Bemerkungen zu der voranstehenden Arbeit von. H. L. Bredée

Schulz, G. V.; Blaschke, F.

doi:10.1002/prac.19411590505

Cited by 3 publications

(2 citation statements)

References 1 publication

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“…He suggested a plot of η sp /c against η sp . This plot, known as the Schulz-Blaschke plot, 33 gave a linearization of the concentration dependence. Figure 9 shows that such a linearization was also obtained with the present celluloses and allowed reliable extrapolation to zero concentration.…”

Section: Resultsmentioning

confidence: 99%

Cellulose Solutions in Water Containing Metal Complexes

Saalwächter¹,

Burchard²,

Klüfers³

et al. 2000

Macromolecules

146

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Aqueous solutions of a number of metal complexes have been found to dissolve cellulose. Recently, a number of new metal complexes have been developed that completely dissolve cellulose by deprotonating and coordinative binding the hydroxyl groups in the C2 and C3 position of the anhydro glucose. A detailed comparative light scattering study is given for cellulose in Schweizer's reagent (cuoxam), Ni-tren, and Cd-tren. Cuoxam is the well-known solution of cupric hydroxide in aqueous ammonia, and the abbreviation tren stands for tris(2-aminoethyl)amine. Cuoxam and Ni-tren are deep blue solvents. The light scattering measurements were carried out with the blue line of an argon ion laser at wavelength λ 0) 457.9 nm, and the data from these solvents required an absorption correction according to the Lambert-Beer law. Cd-tren is almost colorless, and the data could be used without correction. Because of traces of colloid particles, possibly originating from the metal hydroxides, a special treatment for optical clarification became necessary. A large number of samples, cotton linters, various pulp celluloses, and bacterial celluloses, were studied. All three solvents exhibited good solution properties, but only Cd-tren was capable of dissolving also the highest degrees of polymerization of cotton linters and bacterial cellulose (DP w) 9700). The limits for the two other solvents were DPw < 6300 for Ni-tren and DPw < 5300 for cuoxam. A fairly high chain stiffness was found with Kuhn segment lengths of lK) 15.8 (1.4 nm for Cd-tren, lK) 10.2 (0.8 nm for Ni-tren, and lK) 13.1 (1.2 nm for cuoxam, corresponding to characteristic ratios of C∝) 24.6, 15.4, and 19.4, respectively. The problem of preferential adsorption is discussed.

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Section: Resultsmentioning

confidence: 99%

Cellulose Solutions in Water Containing Metal Complexes

Saalwächter¹,

Burchard²,

Klüfers³

et al. 2000

Macromolecules

146

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“…(v) The Trommsdorff effect in styrene. Schulz & Blaschke (1941) observed th in the polymerization of methyl methacrylate, a large increase in the rate of reaction occurs at about 20 % conversion. Trommsdorff (1944) showed th at this is accom panied by a corresponding increase in the degree of polymerization, and pointed out th at the most likely explanation of this is a decrease in the termination coefficient when the medium becomes viscous.…”

Section: Emmentioning

confidence: 90%

Studies in polymerization. I. A method for determining the velocity constants in polymerization reactions and its application to styrene

Bamford

Dewar

1948

Proc. R. Soc. Lond. A

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A general method for determining the velocity constants of initiation, propagation, transfer and termination in polymerization reactions is described. The method depends essentially on the measurement of the rate of increase of viscosity for various rates of chain initiation. In the case of radical polymerizations photochemical initiation is most convenient. Measurement of the photochemical after-effect then gives four independent relations between the four velocity constants. The method has been tested by a detailed study of the thermal and photochemical polymerization of styrene. Velocity constants have been determined at 0 and 25° C, and the activation energies and frequency factors calculated. Results are given in tables 5 and 6. It is shown for the first time that chain transfer is important in the thermal polymerization of pure styrene, occurring 11 times per kinetic chain at 25° C. This result invalidates conclusions which previous workers have reached. Other rather unexpected results are that the initiation reaction has a much higher activation energy than has been generally supposed, and a normal frequency factor, while termination is activated. A detailed kinetic scheme is proposed which removes certain unjustifiable assumptions present in earlier ones. This is shown to be consistent with all the available evidence.

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Über den Anstieg der spezifischen Viscosität makromolekularer Lösungen im Bereich kleiner Konzentrationen

Schulz¹,

Sing²

1943

J. Prakt. Chem.

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Bemerkungen zu der voranstehenden Arbeit von. H. L. Bredée

Cited by 3 publications

References 1 publication

Cellulose Solutions in Water Containing Metal Complexes

Cellulose Solutions in Water Containing Metal Complexes

Studies in polymerization. I. A method for determining the velocity constants in polymerization reactions and its application to styrene

Über den Anstieg der spezifischen Viscosität makromolekularer Lösungen im Bereich kleiner Konzentrationen

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