Characterization of molecular motions in polymer gel networks using intensity-fluctuation spectroscopy

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dc.contributor.advisorArmeniades, C. D.en_US
dc.creatorSchulken, Roger Mooreen_US
dc.date.accessioned2018-12-18T21:16:32Zen_US
dc.date.available2018-12-18T21:16:32Zen_US
dc.date.issued1978en_US
dc.description.abstractThis work seeks to investigate the intrinsic dynamics of synthetic polymer gel networks in terms of cooperative submolecular motions, which give rise to autocorrelation functions, observed by intensity fluctuation spectroscopy. Poly(dimethyl siloxane) samples were purified and chemically crosslinked to three levels of crosslink density. The resulting networks were swollen in toluene. Light scattering data were obtained over a range of swelling ratios from each sample as well as from the uncrosslinked polymer in solution. Due to a large amount of extraneous scattering, indicating the presence of a large component of static scattering, a "background" normalization technique was devised which allowed extraction of the desired correlation function. Also, a computer program utilizing the "method of cumulants" was developed to obtain diffusion coefficients from nonlinear autocorrelation decay data. The "diffusion coefficient" DT calculated for the uncrosslinked polymer in solution indicates scattering entities of about 6 A. This corresponds to a molecular weight of about 16,, considerably less than the molecular weight of the polymer (16,). The values for the diffusion coefficient were found to increase with increasing concentration, contrary to intuition. A similar increase in DT with polymer concentration was observed in swollen crosslinked gels. Also, there was evidence that the diffusion coefficient decreases with increasing degrees of crosslinking. A qualitative model was developed which describes a system of cooperative submolecular scatterers, consistent with the observed changes in D. The results of the light scattering measurements were also compared to mechanical measurements of the tensile elastic modulus for the different crosslinked systems. These tests indicate that not all of the available sites were utilized in the crosslinking reactions.en_US
dc.format.digitalOriginreformatted digitalen_US
dc.format.extent111 ppen_US
dc.identifier.callnoTHESIS CH.E. 1978 SCHULKENen_US
dc.identifier.citationSchulken, Roger Moore. "Characterization of molecular motions in polymer gel networks using intensity-fluctuation spectroscopy." (1978) Master’s Thesis, Rice University. <a href="https://hdl.handle.net/1911/104039">https://hdl.handle.net/1911/104039</a>.en_US
dc.identifier.digitalRICE1665en_US
dc.identifier.urihttps://hdl.handle.net/1911/104039en_US
dc.language.isoengen_US
dc.rightsCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.en_US
dc.titleCharacterization of molecular motions in polymer gel networks using intensity-fluctuation spectroscopyen_US
dc.typeThesisen_US
dc.type.materialTexten_US
thesis.degree.departmentChemical Engineeringen_US
thesis.degree.disciplineEngineeringen_US
thesis.degree.grantorRice Universityen_US
thesis.degree.levelMastersen_US
thesis.degree.nameMaster of Scienceen_US
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