| Epoxy is widely used in these fields such as composite ?adhesive?electronic packaging because of good mechanical properties ? adhesion properties and insulating properties.. Imidazoles is an excellent curing agent and accelerator for epoxy. It can cure epoxy at the middle temperature fastly and make the resin has good heat resistance and insulation properties. One-component resin is widely used in the auto-manufacturing of composites and electronic packaging. The latent curing agent which is largely used can not cured quickly at the moderate temperature.As we know that the latent harder of imidazoles can cure rapidly at the moderate temperatures. But the existed imidazole curing agent has a short incubation period. We have to improve the latent property of imidazole and explore the method of preparing high latent imidazole curing agent has significant value.In this paper, we synthesised three kind of TDI blocked imidazole(TMI, 2TMI, 2TEMI).Then we studied the relationship of the unblocking temperature with the type of imidazole. We studied the curing characteristics and kinetic parameters of TDI blocked imidazole(TMI, 2TMI, 2TEMI) curing epoxy. To studied the i MPact of the amounts and types of TDI blocked imidazole curing epoxy on the room temperature incubation period and bending properties. Then use the homemade single-isocyanate blocked imidazole(GMI, GEMI) and its organic copper salt(1GMIC, 2GMIC) curing epoxy resin, curing characteristics and curing kinetic parameters are studied.The curing mechanism of GMI and the i MPact of the amount on the curing properties was stuied. Studing the effects of different amounts and types of modified imidazole imidazole / epoxy system on the room temperature latenty? heat resistance and bending properties.First, We successfully synthesis the three kind of TDI blocked imidazole(TMI, 2TMI, 2TEMI),and study the effects of different types of imidazole for unblocking temperature. The results showed that the deblocking temperature reduced with the increaing of the substituted groups in the imidazole. The deblocking temperatures of TMI?2TMI and 2TEMI were 150??130??120?. Using the initial curing temperature and storage experiment at room temperature to study the effects of different imidazole on blocked imidazole activity. The results show that the more substituents in the imidazole the lower activity of blocked imidazoles, and the better latent property at room temperature. TMI, 2TMI, 2TEMI initial curing temperature(Ti) and peak temperature(Tp)were 65.7 ?, 78.2 ?, 104 ? and 114?,111?,122 ?. 8% TMI, 2TMI, 2TEMI curing E51 system are close to one level reaction, and the reactive activation energy ?E were 69.7KJ / mol, 68.6KJ / mol, 60.0KJ / mol. TMI, 2TMI, 2TEMI curing epoxy resin system had a decreased storage time with the amount increases from 2% to 10%. 2TEMI curing epoxy system has the longest storage time, has a 30-day storage period at room temperature with 10% amount and 100-day storage period at room temperature with 2% amountt, while TMI and 2TMI just has 3-4 days storage period under 10% amount at room temperature.Secondly, studing the influence of the amount of imidazole of the TMI, 2TMI, 2TEMI cured epoxy resin system on the mechanical strength and the modulus. The three kind of TDI blocked imidazole curing epoxy resins and The strength and the modulus increase with the curing agents increase at first and then decrease with the increase of curing agents. TMI get the maximum flxural strength at the amount of 8%,and the flexural strength is 88.6MPa. 2TMI get the maximum flxural strength at the amount of 10%,and the flexural strength is 79.3MPa. 2TEMI get the maximum flxural strength at the amount of 10%,and the flexural strength is 76.6MPa.Then we study the characteristics and kinetic parameters of homemade single isocyanate modified imidazole(GMI, GEMI) and organometallic copper salts(1GMIC, 2GMIC) cure epoxy. 5% GMI, 5% GEMI, 16% 1GMIC, 16% 2GMIC cured epoxy resin were studied. The extrapolated initial temperature wsa 76.1 ??73.1 ??89.1 ??104 ?. The peak temperature was 111 ??112 ??139 ??157 ?. The activation energy was 60.2KJ / mol?65.0KJ / mol?76.8KJ / mol?77.8KJ / mol. The organic metal salt of GMI reduce the GMI's activity.Again, using infrared and DSC study the mechanism of GMI cure epoxy. The results show that GMI curing epoxy's main reaction was ertiary amine N atom catalysis epoxide etherification. The reaction acco MPanied by GMI deblocked and isocyanate react with hydroxywith in epoxy.The researchers then studied the influence of types and amounts of imidazole harder on the latnent time at ambient temperature of imidazole cure epoxy systems. The results showed that the single isocyanate modify the imidazole increased its incubation period at room temperature, complex with the organic metal salt increase the latent property. A variety of imidazoles cure epoxy system had a decreased room temperature storage time with the amount increases. MI and 2EMI modified by single isocyanate increase the shelf life at room temperature, the amount of 5% 2EMI has one day, GMI has three days, GEMI has four days. After the organic metal complex modified GMI,the latent improved. The 2GMIC is better than 1GMIC,while 16% of 1GMIC storage period is 30 days, 16% of 2GMIC storage period is 43 days.Finally, the i MPact of the amount of curing agent on heat resistance and flexural properties of GMI and GEMI cured epoxy system. The glass transition temperature of GMI and GEMI cured epoxy systems rise with the amount increase firstly and then decreased. When the GMI up to 4% the Tg is 163 ?, GEMI up to 5% the Tg is 164 ?. The flexural modulus of GMI curing epoxy rise with the amount increase firstly and then decrease. While 5%GMI system get the maximum modulus is 3.24 Gpa. The bending strength of GMI curing epoxy rise with the amount increase. While 7%GMI system get the maximum strength is 113.1MPa. The flexural modulus of GEMI curing epoxy rise with the amount increase. While 7%GEMI system get the maximum modulus is 3.12 Gpa. The bending strength of GEMI curing epoxy rise firstly with the amount increase and then decrease. While 6%GMI system get the maximum strength is 75.4MPa. |
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