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Home  >  Journal list  >  Polymer Journal  >  Vol.27  No.6 (1995)  >  pp.631-644

Polymer Journal
<<Previous article Vol.27  No.6 (1995)   pp.631 - 644 Next article>>

Molecular Characterization of Nylon 6,6 and Its Dissolved State in Mixture of Calcium Chloride and Methanol

Makiko Hattori1), Masatoshi Saito1), Kunihiko Okajima1) and Kenji Kamide2)
1) Fundamental Research Laboratory of Natural & Synthetic Polymers, Asahi Chemical Industry
2) Department of Education, Kumamoto University

ABSTRACT:  An attempt was made to evaluate molecular parameters of poly(hexamethyleneadipamide) (nylon 6,6) in mixture of calcium chloride and methanol with various calcium chloride concentrations (weight fraction Wca against weight of the solvent mixture) using light scattering method. Dissolved state of the polymer was discussed in connection with the chain conformation based on data of viscosity, adiabatic compressibility, infrared (IR) spectra and 1H and 13C NMR spectra. The second virial coefficient A2, obtained by the light scattering method, remarkably decreases with a decrease of Wca below 0.15 and is expected to become zero at Wca of ca. 0.115 (i.e., Flory’s Θ solvent). From values of conformation parameter and characteristic ratio of the polymer, evaluated from radius of gyration at the Θ state, the nylon 6,6 molecule is judged to be very flexible in the unperturbed state. The viscosity of the polymer solution showed specific Wca dependence, around Wca=0.15. The results of the viscosity, adiabatic compressibility, IR and NMR measurements on the solvent mixtures revealed that the above Wca=ca. 0.05, mole ratio of the undissociated CaCl2 monotonically increases with Wca and methanol molecules strongly interact with calcium chloride probably forming organometallic complex. The results of 1H and 13C NMR and IR measurements on the polymer solutions suggested that dissolution of nylon 6,6 in calcium chloride-methanol mixture with Wca≥0.1 is realized at least by interaction of methanol and chlorine parts in the complex with amide carbonyl and amine: In the range of 0.1≤Wca<0.15, selective absorption of weakly bound methanol molecules with the complex to nylon 6,6 plays an important role to determine the very compact chain conformation of the nylon 6,6 chain. Above Wca=0.15 dissolution of nylon 6,6 takes place by direct interaction of the very bulky and metastable associate form of solvent to polymer, which brings about large expansion of the nylon 6,6 chain in the solution.

Nylon 6,6/ Calcium Chloride and Methanol Mixture/ Viscosity/ Light Scattering/ Unperturbed Chain Dimension/ Adiabatic Compressibility/ NMR/ Metallic Halide Complex/ Polymer–Solvent Complex Interaction

Published online: April 02, 2005
© Copyright, 2005 by The Society of Polymer Science, Japan



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