Chemistry Reference
In-Depth Information
tons of wood while the economy of labor expenses reaches 800 man-hours
per 1 ton of polymers. About 50% of all polymers used in engineering
industry are consumed in electrotechnique and electronics. The 80% of all
the production of electrotechnique and up to 95% of that of engineering
industry has been produced with help of polymers.
The use of construction plastics allows one to create principally new
technology of creation the details, machine knots and devices what pro-
vides for the high economical efficiency. The construction polymers are
well used by means of modern methods: casting and extrusion to the ar-
ticles operating in conditions of sign-altering loads at temperatures 100-
200 °C.
The modern chemical industry gave constructional thermoplastic ma-
terials with lowered consumption of material and weight of the machines,
devices, mechanisms, reduced power capacities and labor-intensity when
manufacturing and exploiting, increased stint.
Nowadays, the radioelectronics, electrotechnical, avia, shipbuilding
and fields of industry can not develop successively without using the mod-
ern progressive polymers such as polyarylates, polysulfones, polyesterke-
tones and others, which are perspective construction materials. Only Rus-
sian industry involves 50 types of plastics including more than 850 labels
and various modifications [14]. As a result, the specific weight of products
of engineering areas and several other branches of industry produced with
help of plastics grew from 32-35% in 1960 till 85-90% in 1990.
The specific weight of construction plastics among the total world pro-
duction of plastics reached only 5% in 1975 [15]. But plastics of construc-
tional use prevailed in world production of plastics in 1981-1985 [16].
The introduction of polymers has not only positive effect on the state
of already existing traditional areas of industry but also determined the
technical progress in rocket and atomic industries, aircraft industry, tele-
vision, restorative surgery and medicine as a whole et cetera. The world
production of construction polymers today is more than 10 million tons.
The thermal and heat-resistant constructional plastics take special
place among the polymers. The need for such ones arises from fact that
the use of traditional polymeric materials of technological assignment is
limited by insufficient working thermal resistance, which is usually less
than 103-150 °C.
Two classes of polymers have been used for producing high-tonnage
thermally resistant plastics: aromatic polyarylates and polyamides [17].
