Preparation of Polythene, Teflon, and Polyacrylonitrile

Introduction

A polymer is a macromolecule made up of numerous repeating units that are joined together. They can be derived from natural sources such as plants and animals. Here they are known as natural polymers. Alternatively, they can be manufactured artificially, referred to as synthetic polymers. Polymers contain a variety of distinct physical and chemical characteristics that have made them an integral part of our lives.

In subsequent sections, we shall discuss making several vital polymers, including polyethylene, Teflon, and polyacrylonitrile.

Definition

Polymers are defined as macromolecules since they are giant molecules with a higher molecular weight. Polymer is a combination of two Greek words: poly and mer. Poly stands for multiple, and mer stands for one unit or aspect.

Polymers are made up of a large number of repeating units or components called monomers. Polymerization is the name given to the process of developing polymers from individual monomers.

Types of Polymers

Polymers are primarily of three types:

• Natural Polymers
• Semi-synthetic Polymers
• Synthetic Polymers

It is important to note that natural polymers provide the raw material of all three kinds of polymers. This is because plant and animal-based natural polymers are used to make semi-synthetic polymers such as rayon. Upon further synthesis of semi-synthetic polymers, we obtain synthetic polymers like Polythene, Teflon, and Polyacrylonitrile, which will be discussed now.

Polymerization

We know that polymerization is described as the process of developing polymers from individual monomers. This process can be subdivided into two types:

• Polymerization via addition or chain growth
• Polymerization via condensation or step-growth

Additive polymerization produces polythene, Teflon, and polyacrylonitrile.

PolymerizationWhat is Addition Polymerization, and how does it work?

Addition polymerization is a type of polymerization wherein particles of the same or various other monomers combine to create a polymer. Addition polymers are the polymers produced by this type of polymerization. When only one sort of monomeric unit is utilized to develop polymers, the resulting polymer is known as a homopolymer. Polythene, Teflon, and polyacrylonitrile, for instance, fall into the category of homopolymers. Copolymers are those additional polymers that are produced by the polymerization of two distinct monomer units.

The production of free radicals causes chain development in this kind of polymerization. So, as a result, it is also known as chain-growth polymerization.

Polythene

Polymers of the monomer subunit ethene are known as polythene. These are compounds that are generated by the free radical process and are either straight or somewhat branched. Thermoplastic polymers are what these are.
Based on its density, polythene can be classified into two subtypes:

1. Low-density polythene (LDP)

It is created under high pressure via the polymerization of ethene. They are highly branched.

2. High-density polythene (HDP)

It is created under low pressure via the polymerization of ethene. They are more linearly placed.

Uses of Polythene

LDP applications – LDP is a chemically inert material that is solid but pliable and has weak electrical conductivity. It is beneficial in many sectors because of these characteristics. For example, it is found in electrical wiring, pipelines, and squeeze bottle production.

HDP applications – It is used in a variety of applications. It is chemically stable, but it is more robust and stiffer than LDP. Because of these characteristics, it is used to make containers, garbage cans, flasks, and pipelines.

Teflon
Teflon is a tetrafluoroethylene polymer that is also known as polytetrafluoroethylene (PTFE). It is made via high-pressure melting of tetrafluoroethylene using a peroxide or ammonium persulfate catalyzing agent.

Properties of Teflon

• It is a polymer that can be heated and cooled.
• At temperature levels as low as 5K, it retains excellent stiffness, hardness, and oiliness.
• It has a decent amount of heat tolerance.
• It has a melting point of 327 degrees Celsius.
• It is unreactive and poorly soluble in virtually all solutions.
• Corrosive substances do not corrode them.

Applications of Teflon

• Insulant wire for aviation and software industries.
• Bearings, gearboxes, gaskets, and other components utilize it.
• Magnetizing materials, specifically permanent magnets, contain it.
• It is frequently utilized in the manufacturing of composite materials and fiberglass composites.
• It is found in non-stick cookware.

Polyacrylonitrile

Various other names know it. Some of them are Creslan 61 and polyvinyl cyanide. As we know, it is a synthetic polymer. However, it is also semi-crystalline. It is made by polymerizing acrylonitrile with a catalyzing agent, such as peroxide.

Properties of Polyacrylonitrile

• It is a polymer that can be heated and cooled. However, it melts at temperatures exceeding 300°C.
• It is poorly soluble.

Applications of Polyacrylonitrile

• Polyacrylonitrile has several applications, including serving as a wool replacement.
• It is employed in the military.
• It is used to create insulants in airplanes, bikes, camping tents, rockets, missiles, and other equipment.
• It is the primary component of fireproof clothing.
• In cells, it serves as a separator for the electrolytic solution.