Synthesis and characterization of poly(arylene ether s-triazine)s containing alkyl-, aryl- and chloro-substituted phthalazinone moieties in the main chain

Soluble and heat-resistant polymers have great potential for use as processable, high-temperature polymeric materials. In this study, four types of new poly(arylene ether s-triazine)s containing alkyl-, aryl- and chloro-substituted phthalazinone moieties in the main chain were prepared through direct solution polycondensation of 2,4-bis(4-fluorophenyl)-6-phenyl-s-triazine with each of methyl-, phenyl- and chloro-substituted phthalazinones. A key feature of these polymers is the incorporation of phthalazinone and side groups into the poly(arylene ether s-triazine) backbone to endow them with good solubility while maintaining other attractive properties. The polymers were obtained in high yields, and had inherent viscosities ranging from 0.38 to 0.55 dL g(-1). Their structure was characterized using Fourier transform infrared and NMR spectra and elemental analysis. The polymers were almost amorphous, and soluble in N-methyl-2-pyrrolidone, pyridine, N,N-dimethylacetamide, hot N, N-dimethylformamide and sulfolane. Tough and nearly transparent films obtained by direct solution casting exhibited good mechanical properties. The resulting polymers displayed glass transition temperatures ranging from 255 to 265 degrees C and thermal decomposition temperatures for 10% mass loss ranging from 476 to 599 degrees C, according to differential scanning calorimetry and thermogravimetric analysis, respectively. The reactivity of substituted phthalazinones in nucleophilic displacement reactions and the effect of the side groups on the physical properties of the polymers were also investigated. The results obtained revealed that such s-triazine-containing polymers possessed good solubility while maintaining acceptable thermal stability and high mechanical strength with the incorporation of alkyl-, aryl- and chloro-substituted phthalazinone moieties into their backbones, which makes them an attractive series of high-performance structural materials. (C) 2010 Society of Chemical Industry