posted on 2018-01-12, 11:25authored byKristof Debrabandere
Traditionally, dough moulding compounds (DMCs) have been based on
unsaturated polyester resins (UPR), fillers and glass fibre reinforcements. Such
systems however are inflammable and will emit dense, toxic smoke on
combustion.
Phenolic resins, on the other hand, have excellent flame retardant properties,
but slightly inferior mechanical properties. Phenolic DMCs are based on
mineral fillers and glass fibre reinforcements, compounded into a phenolic resol
(heat cure) resin. Compounding these systems using a co-rotating twin screw
extruder, instead of the traditional method using a Z-blade mixer, results in long
fibre DMCs which have better mechanical properties than short fibre DMCs.
In this study, a wide range of inorganic materials, their pH being one of the
selection factors, have been investigated as potential phenolic DMC fillers.
Viscosity measurements were carried out on resin/filler mixtures, while on the
cured samples flexural and impact properties were investigated. Producing
DMCs using a twin screw compounder, the effects of filler loading, types of
glass fibre, glass fibre loading and machine output on flexural and impact
properties were investigated.
Phenolic dough moulding compounds containing 20 wt % high integrity glass
fibres and small amounts of aminosilane treated china clays (40 phr filler) had
superior mechanical properties. These systems have a flexural strength of more
than 120 MPa, which would allow them to compete with traditional UPR-based
DMCs.
History
School
Aeronautical, Automotive, Chemical and Materials Engineering
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Publication date
1994
Notes
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy at Loughborough University.