Details

Autor(en) / Beteiligte

• Kim, Noma
• Sudol, E. David
• Dimonie, Victoria L
• El-Aasser, Mohamed S

Titel

Comparison of Conventional and Miniemulsion Copolymerizations of Acrylic Monomers Using Poly(vinyl alcohol) as the Sole Stabilizer

Ist Teil von

• Macromolecules, 2004-04, Vol.37 (7), p.2427-2433

Ort / Verlag

Washington, DC: American Chemical Society

Erscheinungsjahr

2004

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Particle nucleation and growth mechanisms in conventional emulsion and miniemulsion copolymerizations of n-butyl acrylate (BA) and methyl methacrylate (MMA) (50/50 wt %) employing poly(vinyl alcohol) (PVA) as the stabilizer were investigated in terms of the evolution of the particle size and the number of particles using capillary hydrodynamic fractionation (CHDF). All results strongly indicate the continuous nucleation and limited aggregation mechanism for conventional emulsion polymerizations and primarily droplet nucleation mechanism for miniemulsion polymerizations. Colloidal instability in conventional emulsion polymerizations was investigated and compared with the corresponding miniemulsion polymerizations in terms of the amounts of grafted and serum PVA and the molecular weight of the serum PVA. Unexpectedly, there was no direct correspondence between the amount of grafted PVA and the colloidal stability in the conventional emulsion polymerizations. Also, the colloidal instability in the latter reactions was studied in terms of the degree of aqueous phase grafting (the decrease in degree of hydrolysis of the serum PVA after polymerization) and the surface properties of the grafted PVA. It was found that the grafted PVA in conventional emulsion polymerizations was more hydrophobic than that produced in similar miniemulsion polymerizations. The colloidal instability during the conventional emulsion polymerizations was considered to be related to this difference in the nature of the grafted PVA.