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Approaches to the synthesis of block and graft copolymers with well defined segment lengthsPostma, Almar, School of Chemical Engineering & Industrial Chemistry, UNSW January 2005 (has links)
The synthesis of amine end-functionalised polymers by controlled free radical techniques has been investigated with a focus on methods that provide primary amino end-functionalised polystyrene. The aim of these investigations was to provide precursors to block and graft polyolefins and polyesters by interchain coupling reactions. The approaches investigated involved developing strategies for the synthesis of phthalimido-functional polymers which can be quantitatively deprotected to yield the desired amino-functional polymers. Initially synthesis by atom transfer radical polymerisation (ATRP) was explored. A number of approaches based on ??-functionalisation (end-group substitution) and ??-functionalisation (functional initiator) were examined. A novel ATRP initiator, N-bromomethylphthalimide, provided the most promising results but still had limited applicability because of its low solubility in polymerisation media. The problems encountered with the ATRP approaches prompted an exploration of techniques based on reversible addition fragmentation chain transfer (RAFT) approach. Novel phthalimidomethyl RAFT agents (trithiocabonates, xanthates) were synthesized. The activity and scope of the new RAFT agents was investigated in polymerisations of styrene, n-butyl acrylate, Nisopropylacrylamide, N-vinylpyrrolidone (trithiocarbonate) and vinyl acetate (xanthate). The syntheses of ??-phthalimidomethylpolystyrene were successfully scaled up and hydrazinolysis afforded a range of ??- aminomethylpolystyrenes of low polydispersity and controlled molecular weight. The syntheses of primary amino-functional polymers using the pthalimidofunctional RAFT agents necessitated the development of a convenient method for conversion of trithiocarbonate groups to inert chain ends. Thermolysis proved a most simple and efficient method of achieving this for both polystyrene and poly(n-butyl acrylate). Thermolysis also provided a means of further characterising the mechanism of the RAFT process. A simple and efficient method for amino end-group analysis was developed that involved in-situ derivatisation with trichloroacetyl isocyanate followed by 1H NMR analysis. The method was shown to be a suitable method for determining a wide range protic end-groups (NH2, OH, COOH) in synthetic polymers. Finally, metallocene polyolefin based coupling trials largely with controlled amino-functional polystyrene were conducted as an initial investigation into the production of high value added grafted polyolefins (and polyester). The grafting trials were carried out on a small scale with a view to directing future experiments.
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Confinement of symmetric diblock copolymer thin films /Tang, Wilfred H. January 1999 (has links)
Thesis (Ph. D.)--University of Chicago, Dept. of Chemistry, June 1999. / Includes bibliographical references. Also available on the Internet.
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The Change Process: A Study of the Move to Block Scheduling in Five Pennsylvania High SchoolsLessel, Howard S. 08 August 2011 (has links)
The process of large-scale change is difficult in any organizational structure, and this is particularly true in the field of education. This qualitative study investigated the change process used by five high schools in eastern Pennsylvania while initiating, implementing and sustaining a
large-scale change from traditional to block scheduling. This study looks at the entire large-scale change process from inception through evaluation. Through the lens of the large-scale change to block scheduling, the researcher analyzed change in five schools with similar demographics to determine whether similarities existed in the change process and whether school change can be
linked to a specific model of change.
This study, conducted using a three interview protocol (Seidman, 1998), was guided by one primary research question: What is the process used by high schools to plan, implement and sustain large-scale change? Three research sub-questions supported the primary question: 1)
What was the impetus for change to block scheduling?; 2) What process was used by the district to plan and implement the change to block scheduling?; and 3) How has the change to block scheduling been sustained by the district? The participants interviewed included five superintendents, five high school principals and twenty classroom teachers who worked at the participating schools during the transition to block scheduling.
Several common characteristics were identified which contributed to the successful implementation of a large-scale change initiative. These include the creation of a committee to plan and implement the change, involvement of stakeholders, and the use of professional
development to support the change. A major implication of this study is the identification of the importance of effective leadership during the change process.
It was found that the impetus for change involved an organizational leader with a vision for change. One interesting finding was that though all five schools were successful in implementing the change, very little has been done to help sustain the change. Contrary to the research in the literature, this study found that ongoing professional development is not essential
to sustaining large-scale change. / Dr. George R. Bieger, Indiana University of Pennsylvania
Dr. Patricia S. Smeaton, East Stroudsburg University of Pennsylvania
Dr. Patricia A. Pinciotti
East Stroudsburg University of Pennsylvania
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Synthesis and characterization of well-defined methacrylic-based block ionomers /DePorter, Craig Donald, January 1991 (has links)
Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 275-290). Also available via the Internet.
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A comprehensive review of literature contrasting the advantages and disadvantages of block schedulingChance, Brian Scott. January 2001 (has links) (PDF)
Thesis--PlanB (M.S.)--University of Wisconsin--Stout, 2001. / Includes bibliographical references.
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A comprehensive study of the relationship of block scheduling to the teaching of mathematicsMayo, Amy E. January 2003 (has links) (PDF)
Thesis--PlanB (M.S.)--University of Wisconsin--Stout, 2003. / Includes bibliographical references.
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Block copolymer thin films interfacial and confinement effects /Limary, Ratchana. January 2002 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.
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Teacher's opinions and attitudes toward block schedulingDorwin, Nicole. January 2009 (has links) (PDF)
Thesis PlanB (M.S.)--University of Wisconsin--Stout, 2009. / Includes bibliographical references.
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Block copolymer thin films : interfacial and confinement effectsLimary, Ratchana 06 May 2011 (has links)
Not available / text
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Part I: Block copolymers Part II: Polymers of 1,3-dithiolesLeland, John Everard, 1944- January 1972 (has links)
No description available.
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