Wormlike Chain Parameters of Poly(hexyl isocyanate) in Dilute Solution

Itou, Takashi; Chikiri, Hideaki; Teŕamoto, Akio; Aharoni, Shaul M.

doi:10.1295/polymj.20.143

Cited by 86 publications

(92 citation statements)

References 15 publications

(12 reference statements)

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“…A calibration curve was obtained with poly(hexyl isocyanate) standards. 16 Optical rotation was measured on a JASCO DIP-181 polarimeter. Circular dichroism (CD) spectra were measured on a JASCO J-720 spectrometer.…”

Section: Measurementsmentioning

confidence: 99%

Asymmetric Polymerization of Isocyanates with Optically Active Anionic Initiators

Okamoto

Matsuda

Nakano

et al. 1993

Polym J

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Section: Measurementsmentioning

confidence: 99%

Asymmetric Polymerization of Isocyanates with Optically Active Anionic Initiators

Okamoto

Matsuda

Nakano

et al. 1993

Polym J

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“…4 They are nearly monodisperse in molecular weight, with the polydispersity index Mzf Mw smaller than 1.11, as shown in Table I.…”

Section: Experiments Almentioning

confidence: 96%

Thermodynamic Properties of Concentrated Solutions of Poly(hexyl isocyanate), a Liquid Crystalline Polymer

Itou

Sato

Teŕamoto

et al. 1988

Polym J

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ABSTRACT:Osmotic pressure and sedimentation equilibrium measurements were made on isotropic solutions of poly(hexyl isocyanate), a stiff-chain polymer forming a lyotropic liquid crystal, to determine the osmotic pressure and the solvent chemical potential as functions of polymer concentration. The resulting data were used to test the validity of the theory of Khokhlov and Semenov of polymer liquid crystals, which was almost quantitative in predicting the isotropicliquid crystal phase diagrams for reasonably stiff polymers. It was found that the second virial approximation with respect to free energy basic to this theory was only valid under limited conditions and the scaled particle theory of Cotter on spherocylinders was shown to be a promising alternative. KEY WORDSStiff-Chain Polymer/ Chemical Potential/ Osmotic Pressure / Sedimentation Equilibrium / Liquid Crystal / Phase Diagram / Onsager Theory / Concentrated Solution / In a previous publication 1 we showed that the theory of Khokhlov and Semenov (KS theory) for wormlike cylinders 2 · 3 gives an almost quantitative explanation of experimental phase diagrams for binary systems of poly-(hexyl isocyanate) (PHIC)-toluene and of schizophyllan (a triple-helical polysaccharide)-water, when the geometric parameters of the respective polymers determined from dilute solution properties are used. However, an appreciable discrepancy between the KS theory and experiment was found in the phase diagram of the dichloromethane (DCM) solutions of PHIC characterized by the smallest persistence length and the highest phase boundary concentrations among the systems investigated. This discrepancy may be due to the second virial approximation to free energy which is used in the KS theory. To test the validity of the second virial approximation more directly, other thermodynamic properties, for example, the osmotic pressure should be measured for the systems studied before. for this reason, we determined the chemical potential of the solvent for solutions of PHIC in DCM at 20°c, as well as the osmotic pressure for solutions of PHIC in toluene at 25°C, both in the isotropic state. In this publication, we present the results from these experiments and use them to test the basis of the KS theory, namely, the second virial approximation.

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“…The wormlike cylinder model proposed by YamakawaFujii-Yoshizaki (YFY) [19] for unperturbed condition is usually applied to evaluate the persistent length (l p ) of socalled semi-flexible molecules [20], such as polysaccharides [21], poly(substituted methylenes) [22], and poly(-hexyl isocyanate) [23]. l p can describe the flexibility of chain, which equals the average projection of the end-toend vector on the tangent to the chain contour at a chain end in the limit of infinite chain length.…”

Section: Local Rigidity Analysismentioning

confidence: 99%

Chain Conformation and Local Rigidity of Isomerized Polyimides in Dimethyl Formamide by Size Exclusion Chromatography Coupled with Multi-Detectors

Liu

Qiu

et al. 2011

Chromatographia

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Chain conformation and local rigidity of two isomerized polyimides (PIs), poly(6FDA/3,3 0 -DMB) and poly(6FDA/2,2 0 -DMB) in dimethyl formamide (DMF) with either 0.1 M LiBr or 3.1 mM tetrabutylammonium bromide at 35°C, are investigated. Size exclusion chromatography (SEC) coupled with multi-angle laser light scattering detector, viscometer, and differential refractive index detector was used. The scaling exponents a and m related to conformation are estimated from the above results. The values of a and m for poly(6FDA/3,3 0 -DMB) are 0.68 ± 0.01 and 0.54-0.55 ± 0.01, respectively. The values of a and m for poly(6FDA/2,2 0 -DMB) are 0.65 ± 0.02 and 0.55 ± 0.01, respectively, which indicate that both PIs in DMF have a random coil conformation. In particular, poly(6FDA/3,3 0 -DMB) exhibits more extended conformation than that of poly(6FDA/2,2 0 -DMB). Parameters related to chain flexibility of polymers, including persistence length l p , shift factor M L (relative molecular weight per unit contour length), and backbone diameter d are evaluated from the relationship between intrinsic viscosity and molecular weight based on the wormlike continuous cylinder model. The three parameters (l p , M L , and d) indicate that the two samples are flexible chains with local rigidity, and poly(6-FDA/3,3 0 -DMB) is slightly stiffer than poly(6FDA/2,2 0 -DMB). In addition, influence of salt types on the parameters is also discussed.

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Wormlike Chain Parameters of Poly(hexyl isocyanate) in Dilute Solution

Cited by 86 publications

References 15 publications

Asymmetric Polymerization of Isocyanates with Optically Active Anionic Initiators

Asymmetric Polymerization of Isocyanates with Optically Active Anionic Initiators

Thermodynamic Properties of Concentrated Solutions of Poly(hexyl isocyanate), a Liquid Crystalline Polymer

Chain Conformation and Local Rigidity of Isomerized Polyimides in Dimethyl Formamide by Size Exclusion Chromatography Coupled with Multi-Detectors

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