Transcript Polymer Chemistry

Polymer
Chemistry
Unit 12
Polymers
A large molecule that is made up of many
smaller, repeating units covalently bonded
to each other.
Monomer: The small units that make up a
polymer (hundreds or thousands). Normally
toxic compared to the polymer it makes.
Polymers vs. Macromolecules
 Polymers
contain repeating units
macromolecules do not.
 A polymer is a macromolecule but a
macromolecule may not be a polymer.
Polypropylene
DNA
Applications
 Packaging
 Paint
 Adhesives
 Fibers
 Elastomers
 And
Many More
Historical Background
Natural fibers: wool, silk, and cotton have
been used for hundreds of years
Columbus: Discovery of South American
and uses of natural rubber.
Hevea brasiliensis
History cont.
1839- Charles Goodyear
 Transformed hevea rubber to an
elastomer(vulcanized rubber)
 1st synthetic plastics made from natural
polymer.
1905- Leo Baekeland “Bakelite”
 Not softened by heat
 First true synthetic polymer
1920s – Hermann Staudinger
 Nobel
Prize in Chemistry 1953
 Father of polymer chemistry
What he discovered:
 Polymers are gigantic molecules
 They formed in long chains
 Formulated a structure for rubber
 Demonstrated both natural and synthetic
polymers.
Commercial Polymers
1927-PVC (polyvinyl chloride, used in
construction)
1931-PMMA and Neoprene (glass substitute)
1938-Nylon (fabric)
1941-LDPE (plastic warp to playground slides)
1943-Silicone (sealants)
1947-Epoxy resin (paint, adhesives)
1948- ABS (canoes to recorders)
1957-HDPE (bottle caps to hula hoops)
Natural vs. Synthetic Polymers
Natural
Polysaccharides: Starch and cellulose
Protein: Amino Acid chains
Synthetic
Plastics
Synthetic Rubbers
Synthetic Fibers
Polymerization
A type of reaction in which monomers are
linked together to form large chains.
(creates dimers and trimers first)
Composition of polymers
Homopolymers: contains one type of
repeating unit.
Copolymer: contains 2 or more repeat units.
Skeletal Structure of Polymers
1.
2.
3.
4.
5.
Linear: chain with 2 ends.
Cyclic: chain with no ends.
Branched: polymer has side chains
Dendritic: Tree-like
Network or Cross-linked: polymers linked
together.
Heating plastics
Thermoplastics
 Soft(can melt) and form when heat.
 Rigid when cool
 Can be reheated and reformed into different
shapes.
Thermosetting plastics
 Initially form a cross-linked solid when heated.
 Soft(doesn’t melt) when heated for a 2nd time
but cannot re-shape.
 Example: epoxy resin
Thermoplastics (higher number
means higher melting point