Thermoset resins Composites

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. 

Many matrix choices are available, and each type has an impact on the processing techniques, physical and mechanical properties, and enviromnental resistance of the finished part. Thermoplastic and thermoset materials can be resin matrices. Thermoplastic matrices have been developed to increase hot/wet use temperature and the fracture toughness of composites. Thermosetting resins, however, are more common. The common thermoset matrices for composites include polyester and vinyl esters, epoxy, bismaleimide, polyimide, and cyanate ester and phenolic triazine resins. 

Most processors of fiber-reinforced composites choose a phenol formaldehyde (phenoHc) resin because these resins are inherently fire retardant, are highly heat resistant, and are very low in cost. When exposed to flames they give off very Htde smoke and that smoke is of low immediate toxicity. PhenoHc resins (qv) are often not chosen, however, because the resole types have limited shelf stabiHty, both resole and novolac types release volatiles during their condensation cure, formaldehyde [50-00-0] emissions are possible during both handling and cure, and the polymers formed are brittle compared with other thermosetting resins. 

Currendy, epoxy resins (qv) constitute over 90% of the matrix resin material used in advanced composites. The total usage of advanced composites is expected to grow to around 45,500 t by the year 2000, with the total resin usage around 18,000 t in 2000. Epoxy resins are expected to stiH constitute about 80% of the total matrix-resin-systems market in 2000. The largest share of the remaining market will be divided between bismaleimides and polyimide systems (12 to 15%) and what are classified as other polymers, including thermoplastics and thermoset resins other than epoxies, bismaleimides, cyanate esters, and polyimide systems (see Composites,polymer-matrix-thermoplastics). 

The polyimide shown is a tme thermosetting resin, but the general reaction procedure, coupling the dianhydride with the diamine, is extremely important throughout polyimide chemistry. The intermediate polyamic acid polymers form the basis for many of the polyimide resins used in advanced composites. 

Cold solder is metal powder suspended in a thermosetting resin. The composite material is strong and hard and conducts heat and elec-... 

Because most thermoset composites cure by a thermally activated reaction, a complicated heat transfer process occurs during solidification, the result of an exothermic cross linking reaction in the resin. The complications of thermoset resin curing are compounded by the competing mechanisms of... 

Thermosetting resins are combined with fibers and other fillers to form composites.19 Thermosetting resins with low viscosities are necessary to wet fibers or... 

This book covers what are broadly called plastics materials. Composites based on long fibres and thermosetting resins are mentioned but not studied specifically. Elastomers, coatings, textiles and adhesives are generally excluded but attention is drawn to a companion volume on the life prediction of rubbers [1]. 

Thermosetting resins have been used extensively in industry for applications such as structural adhesives, composites, RIM, coatings and sealants which need to resist severe service conditions. Thermosetting resins are generally composed of low molecular weight oligomers which allow fabrication convenience. 

StructurPly I and II by Multi-Axial are thermoplastic matrix resin prepregs used in the construction of primary-load-carrying composite structures. Unlike the few hours typically required by the thermoset resin materials to cure, StructurPly needs a few minutes at 196°C. 

Favre, J.P. and Jacques, D. (1990). Stress transfer by shear in carbon fiber model composites Part I Results of single fiber fragmentation tests with thermosetting resins. J. Mater. Sci. 25, 1373-1380. 

Favre, J.P. and Jacques, D. (1990). Stress transfer by shear in carbon fiber model composites Part I Results of single fiber fragmentation tests with thermosetting resins. J. Mater. Sci. 25, 1373-1380. Favre. J.P., Sigety, P. and Jacques, D. (1991). Stress transfer by shear in carbon fiber model composites. Part 2. Computer simulation of the fragmentation test. J. Mater. Sci. 26, 189-195. 

Both thermoset and thermoplastic resin systems are employed in the construction of composites (Table 8.3). The most common thermoset resins are polyimides, unsaturated polyesters, epoxys, PFs, and amino-formaldehydes. A wide variety of thermoplastic resins have been developed. 

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