Characterization of the structure and the size distribution of branched polymers formed by co-polymerization of MMA and EGDMA
Chimie et Physique des Matériaux Polymères (UMR CNRS) , Université du
Maine, 72085 Le Mans Cedex 9, France
Revised: 22 October 1998
Published online: 15 May 1999
Free radical co-polymerization of methyl methacrylate (MMA) and ethyl glycol dimethyl methacrylate (EGDMA) in solution leads to the formation of polydisperse branched PMMA which grows in size until the system gels. The structure and the size distribution of the PMMA aggregates were characterized at infinite dilution using static and dynamic light scattering and size exclusion chromatography (SEC). The reaction extent was measured using SEC and Raman spectroscopy. The results show that the structure and size distribution of PMMA aggregates formed close to the gel point are compatible with those of percolating clusters. The structure factor of semi-dilute solutions of PMMA aggregates is the same as that of dilute solutions at distance scales much smaller than the correlation length of the concentration fluctuations (ξ). However, the cut-off function of the pair correlation function at ξ for semi-dilute solutions is more gradual than the cut-off function at Rgz for dilute solutions.
PACS: 36.20.-r – Macromolecules and polymer molecules / 61.10.-i – X-ray diffraction and scattering
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999