Biblioteca Digital do Instituto Politécnico de Bragança   Instituto Politécnico de Bragança

Biblioteca Digital do IPB >
Escola Superior de Tecnologia e Gestão >
Tecnologia Química e Biológica >
DTQB - Publicações em Proceedings Indexadas ao ISI >

Please use this identifier to cite or link to this item: http://hdl.handle.net/10198/921

Título: Molecular architecture of non-linear polymers: kinetic modeling and experimental characterization of the system methyl methacrylate + Ethylene Glycol Dimethacrylate
Autor: Trigo, Ivone
Gonçalves, Miguel
Dias, Rolando
Costa, Mário Rui
Palavras-chave: Crosslinking
Kinetic
Molecular weight
Radius of gyration
Issue Date: 2008
Editora: Wiley
Citação: Trigo, Ivone; Gonçalves, Miguel; Dias, Rolando; Costa, Mário (2008) - Molecular architecture of non-linear polymers: kinetic modeling and experimental characterization of the system methyl methacrylate + Ethylene Glycol Dimethacrylate. Macromolecular Symposia. ISSN 1022-1360. 271:1, p.107-119
Resumo: 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 8C 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.
Arbitragem científica: yes
URI: http://hdl.handle.net/10198/921
ISSN: 1022-1360
Versão do Editor: http://www3.interscience.wiley.com/journal/60500249/home. DOI: 10.1002/masy.200851112
Appears in Collections:DTQB - Publicações em Proceedings Indexadas ao ISI

Files in This Item:

File Description SizeFormat
MACROMOLSYMP2008.pdf286,12 kBAdobe PDFView/Open
Statistics
FacebookTwitterDeliciousLinkedInDiggGoogle BookmarksMySpaceOrkut
Formato BibTex mendeley Endnote Logotipo do DeGóis 

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

 


  © Instituto Politécnico de Bragança - Biblioteca Digital - Feedback - Statistics
  Estamos no RCAAP Governo Português separator Ministério da Educação e Ciência   Fundação para a Ciência e a Tecnologia

Financiado por:

POS_C UE