Energetic block copolymer of polyglycidylazide-b-poly (azidoethyl methacrylate) (GAP-b-PAEMA) was synthesized and characterized. Macroinitiator PECH-Br prepared via the reaction of 2-bromoisobutyryl bromide with hydroxyl-terminated polyepichlorohydrin (PECH-OH) was used to initiate the atom transfer radical polymerization (ATRP) of chloroethyl methacrylate (CEMA). After azidation of the resulting copolymer, energetic copolymer GAP-b-PAEMA was obtained. Increase in the molecular weight determined by gel permeation chromatograph (GPC) is in agreement with the formation of block copolymer. Fourier transform infrared spectroscopy (FTIR) shows that the chlorine groups in the block copolymer can be substituted by azide group easily. Thermogravimetric analysis (TGA) shows that degradation of GAP-b-PAEMA involves two steps: the instantaneous decomposition of the azide groups followed by progressive scission of the polymer backbone. From differential scanning calorimetry (DSC) analysis, the GAP-b-PAEMA copolymer exhibits two glass transition temperatures (T_g) at −18 and 36°C, suggesting that the synthesized copolymer is a thermoplastic elastomer. This research provides a new method for the synthesis of energetic polymer. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers

Methylimidazole-terminated chain-extended urea (MITU) containing polypropylene oxide spacer was synthesized and employed to modify epoxies composed of a diglycidyl ether of bisphenol-A (E-51) and methyltetrahydrophthalic anhydride (MTHPA). The curing behavior, viscoelastic property, impact response, and fracture surface morphology of the curing systems were systematically investigated. Differential scanning calorimeter (DSC) analysis reveals that the curing reactivity of the epoxy system is greatly enhanced with the addition of MITU. From the dynamic mechanical analysis, besides the low-temperature β relaxation, shoulder at higher temperature side appears for the MITU-modified systems. Meanwhile, the addition of MITU leads to the increase of loss factor (tan δ) over the temperature range of 0–75°C. Impact tests show that the modifier can be effective in toughening the epoxy resin at relatively low loading, and the scanning electron microscope (SEM) images of the fracture surface for the modified systems display signs of ductility. Copyright © 2008 John Wiley & Sons, Ltd.