Reactive blends of epoxy resin (DGEBA) crosslinked by anionically polymerized polycaprolactam. II. Mechanical and electrical properties

Various reactive blends of diglycidyl ether of bisphenol A (DGEBA)/polycaprolactam were synthesized by anionic polymerization at 140°C, conducted by sodium hydride catalyst, a strong base, along with N‐acetyl caprolactam as a cocatalyst. The experiments were performed to study the effect of composition on the mechanical and electrical properties of the reactive blends, such as tensile properties, flexural properties, Izod impact strength, Rockwell hardness, and volume resistivity. It was observed that the DGEBA was crosslinked by the polycaprolactam through the rapid reaction of the oxirane group with amide nitrogen. The heat of reaction and heat‐deflection temperature of the reactive blends increased with increasing DGEBA content from 50 to 80 wt %, and increased dramatically above 70 wt % DGEBA content. The mechanical and electrical properties of the reactive blends increased with increasing DGEBA content from 50 to 80 wt %. Substantial increases in these properties were observed above 70 wt % DGEBA content in the reactive blends. SEM studies revealed that the reactive blends show a multiphase system with an increase in the DGEBA content from 50 to 80 wt % as the mixing of the two phases increased. The reactive blend Ep₈₀Ca₂₀, with 80 wt % DGEBA content, resembles a single‐phase system because of better mixing of the two phases; as a result, this reactive blend showed the highest mechanical and electrical properties. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 537–549, 2005     

环氧树脂改性PUA乳液的合成及性能研究

以异佛尔酮二异氰酸酯（IPDI）、聚醚二元醇（N220）、二羟甲基丙酸（DMPA）、1，4-丁二醇（BDO）和甲基丙烯酸甲酯（MMA）为主要原料合成了脂肪族聚氨酯-丙烯酸酯复合乳液（PUA），并用环氧树脂对其进行了改性。研究了nNCO／nOH比、DMPA添加量、环氧添加方式及添加量对其性能的影响，结果表明，当nNCO／nOH为1．35-1．4、DMPA为6％～7％时，以环氧和BDO一起加入，环氧添加量在2％～3％时能获得综合性能较好且贮存稳定的聚氨酯丙烯酸酯复合乳液。     

The curing reaction and physical properties of DGEBA/DETA epoxy resin blended with propyl ester phosphazene

The influences of different amounts of propyl ester phosphazene (FR) on the curing kinetics and physical properties of diglycidyl ether of bisphenol A (DGEBA) epoxy prepolymer cured with diethylenetriamine (DETA) were investigated with DSC, SEM, DMA, and tensile testing. The results revealed that FR could be a catalyst or a diluent depending on the FR content. In addition, the blending systems were partially miscible. The tensile strength and modulus of blends decreased with increasing amounts of FR, but the elongation increased with increasing FR. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 229–237, 1999     

Mechanical properties study of photocured paperboard surface treated with aliphatic epoxy diacrylate

In order to improve the quality of paperboard (a well‐known packing material) surface by photocuring method, different formulations were developed with aliphatic epoxy diacrylate (EA‐1020) oligomer along with reactive monomers of various functionalities. The reactive monomers are tripropylene glycol diacrylate (TPGDA), a difunctional monomer, and trimethylol propane triacrylate (TMPTA), a trifunctional monomer. 2‐Benzyl‐2‐dimethylamino‐1(4morpholinophenyl) butanone‐1 (Irgacure 369), a photoinitiator (2%), was incorporated into the formulations to initiate photocuring reaction. The formulated solutions were coated on clean glass plate and irradiated under UV radiation of different intensities. Different physical properties like pendulum hardness and gel content of the cured films were studied. The formulation containing TMPTA showed better properties. After characterization of the films, these formulations were applied on paperboard surfaces and cured under the same UV radiation. Various physicomechanical properties such as pendulum hardness, tensile properties, surface gloss, adhesion, abrasion, and water uptake were studied. The best performance was obtained at 12 passes of radiation with 18% TMPTA‐containing formulation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1774–1780, 2003     

脂肪族环氧化合物的合成及其共混树脂的研究

以聚丙二醇和环氧氯丙烷为原料合成出了低黏度的脂肪族环氧树脂。使用上述环氧树脂与双酚A型环氧树脂按不同的比例混合后,再加入大分子胺类固化剂,由此构筑出环氧树脂固化体系并对其黏度、凝胶时间和固化物的力学性能进行了表征。结果显示,该环氧树脂固化体系在常温下具有很低的黏度与较长的凝胶时间,其固化物的拉伸与弯曲性能较好,且冲击韧性有了明显的改善。     

Epoxy networks for medicine applications: Mechanical properties and in vitro biological properties

This work describes the physicochemical, mechanical, and in vitro biological properties of three epoxy networks based on diglycidyl ether of bisphenol‐A (DGEBA) epoxy prepolymer cured with triethylenetetramine, 1‐(2‐aminoethyl)piperazine (AEP) and isophoronediamine. The mechanical properties were evaluated with respect to impact and flexural tests. Functionality rules the mechanical behavior of epoxy networks by increasing the crosslink density and the flexural modulus, increasing T_g and decreasing the chain flexibility and the impact resistance. The biological interactions between the obtained epoxy polymers and blood were studied by in vitro methods. Studies on the protein adsorption, platelet adhesion, and thrombus formation are presented. The protein adsorption assays onto polymeric surfaces showed that the epoxy networks adsorbed more albumin than fibrinogen. The results about platelet adhesion and thrombus formation indicated that DGEBA‐IPD and DGEBA‐AEP networks exhibits good hemocompatible behavior. The materials revealed no signs of cytotoxicity to Chinese hamster ovary cells, showing a satisfactory cytocompatibility. In this way, we can assume that the epoxy polymers are biocompatible materials. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Mechanical properties of blocked polyurethane/epoxy interpenetrating polymer networks

The mechanical properties of blocked polyurethane(PU)/epoxy interpenetrating polymer networks (IPNs) were studied by means of their static and damping properties. The studies of static mechanical properties of IPNs are based on tensile properties, flexural properties, hardness, and impact method. Results show that the tensile strength, flexural strength, tensile modulus, flexural modulus, and hardness of IPNs decreased with increase in blocked PU content. The impact strength of IPNs increased with increase in blocked PU content. It shows that the tensile strength, flexural strength, tensile modulus, and flexural modulus of IPNs increased with filler (CaCO₃) content to a maximum value at 5, 10, 20, and 25 phr, respectively, and then decreased. The higher the filler content, the greater the hardness of IPNs and the lower the notched Izod impact strength of IPNs. The glass transition temperatures (T_g) of IPNs were shifted inwardly compared with those of blocked PU and epoxy, which indicated that the blocked PU/epoxy IPNs showed excellent compatibility. Meanwhile, the T_g was shifted to a higher temperature with increasing filler (CaCO₃) content. The dynamic storage modulus (E′) of IPNs increased with increase in epoxy and filler content. The higher the blocked PU content, the greater the swelling ratio of IPNs and the lower the density of IPNs. The higher the filler (CaCO₃) content, the greater the density of IPNs, and the lower the swelling ratio of IPNs. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1826–1832, 2006     

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     

Mechanical and tribological properties of epoxy modified by liquid carboxyl terminated poly(butadiene-co-acrylonitrile) rubber

Diglycidyl ether of bisphenol A (DGEBA)-based epoxy resin was modified using liquid carboxyl-terminated poly(butadiene-co-acrylonitrile) (CTBN) rubber. The liquid CTBN contents used ranged from 2.5 to 20 parts per hundred parts of resin (phr). Mechanical properties of the modified resins were evaluated and the microstructures of the fracture surfaces were examined using SEM technique. The changes in storage modulus and the glass transition temperature were also evaluated using dynamic mechanical analysis (DMA). The tribological tests were performed using a ball-on-disc tribometer. The worn surfaces and the ball counter-mates after tribological tests were investigated using optical microscope technique. The results revealed the influence of liquid CTBN content on mechanical and tribological properties, and also microstructure of the modified epoxy resins. Impact resistance increased whereas the storage modulus and the hardness decreased when the CTBN rubber was introduced to the epoxy network. The coefficient of friction of the CTBN-modified epoxy was lower than that of the neat epoxy. The CTBN content of lower than 10 phr was recommended for improving the wear resistance of epoxy resin. Changes in tribological properties of the CTBN-modified epoxy correspond well to those in mechanical changes, especially the toughness properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

环氧树脂对PUA复合乳液的改性研究

以异佛尔酮二异氰酸酯（IPDI）、聚醚二元醇（N220）、二羟甲基丙酸（DMPA）、1,4-丁二醇（BDO）和甲基丙烯酸甲酯（MMA）为主要原料合成了脂肪族聚氨酯-丙烯酸酯复合乳液,并用环氧树脂对其进行了改性。研究了nNCO／nOH比、DMPA添加量、环氧树脂添加方式及添加量对其性能的影响,结果表明,当nNCO／nOH为1．35-1．40、DMPA为6％-7％时,环氧树脂和BDO同时加入,环氧树脂添加量在2％～3％时能获得综合性能较好且贮存稳定的聚氨酯丙烯酸酯复合乳液。     

Curing of DGEBA epoxy resin by low generation amino‐group‐terminated dendrimers

Low generation amino‐group‐terminated poly(ester‐amine) dendrimers PEA1.0 (NH₂)₃ and PEA1.5 (NH₂)₈, and poly(amido‐amine) dendrimer PAMAM1.0 (NH₂)₄ were used as diglycidyl ether of bisphenol A (DGEBA) epoxy resin hardeners. Thermal behavior and curing kinetics of dendrimer/DGEBA systems were investigated by means of differential scanning calorimetry (DSC). Compared with ethylene diamine (EDA)/DGEBA system, the dendrimer/DGEBA systems gradually liberated heat in two stages during the curing process, and the total heat liberated was less. Apparent activation energy and curing reaction rate constants for dendrimer and EDA/DGEBA systems were estimated. Thermal stabilities and mechanical properties of cured thermosetting systems were examined as well. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3902–3906, 2006     

Mechanical properties of an epoxy resin toughened by polyester

The epoxy resins were toughened by 4–24 phr polyester with average molecular weight 1.9×10⁴ g/mol in this investigation. The mechanical properties were examined and dynamic mechanics analyses were performed for the epoxy resins before and after the modification. The toughening mechanism of polyester to epoxy resin is discussed in light of the scanning electronic microscopy observation of the fracture surfaces. The results showed that the impact strength and tensile strength of the modified epoxy resin were remarkably greater than those of the unmodified cured epoxy resin. The most suitable composition for the modified epoxy resin was the addition of 16 phr polyester, which led to 138 and 46% increments in the impact strength and the tensile strength, respectively. And the mechanical properties depended greatly on the congregating state of polyester added. The polyester dispersing in the epoxy matrix was amorphous when its addition was less than or equal to 12 phr, and was sphere crystals when the addition was over 16 phr. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3384–3389, 2003     

Synthesis and characterization of epoxy based nanocomposites

Epoxy‐clay nanocomposites were synthesized to examine the effects of the content and type of different clays on the structure and mechanical properties of the nanocomposites. Diglycidyl ether of bisphenol‐A (epoxy) was reinforced by 0.5–11 wt % natural (Cloisite Na⁺) and organically modified (Cloisite 30B) types of montmorillonite. SEM results showed that as the clay content increased, larger agglomerates of clay were present. Nanocomposites with Cloisite 30B exhibited better dispersion and a lower degree of agglomeration than nanocomposites with Cloisite Na⁺. X‐ray results indicated that in nanocomposites with 3 wt % Cloisite 30B, d‐spacing expanded from 18.4 Å (the initial value of the pure clay) to 38.2 Å. The glass transition temperature increased from 73°C, in the unfilled epoxy resin, to 83.5°C in the nanocomposite with 9 wt % Cloisite 30B. The tensile strength exhibited a maximum at 1 wt % modified clay loading. Addition of 0.5 wt % organically modified clay improved the impact strength of the epoxy resin by 137%; in contrast, addition of 0.5 wt % unmodified clay improved the impact strength by 72%. Tensile modulus increased with increasing clay loading in both types of nanocomposites. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1081–1086, 2005     

Polyether and polyester polyol based glycidyl-terminated polyurethane modified epoxy resins: Mechanical properties and morphology

A glycidyl-terminated polyurethane prepolymer was synthesized and used to enhance the properties of epoxy resins. Some properties of glycidyl-terminated PU/epoxy with polyether based (PPG) and polyester based (PBA) glycidyl-terminated PU were investigated in this research. The polyether based glycidyl-terminated PU(PPG) modified epoxy resin proved to be superior to conventional epoxy resins in improved impact strength and fracture energy, but not tensile strength, tensile modulus, flexural strength and flexural modulus. On the other hand, the polyester based glycidyl-terminated PU(PBA) modified epoxy resin had increased mechanical properties while showing slight variation of impact strength and fracture energy. Different mechanisms for this behaviour are advanced in this paper.     

Biolignin™ based epoxy resins

Wheat straw Biolignin? was used as a substitute of bisphenol‐A in epoxy resin. Synthesis was carried out in alkaline aqueous media using polyethyleneglycol diglycidyl ether (PEGDGE) as epoxide agent. Structural study of Biolignin? and PEGDGE was performed by solid‐state ¹³C NMR and gel permeation chromatography, respectively, before epoxy resin synthesis. Biolignin? based epoxy resins were obtained with different ratios of Biolignin? : PEGDGE and their structures were analyzed by solid‐state ¹³C NMR. The crosslinking of PEGDGE with Biolignin? was highlighted in this study. Properties of Biolignin? based epoxy resins were analyzed by differential scanning calorimetry and dynamic load thermomechanical analysis as well as compared with those of a bisphenol‐A epoxy‐amine resin. Depending on the epoxy resin formulation, results confirmed the high potential of Biolignin? as a biosourced polyphenol used in epoxy resin applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Intermolecular force and thermal properties of the sulfonyl epoxy blends cured with DGEBA epoxy

The sulfonyl epoxy monomer (SEP) was synthesized and further to blend with the diglycidyl ether of bisphenol A (DGEBA). The glass transition temperature (T_g) of the SEP/DGEBA blended materials increased from 103.7 to 163.8°C. The cross‐linking density and polymer chain self‐association intra‐molecular action affected more than that the polymer–polymer intermolecular action (hydrogen bonding) in the SEP blended with the DGEBA materials. The excess stabilization energy in the overall stabilization was only 0.00145% (14.5 ppm), which indicated that the polymer‐polymer intermolecular action was weak. The thermal degradation of the SEP segments could form various sulfate derivatives at lower temperature and analyzed by the TGA/GC/Mass. The sulfate derivatives could generate the thermal stable chars, which provided the “shielding effect” and antioxidation property. Additionally, these chars could also improve the protective effect and inhibit the thermal‐oxidation decomposition under the air atmosphere. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

新型脂环族环氧树脂的制备与性能

制备了脂环族环氧树脂——1,2-环己二醇二缩水甘油醚,用傅里叶红外光谱对其结构进行表征,测试了其固化物的热性能、力学性能、电性能。结果表明,1,2-环己二醇二缩水甘油醚具有良好的力学性能和电性能,在电工材料、电子封装领域有广泛的应用前景。     

端脂肪氨基聚醚/环氧树脂涂料的耐环境性能研究

采用自制的一种既含柔性链段,又含刚性结构单元的端脂肪氨基聚醚(APPEG)作为固化剂,用于环氧树脂的增韧改性,制备了耐环境性能优异的涂膜。研究表明:涂膜的平衡吸水率为2.1%左右,耐盐雾腐蚀可达500?h以上。     

Influence of aliphatic amine epoxy hardener on the adhesive properties of blends of mono‐carboxyl‐terminated poly(2‐ethylhexyl acrylate‐co‐methyl methacrylate) with epoxy resin

The adhesive properties have been investigated in blends of mono‐carboxyl‐terminated poly(2‐ethylhexyl acrylate‐co‐methyl methacrylate) with diglycidyl ether of bisphenol A and three different aliphatic amine epoxy hardener. The adhesives properties are evaluated in steel alloy substrate using single‐lap shear test. The copolymers are initially miscible in the stoichiometric blends of epoxy resin and hardener at room temperature. Phase separation is noted in the course of the polymerization reaction. Different morphologies are obtained according to the amine epoxy hardener. The most effective adhesive for steel–steel joints in single‐lap shear test is the blends using 1‐(2‐aminoethyl)piperazine (AEP) as hardener. This system shows the biggest lap shear strength. However, the modified adhesives show a reduction in the mechanical resistance. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

新型脂肪族超支化环氧树脂的制备及其改性作用

采用一步法合成了新型脂肪族超支化环氧树脂HTPE-3,利用FT-IR对其结构进行了表征。研究了双酚A型环氧树脂E-51/HTPE-3杂化树脂的力学性能和热性能。结果显示,杂化树脂的韧性和强度随HTPE-3含量的增加先增加后降低,具有极大值;当HTPE-3质量分数为12%左右时,与纯E-51树脂相比,杂化树脂的冲击强度和断裂韧性分别提高了169.8%和35.2%,拉伸强度和弯曲强度分别提高了6.5%,10.0%,维卡软化点温度、玻璃化转变温度和热分解温度略有下降。