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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

FREE RADICAL POLYMERIZATION OF NOVEL COPOLYMER; ETHYLENE-CO-DIETHYL METHYLENE MALONATE COPOLYMERS

Foster, Sydney 20 October 2021 (has links)
Ethylene copolymers are widely used as packaging materials, adhesives and specialty polymers for well-regarded cost savings, durability, chemical resistance, and hot melt character. This work examines the use of diester monomers known as malonates to determine the plausibility of utilizing an uncommon monomer class for producing novel ethylene copolymers. Ethylene is copolymerized with diethyl methylene malonate—a simple malonate representative of more complex and highly modified malonate monomers and macromers—to produce ethylene-co-diethyl methylene malonate in a range of molecular weights. Ethylene-co-diethyl methylene malonate is analyzed to determine physical properties such as glass transition temperature, chain length and monomer incorporation. Successful copolymerization occurred under a range of temperatures and pressures in tetrahydrofuran, diethyl carbonate, and dimethyl carbonate. The produced polymers were found to have a molecular weight of 15-46 kg/mol, a glass transition temperature of 7°C, a melting temperature of 108°C, and a cold crystallization temperature of 64°C. The high concentration of a radical source inhibitor in the diethyl methylene malonate monomer solution negatively impacted molecular weight and ethylene incorporation.
2

Modifikace polypropylenu reaktivním kompaundováním / Modification of Polypropylene by Reactive Compounding

Svítil, Jan January 2018 (has links)
Knowledge of radical initiated grafting was summarized in theoretical part. It also contains a part about adamantane, its derivatives and a study of their use in polymer chemistry. In experimental part radical grafted polypropylene was prepared in batch mixer Brabender at 185 and 195 °C, 40 RPM and reaction time 5 min. Initiator 2,5-dimethyl-2,5-bis(tert-buthylperoxy)hexane (Trigonox 101) in concentrations between 0,2 – 4 wt % was used. 1-vinyladamantane was chosen as a monomer and its concetration ranged from 0,75 to 2,24 wt %. Mechanical properties of prepared samples were tested. Sample with content of initiator 0,2 wt % and monomer 1,4 wt % showed increase in notch toughness by 56,3 %, strength by 8,7 %, ductility by 11,5 % and decrease in MFR (230 °C; 2,16 kg) by 29,7 %. Values of torque indicated grafting reactions which couldn’t be proven by use of FTIR method so more suitable methods have been proposed.

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