Comparison of UF synthesis by alkaline-acid and strongly acid processes

• Tipo: Artigo em Revista Científica Internacional
• Data: 2012

Autores

João M. M. Ferra (Autor) FEUP; Ana Henriques (Autor) FEUP; Adélio M. Mendes (Autor) FEUP; Mário Rui N. Costa (Autor) FEUP; Luísa H. Carvalho (Autor) FEUP; Fernão D. Magalhães (Autor) FEUP

Revista

Título: Journal of Applied Polymer Science

Vol. 123 Nº 3

Páginas: 1764-1772

ISSN: 0021-8995

Editora: Wiley-Blackwell

Indexação

ISI Web of Knowledge - 28 Citações

ISI Web of Science

Scopus - 33 Citações

INSPEC

Classificação Científica

FOS: Ciências exactas e naturais > Química

CORDIS: Ciências Tecnológicas

Projetos Associados

LA 20 - Projeto Estratégico-LA 20 - 2011-2012

Outras Informações

ID Authenticus: P-002-D3N

DOI: 10.1002/app.34642

Abstract (EN): This work discusses two processes for producing urea-formaldehyde (UF) resins. One is the alkaline-acid process, which has three steps: usually an alkaline methylolation followed by an acid condensation and finally the addition of a final amount of urea. The other process, the strongly acid process, consists of four steps, in which the first step involves a strongly acid condensation followed by an alkaline methylolation, a second condensation under a moderately acid pH and finally, methylolation and neutralization under a slight alkaline pH. Two resins were produced using the two above described processes. The molecular weight distribution (MWD) of the resins was monitored off-line by GPC/SEC and the final resins were characterized by GPC/SEC and HPLC. These studies showed that the two resins differ greatly in chemical structure, composition, viscosity, and reactivity. The monitoring of MWD indicated that the first condensation under a strongly acid environment leads to the production of a polymer with a distinctly different chemical structure, therefore increasing the flexibility of polymer synthesis and opening the way to the improvement of end-use properties. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 1764-1772, 2012

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 9