Viscosity and osmotic pressure measurements were carried out on dilute benzene solutions of aluminum dicaprylate, dilaurate, dimyristate, dipalmitate, distearate, and monostearate. From the results it is concluded that these soaps are polymers of high molecular weight formed by weak intermolecular links which are assumed to be hydrogen bonds. Lowering of the molecular weight by dissociation of these bonds is responsible for decreases in solution viscosities. Variations of the molecular weights obtained (60,000 to 900,000) are due, in the main, to the effect of concentration and aging on the extent of this dissociation.
Molecular weight distributions determined by gel permeation chromatography demonstrate that α‐methylstyrene copolymerizes with both β‐pinene and styrene, forming both bi‐ and terpolymers. The composition of precipitated polymer versus crude polymer, as determined by nuclear magnetic resonance, suggests that β‐pinene and styrene also copolymerize. Extraction of the latter bipolymer of β‐pinene and styrene with acetone gives only a small amount of insoluble β‐pinene homopolymer, confirming that β‐pinene and styrene copolymerize in m‐xylene. GPC analysis shows that each copolymer contains some homopolymer. A comparison of Mn with molecular weight calculated from NMR analysis, assuming chain transfer to solvent, indicates that chain transfer is the predominant method of forming dead polymer. The carbonium ions of the growing chain tend to transfer to solvent with increasing ease in the order β‐pinene, styrene, and α‐methylstyrene.
SynopsisStyrene was polymerized with P-pinene a t 30°C and -50°C in methylene dichloride and in mxylene solvents. The styrene-to-terpene ratio on pyrolysis suggests that the polymers made a t 30°C are copolymers, whereas most of the polymers made a t -50°C are not copolymers. On the other hand, ethylene, ethane, and propylene analysis suggests that more of the polymers made a t -50°C are copolymers.
SynopsisThe yield, composition, and molecular weight of homopolymers and copolymers of 8-pinene and styrene are described as a function of the feed, temperature, and solvent. Fractionation, gel permeation chromatography, and nuclear magnetic resonance spectroscopy of GPC fractions are used as analytical tools to present evidence for copolymerization in methylene dichloride. Additional support for copolymerization is obtained from the relation of polymer composition to per cent conversion. The reduction of molecular weights of homopolymers by aromatic solvents was investigated.
The activities of water in aqueous solutions of sodium chloride and of sulphuric acid have been compared by the isopiestic method at 25 °C. over a range of molalities extending up to that of the saturated salt solution. The apparatus, which was of the Sinclair type, proved to be as efficient as any yet devised. The results remove the uncertainties that previously existed in regard to the position of the m1/m2 curve and give a qualitative indication of the second dissociation of sulphuric acid. The calculated activities agree with the best available data. The isopiestic standard chosen by Janis and Ferguson has been confirmed over the whole molality range.
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