1. Polymer Modified Bitumen Oscar Ellison

2. Contents of presentation • Why do we use polymers • What are polymers • History in NZ and internationally • Types and effects of different polymers • Thermoplastic • Plastomer • Elastomer • Thermoset and others • The future

3. Why do we use polymers • Increase demand from the road network • Search for new ideas and technologies • Polymers are an effective solution What is required • Enhance important properties of asphalt • Not detrimental to basic properties • Workable and able to process • Cost effective

4. What are polymers • Very large molecules • Made up of smaller monomers • Common both in nature and everyday life • First synthetic polymers created around 1910 • Varying molecules and lengths

5. The Chemistry: Styrene-butadiene Butadiene C4H6 Styrene C6H5CH=CH2

6. Use in New Zealand • Natural Latex in sealing • SBS, EVA and PBD in sealing • SBS and EVA in asphalt

7. Types of Polymer Used Elastomers Plastomers Thermoplastic Thermoset

8. Elastomers • Natural Rubber Long flexible chains • SBR (Styrene Butadiene Rubber) Random co-polymer Hard styrene and rubbery butadiene Both monomers compatible with bitumen

9. SBS (Styrene Butadiene Styrene) • Most commonly used polymer • Block co-polymer • Entropic – structural • Enthalpic - energy

10. Plastomers • EVA Ethylene Vinyl Acetate Random co-polymer Not crossed-linked Raises stiffness and toughness at low temperatures

13. Thermoset • Uncommon • Epoxy, Polyurethane • Once cured are not affected by temp • Difficult to handle • Created in situ – cross linked polymer network • Increased stiffness, rutting resistance, fuel resistance

14. Embrace the use of polymers • Sustainability etc. peak oil • Price of bitumen trending upwards need to find ways to reduce cost. Polymers can do this. Thinner layers etc. • New polymers. New technologies for mixing. • New thinking…