Studies on the phase separation of polyetherimide modified tetrafunctional epoxy resin. II. Effects of the molecular weight

ABSTRACT The effects of molecular weight on the phase separation of phenyl-terminated polyetherirnide (P-PEI) modified tetraglycidyl-4,4′-di-aminodiphenylmethane (TGDDM) diaminodiphenylsulfone (DDS) systems were investigated by using Differential Scanning Calorimetry (DSC), Time-resolved Light Scattering (TRLS) and Scanning Electron Microscope (SEM). The P-PEI modified systems showed faster cure rate than the neat epoxy resin. An increase of the molecular weight of P-PEI raised the cure rate of the modified systems and changed the morphology from polyetherimide-rich domain in the low molecular weight P-PEI modified system to polyetherimide-epoxy co-continuous phase structure in the high molecular weight ones. The phase separation of high molecular weight P-PEI modified systems may proceed as a two stage process and result in the epoxy-rich spherical domains dispersed in the P-PEI-rich matrix.