聚丙烯酸酯/环氧树脂互穿网络聚合物的研究Ⅲ.橡胶态弹性模量和互穿缠结

采用一步法（Ｓｉｍｕｌｔａｎｅｏｕｓｌｙ）合成了双组分的聚丙烯酸酯／环氧树脂互穿网络聚合物（ＩＰＮｓ）．选择预溶胀方法制备了聚丙烯酸酯和环氧树脂两种组分网络．测定了各种组分比的ＩＰＮ和不同溶胀度下的组分网络的动态力学性能，从橡胶态弹性理论出发讨论了ＩＰＮ和预溶胀网络之间在橡胶态弹性模量上的关系，并据此指出互穿缠结增加了网络的有效“交联密度”，因此，它对ＩＰＮ的橡胶态弹性模量有较大的贡献．密度测量的结果也提供了另一方面的证据     

环状低聚芳醚酮,聚芳醚砜和聚芳香酯的快离子轰击质谱分析

本文采用快离子轰击质谱（ＦＩＢＭＳ）技术分别选用甘油，Ｓ－甘油和间硝基苄醇做底物，对五种环状芳香低聚物进行分析，确定了几种不同大小的芳香环状低聚物的存在，并同时给出各种不同聚合度组分的相对含量。实验证明，质谱是分析环状低聚物的快速，有效地方法。     

动态固化聚丙烯/环氧树脂共混物的研究

将动态硫化技术应用于热塑性树脂 热固性树脂体系 ,制备了动态固化聚丙烯 (PP) 环氧树脂共混物 .研究了动态固化PP 环氧树脂共混物中两组分的相容性、力学性能、热性能和动态力学性能 .实验结果表明 ,马来酸酐接枝的聚丙烯 (PP g MAH)作为PP和环氧树脂体系的增容剂 ,使分散相环氧树脂颗粒变细 ,增加了两组分的界面作用力 ,改善了共混物的力学性能 .与PP相比 ,动态固化PP 环氧树脂共混物具有较高的强度和模量 ,含 5 %环氧树脂的共混物拉伸强度和弯曲模量分别提高了 30 %和 5 0 % ,冲击强度增加了 15 % ,但断裂伸长率却明显降低 .继续增加环氧树脂的含量 ,共混物的拉伸强度和弯曲模量增加缓慢 ,冲击强度无明显变化 ,断裂伸长率进一步降低 .动态力学性能分析 (DMTA)表明动态固化PP 环氧树脂共混物是两相结构 ,具有较高的储能模量 (E′)     

橡胶／纳米无机粒子增韧增强环氧树脂的研究

综述了当前环氧树脂增韧增强改性的研究现状,详细介绍了弹性体增韧环氧树脂、无机纳米粒子改性环氧树脂、粘土改性环氧树脂、纳米SiO2改性环氧树脂以及弹性体／无机纳米粒子协同增韧增强环氧树脂的机理和实验方法。并对其实验结果进行了分析比较。     

氨基硅油改性碳纤维/环氧树脂复合材料的耐老化性能

通过在复合树脂基体中引入氨基硅油进行改性,制备了不同氨基硅油含量的碳纤维/环氧树脂复合材料,在湿热环境下进行老化实验后,通过动态热机械分析(DMA)、热重分析(TGA)、拉伸性能测试、扫描电镜(SEM)及接触角测定等方法研究氨基硅油对于碳纤维/环氧树脂复合材料热力学性能、力学强度保持率和耐水性能的改善效果。实验结果表明,经老化实验后含氨基硅油材料的抗拉强度保持率最高提升了13.23%。当氨基硅油含量为8 wt%时,复合材料表面接触角均值大于90~o。氨基硅油对环氧树脂基体的改性可改善碳纤维/环氧树脂复合材料的耐湿热老化性能。     

亚临界水介质回收酸酐固化环氧树脂/碳纤维复合材料

研究了不同添加剂对碳纤维增强酸酐固化环氧树脂复合材料在亚临界水中降解的影响,通过IR、GC-MS等分析,确定了环氧树脂的分解机理主要为酯键的断裂。 结果表明,KOH与苯酚对酸酐固化环氧树脂的分解没有协同效应,碱性物质更有利于酯键的断裂。 甲基四氢邻苯二甲酸酐固化的环氧树脂增强碳纤维复合材料在反应温度为250 ℃、反应时间为60 min、KOH浓度为0.2 mol/L时可完全分解,回收碳纤维的拉伸强度和表面形貌未受影响。     

接枝环氧树脂的合成,表征,形态及其对环氧树脂的增韧效应

合成与表征了一系列不同分子量的聚氧化丙烯（ＰＰＯ）接枝环氧树脂（ｅｐｏｘｙ－ｇ－ＰＯ），考察了这些接枝环氧树脂和它们网络的形态，以及它们与环氧树脂形成接枝网络后的物理性能．实验结果表明，ｅｐｏｘｙ－ｇ－ＰＯ接枝效率为０．９６左右；随ｅｐｏｘｙ－ｇ－ＰＯ中侧链长度的改变，导致接枝环氧树脂网络发生部分微观相分离行为．在环氧树脂中适量添ｅｐｏｘｙ－ｇ－ＰＯ能较大幅度地提高环氧树脂网络的韧性，与ｅｐｏｘｙ－ｇ－ＰＯ的形态有关．     

环氧树脂的动态力学性能

用声频共振法在25—250℃温度范围内研究了以顺丁烯二酸酐固化的环氧树脂的动态力学性能。杨氏模量及内耗温度谱的实验结果指出:环氧树脂具有典型微少交联高聚物的力学性貭。随着固化程度的不同,大约在150℃左右已固化的环氧树脂由玻璃态转变为高弹态,此时模量急骤下降同时出现内耗峯,在此温度以上试样显示出橡皮高强特征。上述结果与其他一些研究结果一致,然而由内耗峯所确定的玻璃化转变温度却远高于及其同工作者用温度-形变曲綫法所测得的玻璃化转变温度。根据外力对动态力学性能的影响及我们以前的工作,我们认为外力有可能在环氧树脂分子网中产生了某种力化学效应,而动态力学结果与温度形变结果之间的差异可能正是由于此一原因。 根据实验结果还给出了以顺丁烯二酸酐固化的环氧树脂玻璃化转变温度与交联度间的关系,并对结果进行了讨论。     

DAIP改性环氧树脂研究

采用共固化的方法,得到酚醛环氧树脂(F-51)和间苯二甲酸二烯丙基酯(DAIP)的共固化树脂。实验结果表明:DAIP的加入降低了F-51环氧树脂的粘度[体系粘度为150～350mPa·s(25℃)],利于工艺操作;提高了F-51环氧树脂的耐热性,热变形温度达200℃。研究了F-51环氧树脂和DAIP共固化的固化行为、不同配比对共固化物形态结构的影响;并研究了不同配比对固化物耐热性的影响。     

胶粘剂拉伸剪切强度测量结果的不确定度评定

依据GB/T 7124-2008《胶粘剂拉伸剪切强度的测定》,以环氧树脂结构胶为例,对胶粘剂拉伸剪切强度测量结果的不确定度分量进行了分析和量化,计算了合成标准不确定度和扩展不确定度。当环氧树脂结构胶的拉伸剪切强度为28.8 MPa时,扩展不确定度为1.0 MPa(k=2)。     

Novel Epoxy Resins Derived from Biomass Components

Biomass has received considerable attention because it is renewable and offers the prospect of circulation of carbon in the ecological system. The concept “Biorefinery” has been developed rapidly in order to establish sustainable industries. Recently, new types of epoxy resins with polyester chains, which can be derived from saccharides, lignin and glycerol, have been investigated. In the above studies, the relationship between chemical structure and physical properties was investigated. In the present review, the features of the preparation system and the action of biomass components in epoxy resin polymer networks are described. The glass transition temperatures of the epoxy resins increased with increasing content of biomass components in epoxy resin polymer networks. Thermal decomposition temperatures were almost constant regardless of the content of biomass components contents in epoxy resins. Mass residue at 500 °C increased with increasing contents of biomass components in epoxy resins. It was found that the thermal properties can be controlled by changing the contents of biomass components.     

丙烯酸酯/环氧的自由基/阳离子同步光聚合混合体系的研究

科学技术的进步,对新材料的要求逐步向着多功能和高性能的方向发展,单组分材料已难于满足这种要求,在高分子材料方面,人们采用了共混、接枝、嵌段等方法以达到改善和提高性能的目的。感光性高分子是一类很重要的功能材料,至今,大部分采用自由基聚合方式制备。近年来,阳离子引发体系发展很快,特别鎓盐光引发体系受到很大的重视,发展迅速。     

Ceramers Based on Crosslinked Epoxy Resins-Silica Hybrids: Low Surface Energy Systems

Ceramers based on silica and bisphenol-A epoxy resin cured with methyl nadic anhydride (MNA) and diamino diphenyl sulphone (DDS) were prepared in THF solutions. Compatibilization was induced through functionalization of the epoxy resin with amine trialkoxy silanes prior to mixing with a pre-hydrolyzed tetralkoxysilane solution (TEOS).The epoxy ceramers were further modified by the addition of small amounts of a silane functionalized alkane perfluoroether oligomer.A morphology consisting of very fine interpenetrating phases could be easily achieved through the silane functionalization of the epoxy resin. The final ceramer, however, always displayed a reduction in the glass transition temperature (Tg), resulting either from reactions of the anhydride hardener with the ethanol produced from the hydrolysis of TEOS or from the reaction of the acid catalyst with the epoxy groups.The use of the perfluoroether oligomer produced a large reduction in surface energy due to migration of the fluorinated components to the outer layers of the films.     

Diglycidyl ether of bisphenol-A epoxy resin–polyether sulfone/polyether sulfone ether ketone blends: phase morphology, fracture toughness and thermo-mechanical properties

The properties of diglycidyl ether of bisphenol-A epoxy resin toughened with poly(ether sulfone ether ketone) (PESEK) and poly(ether sulfone) (PES) polymers were investigated. PESEK was synthesised by the nucleophilic substitution reaction of 4,4’-difluorobenzophenone with dihydroxydiphenylsulfone using sulfolane as solvent and potassium carbonate as catalyst at 230 °C. The T _g–composition behaviour of the homogeneous epoxy resin/PESEK blend was modelled using Fox, Gordon–Taylor and Kelley–Bueche equations. A single relaxation near the glass transition of epoxy resin was observed in all the blend systems. From dynamic mechanical analysis, the crosslink density of the blends was found to decrease with increase in the thermoplastic concentration. The storage modulus of the epoxy/PESEK blends was lower than that of neat resin, whilst it is higher for epoxy/PES blends up to glass transition temperature, thereafter it decreases. Scanning electron microscopic studies of the blends revealed a homogeneous morphology. The homogeneity of the blends was attributed to the similarity in chemical structure of the modifier and the cured epoxy network and due to the H-bonding interactions between the blend components. The fracture toughness of epoxy resin increased on blending with PESEK and PES. The increase in fracture toughness was due to the increase in ductility of the matrix. The thermal stability of the blends was comparable to that of neat epoxy resin.     

含磷有机硅杂化环氧树脂固化体系性能研究

通过磷酸与γ-环氧丙氧基三甲氧基硅烷反应得到含磷有机硅氧烷,并加入到环氧树脂/4,4'-二氨基二苯基甲烷体系中混合,通过溶胶-凝胶的方法制备了含磷有机硅杂化环氧树脂固化物.对固化体系进行了玻璃化转变温度、热失重、阻燃、拉伸强度、冲击强度测试分析.结果表明,该固化体系的阻燃性得到提高,极限氧指数在25.8～29.3,玻璃化转变温度得到提高,在161～179℃;虽然初始分解温度比纯环氧树脂固化物低,但800℃残炭率可以达到26.5%,提高了36%;拉伸强度得到提高,在71～94 MPa,冲击强度可以达到14.36 kJ/m2,提高了14%.该固化体系具有较好的阻燃性能和热性能,同时具有较好的力学性能.     

FTIR法研究环氧树脂固化反应动力学

用傅里叶红外光谱（ＦＴＩＲ）法研究了双酚Ｓ环氧树脂和甲溴双酚Ａ环氧树脂分别与二胺基二苯砜在恒温条件下的固化反应动力学,得出了各反应的表观活化能。     

Fire Retardancy of Aluminum Hydroxide Reinforced Flame Retardant Modified Epoxy Resin Composite

A novel phosphorous containing flame retardant epoxy resin is synthesized by modifying the epoxy resin initially with phosphoric acid and further with aluminum hydroxide (ATH) to enhance the fire retardancy of the modified epoxy resin. The several phosphorous modified epoxy resin to ATH mass ratios were used to study the effect of ATH addition on epoxy. Thermal and mechanical properties. The structure of the modified flame retardant epoxy resin was characterized using Fourier-transform infrared spectroscopy (FTIR) while thermal degradation behavior and flame retardant properties were examined using thermo-gravimetric analysis (TGA) and UL-94 testing. Furthermore, ultimate tensile strength and young modulus were analyzed to study the effect of ATH addition on mechanical properties. The findings indicated that fire retardancy of ATH reinforced modified ep oxy resin is higher than virgin and phosphorous modified epoxy resin and depicted eminent flame retardant properties with suitable mechanical properties.

     

Pyrolysis and fire behaviour of epoxy resin composites based on a phosphorus-containing polyhedral oligomeric silsesquioxane (DOPO-POSS)

The pyrolysis and fire behaviour of epoxy resin (EP) composites based on a novel polyhedral oligomeric silsesquioxane containing 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO-POSS) and diglycidyl ether of bisphenol A (DGEBA) have been investigated. The pre-reaction between the hydroxyl groups of DOPO-POSS and the epoxy groups of DGEBA at 140 °C is confirmed by FTIR, which means that DOPO-POSS molecules of hydroxyl group could easily disperse into the epoxy resin at the molecular level. The EP composites with the DOPO-POSS were prepared through a curing agent, m-phenylenediamine (m-PDA). The morphologies of the EP composites observed by SEM indicate that DOPO-POSS disperses with nano-scale particles in the EP networks, which implies good compatibility between them. The thermal properties and pyrolysis of the EP composites were analyzed by DSC and TGA, TGA-FTIR, and TGA-MS. The analysis indicates that the DOPO-POSS change the decomposition pathways of the epoxy resin and increase its residue at high temperature; moreover, the release of phosphorous products in the gas phase and the existence of Si-O and P-O structures in the residue Is noted. The fire behaviour of the EP composites was evaluated by cone calorimeter (CONE). The CONE tests show that incorporation of DOPO-POSS into epoxy resin can significantly improve the flame retardancy of EP composites. SEM and XPS were used to explore micro-structures and chemical components of the char from CONE tests of the EP composites, they support the view that DOPO-POSS makes the char strong with the involvement of Si-O and P-O structures.     

Global kinetics of thermal degradation of flame-retarded epoxy resin formulations

A predictive mathematical model to describe mass loss profiles of flame-retardant (FR) containing epoxy resin formulations is proposed. Mass loss is due to thermal degradation of the constituent components and can be described by a generic kinetic scheme with a given set of thermokinetic constants in the form of ordinary differential equations. The scope of this work is to determine the kinetic parameters of the thermal degradation of a known flame-retarded epoxy resin composition by using thermogravimetric analysis and using the acquired data to predict the degradation profiles for other formulations. The mass loss profiles of Visil and intumescent epoxy resin containing formulations were predicted by solving coupled systems of ordinary differential equations and then using Powell minimisation to find the optimal Arrhenius parameters, taking into account the mass ratio of the components in the mixture. The calculated kinetic constants for one formulation (85% resin-15% FR additives) are used to predict the mass loss profiles for other formulations (80% resin-20% FR additives and 90% resin-10% FR additives) with the assumption that the degradation mechanism does not change. The predicted thermal degradation profiles are compared with experimental data acquired using standard laboratory equipment in order to validate the proposed mechanisms. The kinetic parameters obtained adequately describe mass loss history of composite materials studied, even when extremely simplified kinetic schemes have been used.