DOI
https://doi.org/10.25772/PR5B-2034
Defense Date
1990
Document Type
Dissertation
Degree Name
Doctor of Philosophy
Department
Chemistry
First Advisor
Robert G. Bass
Abstract
Three different series of imide/arylene ether block copolymers were prepared using two different imide blocks and two different arylene ether blocks. Block molecular weights studied were 3110 and 6545 g/mole for each block and all four combinations possible were prepared in each series. Also, several segmented copolymers were prepared by forming the imide segment and the copolymer in the presence of the pre-formed arylene ether block.
Two amine-terminated poly(arylene ether) blocks (ATPAE) were prepared by reacting 1,3-bis(4-fluorobenzoyl)benzene with either 2,2-bis(4-hydroxyphenyl)propane (BPA) or 9,9-bis(4-hydroxyphenyl)fluorene (BPF) and 4-aminophenol. Two anhydride-terminated poly(amic acid) blocks were prepared by reacting 4,4'-oxydianiline (ODA) or 1,3-bis(4-aminophenoxy-4’- benzoyl)benzene (BABB) with 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA). The ATPAEs were reacted with the anhydride- terminated poly(amic acids) to provide block copolymers which were either thermally or solution imidized. Thermal imidization was accomplished by heating 1 h each at 100, 200 and 300°C while solution imidization was accomplished by adding toluene to the reaction, heating to 155°C overnight and collecting the toluene/water azeotropic mixture in a Dean-Stark trap. Some of the block copolymers displayed two Tgs indicating incomptability and phase separation, especially for the higher molecular weight blocks.
The copolymer series preapred by reacting the ATPAE (BPA) blocks with the ODA/BTDA blocks in N,N-dimethylacetamide (DMAc) had inherent viscosities as high as 1.37 dL/g. The copolymer series prepared by reacting ATPAE (BPA) blocks with BABB/BTDA blocks in DMAc or N-methyl- pyrrolidinone (NMP) had inherent viscosities as high as 1.73 dL/g. The copolymer series prepared by reacting ATPAE (BPF) blocks with BABB/BTDA blocks in DMAc, NMP or m-cresol had inherent viscosities as high as 1.08 dL/g. The copolymers were characterized by differential scanning calorimetry (DSC), torsional braid analysis (TBA), thermogravimetric analysis (TGA) and wide angle x-ray diffraction (the BABB/BTDA imide is semi-crystalline). Mechanical properties were measured on copolymer films and fracture energies were measured on moldings. One copolymer was end-capped at a controlled molecular weight to improve processing and evaluated as an adhesive and graphite composite matrix. The chemistry and properties of the copolymers will be discussed and compared to those of the homopolymers.
Rights
© The Author
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
10-27-2017
Comments
Scanned, with permission from the author, from the original print version, which resides in University Archives.