Dispersion of particulate additives in rubber using the batch

280 Pages·2016·7.38 MB·English

Loughborough University
Institutional Repository
Dispersion of particulate
additives in rubber using the
batch operated internal
mixer : a study of flow
behaviour and properties of
rubber mixes
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by the/an author.
Additional Information:
• A Doctoral Thesis. Submitted in partial fulfilment of the requirements
for the award of Doctor of Philosophy of Loughborough University.
Metadata Record: https://dspace.lboro.ac.uk/2134/10466
Publisher: (cid:13)c Wan Idris Wan Yaacob
Please cite the published version.
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LOUGHBOROUGH
UNIVERSITY OF TECHNOLOGY
LIBRARY
AUTHOR/FILING TITLE
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VOL. NO. CLASS MARK
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26 JUN 1998
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25 JUN 1999
24 NOV 1993
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30 JUN 199
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DISPERSION OF PARTICUlJl.1E JlDDITIVES IN PJJBBER
USING THE BATGI (ffM1ED IN1ERNAL MIXER -
AS TIIDY OF FLOW BEHAVIaJR .£IM) P~PERTIES OF PJJBBER MIXES
by
WJlN IDRIS \'iJ.IN YM COB
Chem. Ing., M.Sc.
A Doctoral Thesis
..
,
Submitted in partial fulfilment of the requirements for
',./ ' the award of Doctor of Philosophy of the
Loughborough University of Technology.
Loughborough, September 1978
Director: Professor A. W. Birley
Supervisor: Mr. P. K. Freakley
. Institute of Polymer Technology
(§}
by WAN IDRIS WAN YAACOB (197~)
Loughborough Unl.erslty
of Technolo;;~f Library
O.t.]"
Date
Class "
Acc. I S2.0~~ I~l,
No,
/
To my wife, JamaUah, and my daughters, AUza and
Azlin, for'their support and patience while I was
preparing this thesis.
.
" ~
,
ACKNOAl.E)GEl"8IT
I would like to express ll\Ygt:atitude to Mr. P; K. Freakley for the
supervision, guidance and encouragement throughout Il\Y work.
My thanks are also'due to Professor A. W. Birley, director of the
Institute ,of Polymer Technology, and all the members' of academic and
technical staff for their general advice and co-operation.
Notleast I would like to mention the help given to me' by external
organisations; in particular staff of the Special Projects Group of
the Avon Rubber Company and the staff of M.R.P.R.A.
Lastly, Il\Y thanks to Miss Linda Malins for typing this thesis.
ABSTRACT
As an aid to understanding the mechanics of mixing 1n an internal
mixer laboratory scale trials have been carried out using a mixer having
a transparent plastics chamber. The use of a transparent rubber and
coloured 'markers' then permitted direct viewing of the characteristic
flow patterns deriving from the use of three fill factors.
These mixing trials. have indicated the rheological properties
which must be measured in order to predict the mixing behaviour of a
rubber. Also considerable information is contained in the visualisations
which will aid further work into control and instrumentation strategies
and into fundamental design/mathematical modelling studies.
A Banbury mixer and Brabender Plastograph are used to
labor~tory
prepare the rubber compounds which are then characterised for the
dispersion ofoompounding ingredients. For carbon black dispersion
studies several techniques are employed. Capillary rheometry is used
to·study their stress-strain rate relationships and to obtain die swell,
. shear and tensile properties. Creep and elongational tests are also
carried out on uncured mixes. In addition measurements on Mooney
viscometer, Mons ant 0 rheometer and analysis of bound rubber are made.
These tests for filler dispersion are supported by microscopic exam-
ination of microtomed sections. Work is also geared to examine properties
that are not only sensitive to changes in levels. of carbon black
dispersion but also that which are readily measured and can be used in
industry • Measur~ments of mechanical phase angle and electrical
resistivity are considered. Dispersion of non-black compounding ingred
ients is studied by X-ray microradiographic technique and the analysis
of vulcanisate properties.
To relate the performance of the Plastograph and Banbury mix the
concept of mixing energy per unit volume of material is used •
•
CNIDITS
Page No.
1:
~. CHAPTER INTRODUCTION 1
"
'" ,
1.1 RUBBER PROCESSING 1
1.1.1 MIXING SYSTEMS 2
1.1.2 MIXING MACHINERY 5
1.1.2.1 MILLS 5
1.1.2.2 INTERNAL MIXERS 6
..
1.1.2.3 CONTINUOUS MIXERS 8
1.2' PROBLEMS ASSOCIATED WITH THE MIXING PROCESS AND
APPROACHES TO THEIR SOLUTION 11
1. 3 AIM OF WORK 16
REFERENCES 17
CHAPTER 2:" DISPERSION OF PARTICULATE ADDITIVES IN 'THE
INTERNAL MIXER •• 20
2.1 SIMPLE AND DISPERSIVE MIXING 20
2.2 DEFINITION OF 'DISPERSION' AND 'MIXEDNESS' 23
2.3 REVIEW OF SOME HYDRODYNAMIC ANALYSIS 25
2.3.1 MIXER GEOMETRY - ROTOR DESIGN 25/
2.3.2 HYDRODYNAMIC ANALYSIS 28
2.4 FACTORS AFFECTING DISPERSION OF PARTICULATE ADDITIVES
..
IN THE INTERNAL MIXER 36
2.4.1 SHEAR STRESS 37
2.4.2 SHEAR STRA'IN RATE 39
2.4.3. SHEAR STRAIN 39
2.4.4 RAM PRESSURE 40
..
2.l.f.5 ROTOR SPEED 41
2.4.6 COOLING EFFICIENCY 42
..
2.5 MIXING TECHNIQUE •. 44
2.5.1 CONVENTIONAL AND UPSIDE-DOWN MIXING TECHNIQUE 44
•