Concentration dependence of the static properties of randomly branched poly(methyl methacrylate) studied by static-light scattering
Laboratoire de Chimie et Physico-Chimie Macromoléculaire,
CNRS URA 509,
Université du Maine, 72017 Le Mans Cedex, France
Accepted: 22 July 1996
We study the static properties of solutions of randomly branched poly(methyl methacrylate) (PMMA) obtained near the gelation threshold by measuring their structure factor using static-light scattering experiments. The picture of the initial (not yet diluted) system is consistent with a hierarchical interpenetration of the aggregates, as predicted by the percolation theory. The dilution creates in the system a characteristic length dependent on concentration, beyond which excluded-volume interactions are screened. This length is proportional to the apparent radius of gyration Rga. The concentration dependences of Rga and the apparent molar mass Ma associated with Rga are determined by a Guinier analysis of the light scattering data. The self-similarity of the size distribution of the aggregates is clearly shown by the master curve representing the static structure factor of the system as a function of .
PACS: 36.20.-r – Macromolecules and polymer molecules / 61.10.-i – X-ray diffraction and scattering
© EDP Sciences, 1996