Synthesis Study And Property Research On Polyimide Bearing Alicyclic Structure Derived From Natural Products

With the rapid development of electrical, electronic, aerospace, microelectronics industry, the needs of high temperature resistance polymer materials are becoming increasingly urgent.Traditional aromatic polyimide materials have excellect high and low temperature resistance properties, electrical properties, mechanical properties, radiation resistance and thermal stability. However, the electronic polarization and crystallinity of aromatic polyimide give rise to a strong intermolecular interaction and closed backbone molecular packing, so aromatic polymide materials are difficult to melt and solve, difficult to process.According to the latest researches, the introduction of alicyclic structure into main chain of polyimide can bring about raised transparency, reduced dielectric constant and improved solubility,improved process performance Rosin and camphor are two kind of natural products with alicyclic structure and they are very cheap and commercially available, so they are the ideal raw materials to prepare alicyclic dianhydride and diamine monomer.Based upon above-mentioned research background, in this thesis, several polyimide membranes with alicyclic structure derived forestry chemical product, as well as a series of 3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride endcapped imide oligomers, were synthesized, and their properties were investigated.first of all, synthesis of ketone-linked aliphatic dianhydride monomer was reported. Rosin is a kind of natural product with three-membered phenanthrene ring structure. Reaction of rosin with maleic anhydride via Diels-Alder addition offers maleopimaric acid anhydride. In the presence of p-toluene sulfonic acid as a catalyst, decarboxylation of maleopimaric acid anhydride gives aliphatic dianhydride with ketone linkage, which keeps the structure of three-membered phenanthrene rings. The polyamic acid (PAA) solutions with 30 wt-% solids content based on ketone-linked aliphatic dianhydride and ODA,O-Tolidine Base respectively were prepared, which were then thermally imidized to prepare the corresponding polyimide films PI-1,PI-2. whose structure were characterized by IR, TGA and DSC test the thermal stability of polyimide films. Then a series of 3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride endcapped imide oligomers were synthesized based on ketone-linked aliphatic dianhydride monomer, and their properties were investigated by TGA and DSC. Last alicyclic diamine was synthesized via a series of reactions, such as oxidation, acylcholorination, amidization and reduction by LiAlH4 starting from camphor.