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Dispersion Polymerization of Methyl Methacrylate in Supercritical Carbon Dioxide: Control of Molecular Weight Distribution by Adjusting Particle Surface Area
Author(s) -
Mueller Philipp A.,
Storti Giuseppe,
Morbidelli Massimo,
Mantelis Charalampos A.,
Meyer Thierry
Publication year - 2007
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200751326
Subject(s) - supercritical carbon dioxide , methyl methacrylate , materials science , dispersion polymerization , dispersion (optics) , molar mass distribution , particle (ecology) , polymer , particle size , gel permeation chromatography , supercritical fluid , chemical engineering , polymer chemistry , polymerization , monomer , particle size distribution , radical polymerization , scanning electron microscope , poly(methyl methacrylate) , chemistry , composite material , organic chemistry , optics , physics , oceanography , engineering , geology
Summary: Experiments of methyl methacrylate dispersion polymerization are carried out in a reaction calorimeter using PDMS‐mMA as surfactant. Different stabilizer concentrations from 0 to 10 wt% with respect to monomer have been considered in order to control particle morphology. The analysis by scanning electron microscopy reveals a definite decrease of the total particle surface area at decreasing stabilizer concentration. At the same time, the analysis of the polymer microstructure by gel permeation chromatography shows a trend of the average molecular weight towards smaller values. In particular, a second mode at low molecular weights has been observed leading to bimodal molecular weight distributions. The experimental results are compared with simulation results obtained through a detailed kinetic model developed in previous studies.1 The key role of the radical exchange between continuous and dispersed phases is confirmed.