Exploring the World of Polymers: Properties, Types, and Impacts

1. WELCOME TO POLYMER PLANET

2. POLYMERS ARE EVERYWHERE

3. monomers Polymer “Poly” = many “mer” = units Polymers are many units called monomers that can be easily connected into long chains. They are giant molecules usually with carbons building the backbone.

4. POLYMERS (the whole train) are made out of MONOMERS(individual cars of the train) joined together.

5. Polymer: High molecular weight molecule made up of a small repeat unit (monomer). • A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A- • Monomer: Low molecular weight compound that can be connected together to give a poymer

6. Natural Vs Synthetic Polymers

7. Cotton: a natural polymer

8. Cotton fiber is mostly cellulose, and cellulose is made of chains of the sugar, glucose linked together a certain way.

9. Silk • Natural Rubber • Amber • Wool • Molecules of life: proteins and DNA Natural Polymers – found in nature and can be extracted

10. Natural Polymers

11. Properties of plastics :- Breaks Down more easily Wool is good heat insulator Silk is satiny texture Cotton – good air circulation and absorption of moisture Properties of Natural Polymers

12. Velcro • Spandex • Kevlar • Polyester • Nylon • Saran Synthetic Polymers derived from crude oil and made by scientists

13. Range of Synthetic Polymers • Traditionally, the industry has produced two main types of synthetic polymers – plastics and rubbers. • Plastics are (generally) rigid materials • Rubbers are flexible materials which exhibit long-range elasticity.

14. Properties of plastics :- Light Strong Easily molded and shaped and be coloured Inert (unreactive) to chemical Insulators of electricity and heat Cheap Able to resist corrosion Special properties can be made according to specific needs Properties of Synthetic Polymers

15. Human and Environmental Impact The Pros and Cons

16. Positive Impacts of Synthetic Polymers • Manufacturing: of plastic articles involving less energy than that necessary for the same production from traditional materials • Fuel Consumption: lightweight properties reduce fuel consumption in vehicles and space travel • Construction: non-corrosive plastics play a major role in the construction • Medical: Artificial limbs • Environmental: New Research for Oil Spills • Convenience: Everyday items (toothbrush, shower curtain) • Sports: Improvement to equipment and performance • http://www.youtube.com/watch?v=cmlunCbBV_o

17. The Negative Impacts of Synthetic Polymers Disposal problems Most of the polymers are non-biogradeable Cannot be decomposed by bacteria / decomposer So… caused disposal problem when polymer not decay Derived from Oil –non-renewable resource Blockage of rivers Plastics items discarded Blockage of drainage systems & rivers Diseases Polymer containers not buried in the ground Become breeding ground for mosquitoes

18. Harmful to animals The non-biogradeable polymers thrown into rivers -> lakes -> seas Swallowed by aquatic animals Animals die due to choking https://youtu.be/d2J2qdOrW44 Pollutions Open burning of polymers Released harmful, poisonous gases Cause air pollution Contributes to acid rain

19. Recycle • Avoid the use of single use plastics • Plastics can be burned as fuel • Use degradable plastics What you can do?

21. Polymer structures Linear, Branched, Crosslinked

22. Things that are made of polymers look, feel, and act depending on how their atoms and molecules are connected. Some are rubbery, like a bouncy ball, some are sticky and gooey, and some are hard and tough, like a skateboard.

23. By using different starting materials and processing techniques, we can produce polymers having different molecular structures

25. Linear Polymer • Microwaveable food containers, Teflon, Garden Hoses, Dacron carpets and Kevlar ropes. Sturdy and rigid structure. • In reality, the number of monomer units in a polymer commonly ranges from 1,000 to 10,000 or more.

26. Branched Polymer • Soft, flexible due to looser structure. Shampoo and ketchup bottles and milk jugs, plastic food wrap. To find some other examples, look on food containers and other plastics for the LDPE (low-density polyethylene)

27. Cross-linked Polymer • Lightly cross linked – flexible rubber. Heavily cross linked the more rigid and hard plastic. Two or more long chain polymer chains connected by chemical bonds that are not easily broken. Silly putty, Car Tires, Bowling balls.

28. Plastics are sudivided into Elastomers Thermoplastic Thermoset

29. Elastomer • Polymer that can regain its original shape after being stretched or pressed at room temperature. • Fancy word for Rubber

30. Range of Polymers • thermoplastics and thermosets

31. Thermosets • Extensive cross-linking formed by covalent bonds. • Bonds prevent chains moving relative to each other. • Material that cures or hardens when heated. • Chemical resistance, thermal stability, and overall durability

32. Thermoplastics (80%) • No cross links between chains. • Weak attractive forces between chains broken by warming. The Material softens (becomes pliable when heated and can be remoulded. • .Therefore can be melted down and recycled

33. Range of Polymers • Another way of classifying polymers is in terms of their form or function

34. Polymerisation The chemical process that joins the monomers together Addition Polymerisation Condensation Polymerisation Uses of polymers

35. Addition Polymerisation • Many molecules of monomers are added together • A monomer has to have a double bond –alkene • Only the polymer is produced (no other product)

36. Polyethene / Polyethylene Monomer: ethene

37. H H C C H H - - - - C C C C - - - - Ethylene has two carbons; plus, instead of the two carbons sharing just one electron each, they share two electrons each. High temperature or UV light can cause two of these shared (paired) electrons to become unshared (unpaired). H H These unpaired electrons are eager to pair up with another electron. If this ethylene molecule bumps another ethylene molecule, the unpaired electrons will cause the one it bumped into to lend one of its inner electrons. C C - - C C H - - H - - C C - -

38. Here’s another way to see the chain reaction. These are the carbon atoms with their double-bond (2 shared electrons each). The hydrogen atoms are not shown. A collision breaks the first bond. Once the first double bond is broken, a chain reaction will occur. In about a second an entire chamber of compressed ethylene gas turns into the polymer, polyethylene.

40. Polyvinylchloride • Monomer: vinyl chloride

43. Addition Polymerisation You are expected to be able to do the following things with addition polymers: • Predict the repeating unit of the polymer given the monomer • Predict the monomer from the polymer – displayed formula • Pg 102 # 1,2,3

44. Condensation Polymers • Involves 2 monomers that have different functional groups. • They also involve the elimination of water or another small molecule (ex. H2O, HCl) • Monomer A + Monomer B  Polymer + small molecule (normally water - dehydration). • Common condensation polymers include polyesters (the ester linkage) and polyamides (the amide linkage as in proteins).

45. Polyester is a another copolymer. It is made from equal amounts of two different monomers. Polyester is used to make bottles and fabrics.

46. Recall: Esterification Reaction

48. Hence the name POLYESTER ESTER groups formed Polyester is made from the two monomers, terephthalic acid (note: “ph” is silent) and ethylene glycol (car antifreeze). This makes a popular plastic called PETE, which is short for Polyethylene Terephthalate. The synthesis is also a dehydration reaction because water is given off. PETE O C O H

49. Polyesters • The ester linkage is formed between the monomers of a diol and a diacid.