Epoxy resins, aryl-aliphatic

The polymers considered in Sects. 4 to 6, i.e. polyethylene fere-phthalalc), bisphenol A polycarbonate and aryl-aliphatic polyamides, are linear polymers or copolymers without side chains, in which molecular motions occur in the glassy state. Detailed analysis of the transitions, mostly the ft transition, reveals that several processes are involved in this ft transition and that the co- 

In order to complete such a picture, it is interesting to investigate the effect of crosslinks on the secondary transitions, in particular the effect on the development with temperature of the cooperativity of the molecular motions involved. 

A very convenient system for performing this investigation consists of epoxy networks formed by reacting aromatic epoxy on aliphatic diamine. Indeed, the different nature (aromatic or aliphatic) of the units allows one to apply 13 C NMR for identifying the groups involved in the transitions and their motions. Furthermore, in the same way as for polyethylene tere-phthalate), specific small molecule additives act as antiplasticisers, which can offer an additional possibility for investigation of the molecular motions and their cooperativity. 

---

Conclusions on p Transition Motions in Pure Aryl-aliphatic Epoxy Resins... 

It appears that the nature of the cooperativity that develops in aryl-aliphatic epoxy resin is similar to that encountered in bisphenol A polycarbonate a cooperativity directly involving the local interchain packing, which... 

Dynamic mechanical analysis and the 13C NMR experiments performed on pure aryl-aliphatic epoxy networks, as well as on antiplasticised systems, have led to a deeper insight into the molecular motions involved in the glassy state of these epoxy resins. 

---