Estimation of unperturbed chain dimensions of macromolecules from intrinsic viscosity data

Abstract

An attempt has been made to examine the applicability of the methods, proposed b! KAMIDE et al. and STOCKMAYER and FIXMAN, for evaluating the unperturbed chain dimensions of macromolecules from intrinsic viscosity data. In the method of KAMIDE et al., the FLORY'S K value is evaluated from the parameters K, and a in the intrinsic viscositymolecular weight relation (the KUHN-MARK-HOUWINK-SAKURADA equation) expressed by[q] = Km.Ma, which should be established in two or more solvents for a given series of fractions of a flexible polymer. Namely, the K value can be obtained from an intercept at a = 0.5 of the plots of -log K, + log [l + 2{(u -0.5)-l -2}-'] against (a -0.5). STOCK-MAYER and FIXMAN proposed a method for evaluating the K value as an intercept a t M1/2 = 0 of the [q]/M1/2 us. Mli2 plots. The K values were calculated by using the two methods for isotactic poly(butene-1), poly(m-methyl styrene), poly(p-methyl styrene), poly(p-chloro styrene), poly(viny1 acetate), poly(2-vinyl pyridine), poly(ethy1 methacrylate), poly(tetrahydrofuran), poly(acenaphthylene), poly(hexene-1 sulphone), polyether from bisphenol A and 4.$'-dichlorodiphenyl sulphone, poly(propy1ene glycol), nylon 66, poly(ethy1ene terephthalate), chlorinated rubber, p-chloro styrene/methyl methacrylate copolymer, and amylose acetate. The results of analysis on the intrinsic viscosity data showed that in poor solvents the method of KAMIDE et 01. gives similar K values to those obtained by the method of STOCKMAYER and FIXMAN, but in good solvents the former method gives accurate unperturbed dimensions, rather than the latter. ZUSAMMENFASSUNG:Es wurde ein Versuch zur Priifung der Anwendbarkeit der von KAMIDE u. a. sowie von STOCKMAYER und FIXMAN vorgeschlagenen Methoden zur Berechnung der ungestorten Dimensionen von Makromolekiilen aus den Grenzviskositaten unternommen. Bei der Methode von KAMIDE ti. a. wird der K-Wert von FLORY aus den Parametern K, und a berechnet, die durch die Viskositats-Molekulargewichts-Bezeichnung (KUHN-MARK-HOU-WINK-SAKURADA-Gleichung) [q] = K,.Ma verkniipft sind. Diese Werte sollen fur eine gegebene Serie von Fraktionen eines Polymeren mit flexibler Kette in zwei oder mehr Losungsmitteln bekannt sein. Der K-Wert kann dann aus dem Ordinatenabschnitt (a = 0,5) der Auftragung von -log K, + log [l + 2{(a -0,5)-' -2}-1] gegen (a -0,5) er-

Unperturbed Chain Dimensions of Polyethyleneterephthalate and Polyethylene 1,2-Diphenoxyethane p, p′-Carboxylate

“…This expectation was experimentally in part confirmed by measurements of Mw (by the light scattering in trifluoroacetic acid at 30°C) and of Mn (by the membrane osmometry in o-chlorophenol at 45°C) on several fractions. In this case, an increase in Mw/ Mn by combination of the polymer fractions of similar [11] Mn was determined from limc-o rr/C (C, concentration) by extrapolating the plot of rr/C vs. C. Meyerhoff and Shimotsuma3 concluded that Mn, determined by membrane osmometry in o-chlorophenol and m-cresol, is less reliable because of permeation of low molecular weight components through membrane (Sartorius ultracellafilter allerfeinst grade), which was indirectly deduced from the experimental fact that Mn by membrane osmometry is larger than Mn by end group analysis. In this study, for both PET and PEPC solutions, rr value was maintained constant at least several hours and the height of the solvent cup for solvent/solvent combination was not significantly variated.…”

“…Figure 3a and b show the double logarithmic plot of [11] and Mn of PET and PEPC in ochlorophenol and a mixture of P/T (1/2, w/w). The following MHS equations were obtained from viscosity data in Figure 3 by the least square method, where [11] is expressed in ml/g. .,.…”

“…Among them, five groups were prepared by combining similar fractions whose [11] coincide within a range of 20. Each mixture was refractionated separately by dissolution of P/T mixture and subsequent precipitation into 4-5 fractions by SPF in the manner similar to that described above.…”

“…The correction of shear rate dependence of viscosity was not applied. [11] was obtained by extrapolation of linear plot of 11sp/C against C (Huggins plot, 11sp is specific viscosity) to infinite dilution. Figure 3a and b show the double logarithmic plot of [11] and Mn of PET and PEPC in ochlorophenol and a mixture of P/T (1/2, w/w).…”

“…[11] was obtained by extrapolation of linear plot of 11sp/C against C (Huggins plot, 11sp is specific viscosity) to infinite dilution. Figure 3a and b show the double logarithmic plot of [11] and Mn of PET and PEPC in ochlorophenol and a mixture of P/T (1/2, w/w). The following MHS equations were obtained from viscosity data in Figure 3 by the least square method, where [11] is expressed in ml/g.…”