Design And Synthesis Of Novel Dianhydride Molecules And Their Polyimides

As a organic polymer material with thermal stability,good chemical resistance and excellent mechanical properties,the polyimide?PI?is a polymer of imide monomers.Usually,the polyimide materials are widely used in aerospace field,high performance fibres,electrical industries and membrane separating etc.However,most polyimide materials are limited by expensive cost,poor process-ability and bad optical performance.Based upon the theory of molecular design,we use the paradigmatic D_3h symmetry structure,triptycene,which has high internal free volume and three-dimensional rigid structure,as an nanobuilding block to modulate the PIs with low cost,good solubility and excellent comprehensive performance.Based on the theory,we conducted deep research and synthesized a new triptycene-based dianhydride with higher internal free volume.We suppose that higher internal free volume will block the packing of polymer chains,improve the solubility and increase the BET surface area of PIs.The research mainly includes:1.Crystals of 9,10-o-naphthyl anthracene-2,3,6,7-tetracarboxylic dianhydride were prepared by the solvothermal method.And by systematically investigating the solvothermal reaction time,reaction temperature,cooling rate,medium and other factors,the optimal conditions of the solvothermal preparation to obtain high purity and high yield of 9,10-o-naphthyl-2,3,6,7-tetracarboxylic dianhydride crystals was successfully explored.Single crystal structure data of 9,10-o-naphthyl anthracene-2,3,6,7-tetracarboxylic dianhydride crystals were collected by X-ray single crystal diffractometer.The single crystal structure of 9,10-o-naphthyl anthracene-2,3,6,7-tetracarboxylic dianhydride confirmed that the structure was correct.It belongs to monoclinic system,P 21/c space group,unit cell parameters are a=20.630?2??,b=10.8650?11??,c=18.6738?16??,?=90°,?=105.938°,?=90°,V=4024.7?7?A³.2.9,10-o-naphthyl anthracene-2,3,6,7-tetracarboxylic dianhydride crystals which were prepared by the solvothermal method and 4,4'-diaminodiphenyl ether were polymerized by one-step polymerization to obtain a linear polyimide;9,10-o-naphthyl anthracene-2,3,6,7-tetracarboxylic dianhydride prepared by acetic anhydride refluxing method and 2,2'-Dimethyl-4,4'-diamino-1,1'-biphenyl were polymerized by one-step polymerization to obtain linear polyimide.The structures of the two polyimides were characterized by NMR and FT-IR methods;and The thermal weight loss TGA,BET surface area and DSC of the two polyimides were tested.3.2,3,6,7-tetramethyl-9,10-o-?2,3-anthryl?anthracene was synthesized in a high yield by a simple and inexpensive route.The subsequent separation and purification conditions of 2,3,6,7-tetramethyl-9,10-o-?2,3-anthryl?anthracene were optimized.The oxidation of 2,3,6,7-tetramethyl-9,10-o-?2,3-anthryl?anthracene was further explored.