1. 10.2 NOTES Petrochemicals and Polymers

2. Chemists use molecule knowledge to design new molecules
The hydrocarbons not used for energy, lubricants, and road tar can be called builder molecules

3. C.1 Creating New Petrochemicals
Until the early 1800s all objects used by humans were made from wood, stone, or metals or other things that came from living organisms (wool, silk)
Monomers are simple molecules that are the building blocks of many materials

4. Polymers
Very large molecules composed of 500 to 20,000 repeating monomers
Can be both naturally occurring or synthetic
Natural polymers
Celluloid – comes from wood
Shellac – type of varnish that comes from animals
Synthetic polymers
Man made
Nylon, polyester, plastics

6. Many materials common today were unknown before the mid-1900s
Petrochemicals
Compounds produced from oil or natural gas
Direct uses include: detergents, pesticides, pharmaceuticals
Indirect uses include: raw materials for paint, fabrics, insulation, foam, moldings

7. There are very few builder molecules, but they are very versatile
Ethene
Molecular formula - C2H4
Structural formula
Sometimes called ethylene
Has a double covalent bond
4 valence electrons are shared between two atoms

8. Addition reaction
A reaction that takes place at a double or triple bond site in organic molecules
Another two atoms or groups are added to the carbons in the double and triple bond
Example reaction:

9. Addition polymer
Polymer formed through addition reaction
Example:

10. Many different combinations with ethene molecules
Vinyl chloride- adding Cl
Acrylonitrile- adding cyanide (CN)

11. Styrene- adding benzene ring
Molecule properties are very different based on the functional group added

12. C.2 Polymer structure and properties
Unmodified, the arrangements of covalent bonds in long string-like polymer molecules causes the molecules to coil loosely
A collection of polymer molecules (such as those in a sample of molten polymer) can intertwine, much like strands of cooked spaghetti
In this form, the polymer is flexible and soft
Use a pencil line on paper to represent a liner polymer, draw a collection of loosely coiled polymer molecules.

13. Ductiliy – the ability to be drawn into strands
Ductility depends on temperature
Warm: polymers slide past each other, more flexible
Cold: More rigid
Flexibility can also be changed by adding molecules that act as an internal lubricants
Polyvinyl chloride (PVC) is used in rigid pipes and house siding
With added lubricant molecules, polyvinyl chloride becomes flexible enough for use in such consumer goods as raincoats and inflatable pool toys.

14. Branched polymers
Polymers with side chains perpendicular to the original chain
Draw at least two different models of branched-chain polymers.
Try to vary your representations – the forms of branched polymers can differ greatly.
Branching changes the properties of a polymer by affecting the ability of chains to slide past one another and by altering intermolecular forces.

16. Draw several linear polymer chains that have been cross-linked.
Cross-linking
The process of increasing polymer strength and firmness as connecting 2 polymer chains together
Draw several linear polymer chains that have been cross-linked.

18. Draw several cross-linked, branched polymers
Draw several cross-linked, branched polymers. Then describe how cross-linked branched polymers compare to cross-linked linear polymers.
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 Cross linked branched polymers will be stronger than cross-linked linear polymers because there will be more connections.
Polymer strength and toughness is controlled by arranging the polymer chains so that they are arranged so that they lie in the same general direction

20. Draw several aligned linear polymer chains.

21. Draw several aligned and cross-linked linear polymer chains.