COSI 2007
 June 25th - June 29th 2007
Noordwijk, The Netherlands

 
  3th Coatings Science International 2007
  Jeffrey M. Stubbs
  DSM NeoResins, Wilmington, USA
   
  Title lecture
  The dynamics of morphology development in multi-phase latex particles
   
  Authors
  J.M. Stubbs, D.C. Sundberg
   
  Abstract
 

The use of multi-stage emulsion polymerization to produce particles containing multiple polymer phases is widespread throughout the coatings, impact plastics and adhesives industries. Such composite particles often improve various application properties compared to related single phase latexes or latex blends. However, the properties obtained depend in large part on the morphology of the multiphase particles. This creates incentive to understand the underlying mechanisms that drive morphology development in these particles as they are formed in the polymerization reactor. Much research and attention has been devoted to understanding the thermodynamic factors that influence morphology control, but in fact the majority of systems are produced under kinetic control, resulting in non-equilibrium structures.

  There are three main kinetic factors involved as the morphology develops during the second stage polymerization. These are 1) penetration of polymer radical chains into the particle interior after entry from the water phase, 2) phase separation of immiscible polymer chains produced in the different polymerization stages and 3) spatial rearrangement of phase separated domains.
  The factor (or combination of factors) that is dominant will vary from one system to another and is highly dependent on the glass transition temperatures of the different polymers in relation to the reaction temperature. This presentation will provide an overview of the effects that each of these kinetic factors can have on particle morphology using specific experimental examples. It will be shown that one can predict which factor will be controlling, and thus estimate what the resulting morphology will be, by quantifying the diffusion rates of oligomer and polymer chains under the conditions prevalent during the polymerization.
   
  Biography
 

Degrees:

All from the University of New Hampshire, Durham, NH

  • Ph.D. in Materials Science, May 2005

  • M.S. in Chemical Engineering, May 2000

  • B.S.  in Chemical Engineering, December 1996

Received M.S. and Ph.D. degrees under the supervision of Prof. Donald Sundberg and was employed as a research scientist in Prof. Sundberg's lab until August 2006. Currently employed by DSM NeoResins+ as a research scientist in the Emulsions R&D group in Wilmington, Massachussetts.

Research interests include control and characterization of composite latex particle morphology, emulsion polymerization mechanisms and kinetics and diffusion.

Co-authored over 15 papers on the topic of morphology control in multiphase latexes and presented several papers at international conferences.
   
   
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