Radical Entry in Electrosterically Stablized Emulsion Polymerization Systems
The rate of radicals entering into a polymer particle from the aqueous phase is a fundamental parameter that controls the overall polymerization rate.
While the mechanism for this process is well understood for systems stabilized by 'electrostatic' surfactants, little is known about this parameter for sterically (or electrosterically) stabilized emulsion systems.
However, these are what are used to make the latexes employed in most paints and adhesives: a huge and common range of products in everyday use.
New developments using controlled-radical polymerization in emulsion, developed within the KCPC, have allowed the measurement of this entry rate for the first time.
Results demonstrated a significant decrease in rate compared to ionic surfactants, ascribed to radical loss caused by mid-chain radicals on the stabilizing hairs: "hairy radicals".
The implications of these results are wide-ranging for industrial systems, where very small polymer particles are used in surface coatings and adhesives.
This work has recently been published:
"Mechanism of Radical Entry in Electrosterically Stabilized Emulsion Polymerization Systems"
SC Thickett and RG Gilbert
Macromolecules, 39, 6495-6504. (2006).
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