Network epoxies annealing

Fig. 37. Swelling efficiency and free volume estimation in well-cured Fi-berite 934 network epoxies, as affected by sub-Tf annealing. Percent swelling is plotted on the ordinate axis while percent of moisture uptake is plotted on the abscissa...

Fig. 6a and b. Heat capacity ACP(TS) and cubic thermal expansion coefficient jumps AP(Tg) for some epoxy-amine systems.. Experimental results O DGER-mPhDA networks of different P, completely cured and annealed (T = 0.5°/min) DGEBA-mPhDA networks of different P, completely cured and annealed DGEBA-mPhDA unreacted mixture (P = 1) DGER-mPhDA unreacted mixture (P = 1) solid lines — the best fit... 

In paper [43] acceleration of the stress relaxation process was found at loading of epoxy polymers under the conditions similar to those described above (Figure 6.8, curves 2-4). The authors [43] explained the observed effect by the partial rupture of chemical bonds. In order to check this conclusion in paper [39] repeated tests on compression of samples, loaded up to the cold flow plateau and then annealed at T < T, were carried out. It has been established that in the diagram o-e tooth of yield is restored. This can occur at the expense of the restoration of unstable clusters, since the restoration of failed chemical bonds at T < is scarcely probable. In this connection it is also necessary to note that yield tooth suppression as a result of preliminary plastic deformation was observed earlier for linear amorphous polymers, for example, polycarbonate [44], for which the chemical bonds network is obviously absent. 

USING DYNAMIC MECHANICAL ANALYSES TO PROBE THE GLASSY STATE RESPONSE OF A Sub-Tg ANNEALED MODEL EPOXY NETWORK ... 

Research on bisphenol-A epoxy resins composed of the diglycidyl ether of bisphenol-A (DGEBA) monomer have been mixed with respect to the physical aging of the polymer network when subjected to sub-T annealing. 

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