Synthesis And Properties Of Triptycene-Based Novel Polyimide

The polyimide material is a class of main chain containing aromaticheterocyclic polymer materials. Aromatic polyimide material with a very stablearomatic heterocyclic structure, so that it demonstrated the excellentperformance that is the other polymer materials can not rival, So they are widelyused in high-tech fields of aerospace, microelectronics, and automobilemanufacturing, and so on. However, most of wholly aromatic polyimides havehigh melting temperatures and bad solubility in most organic solvents whichmake them generally intractable, thus significantly affecting the value of itsapplication. Therefore, significant synthetic efforts have been carried out toimprove Aromatic polyimide excellent properties through the synthesis of newdiamine or dianhydride monomers or through the synthesis of novel solubleAromatic polyimide.Triptycene and its derivatives, for its unique three-dimensional rigidaromatic structure, and ease of functionalization,gradually caused the people’sattention, has been applied to many areas of supramolecular chemistry,molecular devices and materials chemistry, and demonstrate its outstandingperformance in each field which they related.Given that triptycene unique three-dimensional structure and the excellentperformance of the polyimide, We designed a new type of novel triptycene-2,3,6,7-tetracarboxylic dianhydride, and preparationa a new type and novelstructure Aromatic polyimide containing triptycene structure, And theirproperties have been studied. The highlights of the dissertation are as follows:1) O-xylene and Benzyl alcohol underwent Friedel-Crafts alkylationreaction, By way of Carbonium ion mechanism to afford2,3,6,7-Tetramethylanthracene.2,3,6,7-Tetramethylanthracene and benzyne generated insitu underwent a Diels-Alder reaction to give2,3,6,7-tetramethyltriptycene,Subsequent oxidation of the methyl groups with KMnO4provided triptycene-2,3,6,7-tetracarboxylic acid which was dehydrated in acetic anhydride to afford triptycene-2,3,6,7-tetracarboxylic dianhydride. The structures of the productswere characterized by IR and1HNMR spectrum.2) Based on DHPZ and IPPZ, reactions with4-chloronitrobenzene resulteddinitro compounds, and get two unsymmetrical diamine monomers DH-DA andIP-DA with corresponding reduction in high yields. The structures of theproducts were characterized by IR and1HNMR spectrum.3) Novel structurea new type of polyimide were resulted from condensationbetween triptycene-2,3,6,7-tetracarboxylic dianhydride and The twophthalazinone biphenyl diamine, by low temperature solution polycondensation-chemical imidization, And their structure and properties have been studied, FT-IR spectrum characterization confirmed the chemical structures of the PI. Thetwo polyimides especially can be dissolved in NMP, DMAc, m-cresol,DMF,DMSO and the other common organic solvents. From DSC and TGA test, thereare no detected glass transition below300°C, and their5％weight losstemperatures were529°C and492°C,10％weight loss temperatures were566°Cand503°C. together with high char yield upon prolonged heating at800°C(More than58%). This shows that the preparation of polyimides have goodsolubility and excellent thermal properties.