Molecular Architecture of Non-Linear Polymers: Kinetic Modeling and Experimental Characterization of the System Methyl Methacrylate plus Ethylene Glycol Dimethacrylate

• Tipo: Artigo em Livro de Atas de Conferência Internacional
• Data: 2008

Autores

trigo, imr (Autor) Outra; goncalves, mad (Autor) Outra; dias, rcs (Autor) Outra; costa, mrpfn (Autor) FEUP

Ata de Conferência Internacional

Título: MACROMOLECULAR SYMPOSIA

Páginas: 107-119

Conference on Modelling, Monitoring and Control of Polymer Properties

Lyon, FRANCE, DEC 01-05, 2007

Indexação

ISI Web of Knowledge - 8 Citações

ISI Web of Science

Scopus - 7 Citações

COMPENDEX

INSPEC

Classificação Científica

FOS: Ciências exactas e naturais > Química

CORDIS: Ciências Tecnológicas > Engenharia > Engenharia química

Outras Informações

ID Authenticus: P-004-424

DOI: 10.1002/masy.200851112

Abstract (EN): A general kinetic approach allowing the prediction of the molecular architecture of non-linear polymers is applied to the study of the copolymerization of methyl methacrylate (MMA) with ethylene glycol dimethacrylate (EGDMA). Dynamic predictions of molecular weight distributions, sequence length distributions and mean square radius of gyration are possible before and after gelation. A set of experiments concerning the copolymerization of MMA and EGDMA was carried out in toluene solution at 60 degrees C for which classic radical kinetics is a good approximation. The time evolution of key polymer properties was followed using a SEC system with a refractive index detector coupled with MALLS allowing the determination of absolute weight average molecular weight and apparent molecular size distributions as well as z-average radius of gyration. Special focus was given to assess the influence of the initial amount of cross-linker on the dynamics of the non-linear structure build-up of these products. A kinetic scheme comprising 23 different chemical species and 76 chemical reactions was used in the modeling studies of this chemical system. Most of the kinetic parameters used in the simulations have been collected from previous studies. For experiments at low monomer conversion (up to about 0.5) a good agreement between predictions and experimental measurements is observed for molecular weights and z-average radius of gyration by fitting a small number of parameters describing gel effect (with a conversion dependent but chain length independent termination rate parameter) and the relative propagation on pendant double bonds. However, predicted values of weight-average molecular weights and z-average radius of gyration before gelation are too low at higher monomer conversions with non-linear systems. The likely cause is the presence of intramolecular reactions which should not be neglected in these circumstances.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 13