Model Studies of Transreactions in Condensation Polymers

Devaux, Jacques

doi:10.1002/9783527613847.ch3

Cited by 9 publications

(18 citation statements)

References 37 publications

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“…Following the original work by Yamadera and Murano27 and as shown by Devaux et al,28–32 we have applied their analysis to the current system of PET/MXD6 blends. According to studies by Devaux et al,28–32 analysis of interchange reactions between two dissimilar linear polycondensation polymers yields the following molecular formula. …”

Section: Resultsmentioning

confidence: 99%

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The interchange reaction between poly(ethylene terephthalate) and poly(m‐xylylene adipamide)

Xie¹,

Kim²,

Jabarin³

2009

J of Applied Polymer Sci

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The interchange reaction in blends of poly (ethylene terephthalate) (PET) and poly(m-xylylene adipamide) (MXD6) has been characterized in terms of changes observed in spectra obtained with a 600-MHz 1 H-NMR. The selective degradation of PET components in the blends was carried out in the NMR tubes prior to evaluation. Results indicate that there is no chemical reaction between the PET and MXD6 in the absence of sodium p-toluenesulfonate catalyst. The presence of the catalyst activates the interchange reaction between these two resins. A mathematical method was applied to calculate the degree of randomness of PET-MXD6 copolymer. In addition, the reaction degree was found to be affected by exposure temperature, time, shear rate, and catalyst concentration.

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Section: Resultsmentioning

confidence: 99%

“…In the case of this study, x represents the PET chain segment length and w the MXD6 chain segment length. The analysis of Deveux et al28–32 leads to the specific segment length of the various components in the reacted blended material, as follows: where the degree of randomness ( B ) of the copolycondensate is given by eq. (6).…”

Section: Resultsmentioning

confidence: 99%

The interchange reaction between poly(ethylene terephthalate) and poly(m‐xylylene adipamide)

Xie¹,

Kim²,

Jabarin³

2009

J of Applied Polymer Sci

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“…The determination of the molar fraction of dyads, average sequence length, and degree of randomness (B) of the Ny6/PET copolyesteramides resulting from exchange reactions between Ny6 and PET was performed by 13 C NMR with appropriate statistical methods. 21,22 With the relative intensities of the carbon peaks of the melt-mixed Ny6/PET materials, as those shown in Figure 2, we calculated ( Table 6) the molar fraction of dyad sequences E-T, E-CL, CL-T, and CL-CL; the average sequence length of the ET and CL units; and the degree of randomness in the copolymers obtained by heating equimolar Ny6/PET blends.…”

Section: Copolymer Compositionmentioning

confidence: 99%

“…The molar fractions of dyads and triads, average sequence lengths, and degrees of randomness in the Ny6/PET copolymers obtained by melt-mixing were calculated from the 13 C NMR data with the method of Devaux et al 21,22…”

Section: Nmr Calculationsmentioning

confidence: 99%

Essential role of chain ends in the nylon‐6/poly(ethylene terephthalate) exchange

Samperi¹,

Puglisi²,

Alicata³

et al. 2003

J. Polym. Sci. A Polym. Chem.

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A combination of NMR and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF) techniques were suitable tools for examining the exchange reactions that occur during the melt‐mixing of nylon‐6 and poly(ethylene terephthalate) (Ny6/PET) blends in the presence of p‐toluene sulfonic acid (TsOH) at 285 °C. Some researchers believe that TsOH is an efficient catalyst for the amide–ester exchange reactions in PET/Ny6 and PET/nylon‐66 blends in the molten state. Instead, we have found that TsOH is able to react in the molten state with PET, yielding PET oligomers terminated with carboxyl groups. Because the latter oligomers can quickly react with Ny6 producing a Ny6/PET copolymer, the role of TsOH in the melt‐mixing process is not that of a catalyst but of a reactant. Our study allowed the structural identification of the Ny6/PET copolyesteramide produced in the exchange as a function of melt‐mixing time. The results revealed the essential role of carboxyl end groups in the exchange reaction between Ny6 and PET and allowed a detailed mechanism for this reaction. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2778–2793, 2003

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“…The basic approach to kinetics and mechanism of the intermolecular transesterification reaction was developed in the early works by Devaux et al on the blends of poly(butylenes terephthalate) (PBT) polycarbonate (PC) and PET/PC. [9] Transesterification in PET/PEN system occurs primarily as a 'direct ester-ester exchange reaction' and can be described as a second-order reversible reaction; This means that the rate of consumption of any blend accuracy. This is mainly due to the discrepancy reported for the relation between the forward and backward rate constants, which leads to error in determining the rate constants and hence the extent of reactions.…”

Section: Introductionmentioning

confidence: 99%

An Improved Non‐Isothermal Kinetic Model for Prediction of Extent of Transesterification Reaction and Degree of Randomness in PET/PEN Blends

Golriz

Khonakdar

Jafari

et al. 2008

Macro Theory & Simulations

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An improved non‐isothermal kinetic model was developed based on mass balance and Arrhenius laws using a second‐order reversible reaction capable of predicting the extent of transesterification reaction (X) and the degree of randomness (RD) in poly(ethylene terephthalate) (PET)/poly(ethylene naphthalene‐2,6‐dicarboxylate) (PEN) blends prepared by a twin screw micro‐compounder over a full composition range under different processing conditions. The experimental values of X and RD were determined by 1H‐NMR and a direct relationship between them developed. The model constants were tuned by an optimization method using half of the experimental data, with the other half used for verification. Good agreement was found between the experimental and theoretical data in the verification stage and, therefore, it was concluded that the model is capable of predicting the extent of transesterification reaction with a high level of confidence for a wide range of processing conditions. Similarly to the experimental results, the model showed that, among all parameters affecting the extent of transesterification reaction, the time and temperature play the major role, whereas the blend composition does not have a significant role.magnified image

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Model Studies of Transreactions in Condensation Polymers

Cited by 9 publications

References 37 publications

The interchange reaction between poly(ethylene terephthalate) and poly(m‐xylylene adipamide)

The interchange reaction between poly(ethylene terephthalate) and poly(m‐xylylene adipamide)

Essential role of chain ends in the nylon‐6/poly(ethylene terephthalate) exchange

An Improved Non‐Isothermal Kinetic Model for Prediction of Extent of Transesterification Reaction and Degree of Randomness in PET/PEN Blends

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