Sciencedoze: Science, Education and Technology

1. Butadiene-styrene Copolymer (SBR or Buna-S) Buna-S or SBR is a copolymer of 1,3-butadiene and styrene which is prepared by copolymerization of 1,3-butadiene and styrene along with sodium. In Buna-S, Bu stands for butadiene, Na for sodium which is the polymerizing agent and S stands for styrene. It is tough and is a good substitute for natural rubber. It possesses high abrasion resistance, high load-bearing capacity and is used for the manufacture of automobile tires. Preparation of Buna-S Styrene-butadiene rubber (SBR) or Buna-S can be prepared by copolymerization of a mixture of 1,3-butadiene and styrene in the ratio of 3:1 in the presence of sodium. Properties of Buna-S 1. Buna-S has high abrasion resistance, high bearing capacity, and resilience. 2. Buna-S is very tough and is a good substitute for natural rubber 3. Buna-S swells in organic solvents up to a limited extent. 4. Buna-S gets oxidized in the presence of traces of ozone. Applications of Buna-S 1. Buna-S is used for

What are Polyolefins? A polymer that is produced from a simple olefin monomer (also called alkene having general formula CₙH₂ₙ) is called Polyolefin . For example (a) Polyethene is a polyolefin produced by polymerization of olefin ethylene (b) Polypropylene is a polyolefin produced by polymerization of olefin propylene. The IUPAC nomenclature of polyolefins is poly (alkene) . Polyolefins are produced by different common forming techniques like injection molding, blow molding, extrusion, and thermoforming using standard thermoplastic equipment. Due to low prices and easy processability, polyolefins have a variety of applications in the plastic industry. Application of Polyolefins 1. Polyolefins are used for making blow-molded components in toys. They are also used to make heat-shrink tubing which protects connections in electronic items. 2. Polyolefins are used in the pharmaceutical and medical industry for HEPA filter certification. 3. Polyolefins sheets have packaging applications of