Synthesis Study And Property Research On Polyimide Materials: Films And Reactive Endcapped Oligomers

Aromatic polyimides generally possess excellent thermal and mechanical, electrical,and chemical properties.Therefore,they are being used in many applications such as electrics,coatings,composite material,and membranes.According to the latest research,the introduction of alicyclic structure into main chain of polyimide can bring about raised transparency,reduced dielectric constant and improved solubility;the introduction of silicon modules into main chain of polyimide was expected to endow bettered processability,lowered dielectric constant and water absorption,improved the cohesion and adhesion to metal,glass and their own bond and the atomic oxygen-resistant properties.Based upon above research background,in this thesis,polyimide films derived from different alicyclic dianhydride moiety,crosslinked siliconized film,as well as a series of reactive endcapped imide oligomers,were synthesized,and their properties were investigated.In the first part,alicyclic dianhydride TPDA and TDA were synthesized and prepared as raw materials.Novel PI films were synthesized by TPDA and TDA with ODA,respectively,whose structure were characterized by IR.TGA and DSC showed the thermal stability of polyimide film were acceptable.In the second part,a series of crosslinking PI films were synthesized from TPDA-ODA,BPDA-ODA and BTDA-ODA with APTES and DMDMS as the endcapping agent and crosslinking agent respectively.And it was showed that the thermal stability and processing window of modified polyimide films were improved and widened.In the third part,3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride and 4,7-ethenoisobenzofuran-1,3-dione anhydride were prepared by reacting maleic anhydride with furan and bipentene,respectively.And a series of polyimide oligomers with different chain length were synthesized employing phthalic anhydride, maleic anhydride,3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride and 4,7-ethenoisobenzofuran-1,3-dione anhydride,respectively,as the endcapping agent. Their thermal stability was detected by DSC and TGA and it was shown polyimide oligomer endcapped by 3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride possessed the highest thermal stability.