Effects of entrapment on spherulite morphology and growth kinetics in poly(ethylene oxide)/epoxy networks

Poly(ethylene oxide) (PEO) is known to be miscible with diglycidylether bis phenol-a (DGEBA)/4,4 ' -diamino diphenylsulfone (DDS) epoxy system before a nd after cure. As PEO starts to crystallize in the miscible mixtures (eithe r uncured liquid or cured network), entrapment and interactions between the species can play an important role on the growth kinetic and lamellar/sphe rulitic morphology. Thermal analysis, growth kinetics analysis, and morphol ogy characterization were performed on a PEO-epoxy system, and the results were found to be useful in providing critical interpretation. In general, e ntrapment between the growing species and epoxy/DDS was found to be more ex tensive in the uncured system. In addition, the interactions between the sp ecies are different before and after cure. The interactions between PEO and epoxy/DDS become less in the cured networks. The morphology and growth kin etics of the PEO crystals was in turn affected by the contents and chemical structures (functional soup, molecular weight, crosslink, etc.) of the amo rphous diluents (i.e. epoxy/DDS). The morphology of PEO in the cured PEO/ep oxy system is quite similar to that observed in the neat PEG. This study at tempted to offer a molecular microscopic view on commonly observed depressi on of growth kinetics of semicrystalline polymers in the presence of a dilu ent tan amorphous polymer or other non-crystallizing species) (C) 2001 Else vier Science Ltd. All rights reserved.