Bell Ringer : Bell Ringer Based on our initial look at polymers through the properties of corn starch yesterday: To start today:
Use the K’NEX at your table to build two models of polymer chains like the corn startch we discussed before.
In your Journal:
Explain how your model represents a polymer.
Explain what a monomer would be in your model. Share and Discuss…. : Share and Discuss…. What does your model look like?
How does it represent a polymer?
What represents a monomer? PolymersThe K’nex Analogy : Monomers Polymers PolymersThe K’nex Analogy Ethylene Polyethylene " one part"
(mono = one, mer = part) "many parts"
(poly = many) Plastics : For thousands of years people have been using natural polymers like silk, wool, cotton, wood and leather.
In the last century or so, plastics which are synthetic polymers have been added to this list.
The key to developing the plastics were the discoveries made by the Nobel Prize awarded scientists Karl Ziegler and Giulio Natta in the 1950s. Plastics Plastic Production : Plastic Production 2. A petrochemical plant receives refined oil containing the small monomers they need and creates polymers through chemical reactions.
3. A plastics factory buys the end products of a petrochemical plant - polymers in the form of resins - introduces additives to modify or obtain desirable properties, then molds or otherwise forms the final plastic products. 1. Crude oil contains hundreds of
different hydrocarbons. The oil refinery
separates these materials and also breaks down (or "cracks”) large hydrocarbons into smaller ones. Source: http://nobelprize.org/educational/chemistry/plastics/readmore.html Polymerization : Polymerization Started (usually) by combining the monomers through the use of a catalyst.
Hundreds or thousands of monomers combine to form a polymer chain.
Millions of polymer chains are formed at the same time. The mass of polymers are known as a resin.
Resins are sold to plastics factories, usually in the form of powder, tiny granules, or pellets.
The plastics manufacturer adds coloring agents and other additives that modify the properties.
The resin is formed into the body of a cell phone, fibers for a sweater, or one of a myriad of other plastic products. Source: http://nobelprize.org/educational/chemistry/plastics/readmore.html Thermoplastics & Thermosets : Thermoplastics & Thermosets Plastics are classified into two categories according to what happens to them when they're heated to high temperatures.
Thermoplastics keep their plastic properties: They melt when heated, then harden again when cooled. 80% of the plastics produced are thermoplastics.
There is a huge range of uses including plastic wrap, food containers, lighting panels, garden hoses, and the constantly encountered plastic bag.
Thermoplastics are easy to recycle since they can be melted and reshaped into other products. For example, a plastic bottle that contained a soft drink could be reformed into the fibres of a fleece jacket. Source: http://nobelprize.org/educational/chemistry/plastics/readmore.html Thermoplastics & Thermosets : Thermoplastics & Thermosets Plastics are classified into two categories according to what happens to them when they're heated to high temperatures.
Thermosets are permanently "set" once they're initially formed and can't be melted. If they're exposed to enough heat, they'll crack or become charred.
Thermosets are good to use for things that will be warmed up such as kitchen tools. They're also used in glues, varnishes, and in electronic components.
Thermosets are hard to recycle, but today there are methods of crushing the objects into a fine powder form for use as fillers in reinforced thermosets. Source: http://nobelprize.org/educational/chemistry/plastics/readmore.html Types of Plastics : Thermoplastics Types of Plastics The long, linear polymer chains are only weakly chemically bonded. When heated, the polymers able to glide past each other. The weak bonds between the polymers reform when the plastic object is
cooled. The linear chains are crosslinked – strongly chemically bonded. This prevents a thermoplastic object from being melted and reformed. Source: http://nobelprize.org/educational/chemistry/plastics/readmore.html Thermosets Take-Home Points : Take-Home Points Plastics are synthetic materials derived from organic (carbon-containing) compounds. The most common sources for carbon compounds are oil and natural gas.
Plastics consist of polymers - long molecule chains - often mixed with other substances such as coloring agents and softerners.
The properties of a particular plastic depend on what the polymer chains look like, how they are bonded to each other, and which additives have been introduced.
There are two groups of plastics:
Thermoplastics, which melt when heated and can be remolded easily.
Thermosets, which can't melt or be remolded.
The properties of each type of plastic is determined by the type of bonding between polymer molecules. Source: http://nobelprize.org/educational/chemistry/plastics/readmore.html Reinforcement : Reinforcement Go to http://nobelprize.org/educational/chemistry/plastics/game/
Read/Listen to the Introduction.
Play at least 1 round of the game.