Anisotropic-isotropic transition of solutions of cellulose derivatives: a DSC study. [Differential scanning calorimetry]

Conference · Sat Jan 01 00:00:00 EST 1983 · J. Appl. Polym. Sci.: Appl. Polym. Symp.; (United States)

OSTI ID:7138802

Navard, P; Haudin, J M; Dayan, S; Sixou, P

Cellulose acetate (CA)/trifluoroacetic acid (TFA), cellulose triacetate (CTA)/trifluoroacetic acid, and hydroxypropylcellulose (HPC)/water solutions are able to develop liquid crystalline (cholesteric) order above a certain polymer concentration C/sup **/. When the polymer concentration C is smaller than C/sup **/, no peak is recorded on a DSC trace upon heating. When C>C/sup **/, a well-defined peak for CA/TFA appears at a temperature T/sub t/. This peak is attributed to the anisotropic-isotropic phase transition. The origin and nature of this peak are discussed in the light of available theories. A T/sub t/-C phase diagram is plotted. For CTA/TFA solutions, one or two peaks arise, depending onpolymer concentration. The peak at the higher temperature is attributed to the anisotropic-isotropic transition, and the peak at the lower temperature to the destruction of a ''gel-like'' phase. HPC/water solutions have a very different behavior. Upon heating, they are transformed into a turbid phase regardless of the concentration. 22 references, 11 figures, 1 table.

• Research Organization: Ecole Nationale Superieure des Mines de Paris, Centre de Mise en Frome des Materiaux, Valbonne, France
• OSTI ID: 7138802
• Report Number(s): CONF-8205234-Vol.1
• Journal Information: J. Appl. Polym. Sci.: Appl. Polym. Symp.; (United States), Conference: 9. cellulose conference, Syracuse, NY, USA, 24 May 1982
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
09 BIOMASS FUELS
CELLULOSE
PHASE TRANSFORMATIONS
CELLULOSE ESTERS
ANISOTROPY
CALORIMETRY
ENTHALPY
ISOTROPY
KINETICS
LIQUID CRYSTALS
ORGANIC ACIDS
ORGANIC FLUORINE COMPOUNDS
PHASE DIAGRAMS
QUANTITY RATIO
TEMPERATURE DEPENDENCE
CARBOHYDRATES
CRYSTALS
DIAGRAMS
ESTERS
FLUIDS
LIQUIDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
PHYSICAL PROPERTIES
POLYSACCHARIDES
SACCHARIDES
THERMODYNAMIC PROPERTIES
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