2. Oxidation (thermal and light-catalyzed) Hydrolysis (ester backbone polymers) Loss of polymer components (e.g. plasticizer) Stable (incl. outdoor) Poly(methyl methacrylate) Bisphenol polycarbonate Poly (vinyl fluoride) Scratch-resistant coating Sensitive to UV Aromatic polyurethanes (aliphatic more stable) Sensitive to Oxidation Polyolefins Stabilizers

3. General Mechanism of Oxidation Chain Reaction Backbiting in Polymers

4. General mode of action – formation of weak radicals Examples 1. Aromatic amines (most active) R – aliphatic/aromatic Electron delocalization stabilizes radicals Disadvantages: staining antioxidants

5. 2. Hindered phenols http://patentimages.storage.googleapis.com/US20020142923A1/US20020142923A1-20021003-C00002.png https://www.dispersions-pigments.basf.com/portal/streamer?fid=560036 Disadvantages: good for gasoline, too volatile for use in plastics

6. Higher molecular weight hindered phenols Nitrogen-containing phenols (more effective) Dinitriles

7. -Contain S(II), S(IV), P(III) - Act differently than antioxidants - Synergetic with antioxidants, used together

8. Propylenediamine - Work by metal sequestration Salpn EDTA Citric Acid

9. -Encapsulation of electroluminescent polymers on resins -Addition of carbon black as a pigment -UV screening agents

10. Natural phenols from plants (rosemary, black papper, buckweat, peanut halls) Vitamin E Plant flavanoids (epigallocatechin gallate)

11. What are lubricants? What is their function? When lubricants are not needed: -Bearings suspended by pressurized gas -Nylon and polytetrafluoroethylene (PTFE, Teflon ©) polymers Substances used as lubricants or lubricant alternatives -Carbon-graphite -Polymer cross-linking improves abrasion resistance -Silicon oil -Zirconium particles -MbS 2 -WS 2

12. -Coatings of polyurethane rubber, ultralight polyethylene (metal surfaces) -Making surface harder (cross-linked coatings) - Layer of silica or titania -High energy ion irradiation of polyethylene, nylon, polystyrene, etc -Diamond coating (vapor deposition)