Crystallization kinetics of β-nucleated isotactic polypropylene (β-iPP) under isothermal conditions were investigated by differential scanning calorimetry. iPP was nucleated by a trisamide derivative, namely tris-2,3-dimethyl-hexylamide of trimesic acid (TATA). In the presence of TATA possessing dual nucleating ability, the formation of the α- and β-form occurs simultaneously. An isothermal stepwise crystallization method is suggested in this study, which can separate the crystallization process of β- and α-iPP and consequently their crystallization kinetics can be evaluated separately. The results indicated that the mechanism of crystallization changes in temperature especially in the vicinity of the upper critical temperature of the formation of the β-phase. In addition, it was found that the ratio of the growth rates of β- and α-modification determines the characteristics of crystallization and influences the apparent rate constant of crystallization of both polymorphs.
1. Padden, FJ, Keith, HD. Spherulitic crystallization in polypropylene. J Appl Phys. 1959;30:1479–1484. .
2. Varga, J. β-Modification of isotactic polypropylene: preparation, structure, processing, properties, and application. J Macromol Sci Phys. 2002;B41:1121–1171.
3. Brückner, S, Meille, SV, Petraccone, V, Pirozzi, B. Polymorphism in isotactic polypropylene. Prog Polym Sci. 1991;16:361–404. .
4. Lotz, B, Wittmann, JJ, Lovinger, AJ. Structure and morphology of poly(propylenes): a molecular analysis. Polymer. 1996;37:4979–4992. .
5. Juhász, P, Belina, K. Crystallization and morphology of propylene/pentene random copolymers. J Reinf Plast Compos. 2001;20:2–11.
6. Krache, R, Benavente, R, Lopez-Majada, JM, Perena, JM, Cerrada, ML, Perez, E. Competition between α, β, and γ polymorphs in beta-nucleated metallocenic isotactic polypropylene. Macromolecules. 2007;40:6871–6878. .
7. Leugering, HJ. Einfluss der Kristallstuktur und Überstuktur auf einige Eigeschaften von Polypropylen. J Macromol Chem. 1967;109:204–216. .
8. Shi, GY, Zhang, XD, Qiu, ZX. Crystallization kinetics of β-phase poly(propylene). Macromol Chem Phys. 1992;193:583–591. .
9. Varga, J, Mudra, I, Ehrenstein, GW. Highly active thermally stable β-nucleating agents for isotactic polypropylene. J Appl Polym Sci. 1999;74:2357–2368. .
10. Menyhárd, A, Varga, J, Molnár, G. Comparison of different β-nucleators for isotactic polypropylene, characterisation by DSC and temperature-modulated DSC (TMDSC) measurements. J Therm Anal Calorim. 2006;83:625–630. .
11. Keda N , Kobayashi T, Killough L. Novel β-nucleator for polypropylene. Polypropylene ‘96. World Congress. 1996.
12. Cermak, R, Obadal, M, Ponizil, P, Polaskova, M, Stoklasa, K, Lengalova, A. Injection-moulded α- and β-polypropylenes: I. Structure vs. processing parameters. Eur Polym J. 2005;41:1838–1845. .
13. Dong, M, Guo, Z, Yu, J, Su, Z. Crystallization behavior and morphological development of isotactic polypropylene with an aryl amide derivative as β-form nucleating agent. J Polym Sci Part B. 2008;46:1725–1733. .
14. Mohmeyer, N, Schmidt, HW, Kristiansen, PM, Altstadt, V. Influence of chemical structure and solubility of bisamide additives on the nucleation of isotactic polypropylene and the improvement of its charge storage properties. Macromolecules. 2006;39:5760–5767. .
15. Varga, J, Stoll, K, Menyhárd, A, Horváth, Z. Crystallization of isotactic polypropylene in the presence of a beta-nucleating agent based on a trisamide of trimesic acid. J Appl Polym Sci. 2011;121:1469–1480. .
16. Dou, Q. Effect of calcium salts of glutaric acid and pimelic acid on the formation of β crystalline form in isotactic polypropylene. Polym Plast Technol Eng. 2008;47:851–857. .
17. Dou, Q, Lu, QL. Effect of magnesium malonate on the formation of the β crystalline form in isotactic polypropylene. J Vinyl Addit Technol. 2008;14:136–141. .
18. Dou, Q, Lu, QL, Li, HD. Effect of metallic salts of malonic acid on the formation of β-crystalline form in isotactic polypropylene. J Macromol Sci Part B Phys. 2008;47:900–912. .
19. Dou, Q, Lu, Q. Effect of calcium malonate on the formation of β crystalline form in isotactic poly(propylene). Polym Adv Technol. 2008;19:1522–1527.
20. Zhang, Z, Tao, Y, Yang, Z, Mai, K. Preparation and characteristics of nano-CaCO3 supported β-nucleating agent of polypropylene. Eur Polym J. 2008;44:1955–1961. .
21. Zhang, Z, Wang, C, Yang, Z, Chen, C, Mai, K. Crystallization behavior and melting characteristics of PP nucleated by a novel supported β-nucleating agent. Polymer. 2008;49:5137–5145. .
22. Xiao, W, Wu, P, Feng, J. Effect of β-nucleating agents on crystallization and melting behavior of isotactic polypropylene. J Appl Polym Sci. 2008;108:3370–3379. .
23. Wunderlich, B. Macromolecular physics. London: Academic Press; 1979.
24. Avrami, M. Kinetics of phase change I. General theory. J Chem Phys. 1939;7:1103 .
25. Avrami, M. Kinetics of phase change II. Transformation-time relations for random distribution of nuclei. J Chem Phys. 1940;8:212 .
26. Kolmogoroff, AN. On the statistics of crystallization process in metals. Isvest Akad Nauk SSSR Ser Math. 1937;3:335.
27. Evans, UR. The Laws of expanding circles and spheres in relation of the lateral growths of surface films and the grain size of metals. Trans Faraday Soc. 1945;41:365 .
28. Varga, J. Crystallization, melting and supermolecular structure of isotactic polypropylene Karger-Kocsis, J, eds. Polypropylene: structure, blends and composites. 1 London: Chapmann&Hall; 1995 56–115. .
29. Wei, ZY, Zhang, WX, Chen, GY, Liang, JC, Chang, Y, Liu, LA, Wang, P, Sun, JC. Crystallization behavior of isotactic polypropylene/magnesium salt whisker composites modified by compatibilizer PP-g-MAH. J Therm Anal Calorim. 2011;103:701–710. .
30. Wei, ZY, Zhang, WX, Chen, GY, Liang, JC, Yang, S, Wang, P, Liu, LA. Crystallization and melting behavior of isotactic polypropylene nucleated with individual and compound nucleating agents. J Therm Anal Calorim. 2010;102:775–783. .
31. Chen, YH, Mao, YM, Li, ZM, Hsiao, BS. Competitive growth of α- and β-crystals in β-nucleated isotactic polypropylene under shear flow. Macromolecules. 2010;43:6760–6771. .
32. Varga, J. Melting memory effect of the β-modification of polypropylene. J Therm Anal Calorim. 1986;31:165–172. .
33. Monasse, B, Haudin, JM. Growth transition and morphology change in polypropylene. Colloid Polym Sci. 1985;263:822–831. .
34. Varga, J, Garzó, G. Isothermal crystallization of the β-modification of polypropylene. Acta Chim Acad Sci Hung. 1991;128:303–317.
35. Varga, J, Fujiwara, Y, Ille, A. βα-Bifurcation of growths during the spherulitic crystallization of polypropylene. Period Polytech Chem Eng. 1990;34:255–271.
36. De Santis, F, Adamovsky, S, Titomanlio, G, Schick, C. Scanning nanocalorimetry at high cooling rate of isotactic polypropylene. Macromolecules. 2006;39:2562–2567. .
37. De Santis, F, Adamovsky, S, Titomanlio, G, Schick, C. Isothermal nanocalorimetry of isotactic polypropylene. Macromolecules. 2007;40:9026–9031. .
38. Varga, J, Menyhárd, A. Effect of solubility and nucleating duality of N,N′-dicyclohexyl-2,6-naphthalenedicarboxamide on the supermolecular structure of isotactic polypropylene. Macromolecules. 2007;40:2422–2431. .