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BY-NC-ND 3.0 license Open Access Published by De Gruyter Open Access March 1, 2004

Bimodality of molecular mass distribution of polydienes obtained under the action of dilithium initiators in hydrocarbon media: the reasons, mathematical simulations, and their experimental testing

  • Yakov Estrin EMAIL logo
From the journal Open Chemistry

Abstract

Bimodal molecular mass distribution (MWD) of polymers, obtained upon polymerization of hydrocarbon monomers in the nonpolar media under the action of dilithium initiators, is the consequence of separation of the reaction mixture into two phases. Bifunctional /living/ oligomers produce the insoluble sediment due to tetrameric association of the lithium active sites (the swollen gel-fraction). Part of the active site remains in the solution (the solfraction). Difference in the concentrations of the active sites into the phases leads to difference between the propagation rates of the /living/ chains and, as a result, to Bimodal MWD. The mathematical model of polymerization in the two-phase system is proposed. Satisfactory agreement between the calculations and the experiments is shown for butadiene polymerization in heptane under the action of 1,4-dilithiumpentane. Regulation of MWD up to the complete elimination of bimodality is possible via the programmed dosage of monomer and solvent into the reactor.

[1] M.S. Jacovic, J.S. Favier and H. Janah: “Ionomer-like materials based on 4-vinyl-pyridine copolymers”, Macromol Chem. Rapid Comm. Vol. 10, (1989), pp. 217–225. http://dx.doi.org/10.1002/marc.1989.03010050510.1002/marc.1989.030100505Search in Google Scholar

[2] P. Roderic, R.P. Quirk and J-J. Ma: “Dilithium initiators Based on 1,3-bis(1-phenylethenyl)benzene. Tetrahydrofuran and lithium sec-butoxide effects”, Polym. Int. Vol. 24, (1991), pp. 197–206. Search in Google Scholar

[3] C.J. Bredeweg, A.L. Gatzke, G.Y.-S. Lo and L.H. Tung: “Stulies on dilithium initiators: 2. The bimodal molecular weight distribution in polyisoprene”, Macromolecules Vol. 27, (1994), pp. 2225–2232. http://dx.doi.org/10.1021/ma00086a03710.1021/ma00086a037Search in Google Scholar

[4] G.Y.-S. Lo, E.W. Otterbacher, A.L. Gatzke and L.H. Tung: “Studies on dilithium initiators: 3. Effect of additives and seeding”, Macromolecules Vol. 27, (1994), pp. 2233–2240. http://dx.doi.org/10.1021/ma00086a03810.1021/ma00086a038Search in Google Scholar

[5] G.Y.-S. Lo, E.W. Otterbacher, R.G. Pews and L.H. Tung: “Studies on dilithium initiators: 4. Effect of structure variations”, Macromolecules Vol. 27. (1994), pp. 2241–2248. http://dx.doi.org/10.1021/ma00086a03910.1021/ma00086a039Search in Google Scholar

[6] A.E. Madani, J. Belleney, J.-C. Favier, P. Hemery and P. Sigwalt: “Kinetics of the polymerization of isoprene, initiated by dilithiopolyisoprene in hexane”, Polymer Internatinal Vol. 31, (1993), pp. 169–174. Search in Google Scholar

[7] Ya.I. Estrin, L.T. Kasumova, S.M. Baturin and V.S. Radugin: “Dilithium alkanes soluble in hydrocarbons as initiator for the synthesis of bifunctional oligodienes”, Vysokomolekularnye Soedineniya Ser. A Vol. 38, (1996), pp. 1273–1280 (Russian); Polymer Science Ser. A, Vol. 38, (1996), pp. 813–819 (English). Search in Google Scholar

[8] Ya.I. Estrin: “Bifunctional oligodienes obtained by lithium-initiated polymerization: Molecular homogeneity problems”, Vysokomolekularnye Soedineniya Ser. B Vol. 39, (1997), pp. 351–370 (Russian); Polymer Science. Ser.B, Vol. 39, (1997), pp. 64–81 (English). Search in Google Scholar

[9] Ya.I. Estrin: “On the reasons for bimodal molecular mass distribution in diene polymerization with dilithium initiators”, Vysokomolekularnye Soedineniya Ser. A, Vol. 38, (1996), pp. 748–754. (Russian); Polymer Science. Ser. A, Vol. 38, (1996), pp. 450–455 (English). Search in Google Scholar

[10] Ya.I. Estrin: “Bimodal molecular mass distribution upon polymerization in the presence of dilithium initiators: A two-phase process model”, Vysokomolekularnye Soedineniya. Ser. A Vol. 40, (1998), pp. 1084–1091 (Russian); Polymer Science. Ser. A, Vol. 40, (1998), pp. 651–657 (English). Search in Google Scholar

[11] Ya.I. Estrin, A.A. Grischuk, L.T. Kasumova and G.A. Estrina: “Bimodal molecular mass distribution upon polymerization by the action of dilithium initiators: A refined model for the two-phase process: Comparison of calculations to experiment”, Vysokomolekularnye Soedineniya. Ser. A Vol. 43, (2001), pp. 1340–1351 (Russian); Polymer Science. Ser. A, Vol. 43, 2001, pp. 834–843 (English). Search in Google Scholar

[12] M. Scwarz, Anionnaya Polimerizatsiya, Mir, Moscow, 1971. (The Russian Edition); M. Scwarz, Carbanions. Living Polymers and Electron Transfer Processes, International Publishers, a Division of John Wiley & Sons, N.-Y., London, Sydney, Toronto, 1968 (The English Edition). Search in Google Scholar

[13] R.N. Young, L.J. Fetters, J.S. Huang and R. Krishnamoorti: “Some light on the concept of unreactivity arising from active center association in anionic polymerizations”, Polym. Int. Vol. 33, (1994), pp. 217–231. http://dx.doi.org/10.1002/pi.1994.21033021310.1002/pi.1994.210330213Search in Google Scholar

[14] M.A. Markevich, E.V. Kochetov and N.S. Enikolopian: “Kinetics of polymerization with the participation of zwitter ions”, Vysokomolecularnye Soedineniya, Ser. A, Vol. 13, (1971), pp. 1033–1046 (Russian). Search in Google Scholar

[15] Ya.I. Estrin: ““Living” chain association during the lithium—initiated polymerization: Dependence on the chain length and effect on the process kinetics”, Vysokomolekularnye Soedineniya. Ser. A, Vol. 41, (1999), pp. 1576–1586 (Russian); Polymer Science. Ser. A, Vol. 41, (1999), pp. 1003–1011 (English). Search in Google Scholar

[16] I. Obriot, J.C. Favier and P. Sigwalt: “New perfectly difunctional organolithium initiators for block copolymer synthesis: 3. Kinetics of addition of tret-butyllithium on 1,2-bis(isopropenyl-4-phenyl)ethane”, Polymer Vol. 28, 1987, pp. 2093–2098. http://dx.doi.org/10.1016/0032-3861(87)90047-410.1016/0032-3861(87)90047-4Search in Google Scholar

[17] R.D. Sanderson, A.H.A. Roediger and G.J. Summers: “Hydrocarbon-soluble difunctional organodilithium anionic initiators. A gas-liquid chromatographic study of the reaction of sec-BuLi with m-divinylbenzene”, Polym. Int., Vol. 35, 1994, pp. 263–272. http://dx.doi.org/10.1002/pi.1994.21035030810.1002/pi.1994.210350308Search in Google Scholar

[18] M. Morton, L.J. Fetters, J. Inomata, D.S. Rubio and R.N. Jung: “Synthesis and properties of uniform polyisoprene networks. I. Synthesis and characterization of alpha-omega-dihydroxypolyisoprene”, Rubber Chem. and Technol. Vol. 49, 1976, pp. 303–319. 10.5254/1.3534966Search in Google Scholar

[19] Ya.I. Estrin, L.T. Kasumova and V.K. Kol’tover: “Analysis of the functionality types distribution and mechanism of formation of hydroxyoligobutadienes by polymerization with the lithium initiator”, Vysokomolekularnye Soedineniya. Ser. A, Vol. 33, (1991), pp. 2425–2429 (Russian); Polymer Science. Ser. A, Vol. 33, (1991), pp. 2283–2287 (English). Search in Google Scholar

[20] Entsiklopediya polimerov (Encyclopedia of Polymers), Vol. 3, Sovetskaya Entsiklopediya, Moscow, 1977 (Russian). Search in Google Scholar

[21] Yu.S. Lipatov, A.E. Nesterov, T.M. Gritsenko and R.A. Veselovskii: Spravochnik po khimii polimerov (A Handbook on the Chemistry of Polymers), Naukova Dumka, Kiev, 1971 (Russian). Search in Google Scholar

[22] V.V. Shamanin, E.Yu. Melenevskaya and V.N. Sgonnik: “Influence of the concentration of growing chains on the polymerization rate of butadiene and the microstructure of the polymer formed in polybutadienyllithium-butadiene-alifatic hydrocarbon system”, Acta Polym. Vol. 33, 1982, pp. 175–180. http://dx.doi.org/10.1002/actp.1982.01033030310.1002/actp.1982.010330303Search in Google Scholar

[23] A.A. Tager: Fiziko-Khimiya Polimerov (Physical Chemistry of Polymers), 2nd Ed., Khimiya, Moscow, 1968. Search in Google Scholar

[24] R.A. Barzykina, L.T. Kasumova, V.P. Lodygina and Ya.I. Estrin: “On kinetics and mechanism of interaction of lithium oligobutadienyl with sec-lithium alkane”, Vysokomolekularnye Soedineniya. Ser A Vol. 26, (1984), pp. 1442–1448 (Russian). 10.1016/S0032-3950(84)80049-0Search in Google Scholar

[25] Ya.I. Estrin and L.T. Kasumova: “Chromatography of oligobutadienes with functional groups under critical conditions on silica gel”, Zhurnal Fizicheskoi Khimii, Vol. 68, (1994), pp. 1784–1788 (Russian); Russian Journal of Physical Chemistry, Vol. 68, (1994), pp. 1620–1623 (English). Search in Google Scholar

[26] D. Tischenko and N. Zhokhovets: “Investigation in the chlorine derivatives area. II. Inductive effect and the order of the replacement of hydrogen atoms in alkyl chlorides by chlorine”, Zhurnal Obschej Khimii (Journal of General Chemistry), Vol. 18, (1948), pp. 43–51 (Russian). Search in Google Scholar

[27] J. Stellbrink, L. Willner, O. Jucknischke, D. Richter, P. Lindner, L.J. Fetters and J.S. Huang: “Self-assembling behavior of living polymers”, Macromolecules Vol. 31, (1998), pp. 4189–4197. http://dx.doi.org/10.1021/ma971890e10.1021/ma971890eSearch in Google Scholar

[28] L.J. Fetters, N.P. Balsara, J.S. Huang, H.S. Joen, K. Almdal and M.Y. Lin “Aggregation in living polymer solutions by light and neutron scattering: A study of model ionomers”, Macromolecules Vol. 28 (1995), pp. 4996–5005. http://dx.doi.org/10.1021/ma00118a03110.1021/ma00118a031Search in Google Scholar

[29] Ya.I. Estrin, T.S. Zyubina: “Possible participation of poly(butadienyllithium) nonassociated active centers in chain propagation: Ab initio calculations”, Vysokomolekularnye Soedineniya. Ser A, Vol. 42, (2000), pp. 1647–1656 (Russian); Polymer Science. Ser. A, Vol. 42, (2000), pp. 1059–1066 (English). Search in Google Scholar

[30] J. Stellbrink, L. Willner, D. Richter, P. Lindner, L.J. Fetters and J.S. Huang: “Self-assembling behavior of butadienyllithium headgroups in benzene via SANS measurements”, Macromolecules Vol. 32, (1999), pp. 5321–5329. http://dx.doi.org/10.1021/ma981793110.1021/ma9817931Search in Google Scholar

Published Online: 2004-3-1
Published in Print: 2004-3-1

© 2004 Versita Warsaw

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