Compositions thermoset

Feldman, D. Composites-thermosetting polymers. In Polymeric Materials Encyclopedia, Salamone, J.C., Ed. CRC Press New York, 1996 2, 1383-1389. 

In addition to the common applications of PVC in flooring and floor tiles, there are also applications of PU (coatings for flooring), polyamide (PA) (woven carpets and rugs), linoleum (manufactured by oxidising linseed oil mixed with pine resin and wood flour in the form of sheets on jute backing), wood/thermoset composites (thermosets like PE, UF, polyisocyanates used as veneers, in plywood, particleboard, fibreboard, laminates), wood fibre/thermoplastic composites (for industrial flooring with PE). 

There are two basic classes of polymeric matrices used in FRP composites thermosetting and thermoplastic resins. Thermosetting resins are polymers which are irreversibly formed from low molecular weight precursors of low viscosity. These polymers have strong bonds both in the molecules and between the molecules. They develop a network structure that sets them in shape. If they are heated after they have been cured, they do not melt and will retain their shape until they begin to thermally decompose at high temperatures. 

Although thermoplastics, thermosets and elastomers can be used as matrix of polymer composites, thermosets are more widely used mainly due to the processing techniques employed in their manufactme, that allow for the easy use of long fibers, mats and fabrics as reinforcement. Thermosets are also generally more thermally stable than thermoplastics, and these two reasons lead to products with significantly higher mechanical properties which are less affected by thermal variations than thermoplastic composites [1,2,12],... 

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. 

Chapter 7 focuses on the thermoplastic filament winding process for continuous fiber reinforced composites. Thermoset filament winding has been around for over four decades and is routinely used to make axisymmetric structures. In the last couple of decades, researchers have tried to translate... 

Flbertec Wollastonites are used as functional fillers and reinforcements in composites (thermosets) and conqpounds (thermoplastics) to increase mechanical properties (tensile, flexural, inqpact), minimize distortion at elevated teaqperatures, improve dimensional stability, and provide low moisture absorption. 

The principles of surface pretreatment are now well understood and methods have been developed for each type of substrate encountered in aerospace construction wood, aluminium alloys, titanium alloys, stainless steel, thermoplastic composites, thermosetting composites and non-metallic honeycombs. 

Wood-plastic composites can be further divided into wood-thermosetting composites and wood-thermoplastic composites. Thermosets or thermoset polymers have the property of becoming pennanentiy hard and rigid once been heated or cured. Such polymers contain phenol resins, epoxy resins, unsaturated polyester resins, and so on. Among them, phenol formaldehyde (PF) and urea formaldehyde (UP) are the most widely used thermosets for wood composites. The birth of wood-thermosetting composites can date back to the early 1900s. In 1907, Dr. Leoh... 

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