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A spectroscopic criterion of isotactic polypropylene
Yu. V. KISSIN et al'.
178
7. B. WUNDERLICH and P. SULLIVAN, Polymer 3 (2): 247, 1962 8. V. A. KARGIN, J. Polymer Sci. 30: 247, 1958 9. V. A. KARGIN A. I. KITAIGORODSKII, and T. L. SLONIMSKII, Kolloid. zh. 19: 131, 1957 10. V. A. KARGIN, Vestnik Akad. N a u k SSSR 4 : 19, 1961 11. V. A. KARGIN, and N. F. BAKEYEV, Kolloid. zh. 19 : 133, 1957 12. V. A. KARGIN, and T. L. SLONIMSKII, Kratkie ocherki po fiziko-khimii polimerov. {Short Essays on the Physical Chemistry of Polymers.) Foreign Literature Publishing House, ~[oscow State University, Moscow, 1960 13. E. W. FISCHER, Z. Naturforsch. 12a: 753, 1957 14. R. EPPE, E. W. FISCHER and H. A. STUART, J. Polymer Sci. 34: 721, 1959 15. B. WUNDERLICH and W. H. KASHDAN, J. Polymer Sci. 50 : 71, 1961 16. A. KELLER, Phil. Mag. 2: 1171, 1957 17. A. KELLER, Makromol. Chem. 3 4 : 1, 1959
Letter to the Editor A SPECTROSCOPIC CRITERION OF ISOTACTIC POLYPROPYLENE * Y U . V . K I S S I N , G . t ). B E L O V , I . V . Y E R E M I N A , Y E . A . V E L I C H E N K O V A , V. I. TSVETKOVA and N. M. CHIRKOV
(Received 20 February 1963) WIIEN propylene is polymerized on the catalyst system TiC14--AI(C~Hs)~C1 ( t ~ 4 0 - 5 0 °, [A1]/[Ti] ~ 1.2, [TiCl4] = 2.6-4.2 × 10 -8 mole/l) liquid polymers of molecular weight 280-660 are formed. A distinctive feature of these polymers is that in their infrared spectra the specific optical density of the bands at 1154 and 976 cm -1 (calculated for the same thickness of layer) is different for different specimens. I n polymers prepared by us the intensity of these bands varies from 0 to the value characteristic of crystalline polymers of high molecular weight, the value d e p e n d i n g o n t h e m o l e e u l a r weight of the polymers and on the quantity of AI(C~Hs)CI ~ present in the original AI(C~H5)~C1. We have suggested, and this has also been suggested in a recent paper [1], t h a t the bands at 1154 and 976 cm -I are specific to isotactic polypropylene and are absent from the spectrum of the atactic polymer. I n order to confirm this suggestion the X - r a y spectra of our polymers were recorded. At room temperature none of the polymers has a crystalline structure. The polymers giving bands at 1154 and 976 cm -1 in the infrared spectrum crystallize partially on cooling to -- 100 °, the angle of reflection in their X - r a y spectra being the same as for isotactic polypropylene. The degree of crystallization of our polymers was n o t more t h a n 14-19~o and this is explained by their low molecular weight. The polymers t h a t do not give bands at 1154 and 976 cm -1 show the same halo on cooling to --100 ° as at 20 °. The glass temperature of these polymers is --53 °. F r o m our results it can be ascertained t h a t the bands at 1154 and 976 cm -1 in the infrared spectrum of polypropylene provide a criterion of its isotacticity. The proposed spectro* Vysokomol. soyed. 5: Iqo. 7, 1117, 1963.
Isotactic polypropylene
179
scopic characteristics appear even in polymers with a molecular weight of 400-600, i. e. for molecules containing 3-5 turns of the isotactic helix. Quantitative t r e a t m e n t of the results is now in hand for the purpose of creating direct method for determining the isotacticity of polypropylene, and also for the analysis of the structure of ethylene-propylene copolymers. Translated by E. O. PI~ILLIPS
REFERENCE l. V. L. FOLT, I. I. SHIPMAN and S. KRIMM, J. P o l y m e r Sci. 61 : 517, 1962
178
7. B. WUNDERLICH and P. SULLIVAN, Polymer 3 (2): 247, 1962 8. V. A. KARGIN, J. Polymer Sci. 30: 247, 1958 9. V. A. KARGIN A. I. KITAIGORODSKII, and T. L. SLONIMSKII, Kolloid. zh. 19: 131, 1957 10. V. A. KARGIN, Vestnik Akad. N a u k SSSR 4 : 19, 1961 11. V. A. KARGIN, and N. F. BAKEYEV, Kolloid. zh. 19 : 133, 1957 12. V. A. KARGIN, and T. L. SLONIMSKII, Kratkie ocherki po fiziko-khimii polimerov. {Short Essays on the Physical Chemistry of Polymers.) Foreign Literature Publishing House, ~[oscow State University, Moscow, 1960 13. E. W. FISCHER, Z. Naturforsch. 12a: 753, 1957 14. R. EPPE, E. W. FISCHER and H. A. STUART, J. Polymer Sci. 34: 721, 1959 15. B. WUNDERLICH and W. H. KASHDAN, J. Polymer Sci. 50 : 71, 1961 16. A. KELLER, Phil. Mag. 2: 1171, 1957 17. A. KELLER, Makromol. Chem. 3 4 : 1, 1959
Letter to the Editor A SPECTROSCOPIC CRITERION OF ISOTACTIC POLYPROPYLENE * Y U . V . K I S S I N , G . t ). B E L O V , I . V . Y E R E M I N A , Y E . A . V E L I C H E N K O V A , V. I. TSVETKOVA and N. M. CHIRKOV
(Received 20 February 1963) WIIEN propylene is polymerized on the catalyst system TiC14--AI(C~Hs)~C1 ( t ~ 4 0 - 5 0 °, [A1]/[Ti] ~ 1.2, [TiCl4] = 2.6-4.2 × 10 -8 mole/l) liquid polymers of molecular weight 280-660 are formed. A distinctive feature of these polymers is that in their infrared spectra the specific optical density of the bands at 1154 and 976 cm -1 (calculated for the same thickness of layer) is different for different specimens. I n polymers prepared by us the intensity of these bands varies from 0 to the value characteristic of crystalline polymers of high molecular weight, the value d e p e n d i n g o n t h e m o l e e u l a r weight of the polymers and on the quantity of AI(C~Hs)CI ~ present in the original AI(C~H5)~C1. We have suggested, and this has also been suggested in a recent paper [1], t h a t the bands at 1154 and 976 cm -I are specific to isotactic polypropylene and are absent from the spectrum of the atactic polymer. I n order to confirm this suggestion the X - r a y spectra of our polymers were recorded. At room temperature none of the polymers has a crystalline structure. The polymers giving bands at 1154 and 976 cm -1 in the infrared spectrum crystallize partially on cooling to -- 100 °, the angle of reflection in their X - r a y spectra being the same as for isotactic polypropylene. The degree of crystallization of our polymers was n o t more t h a n 14-19~o and this is explained by their low molecular weight. The polymers t h a t do not give bands at 1154 and 976 cm -1 show the same halo on cooling to --100 ° as at 20 °. The glass temperature of these polymers is --53 °. F r o m our results it can be ascertained t h a t the bands at 1154 and 976 cm -1 in the infrared spectrum of polypropylene provide a criterion of its isotacticity. The proposed spectro* Vysokomol. soyed. 5: Iqo. 7, 1117, 1963.
Isotactic polypropylene
179
scopic characteristics appear even in polymers with a molecular weight of 400-600, i. e. for molecules containing 3-5 turns of the isotactic helix. Quantitative t r e a t m e n t of the results is now in hand for the purpose of creating direct method for determining the isotacticity of polypropylene, and also for the analysis of the structure of ethylene-propylene copolymers. Translated by E. O. PI~ILLIPS
REFERENCE l. V. L. FOLT, I. I. SHIPMAN and S. KRIMM, J. P o l y m e r Sci. 61 : 517, 1962