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Dissertation
Living free radical ring-opening polymerization towards the development of bioapplicable polymers
Doctor of Philosophy (Ph.D.), Drexel University
Jun 1996
DOI:
https://doi.org/10.17918/00000634
Abstract
The first example of a "living" free radical ring-opening polymerization has been achieved by polymerizing 2-methylene-1,3-dioxepane (MDP) in the presence of a nitroxyl stable free radical (SFR) such as 2,2,6,6-tetramethyl-1-piperidinyloxy free radical (TEMPO) with di-tert-butyl peroxide as initiator. The polymerization proceeds via radical attack on the cyclic MDP monomer followed by ring-opening to yield the PMDP polymer with open chain ester repeat units. When a molar excess or more of the SFR is used based on the initiator, the polymerization displays many of the characteristics indicative of a "living' polymerization process. The polydispersity of the polymers decrease with increasing SFR concentration and the number average molecular weight increases linearly with monomer conversion. Following completion of the polymerization, the PMDP polymers remain "alive" and can be used to initiate further polymerization to yield chain extended and block copolymers. Copolymerization of MDP with conventional vinyl monomers such as styrene and methyl methacrylate offers a convenient route to introducing functional repeat units into the polymer backbones for enhanced biodegradability. The ring-opening nature of the MDP polymerization displays a low volume shrinkage on polymerization which has been found to be invaluable in the dental materials industry where low shrinkage is a prerequisite for filling materials.
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Details
- Title
- Living free radical ring-opening polymerization towards the development of bioapplicable polymers
- Creators
- Edward James Connors
- Contributors
- Yen Wei (Advisor)
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- xiv, 322 pages
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- College of Arts and Sciences; Chemistry; Drexel University
- Other Identifier
- 991014970325204721