Polymer Properties & Types PDF

POLYMER  POLYMER A long molecule made up from lots of small molecules called monomers. The term “polymer” (from the Greek polys meaning “many” and meros meaning “part”) Very Large molecules structures chain- like in nature. Structure of Polymer POLYMER Often, the chemical struct...

POLYMER  POLYMER A long molecule made up from lots of small molecules called monomers. The term “polymer” (from the Greek polys meaning “many” and meros meaning “part”) Very Large molecules structures chain- like in nature. Structure of Polymer POLYMER Often, the chemical structure of polymers is represented by the monomer enclosed in a parenthesis The n is the number of repeating units.  Polymerization Polymerization, any process in which relatively small molecules, called monomers, combine chemically to produce a very large chainlike or network molecule, called a polymer.  Some Application of Polymers AUTOMOBILE Used are - Instrument Panels - Engine - Windows - Tires - Body Panels CIVIL ENGINEERING The construction industry uses variety of classic building material like metals, glass, wood, and stone but plastic material are become increasingly important due to there outstanding performance. Some application of polymer in building construction: PVC with stabilizers and additives has been developed for roller shutters, gutters and fences. Polystyrene are used extensively, primarily in insulation applications: Composite materials are being used for load bearing in construction applications. Recycled plastic are also being used in a cement matrices. Polymeric fibers can also use to reinforce cement. Polymer mortars and concerted are used in applications such as protective coating.  Some Application of Polymers ELECTRONICS In general polymer have poor electrical conductivity, but new polymer material has been synthesized which process electrical conductivities. Such polymers are called conducting polymer. This process transforming a polymer to its conductive form via chemical oxidation and reduction called doping. AGRICULTURE Polymer are widely used in the field of agriculture to improve the physical properties of soil and increase productivity. These polymers are known as soil onditioner and used for the following purposes in agriculture: Preventing soil erosion. Reducing irrigation frequency. Increasing water used efficiency. Increasing plant performance especially in drought Addition Vs Condensation Polymer Addition polymer Are formed by a straight forward linking together of monomer units with no loss or gain of material. Addition Vs Condensation Polymer Addition polymer Are formed by a straight forward linking together of monomer units with no loss or gain of material. In Naming, put the word “poly” in front of the monomer’s name (monomer’s bracket) Some Addition Polymers  Addition Vs Condensation Polymer Condensation polymers Are formed by linking together of bifunctional polymers to give polymer and some small molecules like water, polyster and nylon Some Condensation Polymers  Exerise 1 Tell whether the ff. polymers are produced via addition or condensation 1. Polyvinyl chloride 2. Polyacrylamide  THERMOPLASTICS VS THERMOSETS Thermoplastics Thermosets These can be softenedby These hardenafter being heatingand hardenedby heated cooling- easilyrecycled Can easilybe cast into Can easilybe cast into different shapes variousshapes Cannot be reformed Example: polyethylene, Example: Polyurethaneand polypropyleneand Vulcanizedrubber, polystyrene.  ISOSTATIC , SYNDIOTACTIC , ATACTIC Tacticity is simply the way pendant groups are arranged along the backbone chain of a polymer. ISOSTATIC – the side chain is arranged on one side of the backbone chain. SYNDIOTACTIC - the side chain is arranged on alternatively of the backbone chain. ATACTIC- the side chain is arranged on Randomly of the backbone chain.  Copolymers A copolymer is a polymer derived from more than one species of monomer. There are four main types of copolymers Alternating copolymers – monomers are arranged in regular alternating series. Block copolymers – have regions in the material where a single monomer unit is repeated. Random copolymer – monomers are randomly combined Graft copolymer – involve side chains of one polymer attached to a backbone of a different polymer  Properties of Polymers The physical properties of a polymer such as its strength and flexibility depend on: chain length - in general, the longer the chains the stronger the polymer; side groups - polar side groups (including those that lead to hydrogen bonding) give stronger attraction between polymer chains, making the polymer stronger; branching - straight, unbranched chains can pack together more closely than highly branched chains, giving polymers that have higher density, are more crystalline and therefore stronger; cross-linking - if polymer chains are linked together extensively by covalent bonds, the polymer is harder and more difficult to melt. Naturally vs synthetics  Natural Polymers Examples of natural polymers Glucose – most abundant monosaccharide, is the primary chemical energy storage of plants via photosynthesis. Starch - the polymeric form of glucose that serves as the plant’s major energy storage. Cellulose- a liner polymer of glucose, is the major structural component of plant cell walls. It is the most abundant organic polymer material on earth. Only starch and cellulose have a configuration of linkage between carbon 1 and carbon 4 Chitin – an N-acetylglucosame polymer, can be sourced out mainly from crustaceans and bacteria and fungi. Most abundant organic skeletal components of invertebrates. Inorganic Polymers Inorganic polymer It is a polymer with a skeletal structure that does not include carbon atoms in the backbone.