Effect of accelerator on curing property of epoxy resin

- Sep 01, 2018-

According to the corresponding Tm in table 1 at different heating rates, linear regression was performed on (1 / Tm) x 103 with ln(zoos/Tm2), as shown in figure 4.By figure 4 of the straight line of slope and E - 44 Δ Ea/PA/DMP - 30 system, its value is 55.28 kJ/mol, and E - 44 Δ Ea/PA system is 52.5 kJ/mol, [19].This shows E - 44 / PA/DMP - 30 system Δ Ea is akin to E - 44 / PA system.The linear regression of (1 / Tm) x 103 is based on the ln bases, as shown in figure 5.N = 0.899, which is similar to the first order reaction.System response is more complex, involving a variety of material in the Δ Ea and the sum of n reflects the overall reaction.

 

The reaction in the e-44 / PA/dmp-30 system involves not only the reaction between e-44 and PA, but also the interaction between e-44 and dmp-30, as well as the reaction between the products of the reaction between PA and e-44 and dmp-30 [20].E - between 44 and PA reaction of epoxy group and ring opening reaction between amino, first is the primary amine on the lively epoxy group and hydrogen reaction, itself generate secondary amine, react with epoxy group to generate further tertiary amine and tertiary amine can be catalytic epoxy group by anionic polymerization process of gradually open loop all together, but in the presence of primary amine and secondary amine, the reaction generally difficult to achieve, so it is difficult to ensure maximum crosslinking density.DMP - 30 is a nucleophilic promoter and ACTS as a separate catalyst for amine curing E - 44.

Mu China et al. [21] obtained through continuous microwave curing EP/DMP -- 30 system that EP prepolymer and DMP -- 30 generated polyether crosslinking network through anion-catalyzed polymerization. A large amount of heat is released during the reaction, and the higher the temperature, the more intense the reaction between the two is.Under the condition of heat (100 ℃) tertiary amine on the rapid decomposition, catalytic effect [22].At the same time, the addition of hydroxyl group facilitates the generation of hydrogen bond and promotes the reaction between epoxy group and amine group [23].Therefore, the addition of appropriate amount of DMP - 30 can reduce the reaction temperature, shorten the curing time and increase the crosslinking density of the curable.

When the amount of DMP - 30 exceeds, it reacts with part of E - 44 and part of PA is in free state, which further reduces the crosslinking density of the curing substance.DMP - the addition of 30, while making the response of the system is complicated, but the promoter and E - 44 products after decomposition have catalytic effect, at the same time, the reaction of epoxy groups and hydroxyl amino, therefore Δ Ea has not changed much.

3 · conclusion

(1) the optimal dosage of dmp-30 was determined to be 10% of the quality of e-44. At this point, the shear strength and compression strength of e-44 / PA/dmp-30 curing system were respectively 16.19 and 83.32MPa.

(2) the apparent activation energy of e-44 / PA/DMP - 30 is 55.28kJ/mol, and the reaction series is 0.899.A small amount of DMP - 30 can reduce the reaction temperature of the system and shorten the curing time.