Rising concern about escalating price of fossil fuel and their impact on environment has made it necessary to search for substitutes for petrochemical plastics. Biploymers are one of the alternatives of fossil fuels.
What is a Biopolymer?
It is a polymer that is developed from living beings. It is a biodegradable chemical compound that is regarded as the most organic compound in the ecosphere. The name “Biopolymer” indicates that it is a bio-degradable polymer.
History of Biopolymers
This polymer has been present on earth for billions of years. It is older than synthetic polymers such as plastics.
Examples of Biopolymers
Some Biopolymer examples are
- Nucleic acids
- Polysaccharides (such as glycogen, starch and cellulose)
Picture 1: Biopolymer image
All these biopolymers account for a greater part of the human body as well as the ecosphere. The DNA biopolymer is the most important for humans. The entire body structure as well as genetic behaviors that pass from parents to children is based on it. Both DNA and RNA are composed of nucleic acids that alternate in definite patterns to encode huge amount of genetic data.
The most common biopolymer is Cellulose. It is also the most abundant organic compound on this planet. It comprises of 33% of all plant component on Earth.
Classification of Biopolymers
There are four main types of Biopolymers. These are
Sugar based Biopolymers
Starch or Sucrose is used as input for manufacturing Polyhydroxibutyrate. Sugar based polymers can be produced by blowing, injection, vacuum forming and extrusion. Lactic acid polymers (Polyactides) are created from milk sugar (lactose) that is extracted from potatoes, maize, wheat and sugar beet. Polyactides are resistant to water and can be manufactured by methods like vacuum forming, blowing and injection molding.
Starch based Biopolymers
Starch acts as a natural polymer and can be obtained from wheat, tapioca, maize and potatoes. The material is stored in tissues of plants as one way carbohydrates. It is composed of glucose and can be obtained by melting starch. This polymer is not present in animal tissues. It can be found in vegetables like tapioca, corn, wheat and potatoes.
Biopolymers based on Synthetic Materials
Synthetic compounds that are obtained from petroleum can also be used for making biodegradable polymers such as aliphatic aromatic copolyesters. Though these polymers are manufactured from synthetic components, they are completely compostable and bio-degradable.
Cellulose based Biopolymers
These are used for packing cigarettes, CDS and confectionary. This polymer is composed of glucose and is the primary constituent of plant cellular walls. It is obtained from natural resources like cotton, wood, wheat and corn.
The production of biopolymer may be done either from animal products or agricultural plants.
Types of Biopolymers
There are primarily two types of Biopolymers, one that is obtained from living organisms and another that is produced from renewable resources but require polymerization. Those created by living beings include proteins and carbohydrates.
Structure of Biopolymers
Unlike synthetic polymers, Biopolymers have a well-marked structure. These polymers have a uniformly distributed set of molecular mass and appear as a long chain of worms or a curled up string ball under a microscope. This type of polymer is differentiated based on their chemical structure.
Uses of Biopolymers
These polymers play an essential role in nature. They are extremely useful in performing functions like storage of energy, preservation and transmittance of genetic information and cellular construction.
- Sugar based polymers, such as Polyactides, naturally degenerate in the human body without producing any harmful side effects. This is the reason why they are used for medical purposes. Polyactides are commonly used as surgical implants.
- Starch based biopolymers can be used for creating conventional plastic by extruding and injection molding.
- Biopolymers based on synthetic are used to manufacture substrate mats.
- Cellulose based Biopolymers, such as cellophane, are used as a packaging material.
- These chemical compounds can be used to make thin wrapping films, food trays and pellets for sending fragile goods by shipping.
Environmental Benefits of Biopolymers
Some of the environmental benefits of this polymer are:
- These polymers are carbon neutral and can always be renewed. These are sustainable as they are composed of living materials.
- These polymers can reduce carbon dioxide levels in the atmosphere and also decrease carbon emissions. This happens because bio-degradation of these chemical compounds can release carbon dioxide that can be reabsorbed by crops grown as a substitute in their place.
- It is also compostable which means there is less chance of environmental pollution from this compound. This is one of the primary advantages of this chemical compound. However, the materials composed from this compound are not compostable.
- These chemical compounds reduce dependency on non-renewable fossil fuels. These are easily biodegradable and can decrease air pollution. It greatly reduces the harmful effect of plastic use on the environment. Long term use of biopolymer use will limit the use of fossil fuel.
Difference between Polymer and Biopolymer
Biopolymers and Bioplastics are often confused for one another. However, these are different materials. Biopolymers are polymers that can be found in or manufactured by, living organisms. These also involve polymers that are obtained from renewable resources that can be used to manufacture Bioplastics by polymerization.
Bioplastics are the plastics that are created by using biodegradable polymers. The great automobile manufacturer Henry Ford devised a way of manufacturing bioplastic car sections from soybeans back in the middle of the 20th century. However, the beginning of the Second World War stopped production of bioplastic cars. It is only recently that bioplastic cars have made a comeback due to development of new manufacturing techniques through biotechnology.