Solution Properties of Poly(n-butyl isocyanate). 1. Characterization and Intrinsic Viscosity Behavior Over an Extended Molecular Weight Range

Ambler, M. R.; McIntyre, D.; Fetters, L. J.

doi:10.1021/ma60062a004

Cited by 21 publications

(32 citation statements)

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“…In fact, the polymers in this study displayed extremely high viscosity indices ( α ) in the Mark–Houwink–Sakurada plot, η = kM α , in which η and M are the intrinsic viscosity and absolute molecular weight, respectively, and k is a constant. For example, poly( sec ‐octylisocyanide) displays a large α value (1.75),15a and so does poly(butylisocyanate) (1.83),15b owing to its rigid helical conformation. Some substituted helical polyacetylenes also display large α values owing to the conjugated main chain, including poly( N ‐propargyl‐ n ‐hexanamide) (0.98),16 poly( n ‐hexylpropiolate) (1.2),17 and poly( p ‐phenoxycarbonylphenylacetylene) (0.97) 18.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Helical Structure of Poly(1‐methylpropargyl ester)s with Various Side Chains

Suzuki

Shiotsuki

Sanda

et al. 2008

Chemistry An Asian Journal

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Optically active 1-methylpropargyl esters bearing various substituents were polymerized with [(nbd)Rh](+)[eta(6)-C(6)H(5)B(C(6)H(5))(3)](-) (nbd=norbornadiene) as a catalyst to afford the corresponding poly(1-methylpropargyl ester)s with moderate molecular weights in good yields. The polymers have a cis-stereoregular structure, which was determined by (1)H NMR spectroscopy. Large optical rotations and clear CD signals demonstrated that all these polymers take on a helical structure with a predominantly one-handed screw sense. The polymers exhibited large viscosity indices in the range 1.14-1.75. Chiral amplification was observed in R/S copolymerization. Conformational analysis revealed that the polymers form a tightly twisted helical structure with a dihedral angle of 70 degrees at the single bond of the main chain.

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Section: Resultsmentioning

confidence: 99%

Synthesis and Helical Structure of Poly(1‐methylpropargyl ester)s with Various Side Chains

Suzuki

Shiotsuki

Sanda

et al. 2008

Chemistry An Asian Journal

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“…Figure 1 shows double-logarithmic plots of (S 2 )/x (in A 2 ) against x for atactic polystyrene (a-PS) with the fraction of racemic diads fr = 0.59 in cyclohexane at 34.SOC (8) 17 • 18 and in toluene at 15.0°C/ 9 atactic poly(methyl methacrylate) (a-PMMA) with fr=0.79 in acetonitrile at 44.0°C (8) 20 and in acetone at 25.0°C, 21 isotactic (i-) PMMA with fr=O.Ol in acetonitrile at 28.0°C (8) 22 and in acetone at 25.0°C, 23 poly(n-butyl isocyanate) (PBIC) in tetrahydrofuran (THF) at 40°C, 24 and schizophyllan in O.ol N NaOH at 25°C. 25 The data have been obtained from light scattering measurements except for fractions of the flexible polymers with (S 2 ) 1 i 2 ;:S80A, for which those have been obtained from small-angle X-ray scattering (SAXS) measurements.…”

Section: Mean-square Radius Of Gyrationmentioning

confidence: 99%

“…Now the asymptotic ratio ((S 2 )/x) 00 for x= oo, which is proportional to the characteristic ratio Coo, 9 is equal to 8.1 3 , 6.5 7 , and 9.3 1 A 2 for a-PS, a-PMMA, and i-PMMA, respectively, and cannot be directly correlated to the chain stiffness A-1 , as seen from 22 and in acetone at 25.0°C (L:,. )/ 3 PBIC in THF at 40°C (()), 24 and schizophyllan in 0.01 N NaOH at 25oC ( ). 25 The solid curves represent the best-fit HW or KP theoretical values, and the dashed curves connect smoothly the data points.…”

Section: Chain Stiffness and Local Chain Conformationsmentioning

confidence: 99%

“…According to the HW theory, 82 the first cumulant Q(k) of the dynamic structure factor is given by a sum of two terms, (24) where pis the factor defined in eq 8 and 'k is the reduced magnitude of the scattering vector defined by k= <S 2 ) 1 1 2 k. The function F(k) represents the contribution from the internal modes. Thus the so-called "universal" plot of Yf 0 Q(k)jkBTk 3 against k depends on the kind of polymer, and therefore is not universal.…”

Section: Dynamic Structure Factormentioning

confidence: 99%

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A New Framework of Polymer Solution Science. The Helical Wormlike Chain

Yamakawa

1999

Polym J

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ABSTRACT:The object of this review article is to introduce and digest Yamakawa's new book, "Helical Wormlike Chains in Polymer Solutions." A brief description is given of a new model for polymer chains, called the helical wormlike chain, and its applications to dilute solution behavior of polymers, that is, equilibrium, steady-state transport, and dynamical properties. The description follows most of the chapters of the book. It is shown that all theoretical and experimental investigations on the basis of this model provide a new framework of polymer solution science, which takes the place of the Flory-Kirkwood framework.KEY The object of this review article is to introduce and digest Yamakawa's new book 1 entitled" Helical Wormlike Chains in Polymer Solutions." As stated in its Preface, it is intended to give a comprehensive and systematic description of the statistical-mechanical, transport, and dynamic theories of dilute solution properties of both flexible and semiflexible polymers, including oligomers, developed on the basis of the "helical wormlike (HW) chain" model, along with an analysis of extensive experimental data. Much of the material in the book arises from his research reported since the year of publication of his earlier (1971) book. 2 The results of this research were already very often reviewed. 3 -7 Now the framework of polymer solution theory constructed by Flory 8 • 9 consists of three concepts: (I) the excluded-volume effect in long flexible (Gaussian) polymer chains, (2) the universality of the unperturbed ( EJ) state without that effect, and (3) the rotational isomeric state (RIS) model for (unperturbed) real chains of arbitrary length. The study of dilute solution behavior of flexible polymers based on the first two concepts was almost completed around 1970, leading to the so-called two-parameter (TP) theory. 2 It is at almost the same time that the statistical-mechanical method for treating the RIS model, which takes account of the details of the chemical structure and local conformations of the chain on the atomic level, was established by Flory and coworkers.9 However, for many equilibrium and steadystate transport problems on stiff or semiflexible polymers, such details are not amenable to mathematical treatments, and moreover are often unnecessary to consider. Some coarse-graining may then be introduced to replace this discrete model by continuous models. In 1976, for this purpose we proposed a general continuous model, called the HW chain. 10 This new model may describe equilibrium conformational and steady-state transport properties of all kinds of real chains, both flexible and stiff, on the bond length or somewhat longer scales, thus bridging a gap between the RIS model and the classical continuous model, that is, the KratkyPorod (KP) wormlike chain. 11 Specifically, the transport t Professor Emeritus.

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“…Ambler et al 33 reported an acid-catalyzed depolymerization of isocyanate chains triggered by UV decomposition of a chlo- " d and dlmonomer (Lo) are estimates; MW and L are based on viscosity data and are therefore z averages (for rods). Maximum polydimersitv (Pd) is taken to be the sauare root of the ratio of MW from viscometry to MW from vapor phase measurements.…”

Section: Methodsmentioning

confidence: 99%

Dynamics of rodlike macromolecules in nondilute solutions: poly(n-alkyl isocyanates)

Keep¹,

Pecora²

1988

Macromolecules

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Theories of caging of rigid rodlike molecules of length L and diameter d in semidilute solution are extended to higher concentrations. Packing considerations indicate that ordering in concentrated rigid rod systems must occur below CL2d = 2.26, where C is the number concentration of rods. In addition, the concentration at which the mean square deflection of a semiflexible polymer chain is equal to the cage size is calculated in terms of the ratio of the persistence length to the contour length. These and other considerations are used to interpret a series of dynamic light scattering experiments on solutions of low molecular weight samples of poly(n-butyl isocyanate), poly(n-hexyl isocyanate), and poly(n-octyl isocyanate). Samples of these materials were fractionated by a recrystallization procedure that was developed to minimize complications due to the presence of water. The polymer fractions selected for study were characterized by capillary viscometry, differential refractometry, infrared and ultraviolet spectroscopy, vapor pressure measurements, q d total intensity light scattering. The dynamic light scattering experiments in the semidilute region, as analyzed by the programs DISCRETE and CONTIN, usually give multimodal time correlation functions that are qualitatively interpreted in terms of caging theories and rotational-translational coupling. This coupling grows in importance in a fashion consistent with caging theories as the concentration is raised or the molecular diameter is increased. In the high CL2d region the solutions studied form either a mesophase or a gel depending on the method of solution preparation and the molecular mobility (which depends in turn on other parameters such as the axial ratio and the flexibility). Present address: Tennessee Eastman Company, P.O. Box 1972, Kingsport, Tennessee 37662.confluence of two binodal regions) and unstable elliptic types. Sector vertices represent unique systems where the effect of unequal chain lengths is just balanced by interactions to produce a constant critical temperature, independent of composition. Conditions for multiple occurrence of HODCP's and relations for orientation of spinodals a t HODCP's are derived. Special attention is paid to systems located on hyperbolic boundaries between elliptic and hyperbolic regions where HODCP's overlap with heterogeneous double critical points.A criterion is also given for improving the solvent power in terms of interaction parameter perturbations.

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Solution Properties of Poly(n-butyl isocyanate). 1. Characterization and Intrinsic Viscosity Behavior Over an Extended Molecular Weight Range

Cited by 21 publications

References 8 publications

Synthesis and Helical Structure of Poly(1‐methylpropargyl ester)s with Various Side Chains

Synthesis and Helical Structure of Poly(1‐methylpropargyl ester)s with Various Side Chains

A New Framework of Polymer Solution Science. The Helical Wormlike Chain

Dynamics of rodlike macromolecules in nondilute solutions: poly(n-alkyl isocyanates)

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