Synthesis And Properties Of Novel Triptycene Polyimides

Polyimide is an important class of aromatic heterocyclic high-performancematerials. Due to the outstanding comprehensive performance and easily synthesized,Polyimides are widely used in aerospace, electronics which are closely related tonational security and the field of high-tech as advanced structural or functionalmaterial. However, they are insoluble and do not melt below their decompositiontemperature. The infusibility and poor solubility of polyimides are characteristicproperties which restrict processing and applications. Their excellent thermalproperties have been comfirmed the negative influence upon their processibility. Thusin the synthesis of any thermal stable polymer, a compromise has to be reachedbetween thermo-mechanical properties and processibility. Therefore it is veryimportant and challenging to study various structure-prorerty relationgships in orderto predict the effects of structural modificationgs on polymer properties.In organic compounds triptycene has very special D3h symmetry with largeinternal free volume and the planet-like three-dimensional rigid aromatic structure. Itwas found that polymer including triptycene structure exhibits more excellentproperties. Based on the principles of organic synthetic chemistry, selecting thedesired triptycene structure as the starting point and platform, triptycene-2,3,6,7,14,15,16-hexacarboxylic trianhydride and2,6-diamino-13,14,15,16-tetrachloro triptycene monomers were designed and synthesized. Triptycene-2,3,6,7,14,15,16-hexacarboxylic trianhydride provides the material basis for thestudy of hyperbranched polyimide. Series of triptycene Polyimides weresynthesized via a two step polycondensation by using2,6-diamino-13,14,15,16-tetrachloro triptycene diamine. Structure and properties ofpolyimides were studied. The highlight of the dissertation is as follows.(1)2,3,6,7,14,15-hexamethytriptycene was synthesized by Diels-Alder reactionusing4,5-dimethyl anthranilate and2,3,6,7-tetramethyl anthracene. Subsequentoxidation of the methyl groups with potassium permanganate provided triptycene-2,3,6,7,14,15,16-hexacarboxylic acid, which was dehydrated in acetic anhydride togive triptycene-2,3,6,7,14,15,16-hexacarboxylic trianhydride. The structures f all products were characterized by spectroscopy data.(2) Ttrachloro phthalic anhydride, after ammonia solution and Hofmanndegradation, tetrachlorophthalic amino acid was get.1,2,3,4-tetrachlorotriptycene wassynthesized by Diels-Alder reaction using tetrachlorophthalic acid and anthracene.Then by nitration and reduction of1,2,3,4-tetrachlorotriptycene,2,6-diamino-13,14,15,16-tetrachloro triptycene diamine monomer was got. Thestructures f all products were characterized by spectroscopy data.(3) Novel Triptycene Polyimides were synthesized via a two step polycondensationby using2,6-diamino-13,14,15,16-tetrachloro triptycene diamine. The structure ofpolyimides were characterized by1H NMR, FTIR, the properties of the polymerswere investigated by solubility, thermal properties, inherent viscositiesh and BET.The results showed that polyimides containing the tetrachlorotriptycene structure hadgood solubility and excellent thermal properties. Three polymimides also had goodfilm forming properties. Polyimides could form light transparent film. The polyimidebased on hexafluoro dianhydride with BET specific surface area of370m2/g was anovel porous polymer.