胺类固化剂固化的双酚环氧树脂回收再利用的研究

双酚F型环氧树脂的耐酸性较低，在硝酸溶液中能够被安全分解。基于这一特性，本文探讨了一种环氧树脂化学回收再利用的方法。首先，用乙酸乙酯做溶液把该树脂的硝酸分解生成物从中性环境溶液中萃取出来，干燥后，替代部分环氧树脂，混入环氧树脂中，经固化剂固化后，制得再生树脂。并对原树脂和再生树脂的机械性能进行了比较。     

An approach to chemical recycling of epoxy resin cured with amine using nitric acid

An approach to chemical recycling of epoxy resin was pursued. Bisphenol F type epoxy resin cured with 1,8-p-menthanediamine could be completely decomposed in nitric acid solution resulting from low corrosion resistance to nitric acid. Organic decomposed products of the resin with the highest yield were extracted from neutralized solution. The extract was repolymerized to prepare recycled resin, mixed with bisphenol F type epoxy resin and curing agent of phthalic anhydride. The mechanical properties of virgin resin and recycled resins were compared. It was surprising that the recycled resins were far superior to the virgin resin in strength. The results obtained from differential scanning calorimeter (DSC) showed that the glass transition temperature (T_g) of recycled resins was higher than that of virgin resin. The reason that they formed the better network structure was discussed.     

Preparation and properties of one epoxy system bearing fluorene moieties

Diglycidyl ether of bisphenol fluorene (DGEBF) and 9,9‐bis(4‐aminophenyl) fluorene (BPF) were synthesized to introduce more aromatic structures into an epoxy system, and their chemical structures were characterized with Fourier transform infrared spectroscopy, NMR, and mass spectrometric analysis. The dynamic curing behavior of the DGEBF/BPF system was investigated with differential scanning calorimetry. DGEBF was cured with BPF, diaminodiphenylsulfone (DDS), and diaminodiphenylmethane (DDM), and E‐44 (bisphenol A epoxide) was also cured with BPF for comparison. The thermal properties of the obtained polymers were evaluated with dynamic mechanical thermal analysis and thermogravimetric analysis. The cured DGEBF/BPF system showed a remarkably higher glass‐transition temperature, better thermal stability and lower moisture absorption in comparison with the general bisphenol A epoxy resin/BPF system but approximated the heat resistance of the DGEBF/DDS and DGEBF/DDM systems. Such properties make this epoxy system very promising for heat‐resistant applications. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

紫外光固化低黏度环氧丙烯酸酯的合成研究

以双酚F环氧树脂和丙烯酸为原料,合成紫外光固化低黏度双酚F型环氧丙烯酸酯。讨论了引发剂、阻聚剂、反应温度等因素对反应的影响,用IR对环氧树脂及环氧丙烯酸酯的结构进行了表征。     

Epoxy resin containing the poly(sily ether): Preparation,morphology, and mechanical properties

The poly(sily ether) with pendant chloromethyl groups (PSE) was synthesized by the polyaddition of dichloromethylsilane (DCM) and diglycidylether of bisphenol A (DGEBA) with tetrabutylammonium chloride (TBAC) as a catalyst. This polymer was miscible with diglycidyl ether of bisphenol A (DGEBA), the precursor of epoxy resin. The miscibility is considered to be due mainly to entropy contribution because the molecular weight of DGEBA is quite low. The blends of epoxy resin with PSE were prepared through in situ curing reaction of diglycidyl ether of bisphenol A (DGEBA) and 4,4′‐diaminodiphenylmethane (DDM) in the presence of PSE. The DDM‐cured epoxy resin/PSE blends with PSE content up to 40 wt % were obtained. The reaction started from the initial homogeneous ternary mixture of DGEBA/DDM/PSE. With curing proceeding, phase separation induced by polymerization occurred. PSE was immiscible with the 4,4′‐diaminodiphenylmethane‐cured epoxy resin (ER) because the blends exhibited two separate glass transition temperatures (T_gs) as revealed by the means of differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). SEM showed that all the ER/PSE blends are heterogeneous. Depending on blend composition, the blends can display PSE‐ or epoxy‐dispersed morphologies, respectively. The mechanical test showed that the DDM‐cured ER/PSE blend containing 25 wt % PSE displayed a substantial improvement in Izod impact strength, i.e., epoxy resin was significantly toughened. The improvement in impact toughness corresponded to the formation of PSE‐dispersed phase structure. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 505–512, 2003     

Preparation and Application of a New Curing Agent for Epoxy Resin

A new curing agent based on palmitoleic acid methyl ester modified amine (PAMEA) for epoxy resin was synthesized and characterized. Diglycidyl ether of bisphenol A (DGEBA) epoxy resins cured with different content of PAMEA along with diethylenetriamine (DETA) were prepared. The mechanical properties, dynamic mechanical properties, thermal properties, and morphology were investigated. The results indicated that the PAMEA curing agent can improve the impact strength of the cured epoxy resins considerably in comparison with the DETA curing agent, while the modulus and strength of the cured resin can also be improved slightly. When the PAMEA/epoxy resin weight ratio is 30/100, the comprehensive mechanical properties of the cured epoxy resin are optimal; at the same time, the crosslinking density and glass transition temperature of the cured epoxy resin are maximal.     

The Miscibility of Novel Bisphenol-Propylene Epoxy Resin With Liquid NBR

A novel kind of bisphenol-type epoxy resin with a vinyl side-chain was developed and its miscibility behavior with liquid nitrile-butadiene rubber (NBR) was investigated. The diglycidyl ether of bisphenol propylene (DGEBP) was prepared by the condensation of phenol with acrolein in the presence of an acid catalyst and the subsequent epoxidization with epichlorohydrin (ECH). The structures of the bisphenol and corresponding epoxy resin were characterized by infrared (IR) and nuclear magnetic resonance (NMR) spectral analyses and the epoxy value was determined to be 0.34 mol/100 g by titration. The mixture of DGEBP with the liquid NBR containing diglycidyl ether of bisphenol acetone (DGEBA) was prepared and cured with diaminodiphenylmethane (DDM). The miscibility and morphology of the mixture system were studied by dynamic mechanical thermal analysis (DMTA) and transmission electron microscopy (TEM), respectively. The cured mixture of DGEBP/NBR/DDM exhibited good miscibility and, therefore, no separation, along with a transparent appearance at rubber contents of 10 wt% and 30 wt%. For cured DGEBP/DGEBA/NBR/DDM systems at 20 wt% rubber content, the dispersed rubber phase and rubber particles were not observed by DMTA or TEM at DGEBP content above 40 wt%. The DMTA plot showed a single peak related to the glass transition temperature (T _g) which decreased with increasing DGEBP content. The appearance of the system varied from transparent to opaque and the rubber separated from the epoxy matrix to form two phases when the DGEBP content decreased. The T _g values of the rubber- and epoxy-rich phases were strongly dependent on the DGEBP content in the mixed system. The miscibility of epoxy resin with liquid NBR can be altered by varying the ratio of DGEBP to DGEBA.     

Low-temperature fast curable behavior and properties of bio-based carbon fiber composites based on resveratrol

Environmentally friendly materials are an integral part of sustainable chemistry, and bio-based polymer composites are an important class of materials. The manufacture of composites is expected to reduce or even eliminate the use of adjuvants, considering the importance of reducing energy consumption and avoiding health and environmental risks. In this study, a phenyl-containing, polyfunctional, bio-based epoxy resin (TGER) was synthesized, and carbon fiber-reinforced, bio-based epoxy resin composites were fabricated by vacuum-assisted resin infusion using two aromatic amine curing agents, 4,4′-diaminodiphenylmethane (DDM) and 3,3′-diethyl-4,4′-diaminodiphenylmethane (DEDDM). Curing reactions and rheological behavior studies showed that TGER had higher curing reactivity toward DDM and DEDDM than to diglycidyl ether of bisphenol A (DGEBA) and possessed good processability. The results indicated that the resveratrol-based epoxy resin displayed low-temperature fast curing properties. The evaluation of the mechanical properties of the carbon fiber composites showed that the flexural strengths of CF/TGER/DDM and CF/TGER/DEDDM were 520 and 628 MPa, respectively. The initial decomposition temperature of CF/TGER composites is above 200°C. Furthermore, the carbon fiber–reinforced biopolymers possess excellent heat resistance. Therefore, carbon fiber-reinforced, resveratrol-based epoxy resin composites are promising candidates as alternatives to petroleum-based high-performance carbon fiber composites.     

Cure kinetics and thermal stability of micro and nanostructured thermosetting blends of epoxy resin and epoxidized styrene‐block‐butadiene‐block‐styrene triblock copolymer systems

The compatibility of styrene‐block‐butadiene‐block‐styrene (SBS) triblockcopolymer in epoxy resin is increased by the epoxidation of butadiene segment, using hydrogen peroxide in the presence of an in situ prepared catalyst in water/dichloroethane biphasic system. Highly epoxidized SBS (epoxy content SBS >26 mol%) give rise to nanostructured blends with epoxy resin. The cure kinetics of micro and nanostructured blends of epoxy resin [diglycidyl ether of bisphenol A; (DGEBA)]/amine curing agent [4,4′‐diaminodiphenylmethane (DDM)] with epoxidized styrene‐block‐butadiene‐block‐styrene (eSBS 47 mol%) triblock copolymer has been studied for the first time using differential scanning calorimetry under isothermal conditions to determine the reaction kinetic parameters such as kinetic constants and activation energy. The cure reaction rate is decreased with increasing the concentration of eSBS in the blends and also with the lowering of cure temperature. The compatibility of eSBS in epoxy resin is investigated in detailed by Fourier transform infrared spectroscopy, optical and transmition electron microscopic analysis. The experimental data of the cure behavior for the systems, epoxy/DDM and epoxy/eSBS(47 mol%)/DDM show an autocatalytic behavior regardless of the presence of eSBS in agreement with Kamal's model. The thermal stability of cured resins is also evaluated using thermogravimetry in nitrogen atmosphere. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers     

玻璃纤维／环氧树脂复合材料的热性能

本文采用E-玻璃纤维作为增强材料、双酚A环氧树脂和芳胺类固化剂作为基体制成复合材料试样,利用动态与静态热分析方法测定玻璃纤维／环氧树脂基复合材料的热性能,研究了玻璃纤维含量对复合材料动态热机械性能、玻璃化温度等热性能的影响。     

Preparation,curing kinetics,and thermal properties of bisphenol fluorene epoxy resin

Diglycidyl ether of 9,9‐bis(4‐hydroxyphenyl) fluorene (DGEBF) was synthesized to introduce more aromatic structures into an epoxy resin system. The structure of DGEBF was characterized with Fourier transform infrared and ¹H‐NMR. 4,4′‐Diaminodiphenylmethane (DDM) was used as the curing agent for DGEBF, and differential scanning calorimetry was applied to study the curing kinetics. The glass‐transition temperature of the cured DGEBF/DDM, determined by dynamic mechanical analysis, was 260°C, which was about 100°C higher than that of widely used diglycidyl ether of bisphenol A (DGEBA). Thermogravimetric analysis was used to study the thermal degradation behavior of the cured DGEBF/DDM system: its onset degradation temperature was 370°C, and at 700°C, its char yield was about 27%, whereas that of cured DGEBA/DDM was only 14%. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

固化体系对环氧树脂耐高温性能的影响

针对覆铜板的耐高温要求,分别使用胺类固化剂4,4′-二氨基二苯砜(DDS)、4,4′-二氨基二苯醚(DDE)和乙二胺(EDA)固化改性双酚A型环氧树脂,研制适用于耐高温覆铜板的环氧树脂固化物。用示差扫描量热法(DSC)研究其固化过程,讨论了固化剂用量、固化剂种类及固化温度等因素对固化物玻璃化转变温度(Tg)的影响。实验结果表明,固化物耐热性最好的配比不是化学计量,而是偏离化学计量,在理论用量的基础上适当增加固化剂用量,可有效地提高固化产物的玻璃化温度Tg值;使用芳香胺类固化剂固化双酚A型环氧树脂,其固化产物有较高的玻璃化温度,可以满足覆铜板耐高温的要求。     

FTIR法研究芳胺固化双酚S环氧树脂反应动力学

用傅里叶红外光谱 (FTIR)法研究了几种芳香二胺在恒温下分别固化双酚 S环氧树脂(BPSER)的固化反应动力学 ,得出了各固化反应的表观活化能     

Epoxy resin based on 4,4′-dihydroxydiphenysulfone. I. Synthesis and reaction kinetics with 4,4′-diaminodiphenylmethane and 4,4′-diaminodiphenylsulfone

Epoxy resins based on 4,4′-dihydroxydiphenylsulfone (DGEBS) and diglycidyl ether of bisphenol A (DGEBA) were prepared by alkaline condensation of 4,4′-dihydroxydiphenylsulfone (bisphenol S) with epichlorohydrin and by recrystallization of liquid, commercial bisphenol A-type epoxy resin, respectively. Curing kinetics of the two epoxy compounds with 4,4′-diaminodiphenylmethane (DDM) and with 4,4′-diaminodiphenylsulfone (DDS) as well as T_g values of the cured materials were determined by the DSC method. It was found that the ? SO₂? group both in the epoxy resin and in the harener increases T_g values of the cured materials. DGEBS reacts with the used hardeners faster than does DGEBA and the curing reaction of DGEBS begins at lower temperature than does the curing reaction of DGEBA when the same amine is used. © 1994 John Wiley & Sons, Inc.     

Mechanical properties of poly(styrene‐co‐acrylonitrile)‐modified epoxy resin/glass fiber composites

Poly(styrene‐co‐acylonitrile) was used to modify diglycedyl ether of bisphenol‐A type epoxy resin cured with diamino diphenyl sulfone and the modified epoxy resin was used as the matrix for fiber‐reinforced composites (FRPs) to get improved mechanical properties. E‐glass fiber was used as fiber reinforcement. The tensile, flexural, and impact properties of the blends and composites were investigated. The blends exhibited considerable improvement in mechanical properties. The scanning electron micrographs of the fractured surfaces of the blends and tensile fractured surfaces of the composites were also analyzed. The micrographs showed the influence of morphology on the properties of blends. Results showed that the mechanical properties of glass FRPs increased gradually upon fiber loading. Predictive models were applied using various equations to compare the mechanical data obtained theoretically and experimentally. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Hyperbranched aromatic epoxies in the design of adhesive materials

Summary The use of hyperbranched aromatic epoxy polymer 2 (HARE) as a component in various adhesion experiments has been demonstrated. Two different modes of curing were tested, including a photoinitiated cationic curing process and a polyfunctional amine curing process. These processes gave flexible films that showed good adhesion to nylon, steel, and glass. Furthermore, blends of HARE and the commercial epoxy resin bisphenol F diglycidyl ether (BPFG) were cured with 2-ethyl-4-methylimidazole (EMI) at 150 °C on lap-shear assemblies. These cured assemblies displayed adhesive strengths in the range of 15 MPa over a broad range of HARE/BPFG weight ratios. Received: 27 April 2000/Accepted: 7 June 2000     

Effects of glass fibers and polypropylene/glass fiber hybrid fibers on the kinetics and mechanical properties of epoxy composites

Curing reactions of diglycidyl ether of bisphenol F (DGEBP‐F) and pre‐catalyzed methyltetrahydrophthalic anhydride (MTHPA) with benzyl triethyl ammonium chloride (BTEAC) were studied and effects of glass fibers evaluated. The influence on the kinetics of glass fibers and a hybrid blend of maleated polypropylene + glass fibers is studied. Isothermal and dynamic kinetic parameters are determined by differential scanning calorimetry (DSC). Applicability of the autocatalytic model is investigated. The model serves well in the range of degrees of conversion between 25 and 80%. At high conversion rates the diffusion control becomes apparent. Glass fibers accelerate the curing, shortening the time needed to reach the maximum reaction rate; this is reflected in lower activation energies for curing in comparison to the neat resin. The effects observed can be explained by a reaction between the amine group present on the fiber surfaces and the epoxy glycidyl groups. The result of both isothermal and non‐isothermal curing of resin + glass fibers commingled with polypropylene are close to those for the neat resin. The reinforcement increases the elastic modulus 12 times, the tensile strength 2 times, and the impact strength 285 times. The glass fibers + commingled polypropylene reinforcement provides comparable mechanical properties as glass fibers alone when normalized with respected to the density fraction of the fibers.     

Biobased epoxy resin derived from eugenol with excellent integrated performance and high renewable carbon content

Developing biobased epoxy resin with high renewable carbon content and outstanding integrated performance is beneficial for both sustainable development and applications in cutting‐edge fields. Herein, a biobased epoxy monomer (TEUP‐EP) with high renewable carbon content (100%) was synthesized from renewable eugenol with a sustainable process; TEUP‐EP was then blended with 4,4′‐diaminodiphenylmethane (DDM) to develop a new biobased epoxy resin (TEUP‐EP/DDM). The integrated performance of TEUP‐EP/DDM resin was studied and compared with that of petroleum‐based diglycidyl ether of bisphenol A (DGEBA)/DDM resin. Compared with DGEBA/DDM resin, TEUP‐EP/DDM resin has much better integrated performance and not only exhibits a glass transition temperature about 26 °C higher and a 24.4% or 57% increased flexural strength or modulus, but also shows outstanding flame retardancy. Specifically, the limiting oxygen index increases from 26.5% to 31.4% and the UL‐94 grade improves from no rating to the V‐0 level; moreover, the peak heat release rate and total heat release decreased by 63.1% and 57.4%, respectively. All these results fully prove that TEUP‐EP/DDM is a novel biobased high performance epoxy resin. The mechanism behind these attractive integrated performances is discussed intensively. © 2018 Society of Chemical Industry     

双酚F/间苯二酚共聚型环氧树脂

采用间苯二酚、双酚F与环氧氯丙烷共聚合成一种高性能的环氧树脂,研究了不同反应温度、反应时间、双酚F/间苯二酚比例等条件对共聚环氧树脂结构材料性能的影响,确定了合成条件。结果表明所制备的双酚F/间苯二酚共聚型环氧树脂粘度比单纯双酚F环氧树脂低,其热固化结构材料的韧性、耐热性和拉伸强度较纯双酚F和间苯二酚型环氧树脂有明显提高。其最佳合成条件为:醚化温度为80℃,醚化时间5h,加碱闭环温度为60℃,加碱速度为4g/10min。间苯二酚与双酚F质量为20∶80时共聚树脂的综合性能最佳。其粘度为2 1Pa·s,比单纯的双酚F环氧树脂下降了42%;玻璃化温度为165℃,比纯双酚F环氧树脂提高了20℃;拉伸强度为102 3MPa,比纯双酚F环氧树脂提高了27%;弯曲强度为113 6MPa,比单纯的双酚F环氧树脂下降了18%。     

固化剂对环氧玻璃鳞片涂层性能的影响

以双酚A环氧树脂(E20)为主要成膜物,层片状玻璃鳞片和云母氧化铁为主要填料,辅助以铝粉、氧化铁红颜料,以及各种助剂和溶剂,再分别加入固化剂脂肪族胺加成物、聚酰胺TY-650,制得高固体分厚浆型环氧玻璃鳞片涂料。通过常规的力学性能(涂层的硬度、耐冲击性、柔韧性、附着力等)和耐腐蚀性测试,对比了不同固化剂对环氧玻璃鳞片涂层性能的影响。研究结果表明,脂肪族胺加成物与环氧树脂交联固化的玻璃鳞片涂层的硬度、附着力以及交流阻抗值都较高,具有良好的综合性能,加入铝粉对基体可起到阴极保护作用。