Basic knowledge of PVC
About the PVC
PVC: Polyvinyl Chloride, is an important organic synthetic material. Its products have good physical and chemical properties. Besides, they are widely used in industry, construction, agriculture, daily life, packaging, electricity, public utilities and other fields.
PVC is a kind of thermoplastic. Thermoplastics are easy to mold and have a wide range of applications. The main thermoplastics include: polyethylene (PE), polypropylene (PP), polystyrene (PS), polymethyl methacrylate (PMMA, commonly known as plexiglass), polyvinyl chloride (PVC), nylon (Nylon), polycarbonate (PC), polyurethane (PU), acrylonitrile-butadiene-styrene (ABS), polyamide (PA).
1. The chemical properties of PVC
(1) PVC is a non-toxic, odorless white powder.
(2) High chemical stability and good plasticity. Except for a few organic solvents, it can withstand any concentration of hydrochloric acid, less than 90% of sulfuric acid, 50% to 60% of nitric acid and less than 20% of caustic soda at room temperature. It is also quite stable to salts.
(3) PVC has poor thermal stability and light resistance. It can begin to decompose and release hydrogen chloride (HCl) gas above 140°C, causing PVC to change color. The thermal conductivity of polyvinyl chloride (PVC) is only 1/357 that of steel and 1/1250 that of aluminum.
(4) Excellent electrical insulation, generally will not burn. It can burn and release HCl on the flame, but it will self-extinguish when it leaves the flame. It is a “self-extinguishing” and “flammable” substance.
2.The use of PVC
(1) PVC has a wide range of uses, with good processing performance, low manufacturing cost, corrosion resistance, and good insulation.
(2) The most commonly used processing techniques for PVC products are extrusion and injection molding. With the development of additives used in PVC, the continuous improvement of the performance of PVC additives has gradually expanded the use of PVC.
(3) PVC generally needs to be modified and granulated first. After it is prepared into particles, it will be more fully plasticized and easier to process, especially if the process is injection-molded products. Strictly speaking, PVC products with special requirements and PVC modified formulas are made according to customer requirements.