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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Syntheses of Novel Polymer Micro-Spheres with Surface and Interior Grafts

Zheng, Guodong 07 1900 (has links)
<p> Polymers and block copolymers have been grafted from hard and soft polymer micro-spheres by atom transfer radical polymerization (ATRP) and ring opening polymerization (ROP). The hard and soft micro-spheres were prepared by precipitation polymerization of divinylbenzene-80 (DVB80), and of DVB80/hydroxyethylmethacrylate (HEMA), respectively, in neat acetonitrile.</p> <p> Residual vinyl groups in the hard, poly(DVB80) micro-spheres were hydrochlorinated to form benzyl chloride groups that subsequently served as ATRP initiators for poly(styrene) and poly(styrene-block-4-methylstyrene) grafts. Hydrophilic poly(HEMA) and poly(2-( dimethylamino)ethyl methacrylate) poly(DMAEMA) were also grafted from hard micro-spheres containing bromopropionates, using ATRP in the presence of CuBr/Me4Cyclam.</p> <p> Hydroxy groups in soft, poly(DVB80-co-HEMA) micro-spheres were used directly as initiators for ring opening polymerization of ε-caprolactone catalyzed by aluminum compounds. In the addition, they were reacted with α-bromopropionyl bromide to form ATRP initiators.</p> <p> Several combinations of ATRP-ATRP and ROP-ATRP with different monomers were carried out using these initiator micro-spheres. In particular, the soft micro-spheres grafted with poly(methacrylic acid), poly(methylmethacrylate), poly(methylmethacrylate-block-dimethylaminoethylmethacrylate), poly(methylmethacrylate-block-trimethylammoniumethylmethacrylate), poly(methylmethacrylate-block-HEMA), poly(methylmethacrylate-block-glycidylmethacrylate), poly(ε-caprolactone-block- methylmethacrylate), poly(ε-caprolactone-block-dimethylaminoethylmethacrylate).</p> <p> The internal morphology of these homo and block copolymer grafted microspheres was studied using electron microscopy and x-ray microspectroscopy.</p> / Thesis / Doctor of Philosophy (PhD)
2

COMPUTATIONAL STUDIES OF DISUBSTITUTED BICYCLO[m.m.m]ALKANE AND DISUBSTITUTED BICYCLO[8.8.n]ALKANES, SYNTHESIS OF 1,10-DIMETHYLBICYCLO[8.8.8]HEXACOSANE AND 1,10-DIHYDROXYBICYCLO[8.8.8]HEXACOSANE, AND PROGRESS TOWARDS THE SYNTHESIS OF A DISUBSTITUTED 1,10-

Jones, Ian W. January 2008 (has links)
Polymers possess bulk elastic properties due to entanglement of the polymer chains, not due to an inherit elasticity found within the monomers. An appropriately disubstituted bicyclo[8.8.8]hexacosane monomer should impart inherit elasticity when utilized in a polymer. A stochastic search of disubstituted bicyclo[m.m.m]alkanes demonstrated that these systems will adopt an out,out configuration and bicycles with medium and large values of m possess variable bridgehead-bridgehead distances. A stochastic search of disubstituted bicyclo[8.8.n]alkanes demonstrated an even-odd effect within the bite-angle of the bicycle. Two model compounds with methyl and hydroxyl groups at the bridgehead carbons were synthesized that demonstrated solid-state structures that correlated extremely well with the computational search. The solid-state structures were observed with both an out,out configuration and variable bridgehead-bridgehead distances. To investigate this hypothesis, polyurethanes will be made from the following diol monomers: 1,10-decanediol, a monocyclic diol, and a bicyclo[8.8.8]hexacosane diol.

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