Transcript Polymer notes

INTRODUCTION TO POLYMERS AND PLASTICS
ADDITION POLYMERS OF ALKENES



“polymer” – Greek word
“polys” = many and “meros” = parts
Polymers – macromolecules composed of
repeating structural units called monomers
GENERAL REACTION
R
R
R
R
Alkene monomer
R
R
R
R
R
R
R
C
C
C
C
C
C
C
R
R
R
R
R
R
R
heat
pressure
Addition polymer
EXAMPLES OF ADDITION POLYMERS
nCH2=CH2
Ethene
(ethylene)
C
H2
Propene
(propylene)
n
Polyethylene
CH3
nCH2=CH2
C
H2
CH3
C
H2
C
H
n
Polypropylene
YOU TRY!
Draw the polymer that would be made from the
monomer vinyl chloride. What would it be
called?
CH
H2C
+ HC
CH

2
Cl
Cl
ANOTHER PRACTICE PROBLEM

Draw the polymer that would be made from the
monomer styrene. What would it be called?
H2C
CH
+
H2C
CH
COPOLYMERS

When two different monomers are combined by
addition polymerization, a copolymer is formed.
The polymer is random.
H2C
CH2
+
H2C
CH
H2
C
CH3
-E-P-P-E-E-E-P-P-E-P-E-E-E-P-P-P-E-P-
H2
C
H
C
CH2
H2
C
CONDENSATION REACTIONS
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.
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PRODUCTION OF NYLON 66
O
HO
O
CCH2CH2CH2CH2C
HO
H
OH
+
H
H
NCH2CH2CH2CH2CH2CH2N
O
H
O
CCH2CH2CH2CH2C
NCH2CH2CH2CH2CH2CH2N
H
H
H
+
H2O
NATURAL VS SYNTHETIC POLYMERS
The most abundant organic molecules in the
world are polymers
 Examples of Natural Polymers:

 1.
 2.
 3.
 4.
 5.
 6.
cellulose & lignan (main fibers in wood)
starch (stored sugar in plants)
chitin (fiber in the cell walls of algae, fungi and
arthropods)
collagen
DNA, RNA, and protein
cotton, wool, silk and flax
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PLASTICS
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

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USES OF POLYMERS
POLYMER
Neoprene
PROPERTIES
APPLICATIONS
Chemical resistant,
rubbery
Shoe soles, radiator
hoses
Fibrous, strong,
durable
Parachutes, carpet,
hosiery
polyester
Fibers recover
quickly after
extension,
moisture resistant
Filters, insulation,
tire cords, Dacron,
Mylar
Polyurethane
Flexible foams,
elastic quick-drying
fibers, hard-drying
films
Mattresses,
Airplane wings,
Spandex, Lycra,
varnishes
Polyamide (nylon)
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USES OF POLYMERS
POLYMER
PROPERTIES
APPLICATIONS
Polyvinyl alcohol
Colorless, watersoluble, flammable
resin
Adhesives, lacquers,
coatings & films
Polyvinyl chloride
-Rigid when
unplasticized, //
flexible when
placticized
Pipes, records, floor
tiles, credit cards //
Raincoats, shower
curtains
Polyvinyl fluoride
Resistant to
chemicals and
weathering
Protective films for
siding, pipes,
chemical containers
Polyvinylacetate
Water-insoluble resin Carpet backing, latex
paint, adhesive &
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cement
RECYCLING PLASTIC 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
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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
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RECYCLING PLASTIC POLYMERS
INVESTIGATION
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
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PLASTIC RECYCLING CODES
RECYCLING CODE
POLYMER RESIN
DESCRIPTION
Polyethylene
Terephthalate
(PET or PETE)
Usually clear or Peanut butter
green; rigid
jars, salad
dressing & soft
drink bottles
Semi-gloss,
toys; detergent,
crinkly; may be motor oil &
hard when
milk containers
thick
Plastic bags
Semi-rigid,
Shampoo,
glossy
vegetable oil
bottles
High-density
Polyethylene
(HDPE)
Polyvinyl
chloride or
vinyl (PVC-V)
Low-density
polyethylene
(LDPE)
Flexible, not
crinkly
SAMPLE PRODUCTS
Grocery, bread
& garment
bags; shrink17
wrap
PLASTIC RECYCLING CODES
RECYCLING CODE
POLYMER RESIN
DESCRIPTION
SAMPLE PRODUCTS
Polypropylene
(PP)
Semi-rigid,
Low gloss
Yogurt &
margarine
containers,
bottle tops,
medicine bottle
Polystyrene
(PS)
Often brittle,
glossy
Multi-layer
plastics
Squeezable
Coffee cups,
meat trays &
fast food
containers, CD
cases
Squeezable
ketchup &
syrup
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containers
LecturePLUS Timberlake
RECYCLING PLASTICS
From Water Bottles to Polyester
 http://www.youtube.com/watch?v=zyF9MxlcItw
&feature=related
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WHAT DETERMINES THE PROPERTIES OF A
POLYMER?
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?
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STRUCTURE OF POLYMERS

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)
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POLYMER CHAIN STRUCTURES
LINEAR

Monomer units are linked in a chain-like manner
(like a paper clip chain)

Examples:
HDPE – high density polyethylene
 Polytetrafluoroethylene – Teflon
 PP – polypropylene
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Random coil – all tangled up like a plate of
spaghetti
POLYMER CHAIN STRUCTURES
BRANCHED
Has short chains attached to the main chain
 Tends to have less strength and lower solution
viscosity compared to a linear polymer
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Examples:
Polyethylene
Glycogen
POLYMER CHAIN STRUCTURES
CROSS-LINKED

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
THERMOPLASTIC
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
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THERMOSET
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?
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LecturePLUS Timberlake
POLYMER BUILDING
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
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