A Study on Polymerization-Induced Phase Separation (PIPS) of Epoxy Solution in Oligoethylene Glycol Aiming at Controlling the Characteristic Length

We have investigated polymerization-induced phase separation (PIPS) of epoxy solution in oligoethylene glycol (PEG200) using time resolved small-angle X-ray scattering (SAXS). To control the characteristic length or the pore size, especially to realize the nanometer characteristic length, we have investigated the structure formation process as a function of the fractions of crosslinking agent (curing agent) and oligoethylene glycol. It was found that the effects of the crosslinking agent fraction on the characteristic length was small, but those of the oligoethylene glycol fraction were so large to reduce the characteristic length down to 12.6 nm. The structural origin of the characteristic length was not assigned to structure due to the PIPS, but some structure originally existing in epoxy solution in PEG200 fixed by the crosslinking reaction.