types, classification, properties, and uses of polymers

What is a polymer? what are types, classification, properties, and uses of polymers? Polymers or large molecules are very large molecules and chains that are made up of a large number of smaller units called monomers and connect them.

The word polymer is of Greek origin and is made from two parts “poly” which means “many” and “mer” which means part. In the continuation of this article, we intend to learn about the types of polymers, their uses, and their properties, as well as the types of polymerization.

Difference between polymer and monomer

The smallest repeating unit of a polymer is called a monomer. For a better understanding, consider an example of the rosary. If we consider a rosary as a polymer, each of the beads forming its core is considered a monomer.

?What is the polymerization process

 The meaning of polymerization process is a set of chemical reactions that connect monomers and make long chains with high molar mass called polymers. This process is done in different ways. Anionic, cationic, and radical polymerization are among these methods. In the following, we will examine the types of polymers and their use of polymers.

Types of polymerization

According to what is stated in Wikipedia; Polymerization, or the process of converting monomer to polymer, takes place in various ways such as step, chain, ionic, etc.

To learn more about the process of polystyrene, download the following pdf for free.

.Download the pdf file of the polymerization process

Classification of types of polymer

: Types of polymers can be classified based on the following characteristics

1. Classification according to their origin
2. Classification according to the chain structure
3. Classification according to how they react to heat
4. Classification according to crystallinity
5. Classification according to their physical characteristics, construction, and uses
6. Classification according to the order of tacticity

: Next, we describe each category

Classification according to their origin

The first category of polymers that we examine is the classification based on the origin of their production. Polymers are divided into natural and synthetic categories depending on which biological or non-biological agent they are made from.

• Large natural polymers are biomolecules such as polysaccharides, proteins, and natural rubbers. These types of polymers do not harm the environment, are degradable, and have a biological origin. It is also used in medical engineering.
• Synthetic polymers come from the synthesis and combination of small molecules and the construction of larger molecules. Usually, the main bases of this type of polymer are oil and natural gas, and carbon and hydrogen are abundantly found in them. Examples of synthetic polymers include plastic, nylon, polyethylene, and Teflon.
• There is also a third category that is placed between the previous two categories, which is called a semi-synthetic polymer. These polymers are prepared from the chemical modification of natural polymers to use their properties optimally. Such as cellulose acetate and cellulose nitrate.

Classification according to the chain structure

.In another classification, the types of polymers are divided into 3 categories linear, branched and cross-linked (network) polymers based on their chain structure

• In the linear classification, the placement of monomers is in such a way that there are no branches and the molecules are located at a small distance from each other, which causes a high melting point and tensile strength between them, Like nylons.
• Like linear polymers, branched polymers are long chains, with the difference that they have side branches and have a lower melting point, density, and tensile strength.
• In this third category, i.e. network polymers, repeating units are connected and form three-dimensional networks, therefore they are hard, rigid, and fragile, such as melamine, formaldehyde resin, and cured rubbers.

Classification according to how they react to heat

.In this section, we examine the types of polymers in the two categories of thermoplastics and thermostats

• Thermoplastics include long chains that can be molded into different shapes against heat and then cooled and usable at room temperature. Such as polyethylene, PVC, polypropylene, and polystyrene. During the forming process, thermoplastics do not engage in chemical reactions due to heat.
• Thermosets are hard polymers that do not melt or soften in front of the heat they remain solid when reheated until they are destroyed. Therefore, they cannot be recaptured. Thermoset materials are often supplied as semi-polymerized compounds or polymer-monomer mixed liquid so that production units can make them into final products and then bake them. Phenolics, urea, melamine, epoxies, polyesters, and silicones are examples of thermostats.

Classification according to crystallinity

This classification of types of polymers can be considered in 3 categories: crystalline, semi-crystalline, and amorphous. There is another name for the categories of a crystalline and amorphous polymer, which are crystalline and amorphous, respectively.

• Crystalline polymers are polymers whose molecular chains are arranged together in a special arrangement. These types of polymers have high strength due to the structure and the way the chains are placed.
• Unlike the previous category, the amorphous or amorphous polymer has irregular chains and random arrangements. The characteristic of this category is its low resistance to heat and high creep.
• The last category is semi-crystalline polymers. Most polymers include both of the above categories; That is, parts of them are crystalline and parts are amorphous, and in general, it is rare for a polymer to be completely amorphous or crystalline.

Classification according to their physical characteristics, construction, and uses of polymers

.Types of polymers are divided into 4 general categories of plastic, rubber, fiber, and resin in terms of their physical characteristics, construction, and their uses

• Plastics are polymers that have hardened due to heat and pressure. Plastics are usually classified as semi-crystalline, and in terms of intermolecular force, they are placed between fibers and rubber, Like PMMA and PE.
• The second category is polymers with weak intermolecular forces that have high elasticity and elasticity. These polymers are called rubber or elastomer. They are usually categorized as amorphous in terms of crystallinity.
• Fibers are the third category we will examine. These polymers are very long and have a length of about 100 times their diameter. Among their characteristics, we can mention the elasticity and high degree of the crystal, Like nylons.
• Polymers that have a very low weight are usually in liquid form and are cooked to increase their strength, they are called resin. Like air-cured adhesives. Resins are widely used and popular in handicrafts today.

Classification according to the order of tacticity

The concept of tacticity is the placement of side groups in space. Polymers can be divided into 3 isotactic, atactic, and syndiotactic categories based on how they are placed in space.

• If all groups are on the same side of the chain, they are called isotactic.
• If the groups are placed randomly on both sides of the chain, they are called atactic.
• The third category is the situation where the groups are placed on both sides of the chain in an arrangement in the middle, this category is called syndiotactic.

abstract

.The following table summarizes the types of polymers and all that has been discussed up to this part of the article

We are proud that you were with us until the end of the article and you got to know the types of polymers, the use of polymers, and their properties, and you saw what is a  polymer. And how is it different from monomer?