Size Exclusion Chromatography of Poly(2-ethyl-2-oxazoline) Homopolymers and Poly(ethylene oxide)-b-Poly(2-ethyl-2-oxazoline) Copolymers

Size exclusion chromatography is the method of choice for characterizing molecular weights and molecular weight distributions of polymers. An important advancement in SEC is multidetection SEC which includes multi-angle laser light scattering, viscometry, refractive index and UV spectroscopy to analyze block and graft copolymers as well as polymers with oligomeric molecular weights. Oligomeric molecular weights present special challenges since the light scattering and viscosity detectors are more sensitive to higher molecular weights and both detectors have low molecular weight threshold values. The molecular weights and distributions of poly(2-ethyl-2-oxazoline) oligomers and block copolymers as well as poly(2-ethyl-2-oxazoline) were investigated by SEC using multiple detectors. Both a universal calibration method and light scattering were used to determine molecular weights and molecular weight distributions. The solvent was N-methylpyrrolidone that contained 0.05M LiBr used to minimize interactions among the polymers and solvent. SEC was used to establish that the diblock copolymers had heterogeneous compositional distributions. The low molecular weights of the diblock and homopolymer made it necessary to use the universal calibration method with combined refractive index and viscometry detectors to determine absolute molecular weights.

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

2014

Author dc:creator

• Barnes, Suzanne R.

Chair dc:contributor.committeechair

• Riffle, Judy S.

Committee members dc:contributor.committeemember

• McGrath, James E.
• Davis, Richey M.

• Size Exclusion Chromatography
• multi-angle laser light scattering detector
• refractive index detector
• dn/dc
• viscosity detector
• universal calibration
• poly(2-ethyl-2-oxazoline)
• poly(ethylene oxide)

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

vt_gsexam:1981

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/24907