What is polycarbonate - types and specifications
For a long time, silicate glass was a traditional material for creating translucent structures (windows, greenhouses, greenhouses, decorative elements). It has a high degree of translucency, however, the fragility and technical characteristics of glass severely limited the possibilities of application. The opposite of this expensive but unreliable material is polycarbonate. This term unites a whole group of transparent synthetic thermoplastics, which have high strength, high bearing capacity, and plasticity. This article will talk about what polycarbonate is and how it is used for construction.
Composition and production process
All types of polycarbonate belong to the group of thermoplastic synthetic polymers. This material was not specifically developed by scientists, it was discovered during the study of pain-relieving drugs, when chemists turned their attention to a durable, transparent by-product of the reaction. The secret of the strength of this compound lies in the special structure of the molecule, which is obtained in the following ways:
- The method of transesterification of diphenyl carbonate under vacuum conditions with the introduction into the composition of a substance of complex bases under the influence of a stepped temperature. This method is good because no solvent is used in production, however, to obtain a good quality material in this way will not work, since a small amount of catalyst remains in the composition in any case.
- By the method of phosgenating A-bisphenol in a solution with the presence of pyridine not more than a temperature of exactly 25 degrees. The positive side of this method is that production takes place at a low temperature in the liquid phase. However, the high cost of pyridine makes this method uneconomical for the manufacturer.
- The method of interfacial polycondensation of A-bisphenol with phosgene in organic and alkaline solvents. The reaction described is low temperature, which is good for production. However, for flushing the polymer, a lot of water is spent, which is discharged into the reservoirs, polluting the environment.
Interesting! Having excellent technical characteristics, low cost, high load bearing capacity and translucency, not inferior to silicate glass, some types of polycarbonate have been reluctantly used for a long time. Since exposure to ultraviolet radiation has led to the clouding of the material. The introduction of ultraviolet absorber into the composition of the substance has brought polycarbonate to a new level, making it the most rational solution for creating translucent structures and anti-vandal glazing.
Kinds
The term “polycarbonate” unites a large group of synthetic linear polymers that are derived from phenol and carbonic acid. The molecular structure of the granules of this material is an inert, translucent, stable granule. Different production conditions (high pressure, temperature, medium) give the substance different technical characteristics, allowing you to create polycarbonate with different properties. Currently, there are 2 main types of this building material:
- Monolithic. This material resembles silicate glass in appearance; it is transparent and has a smooth, smooth surface. Sometimes monolithic polycarbonate is called “shockproof glass”, as it has high mechanical strength, impact resistance, flexibility and at the same time lightness. The performance characteristics and various thicknesses of monolithic polycarbonate allow the use of this unique material for decorative glazing, curved decorative elements, and anti-vandal structures of the urban environment (stops, signs, road signs, billboards). However, it costs several times more expensive than its cellular counterpart.
- Cellular. Cellular polycarbonate in the production process is profiled in hollow plates with a cellular structure that are filled with air. Cells of this material, formed by 1-5 layers of plastic, can be triangular or rectangular in shape. Cellular polycarbonate is produced by extrusion, when the polycarbonate granules first melt and then are squeezed under the influence of high pressure into the device, which gives the plates a shape. Translucency and high thermal insulation characteristics of the material, which arise due to the cell filled with air, make cellular polycarbonate plastic the best material for creating greenhouses and greenhouses. The thickness of the polycarbonate of this type is larger than that of the monolithic, it has a high impact resistance and noise-suppressing ability, due to which it is used for the construction of noise screens along the tracks.
Important! Manufacturers produce transparent, translucent and matte polycarbonate, which can be colorless or colored. Colorless transparent material with a light transmittance of 84-92% is used for the construction of greenhouses and greenhouses. A translucent and matte color are suitable for decorative glazing of commercial and administrative buildings.
Sizes and properties
Different types of polycarbonate plastic have different operational and technical characteristics, including impact resistance, carrying capacity, insulating qualities and translucency. Material properties also depend on the structure and thickness of the sheet. Choosing polycarbonate it is worth considering the following parameters:
- The width of the polycarbonate plastic plastic is 210 cm, and the monolithic - 2.05 m.
- Manufacturers produce cellular polycarbonate plastic in the form of sheets up to 12 m long, which is convenient for the installation of greenhouses and greenhouses. Monolithic polycarbonate is produced with a length of up to 6 m.
- Cellular polycarbonate is produced with a sheet thickness of 4 mm, 6 mm, 8 mm, 10 mm, 16 mm, 20 mm, 25 mm, it depends on the shape of the cells and the number of layers in the material. The thickness of the polycarbonate monolithic type is 6 mm, 8 mm, 10 mm or 16 mm.
- Monolithic polycarbonate weighs more than the cellular analog, 1 square meter of such a coating is 4.8 kg, however, it is still 2 times less than the weight of glass of the same area. Cellular polycarbonate weighs 0.8 kg / m2.
- The heat resistance of both types of material is 145 degrees, despite this it belongs to the class of self-extinguishing.
- The impact resistance of monolithic polycarbonate is more than 400 J, which is ten times more impact resistant glass. Polycarbonate sheet has a shock resistance of over 27 joules.
Note! Cellular and monolithic polycarbonate have different coefficients of light transmission. The coefficient of light transmission monolithic polycarbonate plastic is 91%, for comparison, the figure for glass is 87-89%. Cellular polycarbonate has a translucency of 80-88%.
Benefits
The performance and technical characteristics of polycarbonate plastic allow this material to be used in many areas of construction. Light weight, impact resistance and transparency of polycarbonate and low production cost gave it the opportunity to compete with silicate glass. Indisputable advantages of this material consider:
- A light weight. Monolithic plastic is 2 times lighter than glass, and honeycomb at 6, which allows you to create lightweight structures that are not weighted by unnecessary supporting elements.
- Strength. The high load bearing capacity gives polycarbonate resistance to intense snow, wind or weight loads.
- Transparency. The monolithic view of the material transmits even more light than silicate glass, and cellular polycarbonate plastic transmits up to 88% of the visible spectrum.
- Insulation quality. Polycarbonate, especially cellular, is an excellent material for sound and noise insulation.
- Security. When breaking the polycarbonate is not formed sharp fragments that cause injury.
Please note! All types of this material do not require serious care, they are washed with water with the addition of soap or dishwashing detergent. In no case should ammonia be used for cleaning, which destroys its structure.
