FORMATION OF 4,4'-THIODIPHENOL-MODIFIED EPOXY-RESINS MONITORED BY GPCAND MALDI-TOF MASS-SPECTROMETER

Reaction intermediates in the reaction of 4,4'-thiodiphenol (TDP) and Epikote 828 (E 828) for the formation of the diglycidyl ether of bisph enol A (DGEBA) epoxy copolymers (ETP) were determined by using a combi nation of two methods, viz. gel permeation chromatography( GPC) and ma trix-assisted laser desorption ionization/time-of-flight (MALDI-TOF) s pectrometer. This combination provides the measurement of true molecul ar weight and distribution, which in turn, enables the structural iden tification of intermediates and determination of their respective cont ents. The content of ideal component, the E 828-(TDP-E 828)(n), n = I in ETP copolymer, was found to be 2.3, 13.0, and 34.4% for ratios of 1 /1, 1/2, and 1/3 of TDP and E 828, respectively. The ETP epoxy copolym ers also exhibited thermal improvement over E 828 and other DGEBA resi ns of the E 1000 series, as indicated by their higher glass transition temperature (T-g) in differential scanning calorimeter (DSC) and bett er thermostability in thermogravimetric analysis (TGA) measurements. ( C) 1998 John Wiley & Sons, Inc.