性又保留了环氧树脂网络交联的特点,其韧性、冲击强度大幅度提高,而不降低耐热性,这是环氧树脂的传统增韧方法所无法比拟的,是实现环氧树脂高性能化的重要途径之一。热致型液晶高分子(TLCP)增韧环氧树脂可以归纳为两类:液晶环氧树脂(LCEP)增韧和其他聚合物液晶共混增韧。概述了LCEP增韧的方法和增韧机理,TLCP共混增韧的方法和增韧机理,综述了热致型液晶增韧环氧树脂的研究进展,并对其今后研究作了展望。     

Mechanical and Dielectric Properties of NiZn Ferrite Powders-CTBN Modified Epoxy Resin Coatings

In this study, the effects of carboxyl terminated butadiene-acrylonitrile liquid rubber (CTBN) addition on the mechanical and dielectric properties of NiZn ferrite powders-CTBN modified epoxy resin coatings were investigated. It was observed that the occurrence of the small, dispersed spherical CTBN domains in the epoxy resin resulted from the phase separation between epoxy and CTBN could enhance the toughness and dielectric constant at low frequency due to the increase in the phase boundary between ferrite powders and epoxy resin for the samples modified with proper CTBN. The addition of ferrite powders can effectively improve the thermal stability of epoxy resin.     

环氧树脂/石英纤维透波复合材料制备

为改善环氧树脂的介电性能及提升石英纤维的界面性能,使用缩水甘油醚基笼型倍半硅氧烷(G–POSS)和γ–氨丙基三乙氧基硅烷(KH–550)分别对环氧树脂和石英纤维进行改性。利用差示扫描量热法研究改性后环氧树脂的固化过程,并通过外推法确定了其固化工艺,根据固化工艺制备环氧树脂/石英纤维复合材料,分别对该复合材料的热稳定性、介电性能和弯曲性能进行表征,结果表明,使用G–POSS和KH–550改性后的环氧树脂/石英纤维复合材料热稳定性、介电性能和弯曲性能达到最佳,初始分解温度达到369.59℃,常温下在12~18 GHz的介电常数稳定在3.2~3.5之间,介电损耗角正切值在0.005~0.02之间,弯曲强度达到376.4 MPa,弯曲弹性模量为21.7 GPa。     

石英纤维织物增强复合材料性能研究

本文分别研究了QW280和TC 8/3-K-TO石英纤维织物/改性环氧树脂复合材料的力学性能和介电性能,结果表明QW280/改性环氧树脂复合材料与TC 8/3-K-TO/改性环氧树脂复合材料力学性能和介电性能基本相当.     

Modeling the dielectric behavior of epoxy resin blends during curing

A model is developed to describe the evolution of dielectric behavior during the cure of epoxy resins and of blends containing soluble polymeric additives. Data on cure kinetics are used to predict: (a) changes in viscosity and hence in ion mobility; (b) gelation times; (c) vitrification times; and (d) dipolar relaxation times, for both resin and blends. These predictions are then used in conjunction with the Maxwell-Wagner-Sillars (MWS) theory to calculate dielectric permittivity ?′ and loss ?″ as functions of cure time and test frequency in both resin and blends. The predictions are compared with experimental data on dielectric behavior obtained during cure of both neat epoxy resin and of blends containing 15 wt% CTBN (carboxyl-terminated poly(butadiene-co-acrylonitrile)).     

低溴环氧/氰酸酯树脂共固化反应及其层压板性能的研究

用差示扫描量热仪(DSC)、傅立叶交换红外光谱(FT-IR)对不同配比的低溴环氧／氰酸酯树脂的共固化反应机理以及固化物的结构特征进行了研究,同时测定和讨论了其层压板的耐热性和介电性能等。研究结果表明,在低溴环氧／氰酸酯树脂的固化体系中,氰酸酯和环氧树脂通过两种途径反应最终生成噁唑烷酮结构：固化反应温度与体系的组成有关,体系中低溴环氧树脂减少固化反应温度降低：加入催化剂能明显促进体系共固化反应,同时也降低了层压板的耐热性和介电性能。在性能方面,低溴环氧树脂中加入氰酸酯使共固化物耐热性增加、Tg升高,但氰酸酯用量增加到一定范围后,低溴环氧树脂／氰酸酯配比对Tg影响不大;低溴环氧树脂／氰酸酯层压板的耐热性和介电性能在一定实验范围内随着氰酸酯用量的增加明显提高。     

Preparation of nano‐Ag particles and their modification on the mechanical and dielectric properties of epoxy resin

Nano‐Ag particles stabilized by a hyperbranched polymer (HBP) template were prepared for modifying the epoxy resin. The effects of preparation condition on the size and size distribution of Ag colloidal particles were studied. The Ag@HBP particles were then compounded with the epoxy resin to obtain the Ag@HBP/epoxy composites and the mechanical and dielectric properties of these composites were investigated. Dynamic mechanical analysis results show that the composites have higher loss factors than does the unmodified epoxy resin, which indicate better dissipation of mechanical energy and hence better shock or impact resistance. Fracture morphology of the composite shows a toughness feature. From the dielectric test results, the breakdown strength and dielectric constant of the composites at room temperature are increased, which can be explained by the Coulomb block effect. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

环氧及酚醛树脂增韧改性氰酸酯树脂研究

用环氧树脂(EP)及酚醛树脂(PF)对氰酸酯树脂(CE)进行增韧改性,对改性CE的凝胶时间和DSC曲线进行研究并确定了改性CE的固化工艺。红外光谱分析表明改性CE固化时形成了柔韧性结构。研究了改性CE的力学性能、热性能、电性能及微观形态,发现EP的加入可增加CE的柔韧性,PF的加入可使CE的热稳定性损失减小。当CE/EP/PF的质量比为70/15/15时改性CE的弯曲强度和冲击强度分别从改性前的123.6 MPa、5.2 kJ/m2提高到134.5 MPa、16.7 kJ/m2,耐热性及电性能改变不大。     

Study on the curing reaction,dielectric and thermal performances of epoxy impregnating resin with reactive silicon compounds as new diluents

Two silicon compounds including (3‐glycidoxypropyl)trimethoxysilane (A187) and (3‐glycidoxypropyl)methyldiethoxysilane (W78) were used and studied as reactive diluents for aluminum (III) acetylacetonate (Alacac) accelerated epoxy/anhydride impregnating resin systems. The dielectric performances were studied and characterized by the dielectric dissipation factor, dielectric constant, volume resistivity, and breakdown strength. The curing behaviors and thermal properties of the cured impregnants were studied by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and thermogravimetry. The activation energies of different epoxy formulations were determined with Kissinger method. The results showed that W78 was effective to decrease the viscosity and had little influence on the curing reaction. The cured sample of 15 parts‐of‐W78‐containing‐epoxy resin/methyl‐hexahydrophthalic anhydride (MHHPA) accelerated by Alacac exhibits good dielectric and heat resistant performances with a dielectric dissipation factor below 0.04 at 155°C. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Dielectric properties of epoxy composites with modified multiwalled carbon nanotubes

We report here a high dielectric percolative polymer nanocomposite, fabricated by a combination of triethylene-tetramine (TETA) modified multiwalled carbon nanotube (named as TETA-MWNT) within epoxy resin matrix. In this composite system, with various TETA-MWNT volume fractions, the dielectric constant (K) is well fitted by the scaling law of the percolation theory with the percolation threshold f _c is 0.042 and the critical exponent p is 0.786. At 1,000 Hz of room temperature, the value of the dielectric constant is as high as 421 with the TETA-MWNT content of 4.14vol%, which is almost 60 times higher than that of epoxy resin. In contrast, a simple blend of pristine MWNT in epoxy composite shows evident lower dielectric constant and much higher loss with the same volume fraction.     

Organic rare-earth compounds as a new latent accelerator for curing of epoxy/anhydride system

Summary A seriesof organic rare-earth compounds has been found to be a latent accelerator for curing the epoxy resin/anhydride system. Incorporation of rare-earth ions into the epoxy resin caused an increase in the glass transition temperature (Tg) of the cured resin and the significant improvement in the dielectric and mechanical properties at high temperature which should be attributed to the higher Tg.