聚氨酯对环氧树脂增韧性能研究

利用甲苯二异氰酸酯(TDI)和聚丙二醇(PPG)合成不同结构的端—NCO聚氨酯(PU)预聚体,然后由聚氨酯预聚体与环氧树脂进行接枝反应,制备聚氨酯改性环氧树脂。研究了聚氨酯预聚体结构和用量对改性环氧树脂力学性能的影响规律。结果表明,当聚醚多元醇选用PPG1000,且TDI∶PPG=2∶1时,制得的聚氨酯预聚体对环氧树脂的增韧效果最好,当ω(PU预聚体)=10%时,改性环氧树脂的应变和拉伸强度分别达到84. 7%和27. 1 MPa,是改性前的30. 47倍和3. 04倍。通过扫描电镜对聚氨酯的增韧机理进行了研究,发现改性前环氧树脂为脆性断裂,聚氨酯改性后的环氧树脂断裂时银纹明显增多,为韧性断裂。     

反应性端基聚丁二烯系列液体橡胶在环氧树脂改性增韧方面的应用

综述了含反应性端基聚丁二烯系列液体橡胶（以下简单PBLR）品种、性能及特点，概括比较了PBLR改性增韧环氧树脂方法及特点；分别列举了PBLR改性环氧树脂在微机电浇注料，树脂砂轮，水利机械涂敷，电子灌封及飞机粘合剂等方面的应用。     

聚碳酸酯对环氧树脂/炭黑复合材料结构与导电性能的影响

利用溶液共混法制备了环氧树脂(EP)/聚碳酸酯(PC)/炭黑(CB)三元及EP/CB二元两种复合材料.采用扫描电子显微镜、光学显微镜、精密阻抗分析仪、高阻计研究了它们的微观形貌及电性能.结果表明,从热力学角度,PC比EP更容易和CB相容,在EP/PC/CB复合材料中,PC可以起到类似表面活性剂的作用;加入PC可以显著提...     

橡胶增韧环氧树脂的新方法

本文讨论了液体端羧基丁腈橡胶增韧环氧树脂存在橡胶交联网络不完整问题,并进一步研究为克服此缺点而使用预制的橡胶微球(即活性微凝胶)作为环氧增韧剂的体系的表面化学性质、流变学性能、及以伯胺类固化剂固化的此体系的胶接强度及力学性能等。     

CO_2基脂肪族聚碳酸酯和环氧树脂共混体系的研究

本文对CO2 基脂肪族聚碳酸酯 环氧树脂共混体系进行了研究。采用示差扫描量热分析、热重分析法考察了该共混体系的相分离状况及耐热性 ,并对其力学性能进行了测试     

聚醚增韧环氧树脂的机理研究

本文以2—乙基—4—甲基咪唑(24EMI)为固化剂研究了新型环氧改性剂一端羧基THF-PO共聚醚(CTCPE)对DGEBA/24EMI固化体系的增韧作用及CTCPE增韧环氧树脂的机理。结果表明,CTCPE使环氧树脂固化物韧性显著提高,添加量达30phr时断裂韧性、冲击强度达极大值,其增韧机理服从孔洞化一剪切屈服模型。     

环氧树脂的改性研究进展

介绍了环氧树脂的特性和环氧树脂改性的主要趋势-提高环氧树脂的韧性,分别论述了橡胶类弹性体增韧环氧树脂、热塑性塑料增韧环氧树脂、热致液晶聚合物增韧环氧树脂、柔性链段固化剂增韧环氧树脂、无机纳米材料改性环氧树脂以及互穿网络(IPN)结构的环氧树脂体系等环氧树脂增韧改性的方法.同时,对聚氨酯的特性、用聚氨酯改性环氧树脂的六种方法以及互穿聚合物网络技术,进行了较为详细的介绍,并分析了改性环氧树脂目前存在的技术问题.     

环氧树脂的增韧研究进展

介绍了几种环氧树脂(EP)的主要增韧方法,包括橡胶增韧法、热塑性树脂增韧法、纳米颗粒增韧法、核壳粒子增韧法、互穿网络增韧法、生物质增韧法以及超支化增韧法。简述了国内外近几年EP增韧改性的研究进展,对增韧后材料的力学性能、热学性能等进行了重点关注。最后对未来EP增韧的发展方向进行了展望,指出基于多领域不同应用需求,使用多种材料、多种方法协同增韧EP机理复杂,过程较难把控,是未来的研究重点。     

聚苯硫醚／聚碳酸酯共混体系的形态及结晶行为

通过熔融共混的方法制备了聚苯硫醚（PPS）／聚碳酸酯（PC）共混体系。用扫描电镜、动态热力学分析以及动态流变测试等方法研究了共混体系内部形态结构。用差示扫描量热仪和X射线衍射法对材料的结晶行为进行了研究。结果表明，在部分相容PPS／PC共混体系中，从熔体冷却结晶时，无定形的PC组分无异相成核作用，反而抑制了PPS的结晶，且随PC含量增加阻碍作用增强；但PC组分的存在不改变PPS的结晶形态。     

Study on epoxy resins modified by polycarbonate polyurethanes

In this article, the structure and properties of the epoxy resin (EP) modified by polyurethane (PU) prepolymers were studied. The three types of polyurethane prepolymers, namely, polycarbonate-type PU (TPC), polyether-type PU, and polycarbonate–polyether-type PU were employed. The samples were analyzed by means of an infrared spectrometer, a differential scanning calorimeter, a scanning electron microscope, a transmission electron microscope, a scanning tunnel microscope, and a thermal gravimeter. The results show that the EP modified by TPC is of excellent thermal resistance and mechanical properties. Specifically, when the ratio of PU to EP is 10/100 (wt/wt), optimal properties are achieved. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 887–893, 1998     

A study on the properties of epoxy resin toughened by a liquid crystal‐type oligomer

A series of novel reactive toughening agents (LCEU_PPG) containing both a flexible spacer and rigid liquid crystalline unit were synthesized to modify the bisphenol epoxy resin/dicyandiamide curing system. The curing reactivity, apparent activation energy, curing mechanism, dynamic mechanical behavior, and impact strength of the modified system were systematically studied. Compared with the unmodified system, the results indicate that LCEU_PPG have greatly accelerated the curing reaction between epoxy resin and dicyandiamide, reduced the apparent activation energy of the curing reaction, enhanced the impact strength 3–7 times, and maintained high dynamic modulus and good thermal properties. In addition, SEM observation of the fracture surfaces showed a two‐phase microstructure in the modified systems. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 177–184, 1999     

Mechanical properties of epoxy resin modified with polycarbonate and reactive polybutadiene

Epoxy resin Epidian 5 cured with triethylene tetramine was modified with hydroxyl‐terminated polybutadiene (PB) and polycarbonate (PC). Compositions with different amount of modifiers were obtained and tested for their impact strength, flexural strength, as well as resistance to crack propagation. The latter was assessed by evaluating the critical stress intensity factor under three‐point bending mode using single‐edge notched specimens. Scanning electron microscopy was used to analyze the fractured sample surfaces. The obtained results revealed that the mechanical properties of epoxy resin were improved due to the formation of heterogeneous phase with rubber particles, which arrest the propagation of cracks. Moreover, synergism effect was observed with the hybrid composition containing 10% PC and 2.5% of reactive PB. The impact strength was higher by ～ 15% than the sum of impact strength of compositions containing only one modifier. Another hybrid composition with 2.5% PB and 2.5% PC also exhibited synergism effect with the flexural strain at break, the energy at break under flexure, as well as the brittle fracture energy estimated from the critical stress intensity factor measurements. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Bisphenol-A epoxy resin reinforced and toughened by hyperbranched epoxy resin

The study on toughening and reinforcing of bisphenol-A epoxy resin is one of important developmental direction in the field. This paper reports a one-pot synthesis of aromatic polyester hyperbranched epoxy resin HTDE-2, an effect of HTDE-2 content on the mechanical and thermal performance of the bisphenol-A (E51)/HTDE-2 hybrid resin in detail. Fourier transform infrared (FT-IR) spectrometer, scanning electronic microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical thermal analysis (DMA) and molecular simulation technology are used to study the structure of HTDE-2, performance and toughening and reinforcing mechanism of the HTDE-2/E51 hybrid resin. It has been shown that the content of HTDE-2 has an important effect on the performance of the hybrid resin, and the performance of the HTDE-2/E51 blends has maximum with the increase in HTDE-2 content. The impact strength and fracture toughness of the hybrid resin with 9 wt-% HTDE-2 are almost 3.088 and 1.749 times of E51 performance respectively, furthermore, the tensile and flexural strength can also be enhanced about 20.7% and 14.2%, respectively. The glass transition temperature and thermal degradation temperature, however, are found to decrease to some extent. __________ Translated from Journal of South China University of Technology (Natural Science Edition), 2006: 34(9): 90–94 [译自: 华南理工大学学报 (自然科学版)]     

Study on relationship between mechanical properties and particle size distribution for polyhexamethylene carbonate diol toughened epoxy resin

The relationship between the mechanical properties and morphology of polyhexamethylene carbonate diol (PHMCD) toughened epoxy resin was investigated. The parameters describing the morphology (e.g., average diameter of particles and volume fraction of dispersed phase, etc.) were determined through SEM observation. It was observed that the particle size distribution changes from a unimodal distribution to a bimodal one and then tounimodal again with an increase in curing temperature. When it was cured at 120°C, an epoxy resin with a bimodal distribution of rubber particle size was obtained. The mechanical properties, especially the impacting strength, of the resin are the best because of the synergistic effect of the PHMCD particles. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67: 569–575, 1998     

Effect of amino-polycarbonate on the curing kinetics and morphology of epoxy resin

The curing kinetics and the glass transition behavior of amino-polycarbonate with diglycidyl ether of bisphenol-A epoxy resin systems were studied by differential scanning calorimetry (DSC). The ASTM E-698 method was chosen to determine the kinetics parameters of the curing reaction, including the activation energy, preexponential factor, rate constant, and 60-min half-life temperature. The amino-polycarbonate was able to accelerate the curing reaction, reduce the apparent active energy, and decrease T_g of the systems. A homogeneous amino-polycarbonate/epoxy resin network was observed in scanning electron microscopy (SEM) pictures. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 833–838, 2001     

液体聚硫聚脲增韧环氧树脂胶粘剂的合成与力学性能

利用异佛尔酮异氰酸酯扩链液体聚硫橡胶，合成了不同硬段含量的液体聚硫聚脲齐聚物，表征了该齐聚物增韧环氧树脂前后巯基含量、环氧含量、粘度及玻璃化温度等变化，并用来增韧环氧树脂-聚酰胺固化体系，研究了增韧环氧树脂的应力应变和粘合强度变化。     

On hybrid toughened DGEBA epoxy resins

Considerable improvements in the fracture resistance of epoxy resins have recently been achieved by adding either rubbery or rigid second phase dispersions, or both, to an epoxy matrix. These multiphase epoxy systems are particularly useful as high performance adhesives and as matrix materials in advanced composites. This paper describes the development of new toughened epoxy hybrids, which contain both rubbery and rigid dispersions. The latter dispersions were either zirconia particles, short alumina fibres or glassy-metal ribbons. Micromechanisms of toughening and failure processes in these new materials are identified and discussed in the light of microstructures.     

含有聚醚多胺环氧树脂网络的形态及力学性能

不同相对分子质量聚醚多胺与环氧树脂于６０℃混合后,加入固化剂二乙烯三胺,在８０℃＊ｈ,１２０℃＊４ｈ下固化,可制备含聚醚多胺的固化环氧树脂网络。     

环氧树脂化学改性有机硅树脂的方法综述

环氧改性有机硅树脂可提高有机硅树脂的力学性能和粘接性能,还可降低有机硅树脂的固化温度.归纳总结了环氧树脂化学改性有机硅树脂的4种反应类型:1)缩聚反应;2)环氧基的开环聚合反应;3)硅氢加成反应;4)引入环氧基的反应.对该领域的近期研究成果进行了简要的综述,并展望了该领域未来的发展方向.