Light scattering of isotactic polystyrene

Trossarelli, L.; Campi, E.; Saini, G.

doi:10.1002/pol.1959.1203512816

Cited by 38 publications

(7 citation statements)

References 22 publications

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“…For the polymerization of unsymmetrical unconjugated dienes, Trossarelli et al 8 have reported the kinetics of cyclopolymerization which has been further developed for simplification by the present authors.' In this work we treat the cyclopolymerization of DAM, the mechanism of which is essentially equivalent to that of unsymmetrical unconjugated dienes except the bicyclo-propagation reaction.…”

Section: Polymerization Kineticsmentioning

confidence: 94%

Polymerization of allyl esters of unsaturated acids. IV. Cyclopolymerization of diallyl maleate

Urushido

Matsumoto

Oiwa

1979

J. Polym. Sci. Polym. Chem. Ed.

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SynopsisRadical polymerization of diallyl maleate is kinetically discussed in terms of cyclopolymerization using 2,2'-azobisisobutyronitrile as an initiator and benzene as a solvent a t 60°C. Thus, the kinetic equations involving bicyclo-intramolecular cyclization are derived by assuming steady-state conditions for the different types of radicals, and various parameters involved in the equations are then estimated approximately from an extension of the corresponding model experimental results. The validity of these treatments is confirmed from the comparison with the experimental data including the relationships between the contents of the unreacted allylic and maleic double bonds and the monomer concentrations. In addition, the sequence distribution of the structural units of the polymer produced is discussed; for example, the content of the bicyclic structural units is estimated to be 47.2% a t a 10% dilution of the pure monomer. EXPERIMENTALDAM, a commercially available reagent, was distilled in vacuo under nitrogen. 2,2'-Azobisisobutyronitrile (AIBN) as an initiator and benzene as a solvent were purified by conventional methods. Polymerization procedure and analyses of polymers obtained were similar to the methods described in a previous article.'

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Section: Polymerization Kineticsmentioning

confidence: 94%

Polymerization of allyl esters of unsaturated acids. IV. Cyclopolymerization of diallyl maleate

Urushido

Matsumoto

Oiwa

1979

J. Polym. Sci. Polym. Chem. Ed.

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“…The majority of this work has involved the measurement of intrinsic viscosities, molecular sizes and second virial coefficients in thermodynamically good solvents. [2][3][4][5][6][7][8][9][10][11] The conclusions drawn from these investigations are that the perturbed molecular dimensions in good solvents are indistinguishable for the atactic and isotactic forms, but that the stereoregular polymers exhibit smaller second virial coefficients (at least for lower molecular weights) in these solvents. This latter conclusion is in agreement with the earlier work of Muthana and Mark,12 who compared crystalline and amorphous samples of poly-(vinyl isobutyl ether).…”

Section: Introductionmentioning

confidence: 99%

The Conformation of Polymer Molecules. Iv. Poly-(1-Butene)

Krigbaum¹,

Kurz²,

Smith³

1961

J. Phys. Chem.

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Poly-( I-butene) was separated into atactic and isotactic portions by extraction and these materials were individually fractionated. The two forms obeyed identical intrinsic viscosity-molecular weight relationships in good solvents; however, the isotactic modification exhibited lower values of the osmotic second virial coefficient for molecular weights below 7 x 10'.This type of behavior in good solvents has been reported by other workers for the two forms of polystyrene and polypropylene, and hence appears to be quite general. Precipitation temperature measurements in anisole gave a higher entropy parameter, $1, for the stereoregular poly-( 1-butene), in agreement with the result reported by Kinsinger and Wessling for polypropylene in phenyl ether. On the other hand, the latter workers found a lower theta, temperature for isotactic polypropylene, whereas we obtained a higher theta temperature for the stereoregular poly-( 1-butene). Thus, atactic poly-( 1-butene) is more soluble in anisole than its stereoregular counterpart for all molecular weights, whereas atactic polypropylene should be the form of lower solubility in phenyl ether for molecular weights above 39,000. Isotactic poly-( 1-butene) appears to have a more highly extended molecular conformation than its atactic counterpart, as judged from unperturbed dimensions estimated from light scattering data obtained using a good solvent. Parameters are given which permit a comparison of the relative extensions of a number of polyolefins. IntroductionThe method of preparation and the physical properties of a number of linear, stereoregular polyolefins were described by Natta and eo-workers in 1955.' Since that time there has been considerable interest in comparing the molecular dimensions and thermodynamic interactions of the isomeric forms of these polymers in solution. The majority of this work has involved the measurement of intrinsic viscosities, molecular sizes and second virial coefficients in thermodynamically good solveiits.2-11 The conclusions drawn from these investigat'ions are that the perturbed molecular dimensions in good solvents are indistinguishable for the atactic and isotactic forms, but that the stereoregular polymers exhibit smaller second virial coefficients (at least, for lower molecular weights) in these solvents. This latter conclusion is in agreement with the earlier work of Muthana and Mark,12 mho compared crystalline and amorphous samples of poly-(vinyl isobutyl ether). Finally, in the

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“…We can suppose that the some sequence of monomer units interacts with the solvent molecule and the sequence distribution differences between two polymer types as demonstrated in Table II bring about the large differences in B parameters, especially in 67 wt% aq nitric acid. On the 9th and lOth columns of Table VI collects, the steric factor 0', is defined as (12) (where Ar is A of a hypothetical chain with free internal rotation (model I) and Ar = 0.423 x w-s em for PAN) and the characteristic ratio Coo is given by (13) (where Mb is the mean molecular weight per skeletal bond ( =26.5) and I is the mean bond length (1.54 x w-s em), both calculated from the most probable A value). Figure 12 shows the effect of the side chain molecular weight on 0' of the vinyl-type polymers.…”

Section: Dmso A(y-pan)>a(r-pan) and B(y-pan)['1](r-pan) In 67 Wt% Amentioning

confidence: 99%

Effects of Stereoregularity on Molecular Parameters of Polyacrylonitrile Polymerized by Gamma-Ray Irradiation

Kamide¹,

Yamazaki²,

Miyazaki³

1986

Polym J

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Polyacrylonitrile prepared by gamma-ray irradiation to urea-canal complex of acrylonitrile (U-PAN) was fractionated from a solution in dimethylsulfoxide (DMSO) at 2j°C, using toluene as a precipitant. Viscosities of fractions, thus prepared, in DMSO and in ethylenecarbonate (EC), were measured for elucidating the unperturbed-chain dimensions together with the long-range polymer/solvent interaction parameter. In conclusion, U-PAN which is comparatively isotactic has almost the same value (the K value is 2.95.10-3) of the unperturbed-chain dimensions as the atactic polyacrylonitrile prepared by conventional, radical polymerization (R-PAN), whilst the long-range parameter of U-PAN is extremely smaller than R-PAN in a poor solvent. The conclusions reached from these experimental facts are in very good consistence with those of other polymers with less difference in the stereoregularity. ZUSAMMENFASSUNG:Polyacrylnitril, welches durch Bestrahlung eines Harnstoff-Einschlul3-Komplexes von Acrylnitril hergestellt worden war (U-PAN), wurde aus einer Dimethylsulfoxid(DMS0)-Losung bei 25 O C mit Toluol als Fallungsmittel fraktioniert. Die Viskositaten dieser Fraktionen in DMSO und in Athylencarbonat (EC) wurden gemessen, um eine Aussage iiber die ungestorten Knaueldimensionen und iiber die durch Polymer-Losungsmittel-Wechselwirkung hervorgerufenen Querkriifte zu erhalten. Es wird geschlossen, dal3 U-PAN, welchcs relativ isotaktisch ist, fast die gleichen ungestorten Knaueldimensionen (K = 2,95 .10W3) hat wie das ataktische Polyacrylnitril, welches in konventioneller Weise radikalisch hergestellt worden ist (R-PAN). Dagegen ist der Parameter der Querkrafte bei U-PAN in einem schlechten Losungsmittel wesentlich kleiner als bei R-PAN. Die Schliisse, die aus diesen experimentellen Tatsachen gezogen wurden, sind in sehr guter ubereinstimmung mit denen bei anderen Polymeren mit geringerem Unterschied in der Stereoregularitat.

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Light scattering of isotactic polystyrene

Cited by 38 publications

References 22 publications

Polymerization of allyl esters of unsaturated acids. IV. Cyclopolymerization of diallyl maleate

Polymerization of allyl esters of unsaturated acids. IV. Cyclopolymerization of diallyl maleate

The Conformation of Polymer Molecules. Iv. Poly-(1-Butene)

Effects of Stereoregularity on Molecular Parameters of Polyacrylonitrile Polymerized by Gamma-Ray Irradiation

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