Saturday, September 14, 2019
Chemistry project 12th Essay
This reaction is highly exothermic, but that is not why the plastic produced is referred to as Ã¢â¬Å"thermosetÃ¢â¬ . Bakelite is a space-network polymer. Unlike linear and branched polymers, which are composed of long molecules that make them more or less crystalline, space-network polymers are highly and irregularly cross-linked throughout the structure. The sheer extent of the cross-linking means that a sample of the material is essentially one gigantic molecule. Although heat softens and melts linear and branched polymers, heating doesnÃ¢â¬â¢t soften space-network polymers because such a softening would require the breaking of covalent bonds. In fact, heating usually produces additional cross-linking in these polymers, making them harder. It is for this reason that space-network polymers, such as bakelite, are called thermoset plastics. PROCEDURE: 1. Take 5ml acetic acid and 2.5ml formaldehyde in a breaker. 2. Add 2mg of phenol to this solution and stir the mixture. 3. Wrap a cloth loosely round the beaker. 4. Stir the solution well while heating. 5. Pass dry hydrochloric acid gas or add a few ml of concentric hydrochloric acid into the mixture. Observation: A large mass of light pink plastic is produce within 5 minutes. Precautions: a) The face of the beaker should not be towards the face of the worker during heating. b) Hydrochloric acid should not be poured into reaction mixture very slowly. c) The contact of phenol with skin should be avoided. Caution: As the reaction is sometimes vigorous while adding hydrochloric acid .It is better to be a few feet away from the beaker till the reaction in complete. Scope of the experiment: Uses of Bakelite are following: Substitute: Bakelite is used as a substitute of porcelain & other opaque ceramic materials. Board/table top: It is used in the area of board & table top games e.g. Billiard balls ,Dominoes etc. Mounting: It is used in mounting of metal samples. It is used in whistles, cameras, solid body& electric guitars. Bakelite is very suitable for emerging Electric & automobile industries because as its extra ordinary resistance but also due to its thermal resistance. It has been widely used in jewellery products. References: 1. Wikipedia http://en.wikipedia.org/wiki/bakelite 2. www.scribd.com 3. Comprehensive chemistry practical class XII Acknowledgment: I owe a great many thanks to a great many people who helped and supported me during the project. My deepest thanks to , the guide of the project for guiding and correcting various documents of mine with attention and care. She has taken pain to go through the project and make necessary correction as and when needed. I express my thanks to the principal, for extending his support. My deep sense of gratitude to the in charge of chemistry lab at CSE for their support and guidance. Thanks and appreciation to the helpful people at for the support. I would also thank my school and my friends without whom this project would have been a distant reality. I also extend my heartfelt thanks to my family and well wishers.