Fibre-reinforced gels

Table 3.11 Mechanical properties of some fibre-reinforced sol-gel glass-matrix composites73...

V. Gunay, P. F. James, F. R. Jones and J. E. Bailey, Continuous Fibre Reinforced Glass and Glass Ceramic Matrix Composites by Sol-Gel Processing, in Inst. Phys. Conf. Ser. Nr. Ill, lOP Publishing Ltd (1990)... 

D. Qi and C. Pantano, Sol-Gel Processing of Carbon Fibre Reinforced Glass Matrix Composites, hr Ultrastructure Processing of Advanced Ceramics. J. D. Mackenzie and D. R. Ulrich ed., J. Wiley and Sons, New... 

Ph. Colomban and M. Wey, Sol-Gel of Matrix Net-Shape Sintering in 3D Fibre Reinforced Ceramic Matrix Composites,/. Europ. Ceram. Soc. 17, 1475-1483 (1997). 

The critical step for gel coat production is the dispersion of the pigments to the base resin to give the right colour and colour solidity. The latter is important to prevent show through of the fibre reinforcement and to obtain consistency of finish. Bead mills and roller mills are used for the dispersion of pigments and additives. 

Bailey JE, Chen M, James PF, Jones FR, Fibre reinforced alumina ceramic composites by sol-gel processing, ECCM III, 1989. 

Manocha S, Vashistha D, Manocha LM, Sol-gel processing of silicon based matrixes for carbon fibre reinforced ceramic composites, Niihara K, Nakano K, Sekino T, Yasuda E eds.. Ceramic Society of Japan, High Temperature Ceramic Matrix Composites III, Proc, 3rd Int Conf, Osaka, Key Eng Mater, 164-165, 137-140, Sep 6-9 1998. 

Wu J, Chen M, Jones FR, James PF, Characterisation of sol-gel derived alumina-silica matrices for continuous fibre reinforced composites, J Eur Ceram Soc, 16(6), 619-626, 1996. 

Incoming raw materials, specifically the matrix constituents and the fibre rovings and mats, should be inspected. Basic inspection includes checking the delivery notes and the labels of containers when the materials arrive. Visual inspection of raw materials is also recommended resins can be inspected for colour and the presence of contamination and gel particles (Evans, 2000) reinforcements can be checked for the presence of knots in the rovings, while simple mass measurements can be made for mats or fabrics. Some pultrusion companies have quality control and/or research and development laboratories where material characterisation tests can be performed (most often such control is executed by raw material suppliers). Fibre reinforcements can be subjected to tensile tests. The moisture content of the constituents (particularly the reinforcements and the fillers) can also be determined. The quality of incoming resins can be tested by means of thermal analysers (resin reactivity) and viscometers (resin viscosity and thixotropic index) (Owens Coming, 2003). 

Bonds (plus a gap-filler), fibre-reinforced composites, plus wood, steel, aluminium and concrete. Available for use with 3 different hardener systems, 273, 275 and 277 offering different gel and cure time. Dual cartridge system eliminates measuring and mixing. Colour change denotes full cure. 

Other recent applications of ToF-SIMS without XPS include the examination of PS [6, 17-19], polyethylene (PE) [20], carbon fibre reinforced epoxy resins [21], polyalkyl methacrylates [22], alkylketene dimers [23], perfluorinated polymers [24], perflnorinated ethers [25], polyethylene glycol (PEG) oligomers [15, 25-29], rubber [30], ethylene-tetrafluoroethylene copolymer [30], Nylon-6 [31], PC [32,33], PDMS [34], polypyrrole coated PS [35], poly-p-phenylene vinylene [36], butyl rubber [37], poly(4-vinyl phenol)/poly(4-vinyl pyridine blends) [38], polypyrrole-silica gel composites [39], y-glycidoxypropyl trimethoxy silane [40], triblock copolymer poly(ethylene glycol)- 3 poly(phenylene ethylene)- 3 poly(ethylene glycol) [41], ethylene-terephthalate-hydroxybenzoate copolymer [42], PS-polyvinyl methyl ether, polycarbonate - PS blends [43] and PDMS-urethane [44],... 

Hggg for water vapour, free water and adsorbed water in hardened fibre reinforced concrete. When free water is adsorbed on the cement gel, its enthalpy content is reduced physically, this means that the water molecules are transferred to a state with lower potential energy. For the adsorption process considered, AH —5 kJ/mol. This is of the same magnitude as AH for freezing of free water. 

The ribs were manufactured from FRP composites. The laminate used glass fibres in tissue form and rovings as additional reinforcement, embedded in a matrix of unsaturated polyester (PU) resin. A gel coating provides protection. 

Blistering is a phenomenon which can occur in gel coated, polyester, vinylester and epoxy laminates reinforced with glass fibre after lengthy contact with water. Boat hulls and swimming pools are therefore particularly prone to be affected. 

Surface veils are lightweight thin surfacing materials usually constructed from swirl mats either in glass or from a synthetic fibre. Their main use is to act as a decorative surface, shielding from view the texture of the underlying structural reinforcement. But they also may be used in conjunction with gel coats for added support. C-glass surface veils are... 

Resin injection moulding is a cold moulding process applied at medium pressures (approximately 450 kPa), where mould surfaces are enriched with release agents and gel coat before GF reinforcement is placed on the bottom of the mould, allowing the plastic to extend beyond the sides of the mould. Then the upper mould is placed in its place and it is clamped to stop followed hy injection of activated resin under pressure into the mould cavity (Figure 9.11). By using this technique, it is possible to obtain a fibre/matrix ratio of 65 wt%. 

As described earlier, the main prerequisite for the creation of high performance self-reinforced polymer composites is a thermoplastic polymer fibre with the necessary mechanical properties to make the creation of the final composites attractive. Ultrahigh molecular weight polyethylene (UHMWPE) fibres with veiy high mechanical properties, produced by gel spinning, became commercially... 

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