| Hyperbranched polyimide is a new kind of polymer materials. It could be used in many potential fields. It has the specific three-dimensional molecular structure. It has highly branched molecular chains. And there are many End-group functional groups on the surface of the molecular. These structural characteristics endue it with many unique properties compared to its linear analogues. The 1,3,5-tris(4-aminophenoxy)benzene (TAPOB) monomer is synthesized through ullmann reaction. And many hyperbranched polymers were synthesized through the polymerization of TAPOB and dianhydrides.The 1,3,5-tris(4-nitrophenoxy)benzene (TNPOB) is Synthesized. Through the reduction of TNPOB, the TATOB could be made. In the reaction, the choice of different catalysts and the control of the reaction conditions are very important to the final product. A reasonable synthetic route of TAPOB is obtained. The phloroglucinol and nitrochlorobenzene were reacted catalyzed by potassium carbonate, under reflux condition, yielding TNPOB. Catalyzed by palladium/hydrazine, under the protection of nitrogen, TNPOB could be reduced to TAPOB.Through the condensation polymerization of TAPOB and dianhydride, hyperbranched polyamide acid (HBPAA) and hyperbranched polyimide (HBPI) were prepared. Detected by IR, it is indicated that the hyperbranched polymer were successfully prepared. Through NMR characterization, it is demonstrated that the value of branching degree (DB) of HBPI is 100%, illustrating that all the amino groups have been reacted. Through the GPC characterization, it is verified that the moderate molecular weight polymers with Broad molecular weight distribution is attained. The hyperbranched polymers possess high solubility and reduced viscosities relative to their linear counterparts. Hyperbranched polyimide has good thermal stability, and the 10% weight loss temperatures of high molecular weight polymer is up to 500℃in nitrogen atmosphere.
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