 to learn biodegradable plastics from a topic chemistry of polymers. This is the learning outcome for today's session. At the end of this session, students will be able to describe definition, example and applications of biodegradable plastic. So, we are going to learn what is the definition of biodegradable plastic or polymer. What are the examples of biodegradable plastics? And what are the uses that is applications of biodegradable plastic? So, what are biodegradable plastics? Biodegradable plastics are obtained by using biodegradable polymers which are a special class of polymers that breaks down after its intended purpose by bacterial decomposition process. To result in natural byproducts such as gases, water, biomass and inorganic salts. These polymers are found both naturally and synthetically made and largely consist of ester, amide and ether as functional groups. Their properties and breakdown mechanisms are determined by their exact structure. These polymers are often synthesized by condensation reaction, ring opening polymerization and by using metal catalyst. So, biodegradable polymers are non-toxic, good in mechanical integrity until they get degraded and capable to control rate of degradation. Factors controlling the rate of degradation include percent crystalline molecular weight and hydrophobicity. The degradation rate depends on the environment surroundings also such as the polymer in which environment it is used such as pH, enzymes, concentration and amount of water. Now, after learning the definition we will see some of the examples of biopolymers which are then used to prepare different varieties of bioplastics which get degraded and which are known as eco-friendly material. So, starch is one of the example of biopolymer. It is found in corn, potatoes, wheat and some other plants. A new world production of starch is well over 70 billion pounds with much of it being used for non-food purposes like making paper, cardboard, textile sizing and adhesives. So, this is the structure of the starch which is mainly obtained from the plant origin and this is used as one of the major source to prepare the biopolymers which is then used to prepare different bioplastics. This is collagen. It is the most abundant protein found in mammals. Gelatin is denatured collagen and is used in casings, capsules for drugs and vitamin preparations and other miscellaneous industrial applications including photography. Cellulose, it is the most plentiful carbohydrate in the world, 40 percent of all organic matter is cellulose and largely used for preparation of biopolymers. Casin commercially produced mainly from cow's skimmed milk. It is used to make biopolymers such as adhesives, binders, protective coatings and other products. Zoya protein, it is obtained from corn, it is used for making adhesives and coatings for paper and cardboard. Polyester is also one of the example of biopolymer. These are produced by bacteria and can be made commercially on large scales through fermentation process. They are now being used in biomedical applications. Lactic acid, it is now commercially produced on large scale through the fermentation of sugar feedstock obtained from sugar beets or sugar cane or from the conversion of starch from corn, potato peels or other star sources. It can be polymerized to produce polylactic acid which is already finding commercial applications in drug capsulation and biodegradable medical devices. Triglycerides are also important examples of biopolymers. This is the structure of triglycerides, glycerol plus fatty acid. When these are reacted we are getting the triglycerides. This can also be polymerized. Triglycerides make a large part of the storage lipids in animal and plant cells. Over 16 billion pounds of vegetable oils are produced in the United States yearly mainly from soya bean and rapcid oil. Triglycerides are another promising raw material for producing biopolymers and plastics. Now after learning what are the examples of that biopolymer, now we will see what are the applications of biopolymer and we will cover some of the important applications. So first, biopolymers that is bioplastics also it is used as a packing material. At present most of the conventional packing materials are the products of petrochemicals like PVC, PET that is polyvinyl chloride, polyethylene turf thalate, polystyrene, polypropylene, polyamide. The only problem with synthetic polymer is their resistance to degradation in the environment. So what happen today can present largely the synthetic polymers which then convert into plastics that is PVC sheets or PET bottles etcetera are used for a packing material mainly for food products, pharmaceutical products and etcetera. So they cause lot of issues with the environment and a promising material coming up to solve this issue is known as the biodegradable plastic. So the biodegradable plastics are capable of undergoing decomposition into carbon dioxide, methane, water, inorganic compounds and biomass. Therefore, biopolymers are largely used as a packing material. So this is the comparison in between the synthetic traditional packing material and the biopolymers are there. So nowadays there is a large strain to use the biopolymers as a packing material because these material are largely used as a degradable material. Prokratik polyhydroxyalkylonates which are commercially known as PHA are considered as promising material to compete with petroplastics on the food packaging market. Generally PHAs are biopolysters of alkyonic acids containing a hydroxyl group and at least one functional group attached to the carboxyl group. Polysaccharides, starch, proteins, cellulose, aliphatic polyesters, polylactide, polyhydroxyalkylonates are used as packing material in food and allied industry. This is the second use we are observing here that is the biopolymers used in agriculture as a agricultural material. Biopolymers are also used for seed coating which serves as soil stabilizer, seed protector, yield enhancer and plant growth regulator. Biopolymers dry quickly, dissolve rapid lean water, form effective water soluble film, radially adhere to seeds, minimize the required dose of fungicides and provide excellent control of plant diseases. By contributing to enhanced plant productivity, new biocompatible and biodegradable biopolymers are produced from plants, microbes, animals, renewable agricultural waste and feedstocks. Biopolymers used in agriculture are mostly prepared from acrylic acids and a crosslinking agent like potassium. By solution or suspension polymerization, the polymers so form is called a polyacrylate. Polymers supported herbicides, insecticides are also used. Biopolymers are also used as a super absorbent which will help to absorb moisture in soil. Biopolymers used in agriculture are obtained from copolymerization of cellulose, starch, lipids, etcetera. This is the third application. Biopolymers are also used in construction as a construction material. Applications of biopolymers in construction are widespread and diverse. In some cases, biopolymers offer distinct advantages in performance and or cost over synthetic polymers. Biopolymers are used for plastering and painting the walls, for avoiding leakages, for providing strength for natural lighting and cooling. So, here I would like to ask you one question. Biopolymers are used for option A, plastering and painting the walls, option B for avoiding leakages, option C for providing strength and option D all of these. Starching for a moment will come with answer and the question is, biopolymers are used for which of the following option is correct and the correct answer is option D all of these. Following biopolymers are used in construction, starch, carboxymethyl starch, polymer produced in industrial fermentation process by microorganisms, biodegradable polymers which can be based on naturally occurring or synthetic polymers, lignosulophonate, humic acid, lignite, cellulose, polyester, etc. It is also used in medicine. Natural polymers are obtained from living organisms and more biocompatible. It is used for wound healing, reconstruction of bones, skin, hurt walls, etc. Cheetosan is used as hemostatic material to stop bleeding and is obtained from exoskeleton of marine animals such as crabs, shrimps, etc. Biopolymers used in manufacture of medical devices which are used to replace or repair some deceased, damaged or non-functional piece of tissue or bone like replacement of joints, hurt wall, teeth, tendons, ligaments, etc. Advances in polymers have led to the development of novel drug delivery devices, a proper understanding of surface and bulk properties of polymers can help in designing the polymers and thus the design and synthesis of novel polymers will expand the scope of new drug delivery system in the future. Biodegradable polymers find widespread use in the drug delivery as they can be degraded to non-toxic component inside the body. All this I have prepared by referring a textbook of engineering chemistry written by Jain and Jain. Thank you.