Virginia Tech
Synthesis and Functionalization of Poly(ethylene oxide-b-ethyloxazoline) Diblock Copolymers with Phosphonate Ions
Abstract
dc:description.abstractPoly(ethylene oxide) (PEO) and poly(2-ethyl-2-oxazoline) (PEOX) are biocompatible polymers that act as hydrophilic "stealth" drug carriers. As block copolymers, the PEOX group offers a wider variety of functionalization. The goal of this project was to synthesize a poly(ethylene oxide)-b-poly(2-ethyl-2-oxazoline) (PEO-b-PEOX) block copolymer and functionalize pendent groups of PEOX with phosphonic acid. This was achieved through cationic ring opening polymerization (CROP) of 2-ethyl-2-oxazoline monomer onto PEO. These polymerizations used tosylsulfonyl chloride as initiator. Size-exclusion chromatography (SEC) was used to determine the molecular weights of the block copolymers. Two samples of 1:2 and one sample of 1:3 of PEO-to-PEOX block copolymers were made. These samples underwent partial hydrolysis of the PEOX pendent groups to form the random block copolymer, poly(ethylene oxide)-b-poly(2-ethyl-2-oxazoline)-co-poly(ethyleneimine) (PEO-b-PEOX-co-PEI). These reactions showed that there was a degree of control based on the moles of acid. Diethyl vinyl phosphonate was attached to the nitrogen of PEI units via Michael addition where the phosphorylation left <1% of PEI units unattached. The ethyl groups on the phosphonates were further hydrolyzed off phosphonate with HCl acid leaving phosphonic acid. After each step of synthesis, structures and composition were confirmed using ¹H NMR. Due to the nature of the phosphonic acid, the polymer can be utilized in the incorporation and release of cationic drugs.
Degree
thesis:*- Name thesis:degree_name
- Master of Science
- Level thesis:degree_level
- masters
- Discipline thesis:degree_discipline
- Macromolecular Science and Engineering
- Department dc:contributor.department
- Macromolecular Science and Engineering
- Grantor dc:publisher
- Virginia Tech
- Year dc:date.issued
- 2013
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Chen, Alfred Yuen-Wei
- Chair dc:contributor.committeechair
-
- Riffle, Judy S.
- Committee members dc:contributor.committeemember
-
- Davis, Richey M.
- McGrath, James E.
Subjects
dc:subject × 7Rights
dc:rights- Statement dc:rights
-
- In Copyright
- Licence dc:rights.uri
Identifiers
dc:identifier.*- Dc Identifier Other
- vt_gsexam:1694
- OAI identifier oai:identifier
- oai:vtechworks.lib.vt.edu:10919/23930