ISSN:
1435-1528
Keywords:
Thermotropic liquid crystal
;
cellulose derivative
;
shear viscosity
;
principal normal stress difference
;
dynamic viscosity
;
storage modulus
;
extrudate swell
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Abstract Samples of cellulose acetate butyrate (CAB) hydroxypropyl cellulose (HPC) and ethyl cellulose (EC) are contrasted with commercial (atactic) polystyrene (PS) and isotactic polypropylene (PP) in studies of (i) differential scanning calorimetry, (ii) quiescent polarized light microscopy (iii) optical retardation variation following an imposed stress field. It is concluced that HPC and EC are thermotropic liquid crystals, while CAB behaves in a manner similar to a vitrifying isotropic melt such as PS. Studies of the shear viscosity and dynamic viscosity indicate HPC and EC exhibit yield values while CAB shows a zero shear viscosity and Vinogradov-Malkin reduced viscosity curve identical to PS. The normal stress and extrudate swell behavior of CAB are also similar to PS. The HPC and EC exhibit substantially reduced extrudate swell. Measurement of the principal normal stress difference behavior of the HPC melt is troubled by the existence of yield values.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01520706
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