Abstract
During mixing of a rubber compound containing silica and silane, the mixer is not only used for the dispersion of the filler and other ingredients, but also for a chemical reaction. These two functionalities of the mixer result in opposite processing requirements: A good dispersion is reached by high shearing forces, increasing the compound temperature. The silanization is not dependent on high shearing forces; it is positively influenced by high temperatures, but with an increasing risk of scorch. Another drawback is the equilibrium between the ethanol concentration in the vapor phase in the void space of the mixing chamber and in the rubber phase, which is limiting the reaction rate of the silanization. Devolatilization of the compound is a crucial factor for the efficiency of the silanization reaction.
In this article a model for devolatilization of a rubber compound in an internal mixer is developed, including a chemical reaction replenishing the volatile component during the devolatilization process. The model is based on the penetration theory, with the main contribution to the devolatilization being convective mass transfer. The main influencing factors, theoretically deducted and practically verified, are temperature, mixer volume, fill factor, rotor speed, reaction time and partial pressure of the volatile component in the void volume of the mixer.
References
1Latinen, G. A.: Am. Chem. Soc. Adv. Chem. Ser. 34, p. 235 (1961)10.1021/advancesSearch in Google Scholar
2Coughlin, R. W., Canevari, G. P.: AIChE J. 15, p. 560 (1969)10.1002/aic.690150416Search in Google Scholar
3Roberts, G. W.: AIChe J. 16, p. 878 (1970)10.1002/aic.690160530Search in Google Scholar
4Biesenberger, J. A., Sebastian, D. H.: Principles of Polymerization Engineering. Wiley-Interscience, New York (1983)Search in Google Scholar
5Denson, C. D., in: Advances in Chemical Engineering, Wei, J. (Ed.), Harcourt Brace Jovanovich, New York, p. 61 (1983)10.1016/S0065-2377(08)60251-3Search in Google Scholar
6Collins, G. P., Denson, C. D., Astarita, G.: AIChE J. 31, p. 1288 (1985)10.1002/aic.690310807Search in Google Scholar
7Valsamis, L. N., Canedo, E. L.: SPE ANTEC Tech. Paper, New York (1989)Search in Google Scholar
8Valsamis, L. N., Canedo, E. L.: Int. Polym. Process. 4, p. 247 (1989)10.3139/217.890247Search in Google Scholar
9Foster, R. W., Lindt, J. T.: Polym. Eng. Sci. 30, p. 621 (1990)10.1002/pen.760301102Search in Google Scholar
10Foster, R. W., Lindt, J. T.: Polym. Eng. Sci. 30, p. 424 (1990)10.1002/pen.760300707Search in Google Scholar
11Keum, J., White, J. L.: Int. Polym. Process. 14, p. 101 (2004)Search in Google Scholar
12Wang, N. H., Sakai, T., Hashimoto, N.: Int. Polym. Process. 10, p. 296 (1995)10.3139/217.950296Search in Google Scholar
13Wang, N. H.: Polym. Eng. Sci., 40 (8), p. 1833 (2000)10.1002/pen.11315Search in Google Scholar
14Wang, N. H.: Chem. Eng. Technol. 24, p. 957 (2001)10.1002/1521-4125(200109)24:9<957::AID-CEAT957>3.0.CO;2-MSearch in Google Scholar
15Cairncross, R. A., Francis, L. F., Scriven, L. E.: AIChE J. 42, p. 55 (1996)10.1002/aic.690420107Search in Google Scholar
16Alsoy, S., Duda, J. L.: Drying Technol. 16, p. 15 (1998)10.1080/07373939808917390Search in Google Scholar
17Alsoy, S., Duda, J. L.: J. Polym. Sci., Part B: Polym. Phys. 37, p. 1665 (1999)10.1002/(SICI)1099-0488(19990715)37:14<1665::AID-POLB11>3.0.CO;2-PSearch in Google Scholar
18Vrentas, J. S., Vrentas, C. M.: J. Poly. Sci., Part B: Polym. Phys. 32, p. 187 (1994)10.1002/polb.1994.090320122Search in Google Scholar
19Okazaki, M., Shioda, K., Masuda, K., Toei, R.: J. Chem. Eng. Japan. 7, p. 99 (1974)10.1252/jcej.7.99Search in Google Scholar
20Siddaramaiah, R. S., Premakumar, U., Varadarajulu, A.: JAPS67, p. 101 (1998)10.1002/(SICI)1097-4628(19980103)67:1<101::AID-APP12>3.0.CO;2-4Search in Google Scholar
21Hunsche, A., Goerl, U., Koban, H. G., Lehmann, Th.: Kautsch. Gummi Kunstst. 51, p. 525 (1998)Search in Google Scholar
22Dierkes, W., Noordermeer, J. W. M.: Paper presented at the European Rubber Research – Practical Improvements of the Mixing Process Conference, Paderborn, Germany (2005)Search in Google Scholar
23Luginsland, H.-D.: Paper presented at the 11. SRC Conference, Puchov, Poland (1999)Search in Google Scholar
24Luginsland, D., Hasse, A.: Paper presented at the Am. Chem. Soc. Rubber Div. Conference, Dallas, TX, USA (2000)Search in Google Scholar
25Görl, U., Hunsche, A., Mueller, A., Koban, H. G.: Rubber Chem. Technol. 70, p. 608 (1997)10.5254/1.3538447Search in Google Scholar
26Görl, U., Parkhouse, A.: Kautsch. Gummi Kunstst. 52, p. 493 (1999)Search in Google Scholar
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