Forming thermoplastic pre-pregs in textile reinforced inorganic phosphate cement composite moulds.

A study has conducted to test the possibility of producing inorganic phosphate cement textile reinforced moulds, in order to form thermoplastic pre-pregs. There is a growing interest in the use of thermoplastic resins. Thermoplastics offer a number of important advantages over thermosets (e.g.: rapid fabrication cycle). However, forming materials that require processing temperatures of 200°C or more in metallic moulds is expensive, while the use of thermoset moulds is becoming impossible. The aim of this work is to propose a new technique using textile reinforced cement (TRC) composites to produce moulds. The TRC used in this study is a combination of inorganic phosphate cement (IPC) with chopped glass fibre textile reinforcement. IPC, which has been developed at the Vrije Universiteit Brussel, shows a neutral pH after hardening. Therefore, unprotected glass fibres are not attacked by the cement matrix. TRC composites with glass fibres as reinforcement exhibit relatively high strength and ductility and thus provide an interesting new material for thin shells. Since another advantage of IPC is its thermal stability, . IPC-TRC composites are interesting materials for moulds to produce thermoplastic composites.
In this study, thin shell type moulds will be produced to assess the possibilities of this new moulding technique. Shrinkage and porosity issues need to be solved. A curing method was developed in order to reduce the shrinkage. The surface was treated with sol gels or heat resistant paint in order to overcome the porosity problem and to improve the surface quality. The results are used in an experimental mould setup in order to determine the possibility of using thermoplastics in a TRC mould.