Polymerization of Methyl Methacrylate with Lithium Triflate. A Kinetic and Structural Study

被引：14

作者：

Hermosilla, Laura ^{[1
]}

Calle, Paloma ^{[1
]}

Tiemblo, Pilar ^{[2
]}

Garcia, Nuria ^{[2
]}

Garrido, Leoncio ^{[2
]}

Guzman, Julio ^{[2
]}

机构：

[1] Univ Autonoma Madrid, Dept Quim Fis, E-28049 Madrid, Spain

[2] CSIC, ICTP, Dept Quim Fis, E-28006 Madrid, Spain

来源：

MACROMOLECULES | 2013年 / 46卷 / 14期

关键词：

FREE-RADICAL POLYMERIZATION; ELECTRON-SPIN-RESONANCE; PROPAGATION RATE COEFFICIENTS; TERMINATION RATE COEFFICIENTS; DENSITY-FUNCTIONAL THEORY; MOLECULAR-ORBITAL METHODS; IONIC LIQUIDS; AB-INITIO; POLY(ETHYLENE OXIDE); MP2; ENERGY;

D O I：

10.1021/ma4008225

中图分类号：

O63 [高分子化学（高聚物）];

学科分类号：

070305 ; 080501 ; 081704 ;

摘要：

The radical photopolymerization of methyl methacrylate in the presence of lithium triflate is investigated by EPR and NMR spectroscopies in order to assess the effect of the ionic medium on the polymerization kinetics. The EPR spectra show a notorious increase in the concentration of propagating radical as result of a dramatic decrease in the average termination rate coefficient. IR spectroscopy experiments and theoretical studies the oxygen atom at the carbonyl position of the ester in the methyl confirm the formation of a complex between the lithium cation and methacrylate. The electrostatic repulsion between the complexed propagating radicals, specifically at the end of the chains, allows explaining the observed low termination rate. This strong interaction would lead to "quasi-living" polymer chains from the first steps of the polymerization.

引用

页码：5445 / 5454

页数：10

共 85 条

[1] Theoretical study of CF3SO3Li, (CF3SO2)(2)NLi, and (CF3SO2)(2)CHLi ion pairs [J].

Arnaud, R ;

Benrabah, D ;

Sanchez, JY .

JOURNAL OF PHYSICAL CHEMISTRY, 1996, 100 (26) :10882-10891

[2] Critically evaluated termination rate coefficients for free-radical polymerization: Experimental methods [J].

Barner-Kowollik, C ;

Buback, M ;

Egorov, M ;

Fukuda, T ;

Goto, A ;

Olaj, OF ;

Russell, GT ;

Vana, P ;

Yamada, B ;

Zetterlund, PB .

PROGRESS IN POLYMER SCIENCE, 2005, 30 (06) :605-643

[3] Chain-length-dependent termination in radical polymerization: Subtle revolution in tackling a long-standing challenge [J].

Barner-Kowollik, Christopher ;

Russell, Gregory T. .

PROGRESS IN POLYMER SCIENCE, 2009, 34 (11) :1211-1259

[4] Termination kinetics of free-radical polymerization in ionic liquids [J].

Barth, Johannes ;

Buback, Michael ;

Schmidt-Naake, Gudrun ;

Woecht, Inga .

POLYMER, 2009, 50 (24) :5708-5712

[5] DENSITY-FUNCTIONAL THERMOCHEMISTRY .3. THE ROLE OF EXACT EXCHANGE [J].

BECKE, AD .

JOURNAL OF CHEMICAL PHYSICS, 1993, 98 (07) :5648-5652

[6] Propagation and termination kinetics of cross-linking photopolymerizations studied using electron paramagnetic resonance spectroscopy in conjunction with near IR spectroscopy [J].

Berchtold, KA ;

Randolph, TW ;

Bowman, CN .

MACROMOLECULES, 2005, 38 (16) :6954-6964

[7] Critically evaluated rate coefficients for free-radical polymerization .2. Propagation rate coefficients for methyl methacrylate [J].

Beuermann, S ;

Buback, M ;

Davis, TP ;

Gilbert, RG ;

Hutchinson, RA ;

Olaj, OF ;

Russell, GT ;

Schweer, J ;

vanHerk, AM .

MACROMOLECULAR CHEMISTRY AND PHYSICS, 1997, 198 (05) :1545-1560

[8] CALCULATION OF SMALL MOLECULAR INTERACTIONS BY DIFFERENCES OF SEPARATE TOTAL ENERGIES - SOME PROCEDURES WITH REDUCED ERRORS [J].

BOYS, SF ;

BERNARDI, F .

MOLECULAR PHYSICS, 1970, 19 (04) :553-&

[9] Determination of addition and fragmentation rate coefficients in RAFT polymerization via time-resolved ESR spectroscopy after laser pulse initiation [J].

Buback, M ;

Hesse, P ;

Junkers, T ;

Vana, P .

MACROMOLECULAR RAPID COMMUNICATIONS, 2006, 27 (03) :182-187

[10] Free-radical termination kinetics studied using a novel SP-PLP-ESR technique [J].

Buback, M ;

Egorov, M ;

Junkers, T ;

Panchenko, E .

MACROMOLECULAR RAPID COMMUNICATIONS, 2004, 25 (10) :1004-1009

← 1 2 3 4 5 6 7 8 9 →