氰酸酯树脂增韧改性研究进展

简要介绍了氰酸酯树脂的增韧改性方法,包括热固性树脂改性、热塑性树脂改性、橡胶弹性体改性、纳米粒子改性及其他改性方法。     

氰酸酯树脂增韧改性研究

主要评述了目前氰酸酯树脂的几种增韧改性途径,其中包括与热固性树脂(EP、BMI、BMI/EP/CE)、热塑性塑料(PSU、PEI)、橡胶弹性体、含不饱和双键的化合物以及纳米粒子的插层增韧改性。同时,还讨论了改性氰酸酯树脂的发展方向及应用前景。     

氰酸酯树脂改性研究进展

氰酸酯树脂(CE)具有优异的介电性能、较高的玻璃化转变温度和强度、良好的耐化学腐蚀性和耐热性等优点,然而其固化物脆性较大,并且其韧性常常不能满足使用要求。从提高CE韧性角度,介绍了各种CE的改性方法(包括橡胶弹性体改性、热固性树脂改性、热塑性树脂改性和互穿聚合物网络改性等)及其应用研究进展。针对改性过程中存在的问题,提出了CE改性的未来发展方向。     

Novel modification of cyanate ester by epoxidized polysiloxane

A novel modification of cyanate ester (CE) resin by epoxidized polysiloxane (E‐Si) has been developed, and the modified system is coded as CE/E‐Si. E‐Si was prepared by the reactions among octamethylcyclotetrasiloxane, hexamethyldisiloxane, (3‐aminopropyl)‐methyldiethoxysilane, and diglycidyl ether of bisphenol‐A resin. Six formulations were designed to evaluate the effect of the weight ratio between CE and E‐Si on performance parameters. Results reveal that the addition of E‐Si in CE resin cannot only significantly decrease the curing temperature of the CE resin but also improve the water resistance and toughness of original CE resin. Moreover, these positive effects increase with the increase of E‐Si concentration in CE/E‐Si systems. Thermal property investigation shows that the glass‐transition temperature and initial degradation temperature of CE/E‐Si systems are lower than that of original CE resin. For the flexural properties of the CE/E‐Si systems, the E‐Si concentration in the system exists a threshold, that is, when the E‐Si concentration is smaller than the threshold, original CE and CE/E‐Si systems have similar flexural properties, whereas when the E‐Si concentration is higher than the threshold, CE/E‐Si systems have lower flexural properties than original CE resin. All these changes of properties are closely correlated to the structure alteration from neat CE to CE/E‐Si networks. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

氰酸酯树脂增韧改性研究

综述了采用热固性树脂(环氧树脂,双马来酰亚胺)、热塑性树脂(聚醚砜,聚苯醚)、橡胶弹性体(端羧基丁腈橡胶,端环氧基丁腈橡胶)、无机纳米粒子(SiO2,SiC)增韧改性氰酸酯树脂的机理及研究进展,并指出了今后氰酸酯树脂改性研究的发展方向。     

氰酸酯树脂的改性及应用研究

综述了热固性树脂、热塑性树脂、橡胶、不饱和化合物、晶须和纳米粒子等改性氰酸酯(CE)树脂的研究现状,并简要概述了改性CE树脂在工业中的应用。     

纳米CaCO_3对CE及CE/EP基体的改性研究

通过力学性能测试和扫描电镜、热重分析以及红外光谱测试研究了纳米CaCO3的加入量对氰酸酯(CE)及CE/环氧(EP)基体力学性能及热性能的影响。结果表明,适量的纳米CaCO3的加入,可有效地改善CE或CE/EP基体的韧性和强度。当纳米CaCO3的质量分数为3%时,两改性体系的冲击强度和拉伸模量均达到最大值,CE/EP/CaCO3体系较CE/CaCO3体系具有更高的冲击强度(7.8kJ/m2)和较低的拉伸模量(100.5GPa)。纳米CaCO3的加入有利提高基体的热稳定性,但CE/EP/CaCO3三元体系的热稳定性仍明显低于纯CE或CE/CaCO3二元体系。     

纳米碳化硅改性氰酸酯树脂研究

采用纳米碳化硅(nm-SiC)对氰酸酯树脂(CE)进行了改性,通过静态力学性能测试,TGA和DMA分析考察了nm-SiC含量对CE/nm-SiC复合材料性能的影响。结果表明,经硅烷偶联剂KH-560表面处理的nm-SiC更能有效地改善CE的力学性能和耐热性:相对纯CE,经KH-560表面处理的nm-SiC质量分数为1.00%的CE/nm-SiC复合材料的冲击强度和弯曲强度分别提高86.26%和29.56%,玻璃化转变温度由246℃提高到287℃,5%热失重温度由388℃提高到455℃。     

Toughening of cyanate ester resin by N‐phenylmaleimide–styrene copolymers

The N‐phenylmaleimide–styrene copolymer (PMS) was prepared and used to improve the brittleness of the cyanate ester resin. PMS was an effective modifier for improving the brittleness of the resin. The morphologies of the modified resins depended on PMS molecular weight and content. The most effective modification of the cyanate ester resin was attained because of the cocontinuous phase structure of the modified resin. Inclusion of 10 wt % PMS (M_w 133,000) led to an 160% increase in the fracture toughness (K_IC) for the modified resin with a slight loss of flexural strength and retention of flexural modulus and the glass transition temperature, compared to the values for the unmodified resin. Low water absorptivity of the parent‐cured resin was not deteriorated by modification. The toughening mechanism was discussed in terms of the morphological and dynamic viscoelastic behaviors of the modified cyanate ester resin system. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2931–2939, 1999     

Toughening vinyl ester networks with polypropylene meso-fibers: Interface modification and composite properties

Polymer-polymer composites comprised of vinyl ester matrices (VE) and polypropylene (PP) fiber meshes were fabricated and tested in this investigation. Results indicated that PP fibers greatly enhanced fracture toughness; however, strength of the VE was significantly reduced as voids were observed at the interface of the PP and VE. A two-step surface modification, oxygen plasma treatment followed by grafting vinyltrimethoxysilane (VTMS), was conducted on PP fibers in an effort to improve interfacial strength. Interfacial discontinuities of composites were improved after surface modification of PP. The oxygen plasma treatment added hydrophilic functional groups but caused surface roughness. Surface treatment of PP slightly increased fracture toughness of the PP-VE composite by enhancing energy absorption capacity at the interface. However, mechanical strength and modulus did not significantly increase for the composite using VTMS grafted PP fibers due to the weak fiber material. Small PP fibers with higher strength may attain the expected improvement in mechanical properties after surface treatment.     

Combustibility of cyanate ester resins

Flaming and non‐flaming combustion studies were conducted on a series of polycyanurates to examine the effect of chemical composition and physical properties on the fire behavior of these crosslinked, char forming, thermoset polymers. Heats of complete combustion of the polymer and fuel gases were determined by oxygen bomb calorimetry and pyrolysis‐combustion flow calorimetry, respectively. Fire calorimetry experiments were conducted to measure the total heat released, the rate of heat release and the smoke generation in flaming combustion. Fire response parameters derived from the data include the thermal inertia, heat of gasification, effective heat of combustion and combustion efficiency. Halogen‐containing polycyanurates exhibited extremely low heat release rate in flaming combustion compared with the hydrocarbon resins yet produced significantly less smoke and comparable levels of carbon monoxide and soot. Published in 2005 by John Wiley & Sons, Ltd.     

改性氰酸酯类耐高温胶粘剂的研究

以双马来酰亚胺(BMI)、双酚A型氰酸酯(BADCy)和苯并噁嗪(BOZ)树脂为基体树脂,纳米二氧化硅(nano-SiO2)为填料,制备耐高温胶粘剂。采用非等温差示扫描量热(DSC)法、Kissinger法和Ozawa法研究了nano-SiO2/BOZ/BMI/BADCy共聚物的固化动力学过程。结果表明:当m(BOZ)∶m(BMI)∶m(BADCy)=1∶1∶2、w(nano-SiO2)=3%时,相应BOZ/BMI/BADCy胶粘剂的表观活化能(47.82 kJ/mol)低于无nano-SiO2体系(59.17 kJ/mol),并具有良好的耐高温性能;在250℃时用该胶粘剂胶接硅钢片,胶接件经250℃老化1 000 h后,其剪切强度仍保持稳定。     

氰酸酯树脂的研究进展

介绍了国内外氰酸酯树脂(CE)领域的最新研究进展,包括新型CE单体开发、与热固性树脂共聚及热塑性树脂共混改性等,简述了各种改性方法的基本机理,并对今后CE的发展趋势作了展望。     

Frontal polymerization of a cyanate ester

Thermal frontal polymerization is an exothermic process that uses a propagating wave to polymerize monomers via an external heat source, such as a soldering iron, to initiate front propagation. Herein, for the first time, the curing of a cyanate ester via thermal frontal polymerization is described with two different external heat sources. However, issues of bubbling due to vaporization of the amine catalyst generally resulted in incomplete frontal polymerization when a soldering iron was used as the external heat source. To counter this issue, dual‐strip polymerization systems were used, wherein the heat from the exothermic polymerization of a free‐radical system was used to initiate the frontal polymerization of a cyanate ester system with an amine catalyst. As a result, complete frontal polymerization occurred. Additionally, the effect of the width of the acrylate strip and its impact on the front temperature, initial velocity, and steady‐state velocity of the adjacent cyanate ester system were studied. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

EVA弹性体对PHBV的增韧改性研究

采用熔融共混法,通过在聚（3⁃羟基丁酸酯⁃co⁃3⁃羟基戊酸酯） PHBV中添加不同比例含量的乙烯⁃乙酸乙烯酯（EVA）弹性体,制备了一系列PHBV/EVA复合材料,并通过傅里叶红外光谱仪、转矩流变仪、差示扫描量热仪、热失重分析仪、力学性能测试、热台偏光显微镜等设备,对PHBV/EVA复合材料的结构和性能进行表征。结果表明,PHBV与EVA之间的氢键作用、链缠结作用以及相似的主链结构使得二者之间的相容性和分散性较好;随着EVA含量的逐渐升高,PHBV/EVA复合材料的结晶度表现出先升高后降低的趋势;EVA添加量小于10 %（质量分数,下同）时,随着EVA含量的增加,PHBV的球晶数量逐渐增加,球晶尺寸逐渐变小;EVA的添加量为30 %时,PHBV/EVA复合材料的断裂伸长率和冲击强度增长幅度最大,与纯PHBV相比,分别增长了87.8 %和338.4 %。     

羧基丁腈橡胶增韧改性苯并噁嗪树脂

采用液态端羧基丁腈橡胶(CTBN)对二苯甲烷二胺型苯并(?)嗪树脂(B-BOZ)进行改性,研究了不同m(CTBN)/m(B-BOZ)体系的性能。结果表明:当CTBN用量为10 phr,温度为110℃,时间为150 min时,树脂黏度小于0.5 Pa·s,其固化产物的拉伸强度和断裂伸长率分别达68.4 MPa和2.1%;固化树脂拉伸和弯曲模量则随CTBN用量增加而下降。固化产物相形态分析表明,CTBN用量达10 phr时,改性产物因CTBN粒子的拉伸撕裂和空洞化剪切屈服共同作用能够吸收较多能量,达到较好的增韧效果。     

环氧树脂改性氰酸酯树脂的研究进展

综述了采用环氧树脂(EP)增韧改性氰酸酯(CE)树脂的共聚反应机理、固化产物的性能和复合材料的性能。CE在水分或残留的酚及金属离子等作用下自聚生成三嗪环,接着与EP反应生成口恶唑烷酮。CE改性后树脂的韧性和弯曲强度提高,而玻璃化温度和耐热性下降很少,且固化产物耐湿热性能和介电性能基本维持不变。     

Triazine networks modified with monofunctional reactive cyanate ester monomers

The preparation of cyanate ester thermosetting resins by coreacting a fluorinated bisphenol A dicyanate (6F-BADCY) monomer with a monofunctional reactive cyanate, namely, the dinonyl phenol cyanate (DNPC), is described in this paper. Our objective in this study was to modify the 6F-BADCY system with reactive diluents of a nonpolar nature and produce matrix resins processable at FR-4 epoxylike conditions. By introducing the monofunctional cyanate as a reactive diluent, it is expected that the molar crosslink density of the resulting network will be reduced. Highly branched triazine polymers will result from this approach. Dinonyl phenol cyanate was quantitatively synthesized by reacting dinonyl phenol with cyanogen bromide in the presence of triethylamine.     

Cure reactions in the blend of cyanate ester with maleimide

Cure reactions of a bismaleimide (4,4′-bismaleimidodiphenylmethane, BMI) associated with a liquid aromatic dicyanate ester (1,1′-bis(4-cyanatophenyl)ethane, BEDCy) and with a powder type aromatic dicyanate ester (bisphenol A dicyanate, BADCy) were investigated by in situ FTIR and DSC dynamic scanning. In non-catalyzed blend systems, co-reactions between dicyanate ester and bismaleimide always occur, and hence the formation of pyrimidine and/or pyridine structures take place. Pyrimidine structures always predominate. Probable reaction paths were also proposed for various formulations of hybrid blends. In addition, N-phenylmaleimide (MI) and p-phenyl-phenylcyanate (S-Cy) were utilized as model compounds and mixed via a melting method and a solution method to explore the corresponding cure reactions by means of FTIR, DSC and NMR. ¹³C NMR spectra of the model compounds demonstrated the formation of linkages of sym-triazine rings, pyrimidine structures, pyridine structures and dioxazine structures. The reaction mechanism or linkage structures produced in the model compound system studied may be somewhat different from those of the real system due to a diffusion effect in real systems or to the different activation energy in both systems.     

Rubber modification of low temperature cure cyanate ester matrices and the performance in glass fabric composites

Low temperature cure cyanate ester resin systems were developed and modified with epoxy‐terminated butadiene acrylonitrile rubber (ETBN) and impregnated into woven glass fabric. Mode I and mode II interlaminar fracture toughness values of the cured laminates were evaluated as a function of rubber concentration. Mode I fracture toughness increased to almost twice that of the unmodified system, while mode II fracture toughness remained essentially unchanged. Composite samples were subjected to aging experiments in water and the absorption/desorption behavior was investigated as was the effect on thermal performance. The presence of rubber was found to reduce the rate of matrix deterioration but also caused a substantial increase in water uptake. It was found that although the addition of rubber to the matrices decreased the unconditioned (dry) T_g all specimens showed the same reduction in T_g, after equilibrium water absorption.