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Study of pitch colloidal stability using a Photometric Dispersion Analyser


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Lee, R, Stack, KR, Richardson, DE, Lewis, T and Garnier, G 2010 , 'Study of pitch colloidal stability using a Photometric Dispersion Analyser' , Appita Journal, vol. 63, no. 5 , pp. 387-391 .

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This paper describes the use of a photometric
dispersion analyser (PDA) to study
and quantify the effect of wood resin
preparation and salt on the colloidal stability
of wood resin dispersions. The PDA
technique has two major benefits over
other techniques in that it can quantify the
aggregation kinetics under dynamic shear
conditions and at low concentrations of
colloidal material. It is very sensitive to
small changes in the solution and provides
information about the floc structure
and homogeneity.
To ensure reproducible results when
analysing colloidal wood resin dispersions,
conditioning of the tubing and a
constant flow rate and stirring rate were
required. The PDA signal response with
time for the wood resin dispersions shows
three distinct regions: a growth region, a
peak region, and a decay region. The
slope of the initial growth region was used
to measure the kinetics of coagulation and
to determine the stability ratio, W. The critical
coagulation concentration of different
salts was also determined. The timeweighted
variance of the PDA output
showed that potassium salts resulted in
more homogeneous aggregates than
those formed with the addition of magnesium

Item Type: Article
Authors/Creators:Lee, R and Stack, KR and Richardson, DE and Lewis, T and Garnier, G
Keywords: Photometric dispersion analyser, PDA, wood extractives, pitch, salt, kinetics, colloid, aggregation.
Journal or Publication Title: Appita Journal
ISSN: 1038-6807
Additional Information:

Copyright © 2010 Appita

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