Aromatic polybenzoxazole (PBO) precursor, hydroxy-substituted polyenaminonitrile, was prepared by direct polycondensation of 1,4-bis(1-chloro-2,2-dicyanovinyl)benzene (CCB) and 4,6-diaminoresorcinol dihydrochloride (D...Aromatic polybenzoxazole (PBO) precursor, hydroxy-substituted polyenaminonitrile, was prepared by direct polycondensation of 1,4-bis(1-chloro-2,2-dicyanovinyl)benzene (CCB) and 4,6-diaminoresorcinol dihydrochloride (DAR) using pyridine and N,N-dimethylacetamide as condensing agent and solvent. The precursor has good solubility in polar aprotic solvent which is due to the strong dipolar nature of the main chain. The soluble precursor was subjected to thermal cyclization in an inert atmosphere to convert it into the corresponding PBO, which has its 5% weight loss temperature at The fully cyclized PBO were characterized by FT-IR and TGA. The introduction of 10% mol 1,3,5- benzenetricarboxylic chloride (BTC) into the main chain not only has little effect on the solubility of PBO precursor but also raises its 5% weight loss temperature to 552°C and char yield at 700°C for the cyclized PBO with BTC.展开更多
A series of polybenzoxazoles(co)polymers bearing crankshaft units in the main chain was synthesized by the conventional solution polycondensation of 4,6-diaminorescinol dihydrochloride, terephthalic acid(TA) and 2,6-n...A series of polybenzoxazoles(co)polymers bearing crankshaft units in the main chain was synthesized by the conventional solution polycondensation of 4,6-diaminorescinol dihydrochloride, terephthalic acid(TA) and 2,6-naphthalene dicarboxylic acid(NDA). All of the polymers show lyotropic liquid crystal behavior in polyphosphoric acid(PPA) and methanesulfonic acid(MSA). The polybenzoxazoles exhibit an excellent thermal resistance although the crankshaft monomer has been introduced into the polymer backbone. The temperature for the 5% weight loss of all the polymers is above 600 ℃.The X-ray diffraction analysis results show that the series of the polymers has a high crystallinity. The introduction of NDA makes a slight decrease in the thermal resistance of the polymers. The maximum absorption peak in the UV-Vis spectra can be adjusted according to the amount of 2,6-naphthalene units in the polymers, which indicates the potential application of the polymers as optoelectric materials.展开更多
基金This work is supported by the 863 Program (No. 2001AA335050) and the 973 Program (No. 2003CB615600) of MOST ofthe People's Republic of China.
文摘Aromatic polybenzoxazole (PBO) precursor, hydroxy-substituted polyenaminonitrile, was prepared by direct polycondensation of 1,4-bis(1-chloro-2,2-dicyanovinyl)benzene (CCB) and 4,6-diaminoresorcinol dihydrochloride (DAR) using pyridine and N,N-dimethylacetamide as condensing agent and solvent. The precursor has good solubility in polar aprotic solvent which is due to the strong dipolar nature of the main chain. The soluble precursor was subjected to thermal cyclization in an inert atmosphere to convert it into the corresponding PBO, which has its 5% weight loss temperature at The fully cyclized PBO were characterized by FT-IR and TGA. The introduction of 10% mol 1,3,5- benzenetricarboxylic chloride (BTC) into the main chain not only has little effect on the solubility of PBO precursor but also raises its 5% weight loss temperature to 552°C and char yield at 700°C for the cyclized PBO with BTC.
基金Supportby the"86 3"Program(No. 2 0 0 1AA335 0 5 0 ) and the"973"Program(No. 2 0 0 3CB6 15 6 0 0 ) of the People's Re-public of China
文摘A series of polybenzoxazoles(co)polymers bearing crankshaft units in the main chain was synthesized by the conventional solution polycondensation of 4,6-diaminorescinol dihydrochloride, terephthalic acid(TA) and 2,6-naphthalene dicarboxylic acid(NDA). All of the polymers show lyotropic liquid crystal behavior in polyphosphoric acid(PPA) and methanesulfonic acid(MSA). The polybenzoxazoles exhibit an excellent thermal resistance although the crankshaft monomer has been introduced into the polymer backbone. The temperature for the 5% weight loss of all the polymers is above 600 ℃.The X-ray diffraction analysis results show that the series of the polymers has a high crystallinity. The introduction of NDA makes a slight decrease in the thermal resistance of the polymers. The maximum absorption peak in the UV-Vis spectra can be adjusted according to the amount of 2,6-naphthalene units in the polymers, which indicates the potential application of the polymers as optoelectric materials.
