A photoelectric apparatus for the measurement of the angular dependence of light scattering from solutions is described in detail and its performance is discussed. Methods of calculation for the determination of the average extension of the scattering molecules from the data are described. Data are presented for two fractions of polystyrene in various solvents, showing the effect of changing solvent power and temperature, and also confirming a theoretically derived formula for the concentration dependence of the scattering.

Apparatus and Methods for Measurement and Interpretation of the Angular Variation of Light Scattering; Preliminary Results on Polystyrene Solutions

Using light scattering, the mean square molecular radius and length of a number of samples of polystyrene have been measured as a function of solvent and temperature. Molecular weights, intrinsic viscosities, and ``osmotic second virial coefficients'' have also been determined on many of the samples. From the data it may be concluded: (1) that polystyrene molecules are extended and stiffened by steric interactions of the phenyl groups; (2) that the molecules are largely unbranched; (3) that the heat of dilution is negative in some solvents, contrary to the usual situation in hydrocarbon systems; (4) that the osmotic second virial coefficient depends strikingly on molecular weight for a given solvent; (5) that there is a good correlation between this coefficient and the mean square radius at a given molecular weight; (6) that the intrinsic viscosity is strictly proportional to a power of the molecular weight over the molecular weight range from 2,000 to 2,000,000, but that deviations occur at lower molecular weights; (7) that the intrinsic viscosity and mean square radius are functions of solvent at high molecular weights but not at very low molecular weights. Theoretical concepts necessitated by these observations are discussed briefly.

Light Scattering Investigation of the Structure of Polystyrene

This paper reviews the most widely used models for explaining how plasticizers render PVC flexible. These models include the gel, lubricity, and free volume theories; kinetic theories; and mathematical models which predict on the basis of plasticizer structure how much a plasticizer will lower the polymer glass transition in a flexible PVC compound. Since plasticization results from interactions between plasticizer and polymer, methods which have been used to study either the strength or the permanence (or both) of those interactions are also briefly discussed. Tools which have often been used to study plasticizer-PVC interactions include infrared and nuclear magnetic resonance spectroscopy, compression and humid-aging tests, dynamic mechanical analysis, torque rheometer tests, plasticizer-resin clear point temperature measurements, plastisol gelation/fusion by hot stage measurements, and others. J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers

A brief overview of theories of PVC plasticization and methods used to evaluate PVC‐plasticizer interaction

Es werden einige Methoden angegeben, nach denen der von ausgeschlossenen Volumeneffekten unbeeinfluste Tragheitsradius 〈R02〉1/2 bestimmt werden kann. Die theoretische Forderung LIFSONS, das selbst dieser Tragheitsradius noch vom Losungsmittel abhangt und sich im allgemeinen vom Tragheitsradius am Θ-Punkt unterscheidet, kann an den Beispielen von Polymethylmethacrylat und Polystyrol bestatigt werden. Als Ursache fur die Losungsmittelabhangigkeit scheint die Wechselwirkung des Losungsmittels mit den Kettengliedern verantwortlich zu sein, die sich nach der Theorie von KOBATAKE und INAGAKI im scheinbaren spezifischen Volumen Vxx ausert.



Several methods are given for the calculation of the radius of gyration 〈R02〉1/2 which is independent from excluded volume effects. Experiments on polymethyl methacrylate and polystyrene confirmed the theoretical postulation of LIFSON that eyen this radius of gyration depends on the solvent and that it differs in general from the radius of gyration at the Θ-point. The solvent effect appears to be due to the interaction of the solvent with the chain links. which is expressed by the apparent specific volume according to the theory of KOBATAKE and INAGAKI.

ÜBer den einfluß der lösungsmittel auf die struktur linearer makromoleküle. I

Die Erniedrigung der Einfriertemperatur organischer Gläser durch Lösungsmittel

The molecular weight-viscosity relationships for polystyrene are reviewed and it is recommended that the Staudinger relationship be discarded in favor of the conventional modification of it, [η] = KMa. An emulsion-prepared polystyrene was fractionated and the viscosities and osmotic molecular weight determined. The corresponding relationship between the viscosities in butanone and toluene is observed to follow the above equation. A table containing the molecular weight-viscosity relationships for polymers is appended.

Intrinsic viscosity‐molecular weight relationship for polystyrene

The viscoelastic properties of plasticized Vinylite VYNW were studied over a wide range of time scale by means of the tensile creep test. A number of different plasticizers were compared as to their plasticizing effectiveness. It was found that different plasticizers imparted distinctly different shapes to the creep curve of the plasticized ferent plasticized resin. The flat creep curve, characteristic of trioctyl phosphate, is considered to be superior to the steep creep curve of tricresyl phosphate. Mixtures of plasticizers were also studied. A number of conjectures are advanced concerning the molecular mechanism of plasticizer action. One important characteristic of a plasticized formulation of the polyvinyl chloride types of resin is the existence of a three-dimensional gel structure of great permanence which prevents the occurrence of irrecoverable viscous flow.

Creep behavior of plasticized vinylite VYNW

As an extension of our original program, one more polystyrene fraction was investigated in numerous laboratories by means of viscosimetry, osmometry, light scattering, and ultracentrifuge. The various results are compared and critically discussed. Possible explanations and suggestions for improvement are offered in those cases in which considerable discrepancies occur. The viscosity results show satisfactory agreement. The discrepancies among osmotic results are believed to be due largely to unsatisfactory performance of the so-called semipermeable membranes. Discrepancies among light-scattering results can mostly be traced back to the unsatisfactory state of the various calibration techniques. The results obtained with the ultracentrifuge agree quite satisfactorily.

Report on molecular-weight measurements of standard polystyrene samples. II. International union of pure and applied chemistry

Solubility of polyethylene in xylene

Diethyl silicon dichloride was prepared by a Grignard synthesis and purified highly. The material in various stages of purification was hydrolyzed and then polymerized. The properties of the hydrolyzate and of the final polymer depended markedly upon the degree of purification of the dichloride. The reaction of diethylsilicanediol with phosphorous pentoxide was also studied; the predominating reaction appears to involve entrance of the pentoxide into the polymeric structure, rather than a simple acceleration of the polycondensation reaction by the removal of water.

Preparation, purification, and polymerization of diethyl silicon dichloride

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