Dispersion polymerization of methyl methacrylate in supercritical carbon dioxide: control of molecular weight distribution by adjusting particle surface area

Expts. of Me methacrylate dispersion polymn. are carried out in a reaction calorimeter using PDMS-mMA (methacrylate-terminated polydimethylsiloxane) as surfactant. Different stabilizer concns. from 0 to 10 wt% with respect to monomer have been considered in order to control particle morphol. The anal. by SEM reveals a definite decrease of the total particle surface area at decreasing stabilizer concn. At the same time, the anal. of the polymer microstructure by gel permeation chromatog. shows a trend of the av. mol. wt. towards smaller values. In particular, a second mode at low mol. wts. has been obsd. leading to bimodal mol. wt. distributions. The exptl. results are compared with simulation results obtained through a detailed kinetic model developed in previous studies. The key role of the radical exchange between continuous and dispersed phases is confirmed.


Published in:
Macromolecular Symposia, 259, Polymer Reaction Engineering--International Workshop, 2007, 218-225
Year:
2007
Keywords:
Note:
CAN 148:308707, 35-4, Chemistry of Synthetic High Polymers, DuPont Engineering Research & Technology,Experimental Station,Wilmington,DE,USA., Journal, 1022-1360, written in English., 78-67-1 (AIBN) Role: CAT (Catalyst use), USES (Uses) (dispersion polymn. of Me methacrylate in supercrit. carbon dioxide with emphasis on control of mol. wt. distribution by adjusting particle surface area); 124-38-9 (Carbon dioxide) Role: NUU (Other use, unclassified), USES (Uses) (dispersion polymn. of Me methacrylate in supercrit. carbon dioxide with emphasis on control of mol. wt. distribution by adjusting particle surface area); 9011-14-7P (PMMA) Role: PRP (Properties), SPN (Synthetic preparation), PREP (Preparation) (dispersion polymn. of Me methacrylate in supercrit. carbon dioxide with emphasis on control of mol. wt. distribution by adjusting particle surface area); 1066-42-8D (Dimethylsilanediol) Role: TEM (Technical or engineered material use), USES (Uses) (surfactant acting as PMMA particle stabilizer; dispersion polymn. of Me methacrylate in supercrit. carbon dioxide with emphasis on control of mol. wt. distribution by adjusting particle surface area)
Laboratories:




 Record created 2009-02-09, last modified 2018-03-18


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