The different types of plastics used in the construction industry are described below.
1. Polyethylene Plastic (PE)
Polyethylene plastic is made from polymerized vinyl monomers.
A monomer is a type of simple compound, which can be polymerized to become a macromolecular compound. Three methods are used to polymerize monomers: high pressure process, medium pressure process and low pressure process.
Different methods create different degrees of crystallinity and density. High pressure polyethylene has low crystallinity and density while low pressure polyethylene has high crystallinity and density. As the crystallinity and density increase, the hardness, softening point, and strength on the one hand increase accordingly; On the other hand, the impact toughness and elongation are reduced.
Polyethylene plastic has better chemical stability and water resistance. Although its strength is not high, but it is quite flexible in low temperatures. A certain amount of carbon black can strengthen the aging resistance of polyethylene.
2. Polyvinyl Chloride Plastic (PVC)
Polyvinyl chloride plastic is a common building plastic made from polymerized vinyl chloride monomers. Polyvinyl chloride plastics have better chemical stability and aging resistance, but poorer heat resistance. It can decompose and metamorphose if the temperature exceeds 100 °C. Typically, it should be used at temperatures below 60-80 °C. Hard and soft polyvinyl chloride plastics can be made by mixing different amounts of plasticizers.
3. Polystyrene Plastic (PS)
polystyrene plastic Is Made from polymerized styrene monomer. It has the properties of good light transmittance, easy pigmentation, better chemical stability, water resistance, light resistance, easy processing and low price.
However, polystyrene plastic has the disadvantages of weak hardness, poor impact toughness, weak heat resistance and easy flammability. These weak points prohibit its use.
4. Polypropylene Plastic (PP)
Polypropylene plastic is made from polymerized acrylic monomer. It has the properties of light weight (density 0.90g/cm.)2), strong heat resistance (100-120 .)0c), Regular flexibility and water resistance. The weak point is that its hardness is poor in low temperature; and poor air resistance. Therefore, polypropylene plastic is suitable for use indoors. Polypropylene has developed rapidly in recent years. Polypropylene, together with polyethylene and polyvinyl chloride, have become the main varieties of manufacturing plastics.
5. Polyrmethyl Methacrylate (PMMA)
Thermoplastic resins, also known as organic glass, can be made from?
Polymerized polymethyl methacrylate. It has the advantages of good light transmittance, high strength at low temperature, low water absorption, better heat resistance, better aging resistance and easier to process. However, it has the disadvantages of poor abrasive resistance and high price.
6. Polyester Resin (PR)
Polyester resin is made by condensing diatomic or polybasic alcohol and diatomic or polybasic acid. Polyester resin has the properties of good bonding ability, elasticity, better coloring ability, ductility, heat resistance and water resistance.
7. Phenolic Resin (PF)
Phenolic resin is made by polymerizing phenol and aldehyde under the influence of an acid catalyst or an alkaline catalyst. Phenolic resin has better cohesion strength, light resistance, water resistance, heat resistance, corrosion resistance and electrical insulation. However, it has poor rigidity. Phenolic resin can be made into phenolic plastics by filling material and curing agent. Phenolic plastics are sleek, strong, durable and inexpensive. It has become a kind of commonly used plastic.
8. Organic Silicon Resin (Si)
Organic silicone resin is made by hydrolyzing one or more types of organic silicon monomers. Organic silicone resin has the properties of heat resistance, cold resistance, water resistance and corrosion resistance. However, it is poor in mechanical performance and cohesive force. These two weak points can be improved by adding synthetic resins (phenolic aldehyde, epoxy and polyester), glass fiber and asbestos etc.