Date of Award

1-1-2013

Document Type

Open Access Dissertation

Department

Chemistry and Biochemistry

Sub-Department

Chemistry

First Advisor

Chuanbing Tang

Abstract

In this dissertation, polymers derived from renewable bio-based resources and degradable functional polymers with stimuli-responsive properties by various polymerization techniques were investigated. The properties of these polymeric materials were characterized and discussed.

In Chapter 1, the overall background and recent development of renewable bio-based polymers as well as degradable stimuli-responsive polymers was introduced. Major research objectives of my doctoral work were described.

The first section of the dissertation, on the preparation of renewable bio-based polymers was provided from Chapter 2 to Chapter 4. In Chapter 2, the preparation of novel polymers derived from renewable gum rosin by atom transfer radical polymerization (ATRP) and reversible addition-fragmentation chain-transfer (RAFT) polymerization was described.

Chapter 3 described the preparation of different rosin containing polycaprolactone (PCL) by a combination of ring-opening polymerization (ROP) and "click" chemistry. The rosin containing PCL showed excellent hydrophobicity, elevated glass transition temperature, low water uptake and full degradability. Also the polymers exhibited good biocompatibility and low cytotoxicity, suitable for potential biomedical applications. In Chapter 4, sustainable graft copolymers derived from renewable cellulose, rosin and fatty acid as novel thermoplastic elastomers were accomplished by ATRP and mechanical properties of the polymers were characterized by tensile stress-strain and creep compliance testing.

The second part of the dissertation is the preparation and characterization of degradable salt-responsive polymers. In Chapter 5, degradable cationic random copolymers containing a PCL skeleton and quaternary ammonium side groups were synthesized by a combination of ring-opening polymerization and copper-catalyzed click reaction. These random copolymers exhibited ion strength-dependent solubility in water. In salt-free water or water with low ionic strength, random copolymers were completely soluble while in high salt concentration solution, the solubility of random copolymers decreased. Also these cationic random copolymers showed good degradability in dilute acid solution. Chapter 6 described the preparation of high molecular weight cationic salt-responsive bottle-brush polymers by ring-opening polymerization, ring-opening metathesis polymerization, and click reaction. These cationic bottle brush polymers exhibited not only good salt responsive properties but also better mechanical properties due to the high molecular weight of the polymers. Both the random copolymers and bottle brush polymers with salt responsive properties showed potential applications in personal hygiene products.

Finally, a summary is given in Chapter 7. In addition, some suggestions about future research directions on the renewable polymer materials and degradable stimuli-responsive polymers are provided.

Included in

Chemistry Commons

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