Block copolymers by combination of LAP and RAFT polymerization Wang Hui Fudan Univ. China Ellen Donkers Lab of Polymer Chemistry, TU/e Bert Klumperman the Netherlands

Background Living anionic polymerization ◇ Excellent control ◇ Pure reactants ◇ Strict reaction conditions ◇ Limited range of monomers (styrene, diene) Elastomer: PB, PI …… Thermoplastic elastomer: SBS

RAFT polymerization ◇ Rather good control ◇ Wide range of monomers ◇ Wide range of operating conditions

Combination of LAP and RAFT

Model reaction with low MW RAFT agent [Styrene]=[maleic anhydride]=1M Reaction temperature: 85 ْC Initiator: Vazo 88 [RAFT]/[Vazo 88]=10 Solvent: MEK/Toluene (1/2) Linear increase of Mn with conversion Final PDI=1.16 Final conversion=95%

Chain extension of P(EB)-macro- RAFT MWmacro-RAFT=4000 g/mol [Styrene]=[maleic anhydride]=1M Reaction temperature: 85 ْC Initiator: Vazo 88 [RAFT]/[Vazo 88]=10 Solvent: MEK/Toluene (2/1) Predictable MW and linear increase of Mn with conversion Final conversion=93% PDI macro-RAFT=1.03 PDI final product=1.15

Chain extension of P(B)-macro-RAFT MWmacro-RAFT=3500 g/mol [Styrene]=[maleic anhydride]=1M Reaction temperature: 85 ْC Initiator: Vazo 88 [RAFT]/[Vazo 88]=10 Solvent: MEK/Toluene (2/1) linear increase of Mn with conversion Final conversion=48% PDI macro-RAFT=1.03 PDI final product=1.37 Cross-linking after long reaction time

Chain extension of P(SB)-macro- RAFT MWmacro-RAFT=4000 g/mol MW styrene block=2000 g/mol [Styrene]=[maleic anhydride]=1M Reaction temperature: 85 ْC Initiator: Vazo 88 [RAFT]/[Vazo 88]=10 Solvent: MEK/Toluene (2/1) Linear increase of Mn with conversion Final conversion=89% PDI macro-RAFT=1.07 PDI final product=1.57

Chain extension of P(SB)-macro- RAFT with rather high MW MWmacro-RAFT=70000 g/mol MW styrene block=60000 g/mol [Styrene]=[maleic anhydride]=0.3M Reaction temperature: 85 ْC Initiator: Vazo 88 [RAFT]/[Vazo 88]=5 Solvent: MEK/Toluene (1/1) If MW of butadiene block is 60000, reaction was stopped in 2 hours, due to the intensive gelation.

Chain extension of P(SEP)-macro- RAFT with rather high MW MWmacro-RAFT=70000 g/mol, MW styrene block=10000 g/mol [Styrene]=[maleic anhydride]=1M Reaction temperature: 85 ْC Initiator: Vazo 88, [RAFT]/[Vazo 88]=5 Solvent: MEK/Toluene (1/1) UV-305nm DRI

Conclusion and discussion ◇ Block copolymers were prepared by combination of LAP and RAFT polymerization, starting from different macro-RAFT agents without too high MW. ◇ Double bonds had some influences on the polymerization in RAFT process. The higher content of PB block is, the sooner cross-linking will take place.

Conclusion and discussion ◇ High viscosity does not effect the RAFT polymerization. MWmacro-RAFT=70000 g/mol MW styrene block=60000 g/mol [styrene]=[maleic anhydride]=1M [RAFT]/[vazo 88]=10 Solvent: MEK/toluene=1 Reaction temperature: 85 ْC

Conclusion and discussion ◇ Macro-RAFT agents with too high MW may act as inhibitor in RAFT polymerization.

Conclusion and discussion ◇ Styrene homopolymerizatio gives less inhibition in chain extension of P(SEP)-RAFT agent with rather high MW. DRIUV-305nm

Conclusion and discussion ◇ Reactive center-tertiary carbon radical may not work well in the RAFT polymerization. New RAFT agent with a secondary living group has been synthesized and tested in the same way.

Future work and recommendations ◇ The reaction conditions to be optimized. ◇ Alternative way to be proposed. ……” Click Chemistry ” ?

Acknowledgement Prof. Daoyong Chen Prof. Ming Jiang Prof. Zhengzhong Shao …… Department of Macromolecular Science Fudan University Ellen Donkers Dr. Bert Klumperman Prof. Cor Koning Prof. P.J. Lemstra Edgar Karssenberg …… Eindhoven University of Technology Dutch Polymer Institute

Thanks for your attention and time!

Questions???

A typical Route

Proposed Mechanism of RAFT