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Description: |
Frontal Polymerization (FP) is a process of converting monomer into
polymer via a localized zone that propagates through the monomer. It bears
a strong resemblence to self-propagating high-temperature synthesis (SHS),
which uses combustion waves to synthesize desired inorganic materials. The
reaction front propagates through the coupling of thermal diffusion and
the Arrhenius reaction kinetics of the exothermic polymerization process.
We utilize a moving free-boundary model to describe free-radical FP. The
focus of attention is the self-sustaining wave which travels through the
reaction vessel as polymer molecules are being formed. Numerical and
analytical techniques are used to determine one-dimensional traveling
waves, and stability analysis (linear and weakly non-linear) of the
reaction front is performed. It is then possible to suggest ways to curb
instabilities in the propagating reaction front. After our initial
analysis, we account for autoacceleration and determine its effect on
frontal stability. In an effort to facilitate the propagation of weakly
exothermic fronts, we consider a one-dimensional polymerization wave in a
sandwich-type setting. First one layer is reactive while the other is
considered to be inert. Heat exchange between layers is possible, and the
effect this has on frontal stability is investigated. Next we allow both
layers to be reactive, thus further enhancing inter-layer heat exhange. We
comment on the effect that this has on the basic state of the system.
Finally two future research directions are outlined. One of our goals is
to determine how the propagating front is affected by bulk polymerization
at the far end of the reaction vessel. This is an important aspect to be
studied in greater depth and incorporated into existing FP models, since
bulk reactions can influence the speed and long-term stability of the
reaction front. We end with a theoretical discussion for the manufacture
of polymer-dispersed liquid crystal films via FP.
Area(s):
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Date: |
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| Start Time: |
14:30 |
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Speaker: |
Donna M. G. Comissiong (Northwestern University, IL, USA, also a postdoc at CMUC)
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Place: |
Room 5.5
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| Research Groups: |
-Numerical Analysis and Optimization
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See more:
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