Stability of crystal forms of syndiotactic polystyrene correlated with their formation in different media having different solubility parameters

Ma, Weiming; Yu, Jiahui; He, Jiasong

doi:10.1016/j.polymer.2005.09.002

Cited by 16 publications

(8 citation statements)

References 45 publications

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“…This conclusion has been verified by a work of Liao et al [22], where the addition of ethanol obviously promoted PC crystallization in scCO 2 . In other studies, the presence of cosolvents was found to affect the melting behavior [23] and crystal form transformation [24,25] of polymers in scCO 2 . However, these studies used organic solvents as the cosolvent, which were less environmentally friendly and very difficult to remove completely from polymers after crystallization [26], limiting the application of mixed supercritical fluids.…”

Section: Introductionmentioning

confidence: 93%

Cosolvent effect of water in supercritical carbon dioxide facilitating induced crystallization of polycarbonate

Zhai

et al. 2007

Polymer Engineering & Sci

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Water-induced crystallization of polycarbonate (PC) was investigated in water-saturated supercritical CO 2 (scCO 2 ) in the range of 80-1608C and 12-20 MPa, with the help of differential scanning calorimetry and wideangle X-ray diffraction. Compared with pure scCO 2 , the enhanced plasticizing effect of water-saturated scCO 2 reduced the energy-barrier for the motion of polymer chains, hence increased the crystallization rate of PC, and reduced the pressure threshold for crystallization from 14 to 12 MPa. On the other hand, the presence of water did not affect the thermodynamics of PC crystallization in scCO 2 . A 3D-diagram was established to show the relationship between crystallization and solubility parameter of mixed supercritical fluid at different temperatures and pressures. The results show clearly that the PC has a wider range of crystallization temperature and pressure in water-saturated scCO 2 than in pure scCO 2 , mostly because the addition of water increased significantly the solubility parameter of mixed supercritical fluid, and decreased the difference in solubility parameter between PC and water-saturated scCO 2 .

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Section: Introductionmentioning

confidence: 93%

Cosolvent effect of water in supercritical carbon dioxide facilitating induced crystallization of polycarbonate

Zhai

et al. 2007

Polymer Engineering & Sci

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“…The clouded solution had particles with a size range of 300–10,000 nm as measured by DLS. The Hildebrand solubility parameters (SP values) of PS, PVP, and DMF are 17.4–19.0 MPa 1/2 , 40 22.5–25 MPa 1/2 , 41 and 24.8 MPa 1/2 , 42 respectively. Thus, PVP is more soluble than PS in DMF.…”

Section: Discussionmentioning

confidence: 99%

Electrospun Porous Nanofibers with Imprinted Patterns Induced by Phase Separation of Immiscible Polymer Blends

et al. 2022

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Nanofibrous nonwoven fabrics have attracted attention as porous adsorbents with high specific surface areas for the safe and efficient treatment of spilled organic dyes and petroleum. For this purpose, a method of fabricating porous nanofibers with high specific surface areas would be highly beneficial. In this study, the phase separation in nanofibers electrospun from blended solutions of immiscible polymers [poly(styrene) (PS) and poly(vinylpyrrolidone) (PVP)] was investigated. The removal of PVP as a sacrificial polymer afforded the imprinting of mesopores (40–70 nm) in the PS nanofibers. The effects of solution composition (PS/PVP in N , N -dimethylformamide) on the structure formation in the fibers were investigated. The nanofibers thus obtained could selectively adsorb low-molecular-weight hydrophobic dyes, such as Nile Red and Oil Red O. Thus, it is expected that the combined approach of electrospinning of immiscible polymer blends and phase separation-induced patterning can be applied to the fabrication of functional nanofibers for diverse applications.

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“…Rudder et al conducted experiments regarding the role of cyclohexane in the formation of γ form and its transition to the β form . Ma et al reported the direct formation of the γ form induced by supercritical fluid CO 2 and its influence on the transition from the γ form to the α or β form. , Rizzo et al reported the formation of the γ form induced by non-guest solvents, such as limonene, carvone, and 1-chlorodecane . Wang et al investigated the crystallization behavior of the γ form using the thermodynamic phase diagram, from which a recrystallization line, equilibrium recrystallization line, and equilibrium melting line were obtained .…”

Section: Introductionmentioning

confidence: 99%

Lamellar Thickness Dependence of Crystal Modification Selection in the Syndiotactic Polystyrene γ-to-α/β Phase Transition Process

Wang

Cui

et al. 2018

Macromolecules

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The syndiotactic polystyrene (sPS) γ-to-α/β phase transition was investigated using temperature-dependent synchrotron wide-angle X-ray diffraction (WAXD) and smallangle X-ray scattering (SAXS) measurement. The sPS γ form samples, which were obtained from acetone solvent induced crystallization followed by annealing at various temperatures (T a ), exhibited a regular manner on the selection of the α or β crystal modification during the phase transition process. As the T a was increased from 25 to 150 °C, the weight fraction of β form in bulk sPS decreased from 55% to 0%, but that of the α form increased from 45% to 100%. In other words, the α form became the dominating crystalline modification at higher T a . The lamellar thickness (d c ) of the γ form at the initial state (before heating) ranged from 4.4 to 5.8 nm, and the weight crystallinity (X c ) was between 0.52 and 0.64. However, the d c values of the γ form at the final state (before γ-to-α/β phase transition) were very close for the samples pretreated at different T a s, which were in the range 7.0−7.4 nm. Therefore, the most plausible interpretation for the crystal modification selection during the γ-toα/β phase transition was that the nucleation of β form was suppressed totally in the γ form with higher initial d c value (>5.8 nm). With the elevated T a and increase of initial d c , the promoted nucleation of α form in the γ form resulted in the enhanced growth of the α crystalline phase during the γ-to-α/β phase transition. As a result, after the phase transition the crystalline phase in bulk sPS had a gradually increased weight fraction of the α form and turned out to be pure α form when T a was increased from 25 to 150 °C.

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Stability of crystal forms of syndiotactic polystyrene correlated with their formation in different media having different solubility parameters

Cited by 16 publications

References 45 publications

Cosolvent effect of water in supercritical carbon dioxide facilitating induced crystallization of polycarbonate

Cosolvent effect of water in supercritical carbon dioxide facilitating induced crystallization of polycarbonate

Electrospun Porous Nanofibers with Imprinted Patterns Induced by Phase Separation of Immiscible Polymer Blends

Lamellar Thickness Dependence of Crystal Modification Selection in the Syndiotactic Polystyrene γ-to-α/β Phase Transition Process

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