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TABLE 3 Thermal Properties of the Films 1a2 and 1b–1e
Obtained by Cyclotrimerization of MDI in the Absence or
Presence of PhNCO
REFERENCES AND NOTES
1 Kogon, I. C. J Am Chem Soc 1956, 78, 4911–4914.
2 Reymore, H. E. J.; Carleton, P. S.; Kolakowski, R. A.; Sayigh,
A. A. R. J Cell Plast 1975, 11, 328–344.
a
a
[MDI]0/[PhNCO]0
(mol ratio)
Td5
Td10
(ꢀC)
Char
yieldb (%)
3 Wang, C. L.; Klempner, D.; Frisch, K. C. J Appl Polym Sci
1985, 30, 4337–4344.
Film
(ꢀC)
4 Kordomenos, P. I.; Kresta, J. E. Macromolecules 1981, 14,
1434–1437.
1a2
1b
1c
1d
1e
a
3.0/0
447
451
441
428
395
467
471
466
461
450
75
75
70
65
61
3.0/0.55
3.0/1.2
3.0/2.0
3.0/3.0
5 Samborska-Skowron, R.; Balas, A. Polym Adv Technol 2002,
13, 653–662.
6 Kordomenos, P. I.; Kresta, J. E.; Frisch, K. C. Macromolecules
1987, 20, 2077–2083.
7 Duff, D. W.; Maciel, G. E. Macromolecules 1990, 23,
3069–3079.
Determined by TGA under N2.
Chair yield at 500 ꢀC under N2.
b
8 Duff, D. W.; Maciel, G. E. Macromolecules 1991, 24, 651–658.
9 Dabi, S.; Zilkha, A. Eur Polym J 1980, 16, 831–833.
10 Dabi, S.; Zilkha, A. Eur Polym J 1981, 17, 35–40.
11 Dabi, S.; Zilkha, A. Eur Polym J 1982, 18, 549–553.
N,N0,N00-tris[(dimethylamino)propyl]-s-hexahydrotriazine as a
catalyst. The thermal stability of the resulting film was much
lower (Td5: 429 ꢀC and Td10: 464 ꢀC) than the networked
polymer film of 1a2 obtained by the p-TolSO2Na-catalyzed
cyclotrimetization reaction. Theses results clarified that the
high conversion of isocyanate achieved by the utilization of
the highly active catalyst p-TolSO2Na was essential for the
high thermal stability of the film. The film of the networked
polymer 1a2 was rather brittle due to its relatively high
crosslinking density; however, the films of 1b–1d obtained
by the copolymerization of MDI and PhNCO were flexible as
shown in Figure 1(c).
ˇ
12 Kramarenko, V. Y.; Ezquerra, T. A.; Sics, I.; Balta´-Calleja, F. J.;
Privalko, V. P. J Chem Phys 2000, 113, 447–452.
13 Kramarenko, V.-Y.; Alig, I.; Privalko, V. P. J Macromol Sci
Part B Phys 2005, 44, 697–709.
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15 Raders, S. M.; Verkade, J. G.
J Org Chem 2010, 75,
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moto, K. Bull Chem Soc Jpn 1990, 63, 3486–3489.
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SUMMARY
18 Duong, H. A.; Cross, M. J.; Louie, J. Org Lett 2004, 6,
4679–4681.
The present work has proven the high potential of the cyclo-
trimerization of isocyanates to develop high-performance
materials with transparency and flexibility in a film state. By
minimizing chemical defect based on highly efficient and
selective cyclotrimerization that was achieved by employing
p-TolSO2Na as a catalyst, the resulting networked polymers
consisting of isocyanurate rings exhibited high heat resist-
ance due to the intrinsic thermal stability of isocyanurate.
The structural diversity of isocyanates is another important
advantage of the present approach, which will expand its
application fields.
19 Nambu, Y.; Endo, T. J Org Chem 1993, 58, 1932–1934.
20 Tanimoto, F.; Tanaka, T.; Kitano, H.; Fukui, K. Bull Chem
Soc Jpn 1966, 39, 1922–1925.
21 Kogon, I. C. J Org Chem 1959, 24, 83–86.
22 Montilla, F.; Clara, E.; Avile´s, T.; Casimiro, T.; Ricardo, A. A.;
da Ponte, M. N. J Organometallic Chem 2001, 626, 227–232.
23 Paul, F.; Moulin, S.; Piechaczyk, O.; Floch, P. L.; Osborn, J. A.
J Am Chem Soc 2007, 129, 7294–7304.
24 Moghaddam, F. M.; Dekamin, M. G.; Khajavi, M. S.; Jalili, S.
Bull Chem Soc Jpn 2002, 75, 851–852.
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