Polyvinylchloride(PVC).

Polyvinylchloride(PVC).

1. Pvc (PolyVinylChloride) Made by: Pankaj Kumar Das Roll no :1308023

2. Content History Preparation of vinyl chloride Synthesis Structure and properties of Pvc Application reference

3. History PVC was discovered accidently at least twice in the 19th century, first by French chemist Henri Victor Regnault and then in 1872 by German chemist Eugen Baumann . In the early 20th century the Russian chemist Ivan Ostromislensky and Fritz Klatte of the German chemical company Griesheim-Elektron both attempted to use PVC in commercial products, but difficulties came due to rigidness. Waldo Semon and the B.F Goodrich Comany developed a method in 1926 to plasticize PVC by blending it with various additives. The result was a more flexible and more easily processed material that soon achieved widespread commercial use.

4. Preparation of vinyl chloride Vinyl chloride (CH2=CH. Cl) is synthesized on commercial scale by following process. Acetylene The earliest route to vinyl chloride was from acetylene and HCl. CH CH +HCl CH2=CH .Cl

5. By Ethylene As Ethylene become more abundant ,technology based on chlorination of Ethylene dichloride (EDC) . CH2=CH2 Cl2 Cl.CH2-CH2.Cl -HCl at 500°C CH2= CH.Cl

6. Synthesis Commercial polymerization of PVC is done by free radical catalyst employing bulk, suspension and emulsion techniques. suspension and emulsion technique are most commonly used in industries. About 80% of production involves suspension polymerization. Emulsion Polymerization   accounts for about 12% and  Bulk Polymerization  accounts for 8%.

7. Bulk polymerization Bulk polymerization done in a rotating cylindrical reactor with tumbling steel balls inside to facilitate removal of heat of polymerization from the monomer –polymer heterogeneous system. Peroxy dicarbonate are used as a initiators in a bulk and suspension polymerization. Suspension and emulsion polymerization It is done in a stirred tank jacketed pressure vessels. For injection moulding ,extrusion and for clear objects and for electrical insulation purpose bulk and suspension grade Pvc resin are used.

8. Structure and Properties It is a linear polymer and thermoplastic in nature. It is a white brittle solid, hard ,rigid material with a characteristics tendency to stick to metallic surface. It contain about 56.8% chlorine content. It is insoluble in all hydrocarbon solvent. There is a few solvent for Pvc like cyclohexane and tetrahydrofuran. The polymer as produce commercially is amorphous in nature. It has a melting point 212 degree celcius. The Tg of Pvc is 80 degree celcius. It’s density is 1.38 g/cm³.

9. Electrical Properties PVC is a polymer with good insulation properties but because of its higher polar nature the electrical insulating property is inferior to non polar polymers such as polyethylene and polypropylene. It is generally suitable for medium or low voltage and low frequency insulation materials. Thermal Properties The heat stability of PVC is very poor, when the temperature reaches 140 °C PVC starts to decompose.

10. Weathering stability - PVC is resistant to aggressive environmental factor is therefore the material of choice for roofing. Fire protection - PVC is a material resistant to ignition due to its chlorine content. Longevity - PVC products can be last up to 100 yrs. and even more. Hygiene - PVC is a material of choice for medical applications, particularly blood and plasma storage containers.

11. Application There are two type of Pvc’s rigid and flexible. Rigid PVC- it exhibits high surface strength and very good rigidity. It is used mainly for pipes, windows. Plasticized PVC- It is used in the manufacture of films, expanded products, sheets, jacketing for electrical cables etc. In building and construction- PVC windows and doors, frames, shutters, panels, piping for drinking water distribution, flooring etc. In packaging- In foodstuffs and pharmaceuticals. In cars- panels for car doors, dashboards, electrical cabinets, matting. In electricity and electronics- jacketing of electrical cables for domestic use,  insulation on electrical cables , telephones, sockets.

12. Reference Polymer science and Technology ( P.Ghosh ). Wikipedia . Google image .

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