Nitroxide-Mediated Living Radical Polymerization: A Controlled Polymerization Method

1. 活性自由基聚合

2. 当前工业化聚合物合成中，以自由基法生产为 主，约占总聚合反应工业化生产的30%。然而自由 基聚合本身却有很多缺点：产物结构控制较难，易 双基终止，以及链转移等副反应的存在，使产物的 分子量分布较宽，并带有支链结构，无法有效的控 制分子量。 如果自由基聚合可以受到控制，无转移，无终 止，接近活性聚合。那么结合自由基聚合自身的优 点，其科学和实际意思将十分重大。

3. Nitroxide Mediated Living radical polymerization (NMP)

4. Craig J. Hawker, Ph.D. is currently Director of the Materials Research Laboratory and a Professor of Chemistry, Biochemistry and Materials at the University of California, Santa Barbara. From 1993-2004 he was a Research Staff Member and an investigator in the IBM Almaden Research Center. He received a Ph.D. in bioorganic chemistry from the University of Cambridge in 1988 under the supervision of Prof. Sir Alan Battersby. Jumping into the world of polymer chemistry, he undertook a post-doctoral fellowship with Prof. Jean Frechet at Cornell University from 1988 to 1990 and then returned to the University of Queensland as a Queen Elizabeth II Fellow from 1991 to 1993. Dr. Hawker is Editor of the Journal of Polymer Science, Polymer Chemistry, Adjunct Professor of Chemistry at the University of Queensland and serves as a consultant to a variety of US and international companies. His research has focused on the interface between organic and polymer chemistry with emphasis on the design, synthesis, and application of well-defined macromolecular structures in biotechnology, microelectronics and surface science1

5. Jean Fréchet MS: the Institut de Chimie et Physique Industrielles (now CPE) in Lyon BS: State University of New York, at Syracuse University. Chemistry Faculty at the University of Ottawa in Canada in 1973. IBM Professor of Polymer Chemistry at Cornell University in 1987. Chemistry Faculty at the University of California, Berkeley in 1997. Chair of Organic Chemistry in 2003 and Professor of Chemical Engineering in 2005.

6. 可以在聚合反应体系中加入一种量可以人为控制的可以在聚合反应体系中加入一种量可以人为控制的 反应物X，反应物不能引发单体聚合及发生其它类型反 应，但是可与活性链自由基P·迅速作用（减活反应）， 生成一个不引发单体聚合的“休眠种”P-X。若减活及活 化转换速率很快，在活性种浓度很低的情况下，聚合 物分子量将不由M·而由P-X的浓度决定。 所以关键是 发现有效的X，我们称X为稳定自由基。

7. When the stable radical is added into free radical polymerization system, the polymerization stops

8. When polymerization of acrylate at 80-100oC in the presence of BPO and hindered nitroxide, low MW oligomer was obtained. This can not be considered living polymerization

9. By increasing the temperature to130 °C and conducting the polymerizations in bulk, a system comprising benzoyl peroxide, 9, and a stable nitroxide, TEMPO (5), in a molar ratio of 1.3:1, gave polystyrene derivatives, 10, by a living process in which the molecular weight increased in a linear fashion with conversion. PDI= 1.2-1.3.

10. Unknown concentration of the initiating species

11. Unimolecular Initiators the R-methylbenzyl radical 12 as well as the mediating nitroxide radical 5 in the correct 1:1

12. Polymerization of MMA, MA monomers did not show living characteristics mainly reason is that the radicals abstract the α- hydrogen?

13. The polymerization rate significantly enhanced. Presumably the ability to form an intra-molecular H-bond leads to a change in mediating ability. This promoted the investigation of a wide range of other TEMPO-like structures

14. Approaches to Alkoxyamines 1). Polymerization method

15. 2). Hydrogen abstraction method When UV irradiation at 300 nm was carried out in this reaction system, the yield is high (> 90%).

16. 3) TEMPO oxidized and proton abstraction

17. Additive reaction

18. Elucidation of Living Nature

19. 1). Star polymer

20. 2). Graft polymer

21. 3). Hyperbranched polymer

22. 4). Dendritic structure

23. Atom Transfer Radical Polymerization, ATRP http://en.wikipedia.org/wiki/Main_Page ATRP or Atom Transfer Radical Polymerization is a Polymerization reaction involving free radicals. It was introduced as an extension to ATRA or Atom Transfer Radical Addition by Jinshang Wang and Matyjaszewski, (1995) and Sawamoto (1994/5).

24. Atom Transfer Radical Addition, ATRA

25. DrKrzysztof Matyjaszewski J.C. Warner Professor of Carnegie Mellon UniversityDepartment of Chemistry4400 Fifth AvenuePittsburgh, PA 15213 Dr. Mistuo Sawamoto Department of Polymer Chemistry Graduate School of Engineering Kyoto University Kyoto

29. Features of Controlled Radical Polymerization Processes • First-order Kinetics Behavior • Pre-determinable Degree of Polymerization • Narrow Molecular Weight Distribution • Long-lived Polymer Chains

30. First-order Kinetics Behavior First-order kinetics behavior, i.e. the polymerization rate (Rp) with respect to the monomer concentration ([M]) is a linear function of time. This is due to the lack of termination, so that the concentration of the active propagating species ([P*]) is constant.

31. This semilogarithmic plot is very sensitive to any change of the concentration of the active propagating species. A constant [P*] is revealed by a straight line. An upward curvature indicates an increase in [P*], which occurs in case of slow initiation. On the other hand, a downward curvature suggests a decrease in [P*], which may result from termination reactions increasing the concentration of the persistent radical, or some other side reactions such as the catalytic system being poisoned or redox processes on the radical

32. Pre-determinable Degree of Polymerization

33. Narrow Molecular Weight Distribution

34. 3.2.2 Fundamentals of an ATRP Reaction • Atom Transfer Radical Polymerization • ATRP in Protic Media • Homogeneous ATRP • Heterogeneous ATRP

35. Atom Transfer Radical Polymerization

36. Activation rate constants of CuI complexes derived from various N-donor ligands in the reaction with EBiB in MeCN at 35 °C.

38. Procedures for Initiation of an ATRP Reaction • Normal ATRP • Reverse ATRP • Simultaneous and Normal Initiation (SR&NT) • Activator Generated by Electron Transfer (AGET) • Activator ReGenerated by Electron Transfer(ARGET) • Initiator for Continuous Activator Regeneration • Halogen Exchange • Equivalent of “Halogen Exchange” in ARGET Chain Extention • ATRP from surface

40. 3.4 RAFT Polymerization RAFT=Reversible Addition-Fragmentation Chain Transfer Polymerization

41. Dr. Graeme Moad CSIRO Molecular and Health Technologies, Bayview Avenue, Clayton, Victoria 3168, Australia He joined CSIRO as a research scientist in 1979 and is currently a chief research scientist. Dr Moad is coauthor of the book ‘The Chemistry of Free Radical Polymerization’ which appeared as a second edition in 2006. His research interests lie in the fields of polymer design and synthesis (free radical polymerization, reactive extrusion), polymerization kinetics and mechanism, and most recently polymer nanocomposites.

42. Dr. Ezio Rizzardo CSIRO Molecular and Health Technologies, Bayview Avenue, Clayton, Victoria 3168, Australia Ezio Rizzardo is a graduate of the University of New South Wales and received his Ph.D. from the University of Sydney for his studies on the photochemistry of nitro compounds. He joined CSIRO in 1976 after a postdoc at Rice University, RIMAC, and the Australian National University. His CSIRO research has focussed on developing methods for controlling free radical polymerization. For this he has received a number of awards including the RACI Australian Polymer Medal and the CSIRO Chairman’s Gold Medal. Currently he is a CSIRO Fellow and a Fellow of the Australian Academy of Science.

43. Dr.San H. Thang CSIRO Molecular and Health Technologies, Bayview Avenue, Clayton, Victoria 3168, Australia San H. Thang was born in Saigon, Vietnam, in 1954 and came to Australia in 1979 as a refugee. He completed his B.Sc.(Hons) degree in 1983 and Ph.D. in 1987 from Griffith University. He joined CSIRO in 1986 as a research fellow. He then moved to ICI Australia in late 1987 to undertake the challenge of industrial research. He returned to CSIRO in late 1990, and in 1995 he was co-inventor of the RAFT Process. He is currently a senior principal research scientist at CSIRO Molecular and Health Technologies where his research focusses on the interface between organic and polymer chemistry.

46. Choice of RAFTAgents

47. The initial RAFT agents and the polymer RAFT agent should have a reactive C=S double bond (high kadd). • The intermediate radicals should fragment rapidly (high kβ, weak S–R bond in intermediate) and give no side reactions. • The intermediate should partition in favour of products (kβ≥k−add). • The expelled radicals (R•) must efficiently re-initiate polymerization (ki>kp).

48. Four equilibrium constants that need to be considered. • KP (=kaddP/k−addP) associated with the main equilibrium. • K (=kadd/k−add) and Kβ(=k−β/kβ) associated with the • pre-equilibrium. • KR (=kaddR/k−addR) associated with the reaction of the