Question

Each question in this section has four suggested answers of which ONE OR MORE answers will be correct. The polymer(s) which contain 1, 3 -butadiene as one of the monomers is/are (a) \(\mathrm{SBR}\) (b) PAN (c) neoprene (d) nitrile rubber

Short answer

Answer: (a) SBR and (d) nitrile rubber.

Step-by-step solution

Recall the chemical structure of 1, 3-butadiene

1, 3-butadiene is a diene (molecule containing 2 carbon-carbon double bonds) with the chemical structure CH2=CH-CH=CH2.

Look at the chemical structure of each polymer

(a) SBR (styrene-butadiene rubber) is a copolymer of styrene (C8H8) and 1, 3-butadiene (C4H6). (b) PAN (polyacrylonitrile) is a polymer made from the monomer acrylonitrile (CH2=CH-CN). (c) Neoprene (polychloroprene) is a polymer made from the monomer chloroprene (CH2=CCl-CH=CH2). (d) Nitrile rubber is a copolymer of acrylonitrile (CH2=CH-CN) and 1, 3-butadiene (CH₂=CH-CH=CH₂).

Identify which polymer(s) contain 1, 3-butadiene as one of the monomers

(a) SBR contains both styrene and 1, 3-butadiene as monomers. Therefore, it is correct. (d) Nitrile rubber contains both acrylonitrile and 1, 3-butadiene as monomers. Therefore, it is correct.

State the final answer

The polymer(s) which contain 1,3-butadiene as one of the monomers is/are (a) SBR and (d) nitrile rubber.

Key concepts

SBR (Styrene-Butadiene Rubber)

Styrene-Butadiene Rubber (SBR) is a versatile synthetic rubber used across various applications, from car tires to children's toys. This elastic material is the product of the copolymerization process, where the molecules of styrene and 1,3-butadiene combine to form long chains.

Imagine tiny beads (the monomers) of styrene and butadiene being strung together in alternating sequences to create a much larger and flexible necklace (the polymer). The strength and durability of SBR come from the double bonds present in butadiene, which create a robust chain structure, while styrene contributes to its hardness and heat resistance.

The ratio of styrene to butadiene can be adjusted during the production process, allowing manufacturers to tailor the properties of the rubber for specific uses. For example, more styrene can make it harder and more resistant to abrasion, which is ideal for tire treads.

Nitrile Rubber

Nitrile rubber, also known as Buna-N or NBR, is a synthetic rubber copolymer of acrylonitrile and 1,3-butadiene. Acrylonitrile provides the rubber with excellent oil and fuel resistance, making nitrile rubber perfect for automotive and industrial applications that encounter oils, such as gaskets, hoses, and o-rings.

The presence of butadiene in its composition lends nitrile rubber its flexibility and elasticity. Manufacturers can vary the acrylonitrile content to create different grades of nitrile rubber to suit specific needs. High acrylonitrile content results in greater resistance to oils but makes the rubber less flexible, whereas lower acrylonitrile content increases flexibility at the expense of reducing resistance to oils and fuels.

This material's structure allows it to maintain its integrity in a wide range of temperatures, making it a robust material for challenging environments.

Copolymerization in Chemistry

Copolymerization is a chemical reaction where two different types of monomers, such as styrene and 1,3-butadiene, are linked together to form a copolymer, like SBR or nitrile rubber. This process is fundamental in creating materials with tailored properties for specific applications.

During copolymerization, the monomers intertwine in repeating patterns, which may be random, alternating, block, or graft. The structure of the resulting copolymer affects its properties - for instance, alternating copolymers usually have a consistent, predictable structure, while random copolymers might have varying degrees of toughness or flexibility.

Controlled copolymerization allows chemists to engineer materials that exhibit a balance between the characteristics of their monomer building blocks. By understanding the behavior of monomers in a copolymer, researchers and manufacturers can innovate new materials that meet the demands of modern technology.

Polymer Chemistry

Polymer chemistry is the science behind the creation and study of polymers, which are large molecules made up of repeating structural units. These units, known as monomers, form chains or networks through chemical reactions such as polymerization or copolymerization.

One fascinating aspect of polymer chemistry is how variations in monomer types and arrangements in the polymer chain can result in materials with a wide range of properties. For example, polymers can be engineered to be strong yet lightweight, flexible or rigid, and resistant to heat, chemicals, or electricity.

The development of polymers like SBR and nitrile rubber showcases polymer chemistry's role in meeting specific needs. By manipulating the molecular structure of polymers, chemists create innovative solutions for everyday challenges, pushing the boundaries of what these versatile materials can do.