Thermal characterization on the relaxation transition of the phenylphosphonate-modified epoxy copolymers by thermally stimulated current technique and relaxation mapping analysis

TSC/RMA study on the depolarization relaxation transitions of the phenylphosphonate-modified epoxy copolymers with thiodiphenol (P2-ETP) or bis-phenol A (P2-EBPA) segments were conducted. P2-ETP resin shows a lower T-g than that of P2-EBPA, indicating that divalent thio-linkage (-S-) is flexible than isopropyl (-C(CH3)(2)-) group. Thermal windowing technique of RMA was used to obtain thermokinetic data in which Delta S of P2-ETP is higher than P2-EBPA, thus confirms the easier motion in P2-ETP which then leads to the lowering of the glass transition (T-g). Methods used for the confirmation on the T-g temperature were illustrated from thermokinetic data obtained by RMA measurement.