Author

Jie WuFollow

Date of Award

Spring 2020

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

School

Polymer Science and Engineering

Committee Chair

Dr. Robson F. Storey

Committee Chair School

Polymer Science and Engineering

Committee Member 2

Dr. Jason D. Azoulay

Committee Member 2 School

Polymer Science and Engineering

Committee Member 3

Dr. Sarah E. Morgan

Committee Member 3 School

Polymer Science and Engineering

Committee Member 4

Dr. Sergei Nazarenko

Committee Member 4 School

Polymer Science and Engineering

Committee Member 5

Dr. Yoan Simon

Committee Member 5 School

Polymer Science and Engineering

Abstract

This dissertation’s key focus is on utilizing Huisgen 1,3-dipolar azide-alkyne cycloaddition (AAC) reaction in copolymer synthesis and modification, including thermoplastic block copolymer and commercially available two-component polyurethane system. It can be divided into two major projects, introduced as follows.

The first project involves the development of a modular synthetic approach toward polyisobutylene (PIB)-based triphasic pentablock thermoplastic elastomer with enhanced moisture permeability. This terpolymer consists of a poly(styrene-b-isobutylene-b-styrene) (SIBS) core and appended hydrophilic polymer blocks (HBs). The SIBS core was synthesized via living cationic polymerization (LCP) of isobutylene followed by sequential addition of styrene. AAC was utilized to chemically attach polyethylene oxide (PEO)-based HBs to the ends of the SIBS core. Structure-morphology-property relationships of those triphasic block terpolymers were investigated. This project is described in detail as Chapter II of this dissertation.

The second project focused on developing a series of non-isocyanate polyurethanes (NIPUs) that cure via AAC. In general, an alkyne-functional prepolymer was produced by reaction of propargyl alcohol with a commercially available allophanate-modified polyisocyanate based on hexamethylene diisocyanate; while an azide-functional prepolymer was produced by azidation of a commercially available acrylic polyol. The two prepolymers were then cured via AAC. Chapter III explores the effects of non-stoichiometric ratios of the two NIPU prepolymer components on the final coating properties. After conducting the coating composition-performance ladder study for this system, it was concluded that formulating with 35 - 50 mol% excess polyazide component produces coatings with optimized performance and higher crosslink density. Chapter IV introduces the design and study of a new type of low viscosity poly(alkynyl carbamate) prepolymer. A plasticizer specially designed to prevent sacrificing alkyne functionalities was incorporated into the poly(alkynyl carbamate) prepolymer. This approach was highly effective in reducing the prepolymer viscosity and maintaining good final coating performance. Finally, Chapter V reports the development and study of waterborne versions of those NIPUs. To achieve this, the poly(alkynyl carbamate) prepolymer was chemically modified with hydrophilic groups. Stable water dispersion of the system was formulated with the help of small amount of external surfactant and organic coalescent. The final coating performance properties were comparable to their solvent-borne counterparts.

Available for download on Thursday, May 14, 2020

Share

COinS