Polymeric (steric and electrosteric) stabilizers, based on water-soluble polymers such as poly(acrylic acid) and poly(ethylene oxide), are widely used to make surface coatings by emulsion polymerization and form a "hairy layer" which provides colloidal stability to the latex particles. It is shown by a combination of NMR and rate studies that the growth of these polymer colloids is dominated by a hitherto unsuspected combination of mechanisms:  an abstraction reaction in the "hairy layer" which results in a radical on the water-soluble polymer which is slow to propagate but quick to terminate (Macromolecules 2006, 39, 6495−6504) and can also undergo β-scission reactions. Termination with radicals which would otherwise lead to particle growth leads to radical loss, i.e., a slower polymerization rate, while β-scission leads to radicals which can enter the water phase and cause secondary particle formation. Both of these effects are undesirable from a manufacturing point of view, and the newly discovered mechanism could be used to mitigate these undesirable features.

Item Type:	Refereed Article
Research Division:	Chemical Sciences
Research Group:	Macromolecular and materials chemistry
Research Field:	Polymerisation mechanisms
Objective Division:	Expanding Knowledge
Objective Group:	Expanding knowledge
Objective Field:	Expanding knowledge in the chemical sciences
UTAS Author:	Thickett, SC (Dr Stuart Thickett)
ID Code:	99406
Year Published:	2007
Web of Science® Times Cited:	30
Deposited By:	Chemistry
Deposited On:	2015-03-23
Last Modified:	2015-04-14
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