Chain stiffness and excluded-volume effects in dilute polymer solutions. Poly(isophthaloyl-trans-2,5-dimethylpiperazine)

Kitagawa, Tooru; Sadanobu, Jiro; Norisuye, Takashi

doi:10.1021/ma00204a037

Cited by 18 publications

(12 citation statements)

References 9 publications

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“…4 • 5 Nagai 15 was the first present a theory for the optical anisotropy factor of a wormlike chain with cylindrical symmetry. For relatively flexible wormlike chains, his expression can be written (6) where £ is defined by (7) with a 1 and a 2 being respectively the lon- in Figure 9, which reproduces the inverse proportionality predicted by the leading term of eq 6 with reasonable accuracy; we note that the O(qML/M) term in eq 6 does not exceed 0.012 in the Mw range studied. The values of I£ I are estimated to be 2.1 and 2.4 for cyclohexane and toluene, respectively.…”

Section: Resultssupporting

confidence: 64%

Stiff-Chain Nature of Poly(1-phenyl-1-propyne) in Dilute Solution

Hirao

Teŕamoto

Sato

et al. 1991

Polym J

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ABSTRACT:Light scattering and viscosity measurements were made on twelve narrowmolecular weight distribution samples ofpoly(l-phenyl-1-propyne) in toluene and in cyclohexane. In cyclohexane at 36°C, the second virial coefficient A2 vanished, the mean-square radius of gyration increased linearly with weight-average molecular weight Mw, but the intrinsic viscosity was not proportional to M!1 2 • Thus poly(l-phenyl-1-propyne) in cyclohexane at 36oC is an unperturbed semiflexible polymer. A2 in toluene was positive, indicating significant intermolecular excluded volume effect. However the intramolecular excluded volume effect became appreciable only at Mw

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Section: Resultssupporting

confidence: 64%

Stiff-Chain Nature of Poly(1-phenyl-1-propyne) in Dilute Solution

Hirao

Teŕamoto

Sato

et al. 1991

Polym J

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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.…”

mentioning

confidence: 73%

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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“…When molecular weight of a polymer is sufficiently low, its excluded volume effect is negligible. [38][39][40] Actually, the experimental relation between ͓͔ and M n in respect to ODMS in toluene 32 ͓͑͒ϰM n 0.50 ͒ gives ϭ0.50. This means that endto-end distance of ODMS chain in uncrosslinked state is equal to its unperturbed dimension over the entire range of 0 .…”

Section: ͑48͒mentioning

confidence: 99%

Elastic modulus and equilibrium swelling of networks crosslinked by end-linking oligodimethylsiloxane at solution state

Urayama

Kawamura

Kohjiya

1996

The Journal of Chemical Physics

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We have investigated the degree of equilibrium swelling and the elastic modulus of networks prepared by end-linking oligo(dimethylsiloxane)s (ODMS) in solution as a function of polymer concentration at crosslinking. The molecular weight of ODMS is so low that entanglement couplings are not formed in uncrosslinked state. It has been found from the preparation concentration dependence of elastic modulus in preparation state that trapped entanglements are formed by the introduction of crosslinks, and those considerably contribute to elastic modulus, even if the prepolymers are not entangled in uncrosslinked state. The experimental results for preparation concentration dependence of the degree of equilibrium swelling and the elastic modulus of equilibrium swollen networks are compared with the theoretical predictions by the two theories, i.e., the affine model and the c* theorem. It has been clearly shown that the affine model describes well the experimental results, while the discrepancies between the experimental results and the predictions by the c* theorem are considerable. These results strongly suggest that preparation concentration should be regarded as a reference state, and the displacement of crosslinks moves affinely on swelling, while the complete disinterpenetration of network chains in equilibrium swollen state, which is a postulate of the c* theorem, does not occur.

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Chain stiffness and excluded-volume effects in dilute polymer solutions. Poly(isophthaloyl-trans-2,5-dimethylpiperazine)

Cited by 18 publications

References 9 publications

Stiff-Chain Nature of Poly(1-phenyl-1-propyne) in Dilute Solution

Stiff-Chain Nature of Poly(1-phenyl-1-propyne) in Dilute Solution

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

Elastic modulus and equilibrium swelling of networks crosslinked by end-linking oligodimethylsiloxane at solution state

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