Composite materials are used in many industries today, beginning from production of household items and finishing with construction of spaceships. Their density, durability and some other technical characteristics allow to use them in extreme conditions – so represents composite material?
Composition of composite material
Composite call continuous non-uniform material which has been artificially created from several components with different physical and chemical properties. Mechanical characteristics of composite material are defined by ratio of properties of matrix and the reinforcing elements and also durability of their communication which is provided at right choice of initial components and way of their combination.
The most primitive composite material are bricks from straw and clay which still ancient Egyptians used.
Most often composite call materials on the basis of pitch or polymeric matrixes. For production of composite materials phenolic, epoxy, vinylradio, polyester and polypropylene polymers are used. As the reinforcing substances at production of composites loose substances and fibers act. Durability of material depends on amount of pitch – the its less, the it is stronger. Today for achievement of ideal proportions of all components in composite material the technology of formation is constantly improved.
Methods of formation of composite materials
In the course of formation the matrix of composite material unites with its reinforcing substance therefore it is possible to make any given product. Thermosetting polymeric matrixes in the course of formation pass through chemical reaction of curing. Thermoplastic polymeric matrixes in the course of formation melt and stiffen in the set form. This process usually takes place in conditions of room temperature and normal pressure.
The most widespread composite cement with metal mountings or asphalt concrete is considered today.
Also there is contact (manual) formation which possesses number of serious shortcomings. The product formed by this method contains the increased amount of pitch that does it to more brittle. Besides, at it it is difficult to reach ideal proportions of matrix and the reinforcing substance and also to observe product thickness, having avoided at the same time the internal air courses. Process of vacuum formation assumes use of the open equipment in which the composite components covered by silicone membrane or plastic film are located. Then on the equipment in the conditions of the atmospheric pressure and the increased temperature impose vacuum.