Light-scattering study on cellulose diacetate in 2-butanone
1982; Elsevier BV; Volume: 18; Issue: 9 Linguagem: Inglês
10.1016/0014-3057(82)90154-9
ISSN1873-1945
AutoresH. Suzuki, Y. Muraoka, M. Satio, Kenji Kamide,
Tópico(s)Lignin and Wood Chemistry
ResumoAbstract Light-scattering measurements were carried out on three well-fractionated samples of cellulose diacetate (degree of substitution = 2.46) in acetone at 25°C and in 2-butanone at 30–60°C. For the system cellulose diacetate-2-butanone, the theta temperature, Θ, has been quoted as 37°C from cloud-point measurements; it was intended to examine further 2-butanone as a theta solvent. The value of Θ, defined as the temperature at which the second virial coefficient vanishes, was found to be 50°C. This difference in Θ was attributed to association of the dissolved polymer molecules. On the other hand, the weight-average molecular weights obtained in 2-butanone at 50°C were in accord with those determined in a good solvent, acetone. It was established that 2-butanone was a theta solvent for cellulose diacetate with Θ = 50°C. The molecular dimensions observed in 2-butanone were however unreasonably large. Therefore, determinations of the unperturbed dimensions and other conformational parameters in this solvent are withheld. Solution stability and association were examined by light scattering. It was deduced that the difficulty in dissolving the polymer in 2-butanone arose from the copolymeric nature of cellulose diacetate.
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