PEO-b-PE Self-assembled into Elongated Nanoribbons During Epoxy Photopolymerization

ILEANA A. ZUCCHI; WALTER F. SCHROEDER

Chiang Mai

Congreso; Macro 2014; 2014

This report describes the preparation of thermoset epoxy matrix containing self-assembled nanostructures of a low-molecular-weight poly(ethylene oxide)-poly(ethylene) (PEO-b-PE) diblock copolymer. The preparation of these nanostructured materials involves firstly the dissolution of PEO-b-PE in an epoxy monomer of the type diglycidyl ether of bisphenol A (DGEBA) at 150ºC followed by polymerization at room temperature via cationic photopolymerization mechanism (induced by visible light exposure). DGEBA monomer undergoes slow photoinitiated polymerization allowing the growth of block copolymer nanoribbons during this term. Transmission electron microscopy (TEM) analysis of samples containing up to 20 wt% PEO-b-PE showed elongated nanoribbons dispersed in the epoxy matrix without any macroscopic phase separation evidence. The micelle structure consisted in a semicrystalline PE core surrounded by a PEO shell. These micelles were typically on the order of 20 to 30 nm in width with variable lengths, comprised between 1 and greater than 10 microns, depending on block copolymer concentration. Small angle X-ray scattering (SAXS) experiments evidenced a lamellar array that increase its intensity with the PEO-b-PE content.