Thermal-induced crystal/conformation transformations in syndiotactic polystyrene films treated with different solvents

Ya Sen Sun, Eamor Woo, Ming Chien Wu

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Solution-crystallized or solvent-induced crystal forms and transitions of these crystals upon post-annealing in solvent-treated syndiotactic polystyrene (sPS) (films cast from o-dichlorobenzene or immersed in 1,2-dichloroethane, respectively) were investigated via wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), and Fourier-transform infrared (FTIR) spectroscopy. IR spectra in the frequency range of 720-820 cm-1, which is attributed to the C-H out-of-plane bending of the phenyl ring for neat syndiotactic polystyrene (sPS) and their crystals/solvent complexes (sPS/o-dichlorobenzene or sPS/1,2-dichloroethane), were examined for the freshly as-cast samples in comparison with those having been subjected to post-annealing by heating to high temperatures. Three bands centered at approximately 779, 769, and 750 cm-1 were observed, the intensity and wavenumber being sensitive to the helical structural changes as a function of the annealing temperature. The band at 769 cm-1, being associated with the intramolecular interactions of the helical chains of the γ-crystal, was used to confirm the formation of such a phase. The bands at 779 cm-1 and 769 cm-1 disappeared and the sharper band at 750 cm-1 remained upon further annealing above the γ → α′ transition temperature. Thus, by examining the temperature dependency as revealed in the IR spectra the thermal-induced phase transition from the δ- to an ordered γ- and then to an α′-phase was successfully proven for the sPS/o-dichlorobenzene complex. Similarly, the other sPS/1,2-dichloroethane complex underwent transition (from a δ- to a disordered γ- and then to an α′-pahse) upon the same thermal treatments, except that the intermediate phase is a disordered γ-phase.

Original languageEnglish
Pages (from-to)1547-1556
Number of pages10
JournalMacromolecular Chemistry and Physics
Volume204
Issue number12
DOIs
Publication statusPublished - 2003 Aug 18

Fingerprint

Polystyrenes
Conformations
polystyrene
Crystals
Annealing
crystals
annealing
casts
Temperature
Superconducting transition temperature
Fourier transform infrared spectroscopy
Hot Temperature
Differential scanning calorimetry
heat measurement
frequency ranges
Phase transitions
transition temperature
infrared spectroscopy
Heat treatment
Heating

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Polymers and Plastics
  • Organic Chemistry
  • Materials Chemistry

Cite this

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title = "Thermal-induced crystal/conformation transformations in syndiotactic polystyrene films treated with different solvents",
abstract = "Solution-crystallized or solvent-induced crystal forms and transitions of these crystals upon post-annealing in solvent-treated syndiotactic polystyrene (sPS) (films cast from o-dichlorobenzene or immersed in 1,2-dichloroethane, respectively) were investigated via wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), and Fourier-transform infrared (FTIR) spectroscopy. IR spectra in the frequency range of 720-820 cm-1, which is attributed to the C-H out-of-plane bending of the phenyl ring for neat syndiotactic polystyrene (sPS) and their crystals/solvent complexes (sPS/o-dichlorobenzene or sPS/1,2-dichloroethane), were examined for the freshly as-cast samples in comparison with those having been subjected to post-annealing by heating to high temperatures. Three bands centered at approximately 779, 769, and 750 cm-1 were observed, the intensity and wavenumber being sensitive to the helical structural changes as a function of the annealing temperature. The band at 769 cm-1, being associated with the intramolecular interactions of the helical chains of the γ-crystal, was used to confirm the formation of such a phase. The bands at 779 cm-1 and 769 cm-1 disappeared and the sharper band at 750 cm-1 remained upon further annealing above the γ → α′ transition temperature. Thus, by examining the temperature dependency as revealed in the IR spectra the thermal-induced phase transition from the δ- to an ordered γ- and then to an α′-phase was successfully proven for the sPS/o-dichlorobenzene complex. Similarly, the other sPS/1,2-dichloroethane complex underwent transition (from a δ- to a disordered γ- and then to an α′-pahse) upon the same thermal treatments, except that the intermediate phase is a disordered γ-phase.",
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Thermal-induced crystal/conformation transformations in syndiotactic polystyrene films treated with different solvents. / Sun, Ya Sen; Woo, Eamor; Wu, Ming Chien.

In: Macromolecular Chemistry and Physics, Vol. 204, No. 12, 18.08.2003, p. 1547-1556.

Research output: Contribution to journalArticle

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AB - Solution-crystallized or solvent-induced crystal forms and transitions of these crystals upon post-annealing in solvent-treated syndiotactic polystyrene (sPS) (films cast from o-dichlorobenzene or immersed in 1,2-dichloroethane, respectively) were investigated via wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), and Fourier-transform infrared (FTIR) spectroscopy. IR spectra in the frequency range of 720-820 cm-1, which is attributed to the C-H out-of-plane bending of the phenyl ring for neat syndiotactic polystyrene (sPS) and their crystals/solvent complexes (sPS/o-dichlorobenzene or sPS/1,2-dichloroethane), were examined for the freshly as-cast samples in comparison with those having been subjected to post-annealing by heating to high temperatures. Three bands centered at approximately 779, 769, and 750 cm-1 were observed, the intensity and wavenumber being sensitive to the helical structural changes as a function of the annealing temperature. The band at 769 cm-1, being associated with the intramolecular interactions of the helical chains of the γ-crystal, was used to confirm the formation of such a phase. The bands at 779 cm-1 and 769 cm-1 disappeared and the sharper band at 750 cm-1 remained upon further annealing above the γ → α′ transition temperature. Thus, by examining the temperature dependency as revealed in the IR spectra the thermal-induced phase transition from the δ- to an ordered γ- and then to an α′-phase was successfully proven for the sPS/o-dichlorobenzene complex. Similarly, the other sPS/1,2-dichloroethane complex underwent transition (from a δ- to a disordered γ- and then to an α′-pahse) upon the same thermal treatments, except that the intermediate phase is a disordered γ-phase.

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