Organosoluble and Thermally Stable of Benzazole-Containing Poly(Imide-Urea)s: One-Pot Synthesis and Characterization

The preparation of new types of poly(imide-urea)s (PIUs) with high thermal stability and improved solubility was investigated. Three series of aromatic poly(imide-urea)s (PIUOa-c, PIUSa-c, and PIUNa-c) bearing pendent benzoxazole, benzothiazole or benzimidazole rings were prepared by one-pot polycondensation reaction of three bis(imide-carboxylic acid)s, 2-[3,5-bis(N-trimellitimidoyl)-phenyl]benzoxazole (1O), 2-[3,5-bis(N- trimellitimidoyl)-phenyl]benzothiazole (1S), or 2-[3,5-bis(N-trimellitimidoyl)-phenyl]benzimidazole (1N) with various kinds of aromatic diamines (a-c). The effects of the benzazole pendent groups on the polymer properties such as solubility and thermal stability were investigated by comparison of the polymers. All of the resulting polymers exhibited excellent solubility in common polar solvents. The glass transition temperature of the polymers determined by DSC thermograms were in the range 192℃ - 236℃. The temperatures at 10% weight loss from their TGA curves were found to be in the range 390℃ - 441℃ in nitrogen.

HEAT STABLE AND ORGANOSOLUBLE BENZOXAZOLE OR BENZOTHIAZOLE-CONTAINING POLY(IMIDE-ESTER)S AND POLY(ETHERIMIDE-ESTER)S: SYNTHESIS AND CHARACTERIZATION

Two series of poly（imide-ester）s （PIEs） and poly（ether-imide-ester）s （PEIEs）, having benzoxazole or benzothiazole pendent groups, were conveniently prepared by the diphenylchlorophosphate-activated direct polyesterification of two bis（imide-carboxylic acid）s （1）, such as 2-[3,5-bis（N-trimellitimidoyl）phenyl]benzoxazole （lo） and 2-[3,5-bis（N- trimellitimidoyl）phenyl]benzothiazole （Is） and two bis（imide-ether-carboxylic acid）s （2）, such as 2-[3,5-bis（4- trimellitimidophenoxy）-phenyl]benzoxazole （2o）, and 2-[3,5-bis（4-trimellitimidophenoxy）-phenyl]benzothiazole （2s） with various aromatic dihydroxy compounds in the presence of pyridine and lithium chloride. The structures, solubilities and thermal properties of obtained polymers were investigated in detail. All of the resulting polymers were characterized by FTIR and IH-NMR spectroscopy and elemental analysis. All of the resulting polymers exhibited excellent solubility in common organic solvents, such as pyridine, tetrahydrofuran and m-cresol, as well as in polar organic solvents, such as N-methyl-2- pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide and dimethyl sulfoxide. The modified polymers were obtained in quantitative yields with inherent viscosities between 0.47 and 0.67 dl·g^-1 Experimental results indicated that all the polymers had glass transition temperature between 198 ℃ and 262 ℃, the decomposition temperature at 10% weight loss between 398 ℃ and 531 ℃ under nitrogen.

Preparation and Characterization of Poly(amide-imide)/ZnO Nanocomposites Containing Pendent Benzoxazole and Benzimidazole Segments

In the present investigation, novel poly（amid-imide）/zinc oxide nanocomposites（PAI/Zn O NCs） containing benzoxazole and benzimidazole pendent groups with different amounts of modified zinc oxide nanoparticles（Zn O NPs） were successfully prepared via the ex situ method. Poly（amid-imide）（PAI） was prepared by direct polycondensation of 2-[3,5-bis（N-trimellitimidoyl）phenyl]benzoxazole（DCA） with 5-（2-benzimidazole）-1,3-phenylenediamine（DAMI） and provided the polymeric matrix with well-designed groups. The surface of Zn O NPs was functionalized with 3-aminopropyltriethoxysilane（APS） coupling agent to have a better dispersion and enhancing possible interactions of NPs with functional groups of polymer matrix. The amount of APS bonded to the Zn O surface was determined by thermogravimetric analysis. PAI/Zn O nanocomposites were characterized by Fourier transform infrared spectroscopy（FTIR）, X-ray diffraction（XRD）, and scanning electron microscopy（SEM）. SEM analysis showed that the modified Zn O nanoparticles were homogeneously dispersed in polymer matrix. In addition, TGA data indicated an enhancement of thermal stability of the nanocomposite compared with the neat polymer.