ACRYLONITRILE, BUTADIENE AND STYRENE (ABS)

1. ACRYLONITRILE, BUTADIENE AND STYRENE (ABS)

2. INTRODUCTION It is a copolymer of three monomers i.e. acrylonitrile, butadiene and styrene. The family name is based on the first letter of each of these monomers. By suitable combination of these three monomers, large quantity of general purposes and tailor made grades with varying properties are available. It is commercially important engineering plastics which possessed good strength and toughness.

4. RAW MATERIALS • ACRYLONITRILE: We can get acrylonitrile from natural gas route. It is also known as ‘vinyl cyanide’. Polyacrylonitrile is a rigid, tough with outstanding chemical & temperature resistance and high impact strength. • BUTADIENE: Various processes are available to make butadiene: a) Butadiene from natural gas, b) Butadiene from acetylene and c) Butadiene from alcohol ( very common). dehydrogenation C2H5OH CH3CHO + H2 CH3CHO + C2H5OH CH2 = CH - CH = CH2 3. STYRENE: Styrene is produced from ethyl benzene (which is obtained by reacting ethylene with benzene) by dehydrogenation process.

5. PREPARATION OF ABS There are many methods of producing ABS , of which the following are important: A) Mechanical blends of SAN copolymer (styrene acrylonitrile) with rubber (butadiene acrylonitrile) & then extrusion.

6. PREPARATION OF ABS First type of polymer is produced by blending on a two roll mill. In the circumstances, the two materials are compatible and there is considerable improvement in the impact strength. Although the nitrile rubber usually contents about 35% acrylonitrile, the inclusion of nitrile rubber with higher butadiene content will increase the toughness at low temperatures.

7. PREPARATION OF ABS 2. Polymerization of a mixture of rubber (often polybutadiene), acrylonitrile and styrene. POLYBUTADIENE + ACRYLONITRILE ABS + STYRENE Second type is produced by adding acrylonitrile and styrene to polybutadiene latex and the mixture is heated to about 50OC to allow absorption of monomers. A water soluble initiator such potassium per sulphate is added to polymerize the styrene and acrylonitrile.

8. PROPERTIES ABS combine a good balance of properties: a) Very high impact strength and excellent surface finish. b) Rigidity can be increased by reinforcing glass fillers but compromising excellent surface finish and toughness. c) Good electrical properties.

9. PROPERTIES d) Adequate chemical resistance (unaffected by water, inorganic salts, alkalis & many acids). Alcohol & hydrocarbon solvent may affect the surface & cause swelling if the exposure is extended. e) Good dimensional stability (moisture). f) Easily decorative- may be metal, gold and chrome plated g) Ease of processing and machining. h) Reasonable economical price.

10. APPLICATIONS Protective & decorative housings for telephones, radios, TV, camera, calculators, typewriters, computers, photocopying, vacuum cleaner, carpet sweeper & hair drier. Automotive components such as car instrument clusters, radiator grills, bumpers, & automotive arm rests etc. Functional parts & product like ladies shoe heels, safety helmets, and electrical parts.

11. APPLICATIONS Refrigerator door handles, appliances, knobs, bearings, wheels cap, gear, wall cloack frames, decorative components for fans & sanitary wares etc. ABS sheets are used for refrigerator main & door liners and interior parts. ABS pipes are used for irrigation & drinking water systems, natural gas transmission and for drainage.

12. Applications

13. Applications Helmet outer cover Wheel’s Cap Automobile sunset

14. Applications Suit Case

15. Applications Door’s Liner Hair Dryer Cabinet Suitcases in formed ABS

16. Applications Bicycle lighting systems in ABS Light’s Cover

17. Applications LCD monitor housing Mobile Housing

18. Applications CRT monitor housing LCD monitor housing

19. Applications LCD Monitor cabinet Computer Cabinet

20. Applications I pot & pen drive cases Calculator cases