SYNTHETIC POLYMERS

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SYNTHETIC POLYMERS
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POLYMERS ARE EVERYWHERE
POLYMER
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INTRODUCTION
monomers
Polymer
The word, polymer, implies that polymers are
constructed from pieces (monomers) that can be
easily connected into long chains (polymer).
When you look at the above shapes, your mind
should see that they could easily fit together.
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Polymers

• Polymerization When carbon molecules combine
  into long chains.
• HOW This happens when a carbon to carbon double
  bond in a monomer is broken and new single bonds
  are formed creating a polymer.

                                                
                                                  
                                                  
        
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Methods for making polymers
The processes involved in the synthesis of
polymers can be divided into two categories
1)Addition polymerization 2)condensation
polymerization
Addition polymerization monomers react to form a
polymer without net loss of atoms
Most common form free radical chain reaction of
ethylene
n monomers
one polymer molecule
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Free-Radical Addition Polymerization of Ethylene
H2C
polyethylene
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MECHANISM

• Initiation

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1)POLYETHYLENE OR POLYTHENE
SOME IMPORTANT VINYL POLYMER

• It is widely used polymer.It is of two types.
• Low density polythene- It is formed by heating
  ethylene to 463-483k under a pressure of
  1500 atm in the presence of trace of
  oxygen.
• High density polythene- It is formed by heating
  ethylene to 333-343 under a pressure of
  6-7atm in the presence of Zeigler-Natta
  catalyst.
• Monomer unit- Ethylene

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• CHARACTERISTICS-
• Low density polythene is chemically inert, tough
  but flexible and poor electrical conductor.
• High density polythene is also chemically inert
  but is tougher harder than low density
  polythene.
• Uses-
• It is used for
• packaging, as insulation for electrical wires.
• In the manufacture of pipes, squeeze bottles
  toys.
• In the manufacture of containers house wares.

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2)POLYVINYL CHLORIDE (PVC)
Monomer unit - Vinyl chloride
Vinyl chloride
PVC
Characteristics - PVC is a hard and horny. It is
an electrical insulator and is resistant to fire
and chemicals. USES It is used for making-
1) Rain coats, hand bags, table
clothes. 2) Plastic dolls,
gramophones records , floor covering.
3) Electrical insulating coating on electrical
cables.
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3) POLYSTYRENE (STYRON) Monomer
unit- Styrene
(C6H5CO)2O2
Styrene
POLYSTYRENE

• USES -
• It is used
• In making light weight packaging materials.
• In the manufacture of food containers, egg boxes,
  etc.
• In making television cabinets.

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Some Common Addition Polymers

Name(s) Formula Monomer Properties Uses
Polyethylenelow density (LDPE) (CH2-CH2)n ethyleneCH2CH2 soft, waxy solid film wrap, plastic bags
Polypropylene(PP) different grades CH2-CH(CH3)n propyleneCH2CHCH3 atactic soft, elastic solidisotactic hard, strong solid similar to LDPEcarpet, upholstery
Poly(vinyl chloride)(PVC) (CH2-CHCl)n vinyl chlorideCH2CHCl strong rigid solid pipes, siding, flooring
Polystyrene(PS) CH2-CH(C6H5)n styreneCH2CHC6H5 hard, rigid, clear solidsoluble in organic solvents toys, cabinetspackaging (foamed)
Polyacrylonitrile(PAN, Orlon, Acrilan) (CH2-CHCN)n acrylonitrileCH2CHCN high-melting solidsoluble in organic solvents rugs, blanketsclothing
Polytetrafluoroethylene(PTFE, Teflon) (CF2-CF2)n tetrafluoroethyleneCF2CF2 resistant, smooth solid non-stick surfaceselectrical insulation
Poly(methyl methacrylate)(PMMA, Lucite, Plexiglas) CH2-C(CH3)CO2CH3n methyl methacrylateCH2C(CH3)CO2CH3 hard, transparent solid lighting covers, signsskylights
Poly(vinyl acetate)(PVAc) (CH2-CHOCOCH3)n vinyl acetateCH2CHOCOCH3 soft, sticky solid latex paints, adhesives