SAFIRE Project Description
May 15th, 1987
Proposal made to Ametex AG
S F Bush
Summary
The project is split into three programmes, A, B, C. Programmes A and B are designed to carry the present technology to the point of commercial production using bought-in fibre granules. Programme C is designed to provide the technology for in-house fibre granule production.
Reinforcement of polymers: the general position
It has long been appreciated that the addition of glass or other stiff fibres to a thermoplastic or thermoset in a suitable fashion usually brings increased strength and stiffness to the processed materials. Fibre reinforcement is readily incorporated in both thermosetting and thermoplastic materials. However, in the case of thermoplastics the glass fibres have until recently been comparatively short – in the range 0.3 to 1.00 mm, while in the case of thermosets, the fibres have usually either been long discrete fibres woven into a loose mat (e.g. chopped strand mat) or actually continuous through a considerable portion of the structure.
If, for thermoset materials, long discrete fibres are used, they are either constructed into a loose woven mat and then impregnated with resin (as in conventional polyester GRP) or scattered in a random overlapping fashion on to a layer of resin with further resin poured on top as in Sheet Moulding Compounds. In either case a form of semi-coherent structure is obtained within the polymer liquid, this structure being maintained after the composite sets solid. This coherent structure is one of the two main reasons (the other being the cross-linked nature of a thermoset polymer) why fibre reinforced thermoset composites show much greater strength and stiffness than do the thermoplastic varieties based on short fibres which do not usually form such structures.
All three programmes were carried out at the Polymer Engineering labs at UMIST from 1987 to 1990, when the project moved to South Africa.