Synthesis of new thermosetting poly(2,6-dimethyl-1, 4-phenylene oxide)s containing epoxide pendant groups

A new class of thermosetting poly(2,6-dimethyl-1,4-phenylene oxide)s containing pendant epoxide groups were synthesized and characterized. These new epoxy polymers were prepared through the bromination of poly(2,6-dimethyl-1,4-phenylene oxide) in halogenated aromatic hydrocarbons followed by a Wittig reaction to yield vinyl-substituted polymer derivatives. The treatment of the vinyl-substituted polymers with m-chloroperbenzoic acid led to the formation of epoxidized poly(2,6-dimethyl-1,4-phenylene oxide) with variable pendant ratios, and the structures and properties were studied with nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and gel permeation chromatography. The ratios of pendant functional groups were tailored for the polymer properties, and the results showed that the glass-transition temperatures increased as the benzylic protons were replaced by bromo-, vinyl-, or epoxide-functional groups, whereas the thermal stability decreased in comparison with the original polymer. Within a molar fraction of 20-50%, the degree of functionalization had little effect on the glass-transition temperature; however, it correlated inversely with the thermal stability of each functionalized polymer. The thermal curing behavior of the epoxide-functionalized polymer was enhanced by the increment of the pendant functionality, which resulted in a significant increase in the glass-transition temperature as well as the thermal stability after the curing reaction. (c) 2006 Wiley Periodicals, Inc.