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Events for May 10, 2007

• May

  10

  Polymer Films by Interfacial Polycondensation: A theory of kinetics and film structure

  Thu, May 10, 2007 @ 01:00 PM

  Mork Family Department of Chemical Engineering and Materials Science

  Conferences, Lectures, & Seminars

  
  

  Graduate SeminarPolymer Films by Interfacial Polycondensation:
  A theory of kinetics and film structureProfessor A.K. SureshDepartment of Chemical Engineering
  Indian Institute of Technology, Bombay
  Powai, MumbaiAbstractInterfacial polycondensation has been used in niche polymerization applications such as the formation
  of thin-film composite membranes and microencapsulation of active intermediates. The technique
  offers the advantage of high rate, is less fussy about monomer purity than the melt methods, and
  directly offers a polymer film as the product. On the other hand, the monomers used are highly
  reactive and difficult. to handle, and the mechanisms of film formation are not well understood, so that
  a prediction of film properties from preparation conditions is difficult. In the applications mentioned,
  the strength of the polymer film and the permeability of solutes through it are the functional properties
  of importance. In this talk, we shall present a modellng framework for interfacial polycondensation,
  which accounts for the interplay between diffusion, multi-step reaction kinetics, solution
  thermodynamics, and phase separation. Experiments to form polyurea microcapsules have been
  carried out under various conditions, and show that the crystallinity of the polymer film formed varies
  considerably depending on the synthesis conditions employed, with a loose inverse correlation being
  apparent between the rate of polymerization reaction and the crystallinity of the polymer film. These
  results point to opportunities for engineering film permeabilities through an understanding of the
  mechanisms involved in the development of crystallinity, since the latter has a strong influence on
  permeability. The modelling framework takes these experimental observations as a basis, and
  accounts for polymer phase separation by nucleation and spinodal decomposition mechanisms. In
  order to test the basic soundness of the postulates, we use simple models such as Flory-Huggins to
  describe the solution thermodynamics. Qualitative and quantitative comparison will be presented
  between certain aspects of the model predictions and experiments, and lines of further development
  will be indicated.Thursday, May 10, 2007
  Seminar at 1:00 p.m.
  HED 116Refreshments at 12:45 p.m.The Scientific Community is Cordially Invited.

  Location: Hedco Pertroleum and Chemical Engineering Building (HED) - 116

  Audiences: Everyone Is Invited

  Contact: Petra Pearce