Most technology involves production of monomers from basic feedstock.

1
Polymerization techniques

• Most technology involves production of monomers
  from basic feedstock.
• Usually involves reaction of simple organic
  molecules, such as alkanes, with CO/CO2/O2 etc.
• Examples Methyl acrylate
• Styrene
• Ethylene glycol
• Methyl acetate
• Ethylene

2
Monomers from natural gas

• Methane
• Natural gas
• Ethane Ethylene
• C2H6 ? C2H4 H2
• 2 C2H6 ? C3H8 CH4
• C3H6 ? C2H2 CH4
• C2H2 C2H4 ? C4H6
• C2H4 C2H6 ? C3H6 CH4

Thermal cracking
3
Monomers from natural gas

Ethylene Ethylbenzene - H2
Cl2 O2 Styrene Ethylene Oxide
- HCl HCN Vinyl
chloride Acrylonitrile
- H2O
4
Polymerization mechanisms
Remember from yesterday Two mechanisms 1) Step
reaction polymerization (Polycondenstation) 2)
Addition polymerization Ionic chain
reaction Complex coordination
polymerization Free radical polymerization
5
Polycondensation

• Melt
• An equilibrium process in which polymer is formed
  by driving the reaction towards completion
• - High temperature
• - Long reaction times (1H - days)
• - High yield
• - Low cost monomers

6
Polycondensation
Solution/interfacial polymerization - Low
temperature - Short reaction times - Expensive
monomers - Solvent removal/recovery can be
troublesome Industrial bulk processes often use
melt techniques Specialty processes often prefer
lower temperature solution/interfacial
techniques
7
Addition polymerization

• Bulk
• By combination of monomer and initiator in
  reactor
• - Used in radical polymerizations
• - Batch/continuous
• - High molecular weight
• - Difficult to remove unreacted monomer
• - Heat effects require special design

8
Addition polymerization
Norris-Trommsdorf effect Decrease in termination
rate in viscous media that results in higher
molecular weight polymers.
9
Addition polymerization
Solution - Better control over weight
distribution - Easier heat control - Complex
solvent removal/recovery - Solvent chain transfer
possible Frequently used in most ionic
polymerizations and polymerizations involving
water-soluble monomers/polymers. Homogeneous
Heterogeneous
10
Addition polymerization

• Suspension polymerization
• Droplets with monomer, initiator (and chain
  transfer agent)
• - Often water-based
• - Monomer insoluble in solvent
• - Initiator insoluble in solvent and soluble in
  monomer
• - Protective colloidal agent required
• - Size 10-1000 nm
• - Polymer isolation by filtration or
  centrifugation

11
Addition polymerization
PVC production using suspension
polymerization (Vinnolit, Germany)
12
Addition polymerization

• Emulsion polymerization
• Droplets with monomer
• Initiator, chain transfer agent and surfactant in
  solution
• - Often water-based
• - Monomer insoluble in solvent
• - Initiator soluble in solvent and soluble in
  monomer
• - Surfactant required
• - Size 0.05-5 nm (very small!)
• - Polymer isolation by coagulation (filtration
  impossible)

13
Addition polymerization