端环碳酸酯基聚醚的合成

采用端环氧基聚醚与二氧化碳为原料,在高温、高压、催化剂的条件下,将环氧基转化为五元环碳酸酯基。讨论了催化剂类型、温度、压力对反应转化率的影响,并通过红外光谱、核磁共振氢谱等方法对端环碳酸酯基聚醚进行结构表征。结果表明,当采用十六烷基三甲基溴化铵为催化剂,温度为120℃,体系压力为2.5 MPa时,环氧基的转化率能够达到90%以上。     

Effect of the physical and mechanical properties of epoxy resins on the adhesion behavior of epoxy/copper leadframe joints

In this study, the adhesion strength of three epoxy resins, which are used as basic materials for epoxy molding compound (EMC) in microelectronics, to copper leadframe was determined using the peel test. The epoxy resins used were O-cresol Novolac (OCN), dicyclopentadiene (DCPD), and biphenyl sulfide (BIPHS) epoxy resins. It was found that DCPD showed the highest peel strength and OCN had the lowest value. The difference in the peel strength was explained by investigating the physical and mechanical properties, as well as the surface properties of the epoxy resins. These properties included the surface energy, viscosity and gelation time, fracture toughness, and the coefficient of thermal expansion. As a result of the lower viscosity of BIPHS and DCPD than OCN epoxy resin, BIPHS and DCPD have a better peel strength than OCN. The DCPD resin has a better peel strength than BIPHS because of its higher fracture toughness.     

环氧化硅油改性邻甲酚醛环氧树脂的研究

采用侧基环氧化硅油(ES)及其改性物(PSA)改性邻甲酚醛环氧树脂(ECN),制备出一系列可用于电子封装等具有高韧性高耐热性的环氧基料。通过对固化物的冲击强度、拉伸强度、断裂伸长率和玻璃化转变温度(Tg)以及断裂面形态的测定,探讨了改性方法、有机硅组成与含量等对改性材料性能的影响。结果表明,用有机硅改性ECN后,其韧性和耐热性均有不同程度的提高,且环氧值高的ES和PSA的改性效果较好。其中环氧树脂经10份(质量份数,下同)ES-16或10份PSA-16改性后,韧性和耐热性均提高,符合电子封装等材料的改性要求,后者的耐热效果更为显著,Tg达183.46℃,比未改性环氧树脂提高了近20℃。     

制刷用环氧树脂胶黏剂的研制

以油脂为原料,对长碳链环氧树脂的合成工艺进行了研究,探讨了合成反应条件对环氧树脂性能的影响。合成可挠性环氧树脂的最佳工艺条件为:反应温度 125℃,时间 2 h,催化剂用量 0.2%。制得的环氧树脂胶黏剂的性能及刷鬃结合强度达到相关企业标准。     

Synthesis of epoxy resins from alcohol‐liquefied wood and the mechanical properties of the cured resins

New wood‐based epoxy resins were synthesized from alcohol‐liquefied wood. Wood was first liquefied by the reaction with polyethylene glycol and glycerin. The alcohol‐liquefied wood with plenty of hydroxyl groups were precursors for synthesizing the wood‐based epoxy resins. Namely, the alcoholic OH groups of the liquefied wood reacted with epichlorohydrin under alkali condition with a phase transfer catalyst, so that the epoxy groups were put in the liquefied wood. The wood‐based epoxy resins and the alcohol‐based epoxy resins as reference materials were cured with polyamide amine. The glass transition temperature (Tg), the tensile strength, and the modulus of elasticity of the wood‐based epoxy resin were higher than those of the alcohol‐based epoxy resin. Also, the shear adhesive strength of the wood‐based epoxy resin to steel plates was higher than those of the alcohol‐based epoxy resins, which was equivalent to the level of petroleum‐based bisphenol‐A type epoxy resins. The higher Tg of the wood‐based epoxy resin than that of the alcohol‐based epoxy resin is one of the evidences that the wood‐derived molecules were chemically incorporated into the network structures. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

棉油酸甲酯改性胺固化剂的合成及性能研究

利用棉油酸甲酯制备了一种环氧树脂固化剂棉油酸甲酯改性胺,研究了棉油酸甲酯改性胺用量对环氧树脂体系的力学性能和热性能的影响,利用红外光谱、热分析、动态力学分析讨论了棉油酸甲酯改性胺的结构、环氧树脂固化物的性能。结果表明,环氧树脂固化物的拉伸性能、弯曲性能和冲击强度随着棉油酸甲酯改性胺用量的增加而增加。     

Aminimide as hardener/curing promotor for one part epoxy resin composition

Three kinds of aminimide compounds were examined as latent hardeners/promotors for epoxy resins. Since aminimides are thermolyzed to generate tertiary amine and isocyanate, the compounds are useful as polymerization initiators for the epoxy group as well as promotors for epoxy–acid anhydride reaction. The pot life was over 30 days at 40°C for a formulated one-part epoxy resin system. In comparison with epoxy resins cured with conventional hardeners, several interesting characteristics of the mechanical and electrical properties were observed. In particular, the epoxy resins cured by aminimides exhibited high tensile strength and high impact strength, which make them excellent curing agents for adhesive applications. The reasons for these unique properties are discussed.     

Bonding properties of epoxy resins containing two mesogenic groups

Liquid‐crystalline epoxy resins, with introduced aliphatic chains between two mesogenic groups, were synthesized and their adhesive bonding properties were compared to those of the bisphenol‐A–type epoxy resin and the liquid‐crystalline epoxy resin, previously reported. The bonding strength of the former resin system was higher than that of the two later systems. We suggest that the high bonding strength of the twin mesogenic epoxy resins, cured with an aromatic amine, was attributable to the large plastic deformation of the adhesive layer in the fracturing process. We also investigated the effects of the aliphatic chain length in the twin mesogenic epoxy resin on their dynamic mechanical and bonding properties. The bonding strength of the cured twin mesogenic epoxy resins increased with an increase in the aliphatic chain length. We suggest that the high bonding strength of the system introduced by the long aliphatic chain was attributable to the large plastic deformation of the adhesive layer because of the higher network mobility. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3721–3729, 2004     

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.     

有机硅聚醚胺增韧改性环氧树脂的研究

采用端环氧基硅油及其聚醚胺预反应物、聚醚胺(D-230)来改性双酚A型环氧树脂(EP)。有机硅与聚醚柔性链段通过环氧树脂主链或固化剂键合到致密的环氧树脂交联网络中。系统研究了端环氧基硅油及其聚醚胺预反应物等对固化物的拉伸强度、断裂伸长率和冲击强度的影响。采用扫描电子显微镜对改性固化物的断裂面形态进行了分析。采用5份端环氧基硅油聚醚胺预反应改性EP后,其拉伸强度略有提高,断裂伸长率由38.62%提高到42.9%,冲击强度由20.23 kJ.m-2提高到25.89 kJ.m-2。依据其断裂伸长率与材料拉伸断面的SEM照片,环氧树脂固化物显示出明显的增韧效果,符合涂料用树脂基料的要求。     

Synthesis,thermal properties,and flame retardance of phosphorus‐containing epoxy‐silica hybrid resins

A novel epoxy resin modifier, phosphorus‐containing epoxide siloxane (DPS) with cyclic phosphorus groups in the Si O network, was prepared from the reaction of 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) with polyhedral‐oligomeric siloxanes, which was synthesized by the sol–gel reaction of 3‐glycidoxypropyltrimethoxysilane. DPS was confirmed by Fourier transform infrared and ²⁹Si NMR measurement, and then was employed to modify epoxy resin at various ratios, with 4,4‐diaminodiphenyl‐methane as a curing agent. In order to make a comparison, DOPO‐containing epoxy resins were also cured under the same conditions. The resulting organic–inorganic hybrid epoxy resins modified with DPS exhibited a high glass transition temperature (T_g), a good thermal stability, and a high limited oxygen index. In addition, the tensile strength of cured products was also rather desirable. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers     

Effect of Processing Conditions on Mechanical Properties of Pretreated Gelatin Samples

Abstract

The flexural strength of epoxy resins cured at different temperatures and times was investigated and compared to the heat capacities obtained during thermal analysis. Theoretical and experimental results indicated that the change in heat capacity at the glass transition temperature of epoxy resins decreases with increasing cure time and temperature. Further, for the given epoxy resin composition, it was determined that those samples with higher ΔC_p values have higher flexural strength than those with lower ΔC_p values.

Epoxy resins show a strong co-relation between flexural strength and measured heat capacities. Since the measurement of heat capacity by the Differential Scanning Calorimetry technique is simple and reproducible, it presents a means of evaluating the flexural properties of epoxy resins which will result from any known set of cure conditions.     

Synthesis of wood‐based epoxy resins and their mechanical and adhesive properties

Wood‐based epoxy resins were synthesized from resorcinol‐liquefied wood. Wood was first liquefied in the presence of resorcinol with or without a sulfuric acid catalyst at high temperature. Because of the hydroxyl groups, the resorcinol‐liquefied wood was considered as a precursor for synthesizing wood‐based epoxy resin. Namely, the phenolic OH groups of the liquefied wood reacted with epichlorohydrin under alkali condition. By the glycidyl etherification, epoxy functionality was introduced to the liquefied wood. The epoxy functionality of the resins was controlled by the concentration of phenolic OH groups in the liquefied wood, which would be a dominant factor for crosslink density and properties of the cured epoxy resins. The flexural strength (150–180 MPa) and the modulus of elasticity (3.2 GPa) of the highly crosslinked wood‐based epoxy resin were equivalent to those of the commercially available epoxy resin, diglycidyl ether of bisphenol A (DGEBA). Also, the shear adhesive strength of the wood‐based epoxy resin was higher than that of DGEBA when plywood was used as the adhesive substrates. The mechanical and adhesive properties suggested that the wood‐based epoxy resins would be well suited for matrix resins of natural plant‐fiber reinforced composites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2285–2292, 2006     

无卤阻燃含磷环氧树脂的研究进展

无卤阻燃含磷环氧树脂中的磷成分具有气相和凝聚相的双重阻燃作用,且材料本身降解产物不产生可持续性环境污染物,因而作为环境友好型阻燃材料而被广泛研究。本文综述了近年来关于含9,10-二氢-9-氧杂-10-磷杂菲10-氧化物(DOPO)环氧树脂体系（包含DOPO环氧树脂、DOPO基固化剂和添加型DOPO改性聚合物）、磷酸酯型环氧树脂体系（包括磷酸酯环氧树脂、环状磷酸酯环氧树脂、磷酸酯型固化剂）、含磷固化剂以及磷腈环氧树脂和磷-硅环氧树脂的研究进展,介绍了每种体系的性能特点。总结了含磷环氧树脂的阻燃性能、热性能、阻燃机理,以及磷-氮协同效应、磷-硅复合二元体系的阻燃机理。     

Modification of epoxy resins for improvement of adhesion: a critical review

Modification of epoxy resins for improvement of adhesion has been the subject of intense research throughout the world. Unlike for thermoplastics, physical blending is not successful for improvement of bond strength and impact strength of epoxy resins. The bond strength of an epoxy resin can be improved only by chemical modification with a suitable flexible modifier. Such chemical modification may either plasticize the epoxy matrix or lead to a two-phase microstructure. Both methods of chemical modifications are discussed critically in the present review.     

多面体低聚倍半硅氧烷在环氧树脂改性中的应用进展

综述了近几年多面体低聚倍半硅氧烷(POSS)在环氧树脂改性中的应用。POSS单独修饰环氧树脂,可提高其力学性能及热稳定性能;POSS协同9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物等功能性分子一起修饰环氧树脂,可增强其阻燃性能;POSS与碳纳米管、石墨烯等纳米材料共同修饰环氧树脂,可提高纳米材料在环氧树脂中的分散性,改善纳米复合材料的导电能力和黏结强度等性能;POSS与纤维共同修饰环氧树脂,可有效增强纤维与环氧树脂间的界面性能。最后展望了POSS修饰改性环氧树脂的未来方向:开发更简易的引入方式,引入更多样的官能分子,协同多种纳米材料修饰环氧树脂。     

Synergic Effect of Acrylate Liquid Rubber and Bisphenol A on Toughness of Epoxy Resins

The synergic effect of acrylate liquid rubber with pendant epoxy group and bisphenol A on the toughness of epoxy resins was presented in this paper. The addition of bisphenol A enhances the impact strength and elongation at break of epoxy resin and actually increases the ductibility of epoxy resin matrix. Much higher toughness efficiency can be achieved for the ALR modified epoxy resins by the incorporation of bisphenol A at the same time. The synergic promotion effect of acrylate liquid rubber and bisphenol A on the toughness efficiency of epoxy resins is attributed to the two-phase morphology and high ductibility of matrix, and the resultant large stress white zones and high shear yielding during the fracture process.     

含巯基聚硅氧烷改性环氧树脂的制备及性能

以双酚A环氧树脂（E51）为基料、聚醚胺（D?230）为固化剂、含巯基聚硅氧烷（PMMS）为改性剂,分别经过简单物理混合和化学改性的方法,制备了一系列聚硅氧烷改性环氧树脂（E51⁃D⁃PMMS）固化物。通过衰减全反射红外（ATR?FTIR）和X射线衍射仪（XRD）表征了固化物的结构特征;通过拉伸测试和冲击实验、扫描电子显微镜（SEM）、接触角测量（CA）、动态热力学分析（DMA）及中性盐雾实验探究了改性固化物的力学性能、热稳定性、防腐性能等。结果表明,化学改性的E51?D?PMMS固化物的综合物理化学性能优于简单物理改性的,当PMMS含量为1 %（质量分数,下同）时,改性固化物的拉伸强度为74.63 MPa,较改性前提高了13.5 %,断裂伸长率提高了40.2 %,冲击强度提高了43.7 %;水接触角从改性前的72.8 °增至100.3 °,表面能从39.4 J/m²降至17.4 J/m²,吸水率下降了44 %,耐水性能大大增强;其防腐性能和玻璃化转变温度（T_g）也有一定的提升。     

Unsaturated ester resins

Vinyl ester resins (VERs) are often described as a cross between unsaturated polyester resins and epoxy resins. VERs offer an upgrade to epoxy resins, and they tend to be selected when chemical and temperature resistance is required. This research was aimed at developing the synthesis of unsaturated ester resins (UERs), which are similar to VERs. UERs were synthesized by the addition of dihydrodicyclopentadienyl hydrogen maleate to the terminal epoxy groups in low‐molecular‐weight bisphenol A/epichlorohydrin epoxy resins. The effect of urethanization of UERs on the properties of the crosslinked polymer was also investigated. As crosslinking monomers, styrene and glycol dimethacrylates were used. The following properties of cured UERs were determined: the heat deflection temperature, alkali resistance, and the mechanical strength. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2627–2631, 2006     

Modification of epoxy resins via m‐chloroperbenzoic acid‐epoxidized carbon nanotubes

In this article, epoxidized carbon nanotubes (CNTs) are used to modify current epoxy resins. The produced epoxy groups on the nanotube surface significantly enriched nanotube chemistry and made them soluble in the organic solvents. Atomic force microscopy characterization indicated that epoxidized nanotubes were well dispersed in the organic solvent and most of them were isolated. Fracture surface of modified epoxy resins suggested that fracture toughness of the modified resins was significantly improved, demonstrating fracture characteristic of typical ductile materials. Epoxidized CNTs‐modified epoxy resins demonstrated a 50% increase in the Young's modulus, 32% improvement in the tensile strength with 1 wt % loading. This study provides an effective way to synthesize novel epoxy resins. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009