Morphology and structure of syndiotactic polystyrene

Greis, O.; Xu, Yao; Asano, Tsutomu; Petermann, J.

doi:10.1016/0032-3861(89)90140-7

Cited by 183 publications

(157 citation statements)

References 15 publications

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“…The particular case of M/N = 2/1 is the most common one and in many cases the s(2/1)2 is the only symmetry found. Translational symmetries tc and tcm have been found in polymorphic forms of sPP 21,22) , sPS [23][24][25][26] , syndiotactic poly(p-methylstyrene) 18) and in syndiotactic poly(1,2-butadiene) 27, 28) (sPB12).…”

Section: Polyolefinsmentioning

confidence: 99%

The role of molecular mechanics in the prediction of the chain conformation of polymers in the crystalline state: Syndiotactic polymers

Napolitano¹,

Pirozzi

1999

Macromol. Theory Simul.

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SUMMARY: Molecular mechanics methods have been used in order to find the conformations of various syndiotactic polymers in crystals. Three different classes of polymers have been examined: i) polyolefins, such as poly(propylene), polystyrene, poly(1-butene) and poly(1,2-butadiene); ii) polydienes, such as cis-1,4-poly(1,3-pentadiene); iii) alternating copolymers of carbon monoxide with styrene or styrene derivatives. The presence of conformational polymorphism in some of the studied polymers is predicted and explained by maps and minimizations of the conformational energy. The calculated internal parameters and chain axis repeats of all the considered polymers result in very good agreement with X-ray experimental data reported in literature. The role of intramolecular nonbonded interactions in determining the conformations of the polymer chains is thoroughly discussed.

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Section: Polyolefinsmentioning

confidence: 99%

The role of molecular mechanics in the prediction of the chain conformation of polymers in the crystalline state: Syndiotactic polymers

Napolitano¹,

Pirozzi

1999

Macromol. Theory Simul.

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“…Many efforts have been devoted in the past to settle a correlation picture between these parameters and the processing conditions [1]. This is particularly relevant for syndiotactic polystyrene (sPS) that presents a complex polymorphic pattern, depending on several factors, further complicated by the presence of structural disorder [2][3][4][5]. In particular, when crystallized from the molten state, sPS solidifies into two different crystal forms, termed α and β.…”

Section: Introductionmentioning

confidence: 99%

“…This transition never occurs in samples that present crystalline β form [2]. For this reason, the sPS β form could represent a polymeric material of industrial interest due to its high melting temperature, fast crystallization rate, good chemical and thermal resistance [2,5]. However, in spite of its thermodynamic higher stability with respect to the α form, it can be obtained only at very low under-cooling (high crystallization temperature), whereas at crystallization temperatures lower than 230°C the α form is always obtained [8].…”

Section: Introductionmentioning

confidence: 99%

Influence of multi-walled carbon nanotubes on the β form crystallization of syndiotactic polystyrene at low temperature

Sorrentino¹,

Vertuccio²,

Vittoria³

2010

Express Polym. Lett.

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Abstract. Syndiotactic polystyrene (sPS) samples were quenched at low temperature (0°C) in the presence of Multi-Walled Carbon Nanotubes (MWCNT) at different concentrations. The influence of carbon nanotubes on the structure and physical properties of sPS composites was investigated by SEM, X-ray diffractograms, DSC (Differential Scanning Calorimetry), and Dynamic Mechanical Analysis (DMA). A good dispersion of the carbon nanotubes in the sPS matrix was found, at least for the low MWCNT concentration, whereas opposite effects were noticed on Tg and elastic modulus, depending on concentration. The pristine sPS sample was almost amorphous at 0°C, whereas in the filled samples the crystallinity increased on increasing the MWCNT concentration, indicating a strong nucleation effect of the nanotubes. Interestingly, in spite of the low temperature, the β crystallinity was induced and this crystalline form increases on increasing the carbon nanotube concentration, being dominant (68% of the total crystallinity) already at 3 wt% of MWCNT concentration.

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“…Recently, subjects of polymorphism of sPS have been widely investigated by using differential scanning calorimetry (DSC), [1,2] X-ray diffraction, [3][4][5] transmission electron microscopy, electron diffraction, [6][7][8] Raman scattering and Fourier-transform infrared spectroscopy (FTIR), [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] etc. There are four known crystals (a-, b-, d-, and g-crystals) in sPS.…”

Section: Introductionmentioning

confidence: 99%

Thermal‐Induced Crystal/Conformation Transformations in Syndiotactic Polystyrene Films Treated with Different Solvents

Sun

Woo

2003

Macro Chemistry & Physics

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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 crystal/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′‐phase) upon the same thermal treatments, except that the intermediate phase is a disordered γ‐phase.FTIR spectra in the frequency ranging from 720 to 820 cm−1 for the δ‐type sPS/o‐dichlorobenzene complex subjected to increase of the temperature by 5 °C steps in the range of 60–245 °C.magnified imageFTIR spectra in the frequency ranging from 720 to 820 cm−1 for the δ‐type sPS/o‐dichlorobenzene complex subjected to increase of the temperature by 5 °C steps in the range of 60–245 °C.

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Morphology and structure of syndiotactic polystyrene

Cited by 183 publications

References 15 publications

The role of molecular mechanics in the prediction of the chain conformation of polymers in the crystalline state: Syndiotactic polymers

The role of molecular mechanics in the prediction of the chain conformation of polymers in the crystalline state: Syndiotactic polymers

Influence of multi-walled carbon nanotubes on the β form crystallization of syndiotactic polystyrene at low temperature

Thermal‐Induced Crystal/Conformation Transformations in Syndiotactic Polystyrene Films Treated with Different Solvents

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