Die molekularen Konstanten von Polycarbonaten in Lösung

Abstract

ZUSAMMENFASSUNG:An einer Reihe von fraktionierten Polycarbonaten werden in zwei Losungsmitteln die Diffusions-und Sedimentationskonstanten, die Viskositatszahlen, die osmotischen Drucke sowie die Lichtstreuung gemessen. Daraus wird eine Eichkurve zur viskosimetrischen Molekulargewichtsbestimmung abgelcitet und aus einem Vergleich der verschiedenen Mittelwerte des Molekulargewichts die Uneinheitlichkeit der Fraktionen abgeschatzt.Aus den Reibungs-und Lichtstreuungsdaten werden die Knauelabmessungen berechnet und mit Hilfe der gemessenen zweiten Virialkoeffizienten a d das indifferente Losungsmittel reduziert. Die Volumbeanspruchung der Polycarbonatmolekiile in Losung ist grol3er als die vergleichbarer Polyvinylverbindungen und etwas kleiner als bei Cellulosederivaten. Der EinfluuB der Kettengliedlange und der Drehbehinderung auf die Knauelabmessungen wird im Vergleich zum Polymethylmethacrylat diskutiert. SUMMARY:Measurements of sedimentation and diffusion constants, intrinsic viscosity, osmotic pressure and light scattering are performed on fractions of polycarbonates. From this a calibrating curve for viscometric molecular weight determinations is established. The differences between x,, and H, render possible the evaluation of the inhomogenity of the fractions.From friction dates, viscosity and light scattering the end to end distances of the molecular coiles are calculated. They have values between the diameters of cellulose derivatives and substituted paraffin chains. The intluence of the length of the chain elements and the hindrance of rotation is examined by comparing polycarbonates with polymethyl methacrylates.

Influence of the degree of substitution on the solution properties of chloromethylated polysulfone

“…The approximation of Schulz and Horbach25 on the polycarbonates, which considered that the chain consists of three valence angles, denoted θ 1 , θ 2 , and θ 3 , and two bond lengths, denoted l and p , with kindred structures to PSF, assumed l = 5.77 Å (corresponding to the bond through the phenylene moiety); p = 1.43 Å (corresponding to the CO bond); and θ 1 = θ 2 ‐θ 3 = 109.5 Å.…”

Acetone Absorption in Irradiated Polycarbonate

“…33 The plot of molecular weight W versus dose <p for irradiated polycarbonate is shown in Figure 2 where K and a are 0.92 x 10-5 and 0.87, respectively, as obtained from Schulz and Horbach. 34 The plot is over a broad range of doses. The glass transition temperature Tg is shown in Figure 2 as a function of dose 4>.…”

Influence of Structural and Topological Constraints on the Crystallization and Melting Behavior of Polymers: 3. Bisphenol A Polycarbonate

“…This actually made polymer collection easier and did not appear to adversely affect the efficiency of the fractionation procedure. Chemical degradation of polycarbonate during fractionation which was reported with this particular solvent/nonsolvent system , was minimized by using HPLC grade solvents stored under dry nitrogen blankets and by predrying each fraction under vacuum at temperatures below 25 °C.…”