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Introduction to Polymers and Plastics. “polymer” – Greek word “polys” = many and “ meros ” = parts Polymers – macromolecules composed of repeating structural units called monomers. Addition Polymers of Alkenes. General Reaction. Examples of addition polymers.
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“polymer” – Greek word “polys” = many and “meros” = parts Polymers – macromolecules composed of repeating structural units called monomers Addition Polymers of Alkenes
Draw the polymer that would be made from the monomer vinyl chloride. What would it be called? YOU TRY!
Draw the polymer that would be made from the monomer styrene. What would it be called? ANOTHER PRACTICE PROBLEM
When two different monomers are combined by addition polymerization, a copolymer is formed. The polymer is random. Copolymers -E-P-P-E-E-E-P-P-E-P-E-E-E-P-P-P-E-P-
Another method of making polymers Two compounds are combined One compound will lose a H atom and the other will lose an –OH group. These combine to form water. Nylons and polyesters are formed by condensation polymerization. They form in an alternating pattern. Condensation Reactions
The most abundant organic molecules in the world are polymers • Examples of Natural Polymers: • 1. cellulose & lignan (main fibers in wood) • 2. starch (stored sugar in plants) • 3. chitin (fiber in the cell walls of algae, fungi and arthropods) • 4. collagen • 5. DNA, RNA, and protein • 6. cotton, wool, silk and flax LecturePLUS Timberlake Natural vs Synthetic polymers
Plastics are a group of materials manufactured primarily from petroleum and natural gas. • All plastics are polymers. • Plastics are distinguished by their ability to be easily formed and molded in many ways for many purposes • 1907 – 1st fully synthetic polymer “Bakelite” • Hard plastic used as an electrical insulator • Paved the way for the >60,000 plastics made today LecturePLUS Timberlake Plastics
LecturePLUS Timberlake Uses of Polymers
LecturePLUS Timberlake Uses of polymers
Between 1960 and 2000, the total annual solid waste in the US doubled from 80 million tons to 160 million tons About 20% of the volume of trash is composed of plastics Plastics, unlike paper and garden debris, are not biodegradable Coding system identifies types of plastics so they can be categorized for recycling purposes LecturePLUS Timberlake Recycling plastic polymers
All plastics with the same recycling code are made of the same polymer The letters under the code symbol tell you from what plastic it is made Recyclers use the codes to separate plastics into groups Recycling plastic polymers
Each lab station has examples of the first 6 recycling codes. Begin at your usual lab station. Then rotate through all stations, 1 - 6 Complete the chart for each recycling code. *Describe the plastics: are they clear, rigid, crinkly, glossy, etc *Name some of the sample products: pop bottles, milk jugs, grocery bags, etc. BE SURE TO NOTE THE SIMILARITIES AND DIFFERENCES AMONG THE DIFFERENT POLYMERS Recycling plastic polymers investigation
From Water Bottles to Polyester http://www.youtube.com/watch?v=zyF9MxlcItw&feature=related LecturePLUS Timberlake Recycling Plastics
STRUCTURE determines the properties and functions of a polymer Stronger attractive forces between chains = stronger, less flexible polymer. Chains able to slide past each other = flexible polymer In polyethylene, attractive forces are weak induced dipole - dipole, will it be flexible or not? Nylon has strong hydrogen bonds, why does this make it a strong fiber? What determines the Properties of a Polymer?
Polymers can be created with all different degrees of hardness, flexibility, strength, and other properties by controlling structural factors such as: Branching Cross-linking Size (molecular mass) Structure of polymers
Monomer units are linked in a chain-like manner (like a paper clip chain) • Examples: • HDPE – high density polyethylene • Polytetrafluoroethylene– Teflon • PP – polypropylene • Random coil – all tangled up like a plate of spaghetti Polymer Chain Structures Linear
Has short chains attached to the main chain • Tends to have less strength and lower solution viscosity compared to a linear polymer • Examples: • Polyethylene • Glycogen Polymer Chain StructuresBranched
Caused by intermolecular forces like hydrogen bonding, covalent bonds between carbon atoms, or by disulfide bridges (bonds between sulfurs) • Examples: • Vulcanized rubber • Curly hair – amino acids methionine and cysteine Polymer Chain StructuresCross-linked
80% of thermoplastic polymers are linear or branched polymers Weak attractive forces between chains broken by warming Change shape - can be remolded Weak forces reform in new shape when cooled thermoplastic
Extensive cross-linking formed by covalent bonds. Bonds prevent chains moving relative to each other. What will the properties of this type of plastic be like? Thermoset
Using different colored paperclips, go back to the lab tables and build: an addition polymer a copolymer a condensation polymer a linear polymer a branched polymer a cross-linked polymer LecturePLUS Timberlake Polymer building