+44 (0)1509 263171
Please use this identifier to cite or link to this item:
|Title: ||Relationships between PVC plastisol rheology and partical size distribution for filled and unfilled systems|
|Authors: ||Cook, John A.|
Particle size distribution
Particle size analysis
|Issue Date: ||1986|
|Publisher: ||© John Alan Cook|
|Abstract: ||To control the rheological properties of PVC plastisols commercial
manufacturers take great care to control the particle size (PS) and
particle size distribution (PSD) of a polymer latex, as these exert a
strong influence over the flow characteristics of an uncompounded
plastisol. However, the fundamental mechanisms controlling viscosity
are not clearly understood.
Several techniques have been developed to measure the PSD
(sedimentation analysis and laser diffraction) and viscosity over an
extended shear rate range for plastisols prepared from carefully
selected paste polymers. Care has been taken to establish the
reliability of these techniques, as previous workers have experienced
problems in obtaining reliable correlations from plastisol systems.
Xany have failed to measure the PSD within the plastisols, incorrectly
basing their observations on latex PSD.
By careful selection of emulsion, seeded emulsion and
microsuspension paste polymers the combined effects of polymerisation
technique, emulsifier type, spray drying, milling and paste preparation
on plastisol rheology have been established.
For many applications plastisals contain mineral fillers, which
have a similar PS to the paste polymers. Addition of these materials
can drastically change plastisol rheology. Until now, it has been
assumed that plastisol viscosity rises with filler content and depends
on plasticiser absorbtion characteristics. To elucIdate the actual
mechanism controlling the response of plastisols to fillers, calcium
carbonate (coated and uncoated), titanium dioxide and Spheriglass filled
systems have been studied.
To establish a model which will allow paste polymer systems to be
designed more accurately, the paste polymers used in the initial part of
this study have been spray dried under widely differing conditions.
Careful measurement of the rheology and PSD of filled and unfilled
plastisols prepared from these materials has highlighted the effect of
PS, PSD, paste polymer porosity and filler interaction on plastisol
It has been clearly demonstrated that the plasticiser absorbtion
characteristics of a filler are not the only factors controlling filled
plastisol rheology, as previously thought. I have shown that the
response of a plastisal to filler addition also depends on the
interaction between filler PS and the paste polymer PSD.|
|Description: ||A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.|
|Appears in Collections:||PhD Theses (Materials)|
Files associated with this item:
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.