Kinetics of polymerization involving reversible deactivation due to aggregation of active centers. Analytical vs. numerical solution for the ε‐caprolactone/dialkylaluminium alkoxide system

Duda, Andrzej; Penczek, Stanisław

doi:10.1002/marc.1994.030150617

Cited by 68 publications

(46 citation statements)

References 18 publications

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“…This is illustrated in Figure 4, for the polymerization of CL (eq 11), showing that at the complete consumption of A 3 in initiation and polymerization of CL, A4 is left almost intact (36,37).…”

Section: Metal Alkoxidesmentioning

confidence: 92%

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Thermodynamics, Kinetics, and Mechanisms of Cyclic Esters Polymerization

Duda¹,

Penczek²

2001

ACS Symposium Series

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Recent advances in pseudoanionic ring-opening polymerization (ROP) of cyclic esters initiated with covalent metal alkoxides and carboxylates are reviewed. General aspects of covalent ROP are discussed: first, thermodynamics, particularly of monomers exhibiting low ring strain. Then, structures of covalent initiators, their behavior in initiation, formation of active species, kinetics, and mechanism of propagation. Polymerization with reversibly aggregating species is analyzed in more detail. Mechanism of initiation and propagation, in the polymerizations induced with metal carboxylates (tin(II) octoate (Sn(Oct) 2 ) is discussed. It is shown that the actually initiating species are formed by converting Sn(Oct) 2 into OctSnOR and/or Sn(OR) 2 in reactions with ROH present in the system. Chain transfer reactions (transesterifications, both intra-and intermolecular), taking place in the polymerization of lactones and lactides, are quantitatively analyzed.Ring-opening polymerization (ROP) of cyclic esters is one of the preferred methods for a synthesis of high molar mass aliphatic polyesters (1-3) and more recently has even been extended to the enzyme catalyzed processes (4-7). Although polycondensation is at the basis of the major industrial aromatic polyesters (e.g. polyterephthalates), ROP has already been used in industrial production of two aliphatic polyesters, namely poly(e-eaprolactone) (1) and poly(L-lactide) (3). These are the ecologically degradable polymers and may play an important role in future polymer industry. Particularly poly(L-lactide), made from renewable starting materials (carbohydrates of various agricultural origin), can become attractive for countries that do not have their own sources of olefins.On the other hand, ROP of cyclic esters became an efficient tool in studies of the mechanism of anionic and pseudoanionic (covalent) ROP. This is because in many cyclic ester/initiator systems the termination could be excluded. There are, however, two well documented chain transfer reactions. Both are based on transesterification, 160

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Section: Metal Alkoxidesmentioning

confidence: 92%

“…In this group of initiators the most extensively studied were dialkylaluminum alkoxides (R 2 A10R') introduced over 30 years ago (55, 56) but studied quantitatively and understood only recently (30,33,34,36,39).…”

Section: Alkylmetal Alkoxidesmentioning

confidence: 99%

Thermodynamics, Kinetics, and Mechanisms of Cyclic Esters Polymerization

Duda¹,

Penczek²

2001

ACS Symposium Series

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“…On the other hand, it is known that the CL polymerization in the presence of aluminum dialkylalkoxides proceeds selectively to products of a linear structure and in some systems products of M n as high as 5!10 5 [44][45][46] and polydyspersity !1.3 can be obtained. In systems with MAO, even for reactions carried out at room temperature a macrocyclic fraction is formed and the M w /M n values for the fractions of linear products are close to 2 ( Table 3, entry 5).…”

Section: Polymerization Of Cyclic Estersmentioning

confidence: 98%

Ring opening polymerization initiated by methylaluminoxane/AlMe3 complexes

Florjańczyk

Plichta

Sobczak

2006

Polymer

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“…They normally have significantly different reactivities depending on the degree of aggregation (m). The m value of metal alkoxides can be determined from the method of Penczek and co-workers [42,43] from a kinetic plot of ln(k app ) versus ln[I] 0 as shown in Eq. (10).…”

Section: Determination Of the Thermodynamic Parametersmentioning

confidence: 99%

Kinetics and thermodynamics analysis for ring-opening polymerization of ε-caprolactone initiated by tributyltin n-butoxide using differential scanning calorimetry

Limwanich

Meepowpan

Nalampang

et al. 2014

J Therm Anal Calorim

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The bulk ring-opening polymerizations (ROP) of e-caprolactone (e-CL) initiated by synthesized tributyltin n-butoxide (nBu 3 SnOnBu) initiator were conducted at 120°C and the molecular mass and polydispersity index of poly(e-CL), PCL, were determined. The coordinationinsertion ROP of e-CL was confirmed by 1 H-NMR. The molecular mass of PCL was successfully controlled with monomer to initiator concentration ratio. The kinetics and thermodynamics of ROP were investigated by differential scanning calorimetry (DSC) using both non-isothermal and isothermal methods. From the non-isothermal method, the activation energy (E a ) of ROP of e-CL initiated by 1.0, 1.5, and 2.0 mol% of nBu 3 SnOnBu was derived from the method of Kissinger (78.3, 61.1, and 59.9 kJ mol -1 ) and Ozawa (82.8, 66.2, and 64.9 kJ mol -1 ). For isothermal method, the values of E a for these three concentrations of nBu 3 SnOnBu were 74.2, 65.8, and 62.0 kJ mol -1 , respectively. The first-order reaction model was employed to determine the apparent rate constant (k app ). The degree of aggregation (m) of nBu 3 SnOnBu in e-CL was also determined using isothermal method which confirmed its nonaggregated form. In addition, the activation enthalpy (DH = ) and entropy (DS = ) were estimated to be 70.5 kJ mol -1 and -100.3 J mol -1 K -1 by isothermal DSC. The Friedman, Kissinger-Akahira-Sunose, and Flynn-Wall-Ozawa isoconversional methods were also applied to non-isothemal DSC data to investigate the dependence of E a with monomer conversion (a). The results of all three methods were discussed and compared with isothermal and non-isothermal methods at 1.0 mol% of nBu 3 SnOnBu. The overall results demonstrate that DSC is a fast, convenient, and reliable method for studying the kinetics and thermodynamics of ROP of e-CL initiated by nBu 3 SnOnBu.

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Kinetics of polymerization involving reversible deactivation due to aggregation of active centers. Analytical vs. numerical solution for the ε‐caprolactone/dialkylaluminium alkoxide system

Cited by 68 publications

References 18 publications

Thermodynamics, Kinetics, and Mechanisms of Cyclic Esters Polymerization

Thermodynamics, Kinetics, and Mechanisms of Cyclic Esters Polymerization

Ring opening polymerization initiated by methylaluminoxane/AlMe3 complexes

Kinetics and thermodynamics analysis for ring-opening polymerization of ε-caprolactone initiated by tributyltin n-butoxide using differential scanning calorimetry

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