Plastics in the future essays

Plastics in the future essays Today, a wide variety of plastic polymers, also called resins, are derived from natural gas, crude oil or other naturally occurring building blocks. Each polymer is a chain of carbon-based molecules, called monomers, bonded together through a chemical reaction. What these molecules are made of, their structure and the strength of the bonds between them will affect the plastic's physical properties. For example, some plastics are flexible while others are rigid, some can be made into crystal-clear items, others into lightweight foam products. There are many advantages of plastics over traditional materials such as metals and glass. Plastics are lighter and safer than glass for domestic applications, e.g., storage containers, bottles. Plastics products are less expensive to make as the processes require less energy due to lower melting points. Typically, finishing by painting or plating is not required and there is ease in creating intricate shapes. Natural Polymers such as protein-polymers of amino acids are critical to life as we know it. Chemists have copied nature by making synthetic polymers or plastics. There are two basic types of synthetic polymers; addition polymers and condensation polymers. Addition polymers form when a radical initiator adds to a carbon-carbon double bond to yield a reactive intermediate. This intermediate reacts with another monomer molecule to form a second intermediate. This monomeric addition process is repeated. An example of an addition polymer is polyethylene used to make plastic bags and plastic containers. Condensation polymers are formed by the reaction between two difunctional molecules. Each bond in the polymer is formed independently of the others. The monomers usually are in alternating order and the polymer often has atoms other than carbon in the main chain. Polyesters used in clothing and polycarbonates used in making bottles are examples of polymers formed by condensation. Though ...