Hi to all
for example comparison between PS and PE chain flexibility from thermodynamic and kinetic point of view
Dear Reza,
The ability to change the conformation of a polymer chain through thermal motion is called equilibrium or thermodynamic flexibility. Whereas, kinetic flexibility is the ability to change the conformation of a polymer chain under the action of external, in particular mechanical, action.
https://books.google.it/books?id=CXwrqM2hU0EC&pg=PA474&lpg=PA474&dq=difference+between+thermodynamic+and+kinetic+flexibility+in+polymer+chain&source=bl&ots=Y4dytrkoQn&sig=wpqcnjhvDn19zvnZkpkA7sjsYbs&hl=en&sa=X&redir_esc=y#v=onepage&q=difference%20between%20thermodynamic%20and%20kinetic%20flexibility%20in%20polymer%20chain&f=false
Hoping this will be helpful,
Rafik
Thermodynamic flexibility depends on potetial difference between two conformational states(minima of the potential curve): ΔU/kT. hinderance parameter and persistence length indicate it well, whereas kinetic flexibility depends on the height of potential barrier between the states, U0,: U0/kT and Tg indicates it well.
Hinderance parameter (thermodynamic flexibility) of PE and PS are close to each other but PE kinetic flexibility is much more than PS (at room temperature)
dear @Catherine esnaashari
i totally understand what u mean.
and another Q i want to ask is without any plot just base on molecular structure( for exp: PVC and PMMA) can u talk about flexibility of their chain and Comparison them base on thermodynamic kinematic? tnx
thermodynamic flexibility of simple vinyl polymers which have C-C bonds in the backbone is very similar to each other since the potential difference between trans and gauche states does not vary much among them unless there are strong interactions or bulky side groups. thermodynamic flexibility of such polymers as cellulosic polymers or poly(p-phenylene) is considerably higher than polymers like pvc and pmma
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