Epoxy Networks with Antiplasticiser Additives

In a way similar to that described for polyethylene fere-phthalate (Sect. 4.2), some antiplasticiser small molecules with a specific chemical structure are able to affect the transition and the yield stress of epoxy resins, but they do not have any effect on the y transition. In the case of HMDA networks, an efficient antiplasticiser, EPPHAA, whose chemical structure is shown in Table 8, has been reported [69]. The investigation of such antiplastidsed epoxy networks by dynamic mechanical analysis as well as soUd-state NMR experiments [70] can lead to a deeper understanding of the molecular processes involved in the p transition and of their cooperativity. 

The antiplasticiser molecule is added to the reacting agents before curing. A single glass transition has been observed in the final samples, indicating that the antiplasticiser is fully miscible with the epoxy networks. 

The code names of antiplasticised systems contain the reference APx, where x corresponds to the wt % of antiplasticiser in the system. They are gathered in Table 9. 

These conclusions are fully corroborated by the Ea and ASa values reported in Table 10. In particular, ASa values as small as 30 J K mol or less are observed for the high-temperature part and the maximum of the p tran- 

Quasi-lmear DGEBA/HA95/AP and Loosely Crosslinked DGEBA/HA60/AP Systems 

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