1. ADVANCED BIO-FRIENDLY POLYMERS
Jaroslav Mosnáček

2. 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

3. Mode of initiation of degradation
Thermal*
Photo (light induced)*
Biological*
Chemical (Hydrolytic)*
Mechanical
High Energy Radiation
*Will be discussed

4. 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

5. 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

6. MECHANISTIC ASPECT OF POLYMER DEGRADATION
Mode of Initiation
Depolymerization
Thermal
Typical for Poly(methyl methacrylate and mainly for other acrylate based polymers
Cross-linking
Thermal, Photochemical,
Mechanical, Chemical
Oxidation
PP with Oxygen Beta-scission of tertiary alkoxy radicals