Polymers are large, packed molecules either in crystalline or amorphous forms. They are chemically described by its degree of polymerization, branching, molar mass distribution, tacticity, distribution of co-polymer, cross links, thermal property, crystallinity, end groups of chain, etc. A branch of chemistry that deals with the synthesis and properties of polymers is called polymer chemistry.
Crystalline polymers are linear and structurally oriented three dimensional molecule. The crystalline property of a molecule increases with increasing opacity, rigidity and tensile strength. Whereas the amorphous form of polymers are coiled and tangled macromolecular chains. These are transparent, easily deformed, less rigid and weaker polymer. Solubility, gelation and viscosity of polymers vary when in liquid form.
Polymers can be divided into various types based on their use, properties, physiochemical characteristics etc. But basically polymers are divided into two types biopolymers and synthetic polymers based on their origin.
(a) Biopolymers: These are the biodegradable polymers that are produced from living organisms i.e., animals or plants, which can be chemically modified based on its application. Biopolymers include cellulose, starch, chitin, lignin and various other polysaccharides. Degradation of these natural polymers decreases with increased chemical modification. The biopolymers have
- Structural proteins such as elastin, collagen, keratin etc.
- Functional proteins (chemical) such as transport proteins, hormones, enzymes etc.
- Storage polysaccharides such as glycogen, starch etc.
- Structural polysaccharides such as chitin, cellulose etc.
- Nucleic acids such as DNA and RNA.
Biopolymers are of four types based on their structural component, they are starch, sugar, cellulose and synthetic based biopolymers. Biopolymers have several economic and environmental advantages, such as packing of in-flight catering products, used for pesticide soil pins, packing dairy products etc.
The current and future research in biopolymers focuses on the scaling-up of production and improving product properties. At large scale production, it is expected to increase availability and price reduction.
(b) Synthetic polymer: These are man-made polymers that are commonly found in various consumer products. These may be straight or cross-linked chains. They are cheap, light weight, long lasting, hard to break and easily mould into different shapes.
Synthetic polymers are used in making plastics, synthetic fibers, paints, building materials, furniture, adhesives and mechanical parts. Polyethylene is one of the most common and versatile synthetic polymer that is made from ethylene monomers. These are used to make various plastic products of different shapes and sizes, such as piping, bottles, toys etc. Synthetic polymers are four types of synthetic polymers, they are Synthetic fibers, thermosets, thermoplastics and elastomers.
“Polymers are the building tool of many components in sciences (either chemistry or physics or biology)”