What are Polymers?
A polymer is a big molecule or macromolecule that essentially consists of a number of different components. In Greek, polymer means "many parts." Everywhere we look, we encounter polymers. From the DNA strand, a biopolymer that occurs naturally, to polypropylene, a plastic that is used all over the world. Natural polymers are those found in plants and animals; synthetic polymers are those manufactured by humans. Different polymers are used daily because of various special physical and chemical characteristics.
All polymers are produced by the polymerization process, in which their monomer building blocks react to form polymer chains, which are the 3-dimensional networks that contain the polymer links. The kind of functional groups connected to the reactants determines the type of polymerization mechanism used.
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Classification of Polymers
Due to their complicated structures, diverse behaviours, and wide range of applications, polymers cannot be categorized into a single group. So, using the following criteria, we may categorize polymers.
Classification of Polymers based on the Source of Availability
This category includes three different types: natural, synthetic, and semi-synthetic polymers.
- Natural Polymers: These polymers are naturally present in plants and animals. Proteins, starch, cellulose, and rubber are a few examples. We also have biopolymers, which are biodegradable polymers.
- Semi-synthetic Polymers are created through further chemical modification of naturally occurring polymers. For example, cellulose nitrate and cellulose acetate.
- Synthetic Polymers: These polymers are created by humans. The most popular and commonly used synthetic polymer is plastic. It is utilized in many sectors and dairy products. Nylon-6, polyethers, etc., are a few examples.
Polymer Classification Based on the Structure of the Monomer Chain
There are three types of classification under this category
- Linear Polymers: This category includes polymers with long, straight chain structures. PVC, or polyvinyl chloride, is a linear polymer commonly used to make pipes and electrical wires.
- Branched-chain Polymers: Branched-chain polymers are defined as those in which a polymer's linear chains produce branches. For example, Low-density polyethene.
- Cross-linked Polymers: They are made up of bifunctional and trifunctional monomers. Compared to other linear polymers, their covalent bond is stronger. Examples of this type of polymer include melamine and bakelite.
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Structure of Polymers
A hydrocarbon backbone makes up the majority of the polymers in our environment. Due to the tetravalent nature of carbon, a hydrocarbon backbone is a lengthy chain of linked carbon and hydrogen atoms. A few examples are the hydrocarbon backbone polymers polypropylene, polybutylene, and polystyrene. There are also polymers whose backbones contain other elements in place of carbon. For instance, the Nylon repeating unit backbone contains atoms of nitrogen.
Types of Polymers
Based on the backbone element
Polymers can be categorized into the following groups depending on the type of backbone chain.
- Organic Polymers: Carbon backbone
- Inorganic Polymers: The backbone is made up of substances other than carbon.
Based on their synthesis
- Natural Polymers
- Synthetic Polymers
Other Types of Polymers
Biodegradable polymers are those that can be broken down and destroyed by bacteria and other microbes. These polymers are utilized in surgery, capsule coatings, and surgical bandages. For example, Poly hydroxybutyrate Covel [PHBV]
At high temperatures, these polymers remain stable. These are not destroyed even at extremely high temperatures due to their high molecular weight. They are widely utilized in the healthcare sector, in the production of heat- and shock-resistant items and sterilization equipment.
It is a particular kind of polymer that softens above a certain temperature, allows molding, and solidifies after cooling. It has many uses since it can be easily molded into various shapes. Some of these can be found in speakers, reusable containers, automobile parts, and stationary equipment, among many other things. The polymer is fused utilizing the welding technique rather than glue because of its surface's relatively low energy level.
It is the most prevalent kind of plastic in our environment. Mostly utilized in packaging, including plastic bottles and bags. Polyethene comes in many varieties, but they all share the chemical formula (C2H4)n.
Properties of Polymers
Polymer characteristics are determined by their structural composition and are categorized based on their underlying physical principles. A polymer's behavior as a continuous macroscopic material is described by several physical and chemical properties.
- The tensile strength of the polymer improves with chain length and cross-linking.
- Instead of melting, polymers transition from a crystalline to a semi-crystalline state.
- The polymer is enabled with hydrogen bonding and ionic bonding, resulting in a stronger cross-linking strength than ordinary molecules with various side molecules.
- The polymer's remarkable flexibility is made possible by the side chains' dipole-dipole bonding.
- Van der Waals forces, which link chains, are known to weaken polymers but give them a low melting point.
They are utilized in lasers for spectroscopic and analytical purposes because, like PMMA and HEMA: MMA, they have the ability to vary their refractive index with temperature.
Applications of Polymers
Here is a list of some of the significant applications for polymers in daily life.
- Many sectors use polypropene, including textiles, packaging, stationery, plastics, aircraft, construction, rope, toys, etc..
- One of the most popular plastics, polystyrene, is widely used in packaging. Some everyday items manufactured of polystyrene include bottles, toys, containers, trays, throwaway glasses and plates, tv cabinets, and lids. In addition, it serves as an insulator.
- Making sewage pipes is polyvinyl chloride's most significant application. It serves as an insulator for electrical wires as well.
- In addition to making apparel and furnishings, polyvinyl chloride is increasingly used to make doors and windows.
- The production of adhesives, molds, laminated sheets, unbreakable containers, etc., uses urea-formaldehyde resins.
- Paints, coatings, and lacquers are made with glyptal.
- Electrical switches, kitchenware, toys, jewelry, guns, insulators, computer discs, and other items are made of bakelite.
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