Date of Award

5-1-2003

Degree Type

Dissertation

University or Center

Clark Atlanta University(CAU)

Doctor of Science

Department

Chemistry

First Advisor

Dr. Issifu I. Harruna

Abstract

Polyimides were synthesized from bicylic dianhydrides and diamines. The bicyclic monomers used were bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 1,4,7,8-tetrabromobicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride and 1,4,7,8-tetrachlorobicyclo [2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride. The diamines used were benzidine, 4,4’-diaminodiphenyl ether, 4,4’-(hexafluoroisopropylidene)dianiline and 4,4’-(1,4-phenylenedioxy)dianiline. Each dianhydride was polycondensed with each of the diamines in N-methyl pyrrolidinone (NMP) at elevated temperatures. The polymers were characterized by means of IR and 13C NMR spectroscopy, elemental analysis, solubility and thermal analysis such as differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). TGA studies indicate that the polymers were all stable to above 320°C. Most of the polymers were found to be soluble in highly polar, high boiling point solvents such as dimethyl sulfoxide (DMSO), N-methyl pyrrolidinone (NMP), dimethyl acetamide (DMAc) as well as concentrated sulfuric acid. Selected comparative solubility studies with wholly aromatic analogues of the bicyclic polyimide indicate that the bicyclic polymers show better solubility. Thermal studies of the behavior of the bicyclic components of the polyimides were carried out by the use of low molecular weight imide dimers. The results obtained indicate that the bicyclic ring system undergoes a thermal retro Diels-Alder reaction thus separating into two fragments.

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