Composites Contact moulding

Contact moulding is a simple and well known method for fabrication of fibre-reinforced thermoset composites. Thermoset resins which cure at room temperature such as unsaturated polyester, vinyl ester, and epoxy are used to make glass, jute or carbon fibre-reinforced composites using contact moulding. A wide variety of structures can be fabricated using this technique without limitation with respect to the size and complexity of the shape of the structure. However, the process is very labour-intensive and time-consuming, so is used only for a short run or one-off production. 

A easily sanded, porosity-free, high build (2mm mx. wet-on-wet) primer, designed for the repair of osmosis and blister damage on composite surfaces. Excellent adhesion to composites manufactured of vinyl ester, polyester and most epoxies. Suitable for RTM, vacuum forming and contact moulds. 

The hydrophilic/hydrophobic SIN composition of PDMS with poly(HEMA) and poly(AAC) were proposed as a potential apphcation for high-permeability soft contact lenses. Other sUicone-containing IPNs for contact lenses include polymerization of MMA in the presence of polymerized methacryloxypropyl trimethoxysilane, the cross-linking of a polymeric hydrogel of a copolymer of NVP during the final compression or injection-moulding process. 

JMAC antimicrobial masterbatches are described. The products are based on the controlled release of silver ions. A silver chloride/titanium dioxide composite particle releases silver ions on contact with water and then maintains an equilibrium concentration in solution, releasing more ions as required to give effective preservation. Its antibacterial performance in PP mouldings, in thin section PE, itylon, PETP and PP fibres is reported. JMAC masterbatches are available in most polymeric carriers including PE, PP, polystyrene, ABS, PETP and nylon, with typical addition rates of around 1%. 

If the product demands complete protection from metal contact, a polyethylene liner can be used. The liner can be applied in situ by a sintering process or formed as a separate blow-moulded bottle. The resultant container is more accurately described as a composite container rather than a steel drum, as it combines the virtues of plastic and metal in one container. 

A third experiment which shows unequivocally that molecules leap into adhesive contact was performed by Johnson, Kendall and Roberts in 1970. This experiment was similar to Newton s original test on glass telescope lenses (Fig. 3.1) but used rubber surfaces because they adhere much more reliably than glass. Roberts had developed a way of moulding rubber in concave glass lenses to produce remarkably smooth elastomeric spherical surfaces as shown in Fig. 3.12. The rubber composition was mixed and then pressed hot into the glass lens. After... 

The modification of the tow orientation and local variations of fiber volume fraction have a significant impact on the resin impregnation step as the local permeabilities (inplane and transverse) of the reinforcement may be affected [30,31]. In the most severe cases, the ply of fabric can wrinkle or lose contact with the mould, hence severely reducing the quality of the finished product [32]. Another defect called tow buckling has also been reported for flax woven fabrics [33,34]. As the quaHty of the preform is of vital importance for the final properties of the composite parts, it is important when forming of complex shape is considered to prevent the appearance of such defects. 

The first two materials are based on an unspecified epoxy resin, though the resin and size will be compatible. The second two composites are made with Stratyl 108, a polyester resin. The S-2 glass composite is an epoxy prepreg system. Manufacture was achieved by contact or prepreg moulding. 

---