ADVANCED BIO-FRIENDLY POLYMERS

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ADVANCED BIO-FRIENDLY POLYMERS
Jaroslav Mosnácek
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What is degradation of polymers?

• Any change of the polymer properties relative to
  the initial, desirable properties.
• In this sense, "degradation" is a generic term
  for any number of reactions which are possible in
  a polymer.
• These reactions, in turn, lead to a change in
  the physical and optical properties of the
  polymer.
• It is accompanied with change in molar mass of
  the polymers

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Mode of initiation of degradation

• Thermal
• Photo (light induced)
• Biological
• Chemical (Hydrolytic)
• Mechanical
• High Energy Radiation
• Will be discussed

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MECHANISTIC ASPECT OF POLYMER DEGRADATION
Mode of Initiation
Chain scission
Random Chain scission (Hydrocarbons)
Thermal
Norrish Type (I, II) chain scission (SSR)
Photochemical
Enzymatic or hydrolytic attack of esters, amides
and glucosides (SSR) Biological/hydrolytic
Norrish I and II
SSR Single step reaction
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MECHANISTIC ASPECT OF POLYMER DEGRADATION
Mode of Initiation
Side Chain elimination
Solvolysis (Hydrolysis) of ester linkage (SSR)
Chemical (hydrolytic)
Thermal
Elimination of HCl (PVC) (CR)
Hydrolysis of ester linkages
SSR Single step reaction CR Chain reaction
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MECHANISTIC ASPECT OF POLYMER DEGRADATION
Mode of Initiation
Thermal
Depolymerization
Typical for Poly(methyl methacrylate and mainly
for other acrylate based polymers
Cross-linking
Thermal, Photochemical, Mechanical, Chemical
Oxidation
PP with OxygenBeta-scission of tertiary alkoxy
radicals
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