The effects of crosslink density on thermo-mechanical properties of shape-memory hydro-epoxy resin

摘要

The objective of this work is to reveal the relationship between the molecular structure and shape-memory property of a hydro-epoxy resin system. The system is prepared using hydro-epoxy, menthane diamine (MDA), and poly(propylene glycol) diglycidyl ether (PPGDGE) with different molecular weights. By keeping the PPGDGE content constant, the crosslink density of the shape-memory hydro-epoxy resin system can be changed by varying the molecular weight of PPGDGE. The results indicate that the glass transition temperature (T_g) and rubber modulus (E_r) decrease as the crosslink density decreases. The crosslink density has little influence on shape recovery ratio (R_r). Full recovery can be observed after only several minutes when the temperature is equal to or above T_g. However, the crosslink density has a profound effect on the shape fixity ratio (R_f). If the crosslink density is too low, the shape fixity ratio of shape-memory hydro-epoxy resin would not reach 100％.