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Orientador(es)
Resumo(s)
A new analytical procedure based on selective acid hydrolysis was developed to measure the chain length distribution of hard segments (HSCLD) of polyester-polyurethanes. It was tested with
polymers made from 4,4'-methylenebis(pheny1 isocyanate), 1,6-hexanediol, and a,w-dihydroxypoly-
(hexamethylene adipate) with number-average molecular weight 2200. Heating samples with 0.25 M
HC1 solution in dimethyl sulfoxide with 8.2% water for 36 h leads to nearly complete hydrolysis of the
ester groups, leaving the urethanes largely unaffected. The resulting mixture of oligomers can be analyzed
by size exclusion chromatography, using dimethylformamide at room temperature as the solvent.
Experimentally measured HSCLDs were most often very different from those theoretically predicted for
homogeneous reaction.
Descrição
Palavras-chave
Sequence Polyester-Polyurethanes
Contexto Educativo
Citação
Barreiro, M.F.; Dias, Rolando; Costa, Mário (1994). Experimental determination of sequence length distribution of hard segments in polyester-polyurethanes. Macromolecules. ISSN 0024-9297. 27:26, p.7650-7653
Editora
American Chemical Society