Kinetic Study of <scp>D</scp>,<scp>L</scp>‐Lactide and Glycolide Homopolymerizations by Differential Scanning Calorimetry

Mazarro, Rosario; Lucas, Antonio de; Gracia, Ignacio; Rodrı́guez, Juan F.

doi:10.1002/macp.200700527

Cited by 17 publications

(16 citation statements)

References 15 publications

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“…For a constant a, the E a can be determined from the slope of the plot of ln b versus 1/T. To support the kinetic results from non-isothermal method, the isothermal method is used to determine the kinetic parameters for ROP of cyclic ester monomer as previously reported [17,18]. The polymerization of lactones and lactides using metal alkoxides initiator is a firstorder reaction with respect to monomer concentration as described in previous works [35][36][37][38].…”

Section: Poly(e-caprolactone)s Characterizationmentioning

confidence: 99%

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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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Section: Poly(e-caprolactone)s Characterizationmentioning

confidence: 99%

“…Recently, DSC has been used to study the kinetics of ROP of cyclic ester monomers [17][18][19][20]. DSC provides a continuous history of the heat evolved during the polymerization which can be analyzed kinetically, either by the isothermal or non-isothermal methods.…”

Section: Introductionmentioning

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 effect of the operating variables in the copolymerization process (temperature, MC ratio and IC ratio) and their possible interactions on the mass conversion (X) and number-average molecular weight (M n ) as response variables were carried out using a 23 full factorial design with two central points. The levels of each factor are indicated in Table 1 and were selected on the basis of preliminary studies of this polymerization system [10,[13][14][15]. In order to allow a direct comparison of each variable the independent variables were normalized in the range -1 to +1 according to Equation (1): (1) where x i is the normalized value of variable X at condition i, X i the dimensional value, and X min and X max represent the dimensional inferior and superior limits, respectively.…”

Section: Response Surface Methodology (Rsm)mentioning

confidence: 99%

“…Moreover, the mathematical model obtained provides a useful tool to select quickly and effortlessly the proper experimental conditions to achieve the desired properties of the polymer as a previous step in the synthesis and impregnation of biodegradable scaffolds [11,12] without having to carry out complex mathematical calculations based on a rigorous theoretical model. Considering that this work represents only a practical approach in order to estimate the properties of the synthesized PLGA for a further step of impregnation, the rigorous study of the reactions that are taking place is not an end in itself (unlike other specific mechanistic or kinetic studies [10,[13][14][15][16]) so that this model of 'black box' is only a practical method to choose a set of conditions for the polymerization process.…”

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confidence: 99%

Optimizing the bulk copolymerization of D,L-lactide and glycolide by response surface methodology

Cabezas¹,

Mazarro

Gracia³

et al. 2013

Express Polym. Lett.

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Poly(D,L-lactide-co-glycolide), PLGA, is a biodegradable polyester with high interest in medical industry, especially when zinc (II) 2-ethylhexanoate (ZnOct2) is used as catalyst substitute in polymerization processes as a substitute of the toxic tin (II) 2-ethylhexanoate (SnOct2) together an initiator such as methanol to improve the reaction rate. This article shows the optimization of the bulk copolymerization method by using a factorial design approach on three experimental parameters: temperature (T), molar ratio monomers/catalyst (MC ratio) and molar ratio initiator/catalyst (IC ratio). Their influence on mass conversion (X) and number-average molecular weight (Mn) was also discussed. Also it provides a useful tool to select in a fast way the proper experimental conditions for the obtaining of this polymer as a previous stage in the synthesis and impregnation of biodegradable scaffolds. This analysis revealed that the most relevant variable in the process is the temperature, being desirable to use the high value (160ºC) in order to obtain high values of conversion and molecular weight

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“…The DSC technique is frequently used to study the kinetics of the polymerization process [9,13,26,27]. It is accepted that this technique is fast to study the kinetics of polymerization reactions [9,13].…”

Section: Introductionmentioning

confidence: 99%

DSC Kinetics Analysis for the Synthesis of Three‐Arms Poly(ε‐caprolactone) Using Aluminum Tri‐sec‐Butoxide as Initiator

Limwanich

Punyodom

Kungwan

et al. 2015

Int J of Chemical Kinetics

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The kinetics of the ring-opening polymerization (ROP) of ε-caprolactone (ε-CL) initiated by soluble aluminum tri-sec-butoxide (Al(OsecBu) 3 ) has been investigated by the differential scanning calorimetry (DSC). The DSC polymerizations were carried out under nonisothermal and isothermal conditions to obtain three-arms poly(ε-caprolactone) (PCL). From nonisothermal DSC, the polymerization rate (dα/dt) increased with increasing heating rates. The values of E a were determined from Kissinger (63 ± 2 kJ mol −1 ), Friedman (31.0 -63.0 kJ mol −1 ), and Starink (64.0 -71.0 kJ mol −1 ) methods. From isothermal DSC, the dα/dt and the apparent rate constant (k app ) increased with increasing polymerization temperatures. The ROP of ε-CL initiated by Al(OsecBu) 3 occurred via the coordination insertion mechanism. The number average molecular weight (M n ) and percent yield of the synthesized PCL was enhanced by increasing polymerization temperature. The synthesized PCL withM n of 2.4 × 10 4 was obtained using a molar ratio of monomer to Al-O active center ([M]/[Al-O]) of 400 at 150ºC for 24 h. Al(OsecBu) 3 is one of the promising initiator due to its solubility, low transesterification reaction, and high efficiency in ε-CL polymerization. C 2015 Wiley Periodicals, Inc. Int J Chem Kinet 47: [734][735][736][737][738][739][740][741][742][743] 2015

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Kinetic Study of D,L‐Lactide and Glycolide Homopolymerizations by Differential Scanning Calorimetry

Cited by 17 publications

References 15 publications

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

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

Optimizing the bulk copolymerization of D,L-lactide and glycolide by response surface methodology

DSC Kinetics Analysis for the Synthesis of Three‐Arms Poly(ε‐caprolactone) Using Aluminum Tri‐sec‐Butoxide as Initiator

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