2016 INDO-FRENCH CONFERENCE
Functional polymers and self-assembled systems
23-25 May 2016, Strasbourg, France
Effect of solvent molecules on the Syndiotactic Polystyrene/Solvent Complex
N. SUDHAKAR NAIDU and C. RAMESH
Division of Polymer Science and Engineering,
National Chemical Laboratory,
Pune, India. 411 008
2016 INDO-FRENCH CONFERENCE
Functional polymers and self-assembled systems
23-25 May 2016, Strasbourg, France
Abstract: Amorphous syndiotactic polystyrene (sPS) was crystallized at room temperature by two groups of solvents. Group A solvents comprised of dichloromethane, chloroform, toluene, o-dichlorobenzene, and decalin (cis-trans). Group B solvents were Norbornadiene, 1,3,5-Trimethylbenzene, 1,4-Dimethylnaphthalene and 3-Carene. These two groups of solvents formed clathrate structure ( form) with respective solvent molecules.
In-situ high temperature wide angle x-ray diffraction studies on clathrates with Group A solvents showed that the room temperature form transformed into form on heating above the glass transition temperature of the sPS. The transformation temperature showed a linear dependency on the amount of solvent absorbed; higher the solvent molecules absorbed, higher the transition temperature. However, the transition temperature does not depend on the nature of the solvent. The emptied clathrate form transformed into form at the glass transition temperature.
However, in the case of clathrates with Group B solvents (Norbornadiene, 1,3,5-Trimethylbenzene, 1,4-Dimethylnaphthalene and 3-Carene) the transition occurs below the glass transition temperature. Furthermore the transition temperature decreased with increasing solvent content in the sample. The glass transition temperature was measured using the modulated differential scanning calorimeter (DSC) and found that the Tg correlates well with the transition temperature, indicating that the form transformed into form at the glass transition temperature.
The form transformed into '' form at ~ 200 oC on heating and is independent of the amount of solvent absorbed in the clathrate structure and the solvent used for crystallization.
Glass transition temperature was also measured for the emptied clatharates: Group A clathrates showed Tg around 102°C while the Group B clathrates it was about 110°C. The difference in the Tg values between the two groups of clathrates indicated the difference in the semicrystalline morphology between these two groups of clathrates.
Fig. 1: Dependence of form to form transition temperature on glass transition temperature
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2016 INDO-FRENCH CONFERENCE
Functional polymers and self-assembled systems
23-25 May 2016, Strasbourg, France
Key words: solvent complex, clatherates, glass transition, syndiotactic polystyrene, intercalates, crystalline transition
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