Date of Award

Spring 5-2017

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Polymers and High Performance Materials

Committee Chair

Dr. Robson Storey

Committee Chair Department

Polymers and High Performance Materials

Committee Member 2

Dr. Derek Patton

Committee Member 2 Department

Polymers and High Performance Materials

Committee Member 3

Dr. James Rawlins

Committee Member 3 Department

Polymers and High Performance Materials

Committee Member 4

Dr. Jeffrey Wiggins

Committee Member 4 Department

Polymers and High Performance Materials

Committee Member 5

Dr. Jason Azoulay

Committee Member 5 Department

Polymers and High Performance Materials

Abstract

This volume focuses on the development of telechelic polyisobutylene (PIB) prepolymers by combining end-capping of living carbocationic polymerization of isobutylene (IB) with suitable reactants and post-polymerization modifications. Alkylation kinetics of PIB tert-chloride with alkoxybenzenes using either TiCl4 or AlCl3 were investigated. Quantitative para-position end-capped products were only achieved if the alkoxybenzene/AlCl3 molar ratio was greater than unity; while no such molar ratio is required for TiCl4, but the alkylation rate was slower than AlCl3 under the same conditions. Photopolymerization kinetics analysis of PIB triphenol tri(meth)acrylates with low and high Mns, and control aliphatic PIB triol triacrylate with similar high Mn showed that Darocur 1173 afforded the highest photopolymerization rate and conversion. Kinetics analysis also indicated despite of end-funtionality and acrylate structure, photopolymerization rate for PIB prepolymers with high Mns, attributed to reduced diffusional mobility, resulting in decreased rate of termination and autoacceleration. Structure-property relationships indicated the Tg of PIB networks decreased as the Mn of PIB macromer increased regardless of end-group type, and thermal stability remained constant regardless of end-group type. Tensile properties were characteristic of weak rubbery networks. Quantitative synthesis of PIB telechelic prepolymers with various types of epoxides, including aliphatic and phenyl glycidol ether, exo-olefin epoxide, and cyclohexene epoxide have been developed through post modifications. A novel method for PIB chain end functionalization was developed whereby living PIB is end-capped with the bulky comonomer, 4-(4-allyloxyphenyl)-2-methyl-1-butene (AMB) at full IB conversion. Addition is readily limited to one or two comonomer units per chain end at a low [AMB]/[chain end] ratio. The mechanism suggested that upon addition of AMB, the resulting carbocation tends to undergo terminative chain transfer consisting of alkylation of the 4-allyloxyphenyl ring at C2, via a five-membered cyclic intermediate. Grubbs 3rd generation mediated ROMP of PIB (oxa)norbornene macromonomers via a grafting “through” methodology were conducted successfully, producing PIB bottlebrush polymers with controlled molecular weight and low dispersities. Both 1H NMR and SEC kinetics analyses showed pseudo first-order kinetic behavior for these macromonomers. Besides, both kinetic studies demonstrated that the ROMP propagation rate of PIB norbornene is at least 2.2 times greater than that of PIB oxanorborne macromonomer.

ORCID ID

orcid.org/0000-0002-0322-6764

Available for download on Saturday, May 12, 2018

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