Volume : VIII, Issue : I, January - 2019

THERMODYNAMIC BEHAVIOR OF GLASS FORMING POLYMERIC MELTS

Prapti B. Pandya, Ashmi T. Patel, Arun Pratap

Abstract :

 

Polymer molecules segments can exist in two specific physical structures. They can exist in either crystalline form or amorphous form.Crystalline polymers are possible in such conditions if there is a regular chemical structure (e.g., homopolymers or alternating copolymers), and the chains possess a highly ordered arrangement of their segments. Symmetrical polymer chains are never 100% and crystallity in polymers is due to symmetrical polymer chains. Thus, polymers form mixtures of small crystals and amorphous material. These semi–crystalline polymers have a kind of typical liquifiction pathway, having their solid state until they reach their melting point at Tm. So it is interesting to study the thermodynamic behavior of polymers.

  The temperature dependence of the Gibbs free energy difference (ΔG), enthalpy difference (ΔH) and entropy difference (ΔS) between the undercooled melt and the corresponding equiliium solid has been analysed for glass forming polymeric materials. It is done by calculating ΔG for  one sample of glass forming polymeric melt ;  polyethylene terephthalate (PET) and two simple organic liquids: tri–α–naphthyl benzene(tri–α–NB) phenyl salicylate (salol)  in the entire temperature range Tm (melting temperature) to Tg (glass transition temperature). The expression for ΔS and ΔH has been derived assuming hyperbolic dependence of ΔCp on T. The calculation of enthalpy difference (ΔH) and entropy difference (ΔS) is made for two samples of glass forming polymeric melts ; polyamid–6 (PA–6), polypropylene oxide (PPO) and one simple organic liquids: tri–α–naphthyl benzene (tri–α–NB).

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Article: Download PDF   DOI : 10.36106/ijsr  

Cite This Article:

THERMODYNAMIC BEHAVIOR OF GLASS FORMING POLYMERIC MELTS, Prapti B. Pandya, Ashmi T. Patel, Arun Pratap INTERNATIONAL JOURNAL OF SCIENTIFIC RESEARCH : Volume-8 | Issue-1 | January-2019


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