A new aromatic asymmetrical ether diamine, 1,4-bis（3＇,4’-diaminophenoxy）benzene 3 was synthesized in three steps, using hydroquinone as starting material. A new aromatic polyimide containing asymmetrical diaryl et...A new aromatic asymmetrical ether diamine, 1,4-bis（3＇,4’-diaminophenoxy）benzene 3 was synthesized in three steps, using hydroquinone as starting material. A new aromatic polyimide containing asymmetrical diaryl ether segments was prepared from the resulting diamine with 4,4＇-oxydiphthalic anhydride （ODPA） via a conventional two-step thermal or chemical imidization method. The resulting polyimide exhibits high thermal resistance, excellent solubility, film-forming capability, high mechanical strength and modulus.展开更多
A new kind of aromatic diamine monomer containing pyridine unit,2,6-bis[4-(4-aminophenoxy)phenoxy]pyridine(BAPP),was synthesized in three steps,using hydroquinone as starting material.A novel pyridine-containing polyi...A new kind of aromatic diamine monomer containing pyridine unit,2,6-bis[4-(4-aminophenoxy)phenoxy]pyridine(BAPP),was synthesized in three steps,using hydroquinone as starting material.A novel pyridine-containing polyimide was prepared from the resulting diamine BAPP with 4,4 -oxydiphthalic anhydride(ODPA) via a conventional two-step thermal imidization method.The resulting polyimide exhibits excellent solubility,film-forming capability and high thermal resistance.展开更多
A new aromatic diamine monomer containing pyridine unit, 2,6-bis （4-aminophenoxy- 4＇-benzoyl）pyridine（BABP）, was synthesized in three steps, starting from 2,6-pyridinedicarboxyl chloride. A series of novel pyridi...A new aromatic diamine monomer containing pyridine unit, 2,6-bis （4-aminophenoxy- 4＇-benzoyl）pyridine（BABP）, was synthesized in three steps, starting from 2,6-pyridinedicarboxyl chloride. A series of novel pyridine-containing polyimides were prepared v/a the polycondensation of BABP with various aromatic dianhydrides through poly（amic acid） precursors, and thermal or chemical imidization of the precursors. The polyimides exhibit desirable properties, e.g., good solubility in N-methyl-2-pyrrolidone and m-cresol, excellent thermal stability and film-forming capability, as well as high inherent viscosity, indicating high molecular weight.展开更多
A new kind of asymmetrical ether diamine,3,4＇-bis（4-aminophenoxy）benzophenone（BABP）,was synthesized from the nucleophilic substitution reaction of 4-chloronitrobenzene and 3,4＇-dihydroxybenzophenone in the prese...A new kind of asymmetrical ether diamine,3,4＇-bis（4-aminophenoxy）benzophenone（BABP）,was synthesized from the nucleophilic substitution reaction of 4-chloronitrobenzene and 3,4＇-dihydroxybenzophenone in the presence of potassium carbonate,followed by catalytic reduction with SnCl_2-6H_2O and concentrated hydrochloric acid.The prepared diamine was employed in the preparation of a novel polyimide containing asymmetrical diaryl ether segments via the polycondensation of it with BTDA by a two-step method.The resulting polyimide exhibits excellent solubility,film-forming capability and high thermal resistance.展开更多
1 Results and DiscussionTwo diamines 1,4-phenylene di(oxy-4,4′-aniline) and 4-aminophenyloxy-N-4-[(4-amiophenyloxy)benzylidene]aniline were prepared via the nucleopilic substitution reaction and were polymerized with...1 Results and DiscussionTwo diamines 1,4-phenylene di(oxy-4,4′-aniline) and 4-aminophenyloxy-N-4-[(4-amiophenyloxy)benzylidene]aniline were prepared via the nucleopilic substitution reaction and were polymerized with 3,3′,4,4′-benzophenonetetracarboxylic acid dianhydride (BP), 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (HF) , 3,4,9,10-perylenetetracarboxylic acid dianhydride (PD) and pyromellitic dianhydride (PMDA) either by one step solution polymerization reaction or two step procedure. The l...展开更多
High-performance polymers(HPPs)are increasingly used in different industrial machinery components,particularly for rubbing parts that demand reliable and durable operation at extreme sliding conditions such as elevate...High-performance polymers(HPPs)are increasingly used in different industrial machinery components,particularly for rubbing parts that demand reliable and durable operation at extreme sliding conditions such as elevated temperature environments,where the use of conventional lubricants is not feasible.The current study investigates the role of environmental temperature on the tribological properties of three advanced HPPs,namely aromatic thermosetting copolyester(ATSP),polyimide(PI),and polyether ether ketone(PEEK)based polymer composites.Tribological experiments were carried out at different environmental temperatures from room temperature up to 300℃,and under dry sliding conditions.Specific attention was given to the role of temperature on the development of transfer films and its subsequent effect on the tribological performance.The ATSP composite was recommended as the best performing material,based on the overall tribological performance at all examined operating temperatures.展开更多
文摘A new aromatic asymmetrical ether diamine, 1,4-bis（3＇,4’-diaminophenoxy）benzene 3 was synthesized in three steps, using hydroquinone as starting material. A new aromatic polyimide containing asymmetrical diaryl ether segments was prepared from the resulting diamine with 4,4＇-oxydiphthalic anhydride （ODPA） via a conventional two-step thermal or chemical imidization method. The resulting polyimide exhibits high thermal resistance, excellent solubility, film-forming capability, high mechanical strength and modulus.
基金support from the Research Foundation of the State Key Laboratory of Applied Organic Chemistry
文摘A new kind of aromatic diamine monomer containing pyridine unit,2,6-bis[4-(4-aminophenoxy)phenoxy]pyridine(BAPP),was synthesized in three steps,using hydroquinone as starting material.A novel pyridine-containing polyimide was prepared from the resulting diamine BAPP with 4,4 -oxydiphthalic anhydride(ODPA) via a conventional two-step thermal imidization method.The resulting polyimide exhibits excellent solubility,film-forming capability and high thermal resistance.
文摘A new aromatic diamine monomer containing pyridine unit, 2,6-bis （4-aminophenoxy- 4＇-benzoyl）pyridine（BABP）, was synthesized in three steps, starting from 2,6-pyridinedicarboxyl chloride. A series of novel pyridine-containing polyimides were prepared v/a the polycondensation of BABP with various aromatic dianhydrides through poly（amic acid） precursors, and thermal or chemical imidization of the precursors. The polyimides exhibit desirable properties, e.g., good solubility in N-methyl-2-pyrrolidone and m-cresol, excellent thermal stability and film-forming capability, as well as high inherent viscosity, indicating high molecular weight.
基金the financial support from the Natural Science Foundation of Gansu Province(No. 096RJZA047)the Fundamental Research Funds for the Central Universities(No.lzujbky-2011-24)
文摘A new kind of asymmetrical ether diamine,3,4＇-bis（4-aminophenoxy）benzophenone（BABP）,was synthesized from the nucleophilic substitution reaction of 4-chloronitrobenzene and 3,4＇-dihydroxybenzophenone in the presence of potassium carbonate,followed by catalytic reduction with SnCl_2-6H_2O and concentrated hydrochloric acid.The prepared diamine was employed in the preparation of a novel polyimide containing asymmetrical diaryl ether segments via the polycondensation of it with BTDA by a two-step method.The resulting polyimide exhibits excellent solubility,film-forming capability and high thermal resistance.
文摘1 Results and DiscussionTwo diamines 1,4-phenylene di(oxy-4,4′-aniline) and 4-aminophenyloxy-N-4-[(4-amiophenyloxy)benzylidene]aniline were prepared via the nucleopilic substitution reaction and were polymerized with 3,3′,4,4′-benzophenonetetracarboxylic acid dianhydride (BP), 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (HF) , 3,4,9,10-perylenetetracarboxylic acid dianhydride (PD) and pyromellitic dianhydride (PMDA) either by one step solution polymerization reaction or two step procedure. The l...
文摘High-performance polymers(HPPs)are increasingly used in different industrial machinery components,particularly for rubbing parts that demand reliable and durable operation at extreme sliding conditions such as elevated temperature environments,where the use of conventional lubricants is not feasible.The current study investigates the role of environmental temperature on the tribological properties of three advanced HPPs,namely aromatic thermosetting copolyester(ATSP),polyimide(PI),and polyether ether ketone(PEEK)based polymer composites.Tribological experiments were carried out at different environmental temperatures from room temperature up to 300℃,and under dry sliding conditions.Specific attention was given to the role of temperature on the development of transfer films and its subsequent effect on the tribological performance.The ATSP composite was recommended as the best performing material,based on the overall tribological performance at all examined operating temperatures.
