Second and Third Virial Coefficients for Polyisobutylene in Heptane, an Intermediate Solvent

Akasaka, Kazutomo; Nakamura, Yo; Norisuye, Takashi; Teŕamoto, Akio

doi:10.1295/polymj.26.1387

Cited by 10 publications

(3 citation statements)

References 25 publications

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“…The B value of 0.50 nm for the CTDC chain is comparable to those for flexible polymers ,,, in good solvents, but the reduced strength parameter B /2 q (or λ B ), which determines z̃ at a given λ L (= n K ), is only 0.032 for the former and 1 order of magnitude smaller than the latter group of systems because of the high stiffness of the CTDC chain. This small B /2 q for CTDC in NMP is responsible for the excluded-volume effects (on both 〈 S 2 〉 z and [η]) that remain small up to as large an n K as 40.…”

Section: Resultsmentioning

confidence: 76%

Chain Stiffness and Excluded-Volume Effects in Dilute Polymer Solutions: Cellulose Tris[(3,5-Dimethylphenyl)carbamate]

1996

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Nineteen fractions of cellulose tris[(3,5-dimethylphenyl)carbamate] (CTDC) ranging in weight-average molecular weight M w from 2.5 × 104 to 7.5 × 106 have been studied by static light scattering, sedimentation equilibrium, and viscometry in 1-methyl-2-pyrrolidone at 25 °C. Since this cellulose derivative exhibits pronounced optical anisotropy, light-scattering data are corrected for the anisotropy effect on the basis of Nagai theory for the Kratky−Porod (KP) wormlike chain with cylindrically symmetric polarizabilities. It is shown that the data for 〈S 2〉z (the z-average mean-square radius of gyration), δ (the optical anisotropy factor), and [η] (the intrinsic viscosity) and those reported previously for 11 fractions are described accurately by the known theories for the unperturbed KP chain if M w is lower than 7 × 105. From the comparison, the persistence length and the monomeric projection of the CTDC chain are estimated to be 7.8 and 0.52 nm, respectively. When M w exceeds 106, i.e., when n K (the Kuhn segment number) increases above 50, excluded-volume effects on 〈S 2〉z and [η] become experimentally observable. Though such a large n K value for the appearance of volume effects has been considered inconsistent with the Yamakawa−Stockmayer−Shimada (YSS) theory for KP or helical wormlike chains, the observed excluded-volume effects are found to be explained quantitatively in the YSS scheme, i.e., by the YSS perturbation theory combined with the Domb−Barrett function for the radius expansion factor and the Barrett function for the viscosity expansion factor. Thus, this theoretical scheme should have a wider applicability than what might be anticipated from earlier studies.

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Section: Resultsmentioning

confidence: 76%

Chain Stiffness and Excluded-Volume Effects in Dilute Polymer Solutions: Cellulose Tris[(3,5-Dimethylphenyl)carbamate]

1996

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“…from the unperturbed lines. The B value of 0.50 nm for the CTDC chain is comparable to those for flexible polymers (Refs [40][41][42][43]. in good solvents, but the reduced strength parameter hB (or B/2q), which determines 1 at a given liL (or n~) , is only 0.032 for the former and one order of magnitude smaller than those for the latter group of systems because of the high stiffness of the CTDC chain.…”

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confidence: 75%

Solution properties of cellulose tris(3,5‐dimethyl‐phenylcarbamate)

Norisuye

Tsuboi

Sato

et al. 1997

Macromolecular Symposia

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The dilute-solution behavior and liquid crystal formation of cellulose tris(3,5-dimethylphenylcarbamate) (CTDC) in 1-methyl-2-pyrrolidone (NMP) at 25OC are discussed by summarizing our recent studies, and its molecular characteristics are compared with those of cellulose tris(pheny1carbamate) (CTC) in the same solvent. The molecular weight dependences of optical anisotropy factor, radius of gyration, intrinsic viscosity ([q]), and isotropic-cholesteric phase boundary concentration for CTDC are explained consistently by current theories based on the wormlike chain. An analysis of the newly measured [q] for CTC shows that the backbone conformation and chain stiffness are substantially the same for the two cellulose derivatives in NMP. However, a distinct difference in optical anisotropy is found and briefly discussed in relation to the higher optical resolution capacity of CTDC than that of CTC in chromatographic separation of racemic compounds.

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“…This B value is the smallest among those for the four stiff chains but comparable to the reported values for typical flexible polymer+ good solvent systems such as polystyrene in toluene (0.61 nm) 8 and polyisobutylene in cyclohexane (0.31 nm). 25 Another point to note in the table is that the A -1 values for Na-HA in 0.2 and 0.5 M aqueous NaCl are essentially the same and thus indicate negligible contributions from electrostatic interactions between charged groups to the chain stiffness. Figure 3 shows the plots of A 2 (S 2 ) vs. AL constructed from the reported (S 2 ) data for the four polymers6·13·14'17•18 and the values of A -1 and ML in Table I; the (S 2 ) data for PHIC have been reproduced from Figure I, and those for Na-HA (in 0.5 M aqueous NaCl) Polym.…”

Section: Model Parameters and Onset Of Volume Effectmentioning

confidence: 95%

Remarks on Excluded-Volume Effects in Semiflexible Polymer Solutions

Norisuye¹,

Tsuboi²,

Teŕamoto³

1996

Polym J

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ABSTRACT:Intramolecular excluded-volume effects in stiff chains are examined by analyzing typical data of (S 2 ) (the mean-square radius of gyration) and ['7] (the intrinsic viscosity) for four different polymers with Kuhn segment lengths A. -l of 7.8-86 nm on the basis of the wormlike chain. The data are shown to be explained almost quantitatively in the YamakawaStockmayer-Shimada scheme for wormlike or helical wormlike chains, leading to the conclusion that the expansion factor versus scaled excluded-volume parameter relations established by Yamakawa, Einaga, and coworkers for (S 2 ) Molecular characterization of semiflexible polymers in dilute solution often requires knowledge of intramolecular excluded-volume effects, but our understanding of those effects in stiff chains still leaves much to be desired. The situation may be explained as follows. More than 10 years ago, Norisuye and Fujita, 1 analyzing available data for the mean-square radius of gyration (S 2 ) on the basis of the Kratky-Porod (KP) wormlike chain, 2 concluded that excluded-volume effects on (S 2 ) of various polymers become experimentally observable when the Kuhn segment number nK exceeds 50 ( ± 30).This nK value was one order of magnitude larger than that predictable from the Yamakawa-Stockmayer perturbation theory 3 for KP bead chains, suggesting that intramolecular volume exclusion in actual stiff polymers is less enhanced than predicted by the theory. Later, Yamakawa and Shimada 4 examined the discrepancy by directly comparing theoretical and experimental (S 2 ) values, and reached the conclusion that the YamakawaStockmayer scheme, now extended to helical wormlike (HW) chains 5 and called the Yamakawa-StockmayerShimada (YSS) scheme, breaks down for poly(hexyl isocyanate) (PHIC), a typical stiff chain, in hexane. 6 Little progress has since been made on the subject, though, as far as flexible polymers are concerned, the validity of the YSS scheme has been substantiated for both dimensional and hydrodynamic properties. 7 -12 Very recently Tsuboi et al.U analyzed data of (S 2 ) and [17] (the intrinsic viscosity) for cellulose tris(3,5-dimethylphenylcarbamate) (CTDC) in 1-methyl-2-pyrrolidone (NMP) to reconcile the YSS theory with Norisuye and Fujita's conclusion mentioned above. The point was that the theory was capable of explaining the observed volume effects that were practically negligible for nK < 40 and appreciable for nK >50. This motivated us to re-examine literature data of (S 2 ) and [17] including those for PHIC with a hope of deepening our understanding of the intramolecular excluded-volume effects in semiflexible polymer solutions. To make our analysis more quantitative than in the earlier work by Norisuye and Fujita, we here confine ourselves to polymers whose (S 2 ) or [17] data show both unperturbed and perturbed behaviors in the molecular weight range studied. They are CTDC in NMP, 13 • 14 sodium salt of hyaluronic acid (Na-HA) in 0.2 and 0.5 M aqueous sodium chloride/ 5 -1 7 and poly(l-phenyl-1-propyne) (PPP) i...

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Second and Third Virial Coefficients for Polyisobutylene in Heptane, an Intermediate Solvent

Cited by 10 publications

References 25 publications

Chain Stiffness and Excluded-Volume Effects in Dilute Polymer Solutions: Cellulose Tris[(3,5-Dimethylphenyl)carbamate]

Chain Stiffness and Excluded-Volume Effects in Dilute Polymer Solutions: Cellulose Tris[(3,5-Dimethylphenyl)carbamate]

Solution properties of cellulose tris(3,5‐dimethyl‐phenylcarbamate)

Remarks on Excluded-Volume Effects in Semiflexible Polymer Solutions

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