Über hochpolymere Verbindungen, 111. Mitteil.: Viscositäts‐Messungen an Paraffinen

Staudinger, H.; Staiger, F.

doi:10.1002/cber.19350680430

Cited by 39 publications

(5 citation statements)

References 6 publications

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“…Staudinger and Staiger (17) determined the viscosities of pure paraffin hydrocarbons, C»H2" + 2, in benzene where n ranged from 27 to 35, and from these data the value of Kcm is calculated to be 2.45 to 2.62 X 104, with an average of 2.56 X 104. Since Staudinger's rule states that the viscosities of equimolar solutions of linear polymers are proportional to their chain lengths, it is possible to calculate the Kem value of rubber from that of paraffin by considering the relative lengths of the base molecules of both substances.…”

Section: Solutions Of High Polymersmentioning

confidence: 99%

Viscosity–Molecular Weight of Rubber

Kemp¹,

Peters²

1941

Ind. Eng. Chem.

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Section: Solutions Of High Polymersmentioning

confidence: 99%

Viscosity–Molecular Weight of Rubber

Kemp¹,

Peters²

1941

Ind. Eng. Chem.

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“…The reaction forming the meso-polyester is more rapid, and assuming an average value for Kc,,. (10,11,13) the ~nolecular weight indicates the formation of an w-polyester. During polymerization there is a loss in weight of less than 2%.…”

mentioning

confidence: 99%

Hydrolysis and Polymerization of Cyclic Dimethylethylene Oxalates

Ripley¹,

Watson²

1951

Can. J. Chem.

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Macrocrystalline cyclic osalates (2,3-dimethyl-5-6-p-dioxanediones) were prepared by vacuum distillation of the polymeric mixture formed on heating ethyl oxalate, and I, 2-dimethylethylene glycol with an ester-interchange catalyst.Monomeric dirnethylethylene oxalate polymerizes less readily than propylene oxalate, and only a t an elevated temperature in the presence of a catalyst. Dimethyl substitution therefore confers marlied stability on the six-membered ring. Hydrolysis reaches 50Yo completion almost ir~stantaneously, follo~vecl by a slow first order reaction resulting in complete cleavage of the monobasic acid in about one month a t room temperature. Hydrolysis constants for the l e~o -and meso-oxalates are 0.069 and 0.076 days-' respectively. The crystalline monorners do not possess sharp melting points and represent stereoisorneric mixtures which display optical activity in solution.Reversible polymerization is a well known characteristic of six-membered cyclic esters (I). The unsubstituted esters, e.g. 6-valerolactone (6), the lactone of hydroxyetl~ylglycolic acid (7), and ethylene oxalate (I) polymerize spontaneously a t room temperature. As a general rule the presence of substituent groups markedly affects ring stability. The substituted six-membered esters, e.g. the lactone of 2,3,4-tl-in1ethyl-l-arabonic acid (5), propylene oxalate (I), and a-n-propyl-6-valerolactone (2) require either heat or catalysts or both to effect polymerization. Carothers et al. (2) have noted that ease of polymerization is related to susceptibility to hydrolysis. Tlle present investigation explores the relation between hydrolysis and polyn~erization in the previously uninvestigated dimethylethylene oxalates.Immediate titration with 0.01 N sodium llydroxide of aliquots of freshly prepared aqueous solutions of the levo-and meso-oxalates showed 50-52% of the calculated total acidity. I t appears therefore that 50y0 of the linkages in the dimethyl-substituted monomers are readily hydrolyzed. This anomaly may be explained by assuming rapid ring opening, followed by slow hydrolysis of the hydroxy acid. As shown in Fig. 1 hydrolytic cleavage of the monobasic acid is complete in about one month a t roo111 temperature. Hydrolysis constants of the levo-and nzeso-oxalates in this slow latter phase, determined from aliquots of aqueous solutions (see experimental section), were 0.069 and 0.076 days-' respectively.Both dimethylethylene oxalates polynlerize less rapidly than propylene oxalate (I). Repeated vacuum sublimation of the pure dimethyl monomers at temperatures just below their melting ranges failed to effect any apparent change in properties. Both the levo-and meso-monorners remained unchanged after storage under anhydrous conditions for more than one year. However, when either was heated with a trace of potassiunl carbonate a t llO°C. under deoxygenated nitrogen, amorphous polyesters were formed in about one day. The highest polymer obtained under these conditions from the nzeso-oxalate was a hard resin, while the corres...

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“…Smooth curve is plot of Huggins' theoretical equation for randomly kinked chain. Data were taken from Staudinger and Staiger (79) and from Meyer and van der Wyk (54). (From Huggins (30).)…”

Section: Ax Experimental Examination Of the Hydrodynamic Approachmentioning

confidence: 99%

Experimental Facts Pertaining to the Relationship between Viscosity, Molecular Size, and Molecular Shape.

Lauffer¹

1942

Chem. Rev.

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Über hochpolymere Verbindungen, 111. Mitteil.: Viscositäts‐Messungen an Paraffinen

Cited by 39 publications

References 6 publications

Viscosity–Molecular Weight of Rubber

Viscosity–Molecular Weight of Rubber

Hydrolysis and Polymerization of Cyclic Dimethylethylene Oxalates

Experimental Facts Pertaining to the Relationship between Viscosity, Molecular Size, and Molecular Shape.

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