Synthesis of rosin‐based flexible anhydride‐type curing agents and properties of the cured epoxy

BACKGROUND: Although rosin acid derivatives have received attention in polymer synthesis in recent years, to the best of our knowledge, they have rarely been employed as epoxy curing agents. The objective of the study reported here was to synthesize rosin‐based flexible anhydride‐type curing agents and demonstrate that the flexibility of a cured epoxy resin can be manipulated by selection of rosin‐based anhydride‐type curing agents with appropriate molecular rigidity/flexibility. RESULTS: Maleopimarate‐terminated low molecular weight polycaprolactones (PCLs) were synthesized and studied as anhydride‐type curing agents for epoxy curing. The chemical structures of the products were confirmed using ¹H NMR spectroscopy and Fourier transform infrared spectroscopy. Mechanical and thermal properties of the cured epoxy resins were studied. The results indicate that both the epoxy/anhydride equivalent ratio and the molecular weight of PCL diol play important roles in the properties of cured resins. CONCLUSION: Rosin‐based anhydride‐terminated polyesters could be used as bio‐based epoxy curing agents. A broad spectrum of mechanical and thermal properties of the cured epoxy resins can be obtained by varying the molecular length of the polyester segment and the epoxy/curing agent ratio. Copyright © 2009 Society of Chemical Industry     

Computer simulation of structure and properties of crosslinked polymers: application to epoxy resins

In this work, a methodology has been developed for construction of atomistic models of crosslinked polymer networks. The methodology has been applied to low molecular weight water soluble epoxy resins crosslinked with different curing agents that are being considered for use as a primer coating on steel. The simulations allowed the crosslink density and the amount of free crosslinking sites in the coatings to be predicted. Shrinkage of the resin upon curing was reproduced by the simulation. In addition, the barrier properties of the model coatings were estimated. The interface between an inorganic substrate and cured epoxy resin has been constructed and the strength and molecular mechanisms of adhesion have been revealed. The developed methodology has a potential to significantly impact on the design and development of new coatings with improved barrier and adhesion properties.     

采用Hansen溶解度参数进行环氧固化体系的匹配

实验测定了25～80℃时3种环氧树脂、3种改性树脂和3种固化剂在77种溶剂中的溶解情况,并经计算得到了相应的Hansen溶解球参数。利用树脂-改性树脂、树脂-固化剂、树脂-改性树脂-固化剂的Hansen溶解球的重叠率,可进行共溶剂的选择及防腐防污自分层涂料的树脂匹配和溶剂配方的选择;对于无溶剂的固化体系则由测得的溶解度参数计算Flory-Huggins相互作用参数χ₁₂,进而计算其相平衡曲线或直接由χ₁₂数值判断其相容性。根据实验结果,可以筛选得到符合制备自分层涂层要求的环氧树脂-改性树脂-固化剂匹配体系,并通过适当的混合溶剂配方,使得涂层中的树脂能有足够的时间进行扩散、分层,最终得到防腐防污性能最佳的效果。     

水性环氧地坪涂料的研制

选用低相对分子质量的液体环氧树脂作为甲组分,采用适宜的水性胺固化剂、颜填料、及助剂制成乙组分,制备了性能优良的水性环氧地坪涂料,可广泛用于各类室内工业地坪涂装。     

混凝土湿表面固化封闭底漆结合强度的研究

通过对混凝土湿表面底漆固化特点的分析,研究了不同的环氧树脂、溶剂和助剂对潮湿表面的湿态附着力的影响,表明选择合适的树脂和助剂可制备出性能优良的湿固化封闭底漆,适用于海港工程混凝土结构表面的湿固化防腐涂装。     

水性环氧涂料用固化剂的探索

水性环氧涂料是水性涂料发展的重要品种之一,水性环氧涂料用固化剂是影响其涂料性能的主要因素之一,因此开发新型水性环氧涂料用固化剂则别具现实意义.文中对水性环氧涂料用固化剂的发展历程作了探讨,并对各类水性环氧涂料用固化剂的特点进行扼要的解说,从中探索出水性胺加成物固化剂是水性环氧涂料用固化剂中最具发展前景的品种.     

2007-2008年国外环氧树脂工业进展

综述了国外环氧树脂工业2007-2008年市场需求,公司经营,原料(甘油法环氧氯丙烷)生产和新产品(环氧树脂、固化剂、水性脱模剂等助剂和填料)开发情况并介绍了环氧树脂应用领域如胶粘剂、涂料、光固化产品和复合材料(如风力发电机叶片配套产品)的发展。     

2008-2009年国外环氧树脂工业进展

综述了2008-2009年国外环氧树脂企业的经营活动,环氧树脂及其固化剂和改性剂等新产品的开发以及环氧树脂胶粘剂、涂料、UV固化产品、复合材料等应用领域的技术进展。     

水性环氧树脂应用性能研究

采用巴陵石化的自乳化性中分子质量水性环氧乳液CYDW-112W50及液体双酚A型环氧树脂CYDW-100与4种胺固化剂配制成4种水性体系,通过对涂膜物理、力学和耐腐蚀性的测试研究了不同固化体系和不同环氧与胺氢的配比对水性体系性能的影响。结果表明:离子型水性环氧体系硬度最高,附着力等比较优异,适合用于底涂或中涂;乳液型水性环氧体系柔韧性能较好,适合用于中涂和面涂;胺氢与环氧基团物质的量比为1.0～1.1∶1时,固化物综合性能最优,据此提出了防腐涂料及改性混凝土的参考配方,产品经性能测试达到使用要求。     

环保节能型水性环氧树脂涂料的研制

利用相对分子质量低的双酚A型环氧树脂、二乙烯三胺和脂肪族环氧化合物合成自乳化环氧树脂乳液和水性固化剂,介绍了乳化剂和固化剂的设计原理。制备了水性环氧树脂涂料,考察了涂料组成对涂料性能的影响。     

Novel imidazole derivatives with recoverable activity as latent curing agents for epoxy

A series of latent curing agents were developed by replacing the hydrogen atom on secondary amine in imidazole with methoxy polyethylene glycol maleate diesters via Michael addition reaction. Methoxy polyethylene glycol maleate diesters with different molecular weight also restrained the reactivity of tertiary amine in imidazole ring. The curing properties and pot-life of the modified imidazole/epoxy systems were measured by differential scanning calorimeter and rotational rheometer. The modified imidazole/epoxy system could be cured quickly at 175°C. The modified imidazole shows good latency. After stored for more than 1 month, viscosity of modified imidazole/epoxy system remains unchanged. The longer chain polyether had the better thermal latency these curing agents had. Compared with unmodified imidazole, the novel latent curing agents led to better impact strength for cured epoxy. However, the compatibility between epoxy and latent curing agent will get worse if the molecular weight of polyether unite is over 750.     

Curable resins based on recycled poly(ethylene terephthalate) for coating applications

Poly(ethylene terephthalate) waste was depolymerised in the presence of diethylene- or tetraethylene glycol and manganese acetate as a catalyst. An epoxy resin was then prepared by the reaction of these oligomers with epichlorohydrin in presence of NaOH as a catalyst. The produced oligomers were condensed with maleic anhydride and ethylene glycol to produce unsaturated polyester. The chemical structures of the resulting epoxy and unsaturated polyester resins were confirmed by ¹HNMR. The vinyl ester resins were used as cross-linking agents for unsaturated polyester resin diluted with styrene, using free radical initiator and accelerator. The 2-amino ethyl piprazine was used as hardener for epoxy resins. The curing behaviour of the unsaturated polyester resin, vinyl ester resins and styrene was evaluated at different temperatures ranged from 25 to 55 °C to calculate the curing activation energy of the system. The cured epoxy and unsaturated polyester resins were evaluated in coating application of steel.     

Epoxy Resins from 1980 to Date. Part 1

Epoxy resins are essentially prepolymers that contain on an average two or more epoxide groups per molecule. The object of the present review article is to give up-to-date information regarding the reactions of these resins with various curing agents leading to crosslinked or thermoset resins with excellent strength, toughness, and chemical resistance. The end-use consumption of epoxy resins covers a broad range of applications such as adhesives, bonding, construction materials (flooring, paving, and aggregates), composites, laminates, coating, molding, and textile finishing. Recently these resins have penetrated into the aero- and spacecraft industry. It is expected that anybody engaged in industry or academic research will find enough material in this review to start work, and need not search the literature before 1990.     

SiC陶瓷表面增韧用环氧树脂基增韧剂的制备与性能研究

碳化硅陶瓷在磨削加工中极易产生崩碎损伤,在碳化硅陶瓷磨削层实时涂覆增韧剂是降低崩碎损伤的新方法。以E51双酚A型环氧树脂、无水乙醇、651型低相对分子质量聚酰胺树脂和1,8-二氮杂二环十一碳-7-烯(DBU)为主要成分制备了一种增韧剂,通过测量增韧剂在碳化硅陶瓷表层的接触角、浸润深度与固化时间,探究了增韧剂各组分的添加量与碳化硅陶瓷表面粗糙度对增韧剂润湿性能与固化速率的影响规律,优化出一种润湿性能好、固化速率快的增韧剂。结果表明:增韧剂的最佳质量配比为m(E51双酚A型环氧树脂)∶m(无水乙醇)∶m(651型低相对分子质量聚酰胺树脂)∶m(DBU)=1∶0.9∶0.5∶0.02,该增韧剂在碳化硅陶瓷表层的浸润时间约为160 s,浸润深度约为40 μm,可使碳化硅陶瓷的表层硬度降低约25%;增韧剂的润湿性能随着溶剂的增加或碳化硅表面粗糙度的增大而提高,促进剂添加量的改变对增韧剂的润湿性能几乎无影响;增韧剂的固化速率随溶剂的增加而降低,随促进剂的增加而提高,但当促进剂达到饱和时,固化速率不再提高。     

Synthesis,characterization, thermal and flame-retardant properties of silicon-based epoxy resins

A new silicon-containing oxirane triglycidyl phenyl silane oxide (TGPSO) and its corresponding silicon-containing epoxy resins are synthesized and characterized. The activation energies of TGPSO curing reaction with various curing agents, including 4,4-diaminodiphenylmethane, 4,4-diaminodiphenylsulfone, and dicyanodiaminde, are found to be 180, 196.5, and 154 kJ/mol. The curing reaction of TGPSO with diamines is determined to be a first-order reaction through means of Arrhenius plots. The introduction of the silicon-containing group results in higher curing reactivity. This silicon-containing resin possesses higher char yield as well as higher limiting oxygen index (LOI = 35) than the commercial epoxy resins, confirming the usefulness of these silicon-containing epoxy resins as flame retardants. Char yields and LOI measurements demonstrate that incorporating silicon into epoxy resins is able to improve their flame retardancy. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 1231–1238, 1999     

酚醛胺固化剂的合成及其在可复涂高固体分环氧防锈漆中的应用研究

以摩尔比为1∶2∶2.5∶5的腰果酚、苯酚、二乙烯三胺、甲醛制得了一种新型的常温交联型环氧固化剂。在合成的低黏度环氧固化剂中,加入适当的颜填料、助剂制成高固体分环氧防锈漆A组分,与低相对分子质量环氧树脂(B组分)固化后漆膜的综合性能优异,硬度较高,柔韧性及抗冲击性能较好,耐高温、耐化学品性好,耐盐雾性达2 000 h以上,且涂层具有较好的可复涂性,可用作油管内壁涂料。     

室温固化型水性环氧防腐涂料的研制

以BPO为引发剂,用α-甲基丙烯酸与E-44型环氧树脂接枝共聚反应合成了环氧-丙烯酸多元接枝共聚物,并用有机酸中和剂调节pH为7～8,制得水性环氧-丙烯酸乳液,进一步制得水性环氧涂料。涂膜固化中用新型低分子水性聚酰胺固化剂加适量促进剂使固化反应在室温下进行。通过测定该涂料的各项性能,结果表明,该涂料附着力、耐冲击性、耐腐蚀性等各项性能良好且施工简单又环保,适用于不能加热的金属底材的防护。     

New polymeric polyol for thermoset coatings: Superacid-catalyzed copolymerization of water and epoxy resins

Though free-radical emulsion polymerization has been studied extensively, published reports of cationic (i.e., acid-catalyzed) polymerizations of emulsified monomers are rare. It was recently discovered that treatment of an emulsion of liquid epoxy resin with select superacid catalysts yields a polymeric polyol. Catalysis with one percent perchloric acid at room temperature yields a product with a number average molecular weight of 1650, and a polydispersity of 5.0 as measured by GPC. The polyol’s structure differs from that of conventional high molecular weight epoxy resins prepared by the advancement process in several ways, including the incorporation of two glycidyl units in the repeat unit. In essence, the product is a copolymer of the epoxy resin and water, in which water is incorporated in the repeat unit structure by reaction with two epoxide groups. A similar product can be prepared by solution polymerization, where the molecular weight is controlled by the ratio of water to epoxy resin. The product was shown to have lower levels of residual bisphenol-A diglycidyl ether (BADGE) and bisphenol-A than conventional advanced epoxy resins. Polyols prepared by these new processes were crosslinked with melamine-formaldehyde resins in waterborne coating formulations which were free of added cosolvent, as well as solventborne coating formulations. The coatings developed excellent solvent resistance at lower bake temperatures than traditional epoxy resins. Presented at the 79th FSCT Annual Meeting in Atlanta, GA, Nov. 5–7, 2001. 7201 Hamilton Blvd., Allentown, PA 18195-1501.     

固化剂对有机改性凹凸棒石/聚苯胺环氧树脂复合涂层性能的影响

固化剂对涂层的防腐、力学性能起着至关重要的作用.以环氧树脂为成膜物质,采用原位复合法在环氧树脂体系中合成有机改性凹凸棒石/聚苯胺(OAT/PAn)复合涂层,分别使用改性脂肪胺固化剂593、酚醛胺固化剂T-31以及聚酰胺固化剂650对上述涂层进行固化,讨论了不同种类固化剂对涂层的化学结构、防腐和力学性能以及耐水性能的影响.利用FTIR 对比了各涂层的固化结构,证明了三种固化剂均可使复合涂层固化;SEM结果表明,593固化剂固化涂层的致密性最好;电化学实验结果表明,593固化剂的固化涂层防腐性能最佳,腐蚀电位达到了Ecorr=-318 mV,腐蚀电流密度Icorr=1.193×10-6 A·cm-2;通过划格法评价了各涂层的附着力,发现593固化剂固化效果最好,附着力可达5B;对比浸泡168 h后涂层的耐水性发现,593固化剂耐水性最好.     

环氧-聚氨酯导静电防腐蚀油罐漆的试验研究

选用中等相对分子质量的双酚A型环氧树脂和聚氨酯固化剂配制成了导静电防腐蚀油罐漆,讨论了聚氨酯的类型、NCO和OH的比例对涂膜导电性的影响,并与多元胺固化的环氧油罐漆进行了性能和成本对比。