Pronounced effects of temperature and monomer concentration on isotactic specificity of triphenylmethyl methacrylate polymerization through free radical mechanism. Thermodynamic versus kinetic control of propagation stereochemistry

Polymer Journal

Volumn 28, Issue 6, 1996, Pages 556-558

  Nakano, Tamaki ^a   Matsuda, Akihiro ^a   Okamoto, Yoshio ^a  

^a NAGOYA UNIVERSITY   (Japan)

Author keywords

Helix; Monomer Concentration; Radical Polymerization; Tacticity; Temperature; Triphenylmethyl Methacrylate

Indexed keywords

ANIONIC POLYMERIZATION; MACROMOLECULES; MOLECULAR STRUCTURE; MONOMERS; SOLUTIONS; SOLVENTS; THERMAL EFFECTS; THERMODYNAMIC STABILITY;

HELIX; MONOMER CONCENTRATION; PHENYLDIBENZOSUBERYL METHACRYLATE; STEREOCHEMISTRY; TACTICITY; TRIPHENYL METHACRYLATE;

FREE RADICAL POLYMERIZATION;

EID: 0029697089     PISSN: 00323896     EISSN: None     Source Type: Journal    
DOI: 10.1295/polymj.28.556     Document Type: Article

References (25)

1. For reviews of radical reactions, see; (a) B. Giese, "Radicals in Organic Synthesis. Formation of Carbon-Carbon Bonds," Pergamon, Oxford, 1986.
2. (b) D. P. Curran, "Comprehensive Organic Synthesis," Vol. 4, Pergamon, Oxford, 1991, pp 716-777.
3. H. Yuki, K. Hatada, Y. Niinomi, and Y. Kikuchi, Polym. J., 36, 1 (1970).
4. T. Nakano, M. Mori, and Y. Okamoto, Macromolecules, 26, 867 (1993).
5. (a) N. A. Porter, T. R. Allen, and R. A. Breyer, J. Am. Chem. Soc., 114, 7676 (1992).
6. (b) W.-X. Wu, A.-T. McPhail, and N. A. Porter, J. Org. Chem., 59, 1302 (1994).
7. For other examples of stereospecific radical polymerization, see the references (No. 2) cited in ref 3.
8. 0 effects and interpreted the solvent effect in terms of solubility parameter of the polymer and the solvents; in addition, the highest mm content achieved in the report was 88%. Our work was performed independently from the aforementioned research.
9. S. Arano, H. Sekimura, and T. Kimura, Proc. Fac. Eng. Tokai Univ. (in Japanese), 113 (1977); for abstract, see Chem. Abstr., 89, 164057n (1978).
10. S. Arano, H. Sekimura, and T. Kimura, Proc. Fac. Eng. Tokai Univ. (in Japanese), 113 (1977); for abstract, see Chem. Abstr., 89, 164057n (1978).
11. Influence of monomer concentration on stereospecificity has been reported for the coordination polymerization of propylene and explained in terms of isomerization (epimerization) of the growing end of a polymer chain. See: (a) V. Buisco and R. Cipullo, J. Am. Chem. Soc., 116, 9392 (1994). (b) L. Resconi, A. Fait, F. Piemontesi, M. Colonnesi, H. Rychlicki, and R. Zeigler, Macromolecules, 28, 6667 (1995).
12. Influence of monomer concentration on stereospecificity has been reported for the coordination polymerization of propylene and explained in terms of isomerization (epimerization) of the growing end of a polymer chain. See: (a) V. Buisco and R. Cipullo, J. Am. Chem. Soc., 116, 9392 (1994). (b) L. Resconi, A. Fait, F. Piemontesi, M. Colonnesi, H. Rychlicki, and R. Zeigler, Macromolecules, 28, 6667 (1995).
13. For asymmetric anionic polymerization of TrMA, see: (a) T. Nakano, Y. Okamoto, and K. Hatada, J. Am. Chem, Soc., 114, 1318 (1992). (b) Y. Okamoto, K. Suzuki, K. Ohta, K. Hatada, and H. Yuki, ibid., 101, 4796 (1979).
14. For asymmetric anionic polymerization of TrMA, see: (a) T. Nakano, Y. Okamoto, and K. Hatada, J. Am. Chem, Soc., 114, 1318 (1992). (b) Y. Okamoto, K. Suzuki, K. Ohta, K. Hatada, and H. Yuki, ibid., 101, 4796 (1979).
15. For the synthesis of TrMA, see: Y. Okamoto and H. Yuki, "Macromolecular Syntheses," Vol. 10, J. K. Stille, Ed., Robert E. Krieger, Florida, 1990, pp 41-44.
16. The anionically obtained optically active poly(TrMA) exhibits an excellent chiral recognition ability to many classes of racemic compounds: (a) Y. Okamoto, S. Honda, I. Okamoto, H. Yuki, S. Murata, R. Noyori, and H. Takaya, J. Am. Chem. Soc., 103, 6971 (1981). (b) H. Yuki, Y. Okamoto, and I. Okamoto, ibid., 102, 6356 (1980).
17. The anionically obtained optically active poly(TrMA) exhibits an excellent chiral recognition ability to many classes of racemic compounds: (a) Y. Okamoto, S. Honda, I. Okamoto, H. Yuki, S. Murata, R. Noyori, and H. Takaya, J. Am. Chem. Soc., 103, 6971 (1981). (b) H. Yuki, Y. Okamoto, and I. Okamoto, ibid., 102, 6356 (1980).
18. For reviews of helical polymethacrylates and the other kinds of helical polymers, see: (a) Y. Okamoto and T. Nakano, Chem. Rev., 94, 349 (1994) and the references cited therein, (b) G. Wulff, Angew. Chem. Int. Ed. Engl., 28, 21 (1989); G. Wulff, CHEMTECH, 364 (1991).
19. For reviews of helical polymethacrylates and the other kinds of helical polymers, see: (a) Y. Okamoto and T. Nakano, Chem. Rev., 94, 349 (1994) and the references cited therein, (b) G. Wulff, Angew. Chem. Int. Ed. Engl., 28, 21 (1989); G. Wulff, CHEMTECH, 364 (1991).
20. For reviews of helical polymethacrylates and the other kinds of helical polymers, see: (a) Y. Okamoto and T. Nakano, Chem. Rev., 94, 349 (1994) and the references cited therein, (b) G. Wulff, Angew. Chem. Int. Ed. Engl., 28, 21 (1989); G. Wulff, CHEMTECH, 364 (1991).
21. We reported the mm contents of poly(PDBSMA)s obtained under the conditions identical to those of run 8, 9, and 10 to be 97%, 98%, and 93%, respectively,3 but in the repeated experiments we found the polymers with higher isotacticity are obtained with a high reproducibility. The lower mm contents in the previous study can be ascribed to contaminants in the monomer such as methacrylic acid. Evidentially, the copolymerization of PDBSMA with 2 mol% of methacrylic acid under the reaction conditions of run 10 gave a polymer having a triad tacticity of mm/mr/rr = 95.8/2.9/1.3 and the copolymerization of TrMA with a 1 mol% of methacrylic acid under the reaction conditions of run 3 resulted in a triad tacticity of mm/mr/rr = 88.0/9.0/3.0.
22. K. Hatada, T. Kitayama, and K. Ute, Prog. Polym. Sci., 13, 189 (1988).
23. Depolymerization could also lead to the thremodynamically more stable radical having a higher meso addition possibility.
24. It has been reported that electron spin resonance spectra of TrMA polymerization systems at the temperatures ranging form -90°C to 30°C using photoinitiation suggests the existence of two conformers of radicals though the relation between the two and our radical models is currently unknown. See: M. Kamachi, Adv. Polym. Sci., 82, 209 (1987); M. Kamachi, Y. Kuwae, S.-i. Nozakura, K. Hatada, and H. Yuki, Polym. J., 13, 919 (1981).
25. It has been reported that electron spin resonance spectra of TrMA polymerization systems at the temperatures ranging form -90°C to 30°C using photoinitiation suggests the existence of two conformers of radicals though the relation between the two and our radical models is currently unknown. See: M. Kamachi, Adv. Polym. Sci., 82, 209 (1987); M. Kamachi, Y. Kuwae, S.-i. Nozakura, K. Hatada, and H. Yuki, Polym. J., 13, 919 (1981).