Catalytic Chain Transfer for Molecular Weight Control in the Emulsion Polymerization of Methyl Methacrylate and Methyl Methacrylate−Styrene

Autor:	John Patrick O'donnell, David M. Haddleton, Kevin G. Suddaby, Stuart N. Richards, Jeremy J. Hastings
Rok vydání:	1996
Předmět:	Polymers and Plastics Organic Chemistry Dispersity Radical polymerization Emulsion polymerization Chain transfer Styrene Inorganic Chemistry chemistry.chemical_compound chemistry Catalytic chain transfer Polymer chemistry Materials Chemistry Copolymer Methyl methacrylate
Zdroj:	Macromolecules. 29:8083-8091
ISSN:	1520-5835 0024-9297
DOI:	10.1021/ma960528h
Popis:	The application of catalytic chain transfer in the emulsion homopolymerization of methyl methacrylate and copolymerization of methyl methacrylate and styrene has been examined. [Bis[μ-[(2,3-butanedione dioximato)(2−)-O:O‘]] tetrafluorodiborato(2−)-N, N‘,N‘‘,N‘‘‘]cobalt (COBF, 1) has been used as a low-spin cobalt(II) catalytic chain transfer agent. The number-average molecular weight of poly(methyl methacrylate) is decreased from over 120 000 in the absence of catalytic chain transfer agent to less than 3000 on addition of 36 ppm of 1 remaining constant throughout the reaction while the polydispersity index was maintained at approximately equal to 2. The mechanism is essentially the same as in solution or bulk with very small amounts of primary radical initiation, undetectable by matrix-assisted laser desorption ionization time of flight mass spectrometry, and vinyl unsaturation at the terminal end of each polymer molecule. Copolymerization of methyl methacrylate with styrene has also been demonstrated. C...
Databáze:	OpenAIRE
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