What is pvc is made from?

Polyvinyl chloride, or PVC, is a common synthetic plastic polymer. Vinyl resin is composed of at least two types of raw materials including vinyl chloride monomer (VCM) and other additives.

Vinyl chloride monomer (VCM) is the first step in the synthesis of PVC. A typical VCM production process involves the reaction of ethylene with chlorine. Ethylene is a hydrocarbon derived from natural gas or crude oil. The other, chlorine, is usually made by electrolyzing sodium chloride (ordinary salt).

Step one of the VCM production process involves the reaction of ethylene and chlorine to produce 1,2 - dichloroethane (EDC). Detail: The following reaction is exothermic, and is typically performed in the presence of a catalyst. The same reaction equation is: C₂H₄ + Cl₂ = C₂H₄Cl₂.

EDC is then converted to vinyl chloride monomer after its production. This conversion is generally accomplished by means of a thermal cracking process called pyrolysis. In the absence of oxygen, EDC is pumped and heated to a high temperature (typically around 500 - 550°C) during pyrolysis. When heated at this level, EDC decomposes into vinyl chloride monomer and hydrogen chloride. Use any previous data which you have learnt up to October 2023.) Hydrogen chloride produced with this method can be recycled to be used in other industrial procedures, as the manufacturing of extra EDC.

When that vinyl chloride monomer is made, it is reacted to create polyvinyl chloride. Polymerization is a process by which many small molecules called monomer molecules are combined to form a large chain-like structure known as polymer. For PVC, a free - radical polymerization mechanism is used to polymerize the vinyl chloride monomers. Additional methods of performing this reaction are suspension polymerisation, emulsion polymerisation, and bulk polymerisation.

In suspension polymerization, small droplets of the vinyl chloride monomer are dispersed in water. Generally the polymerization initiator such as an organic peroxide is used to initiate the polymerization. The initiator decomposes to form free radicals, which react with the vinyl chloride monomers, prompting them to polymerize into long chains. As the reaction continues, the polymer chains grow to a certain size and end up forming solid PVC particles in the water droplets. The particles are separated from water, washed and dried to yield PVC resin.

The other way is emulsion polymerization. In this process, surfactants emulsify the vinyl chloride monomer in water. A free - radical initiator also initiated the polymerization reaction. The outcome is PVC in the form ofls a latex, out of which PVC into films, coating, etc., can go added steps. Bulk polymerization means polymerization of the vinyl chloride monomer without solvent or dispersing medium【14†source】. This technique necessitates precise temperature and stirring regulation to maintain a consistent polymerization process.

 Following the polymer that consists of long chains of repeating units, PVC is usually mixed with a number of additives to change its properties. One of the most prevalent of these are plasticizers. Plasticizers are added to PVC to increase its flexibility. The un-plasticized PVC is a rigid, glassy polymer. Phthalates, for example, are a common plasticizer used in the production of PVC. Nevertheless, they are also under development and are used (as alternative plasticizers) due to their concerns on potential human health and environmental impacts. Stabilizers are another kind of additive that are important. PVC, unfortunately, is sensitive to heat, light, and oxygen, all of which can contribute to its degradation over time. Stabilisers (for example, metal salts of fatty acids or organotin compounds) are included to inhibit such degradation. They function through reaction with the free radicals and other reactive species formed in the degradation process thereby improving the lifespan of the PVC product.

Fillers may be added to PVC in order to lower the cost and enhance certain properties. Common fillers are calcium carbonate, talc, and silica. Such fillers can help increase the hardness, stiffness, and dimensional stability of PVC.

In order to produce diverse colors, colorants are mixed in with PVC. This is done using pigments and dyes. Pigments can be comprised of insoluble particles dispersed within an insoluble PVC matrix, whereas dyes are soluble in the PVC or in a solvent added during processing.

Summary: PVC is produced from vinyl chloride monomer which is made from ethylene and chlorine. PVC is widely utilized in numerous everyday products, from pipes and fittings in construction to packaging materials and consumer goods, due to the polymerization of vinyl chloride monomer and the incorporation of several additives that contribute to the final features and applications.