Degradation kinetics of poly(ethylene terephthalate) and poly (methyl methacrylate) blends

Al‐Mulla, Adam; Shaban, Habib I.

doi:10.1007/s00289-006-0712-2

Cited by 15 publications

(11 citation statements)

References 6 publications

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“…During the first stage (Figures 4d and 5d) at <80% conversion, with an apparent activation energy of 193 kJ/mol, PET decomposes mainly by β-H transfer reactions, where hydrogen atoms in β position are transferred to a more stable carbon with subsequent scission of the molecule; rearrangement reactions leading to formation of new ester links and decarboxylation reactions (CO2 evolution) occur as well to obtain the major products, benzoic acid and vinyl terephthalate [76]. The increasing apparent activation energy above 80% conversion (Table 3 and Figure 5d) is signature of char formation [77,78], as mentioned above.…”

Section: Pyrolysis Kinetics and Thermodynamicsmentioning

confidence: 99%

“…For synthetic polymers, and PMMA in particular, dissociation of C-C bonds located at both the extreme of the chain (end-chain scission) and at any other point in the chain (random scission) have been taken into account. In the case of PET, we considered homolytic scission of the C-O bond [77,78,89,90]. The enthalpies that characterize biomass pyrolysis were evaluated by taking into account its lignocellulosic character and the primary depolymerization stages that occur through the rupture of main covalent bonds between monomers.…”

Section: Structure-reactivity Relationshipmentioning

confidence: 99%

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Structure-reactivity relationship in pyrolysis of plastics: A comparison with natural polymers

Larraín

Carrier

Radović

2017

Journal of Analytical and Applied Pyrolysis

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Highlights• Global activation energy depends on conversion in pyrolysis of all polymers.• Activation energy variability is proportional to chemical complexity of polymers.• An Evans-Polanyi relationship for initiation reactions of polymer pyrolysis is proposed. AbstractRecent advances in plastics recycling confirm the high potential of pyrolysis technologies to enhance recovery and selectivity rates. Modelling the kinetics of this complex process to stimulate scaling-up opportunities remains a major challenge.This study is an attempt to develop practical quantitative reactivity indices for the pyrolysis of natural and synthetic polymers. Representative samples from both categories (coal and pine vs. PET, PE and PMMA) were selected. Their weight loss during pyrolysis was determined experimentally and analyzed using judicious lumping procedures for its initiation, propagation and termination steps. The combined experimental and theoretical approach allowed us to determine apparent activation energies using the isoconversional Friedman method; and the use of Benson's group contribution method generated reaction enthalpies for the initiation reactions. Increasing activation energies with conversion in each case indicated that bond scission proceeds in order of increasing bond strength. The greater chemical complexity of natural polymers was reflected in the higher coefficients of variability for activation energy and wider ranges of reaction enthalpies. A structure-reactivity relationship based on the Evans-Polanyi theory was used to test the hypothesis that primary pyrolysis kinetics is controlled by cleavage of weakest chemical bonds. While the results show that this approach is promising, especially if confirmed by extension to a larger data set, they also suggest the need to compare the relative kinetic importance of initiation and propagation steps in the sequence of polymer pyrolysis reactions.

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Section: Pyrolysis Kinetics and Thermodynamicsmentioning

confidence: 99%

Section: Structure-reactivity Relationshipmentioning

confidence: 99%

Structure-reactivity relationship in pyrolysis of plastics: A comparison with natural polymers

Larraín

Carrier

Radović

2017

Journal of Analytical and Applied Pyrolysis

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“…In this study the crystallization enthalpy (ΔH) values were found to be dependent on the cooling rate and composition of the blend. Thermogravimetric analysis of PET/PMMA blends were carried out by Al-Mulla et al [2]. TGA analysis revealed that the blends were heterogeneous in nature.…”

Section: Introductionmentioning

confidence: 99%

Isothermal crystallization kinetics of poly(ethylene terephthalate) and poly(methyl methacrylate) blends

Al‐Mulla

2007

Express Polym. Lett.

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Abstract. Different kinetic models like the Avrami, Tobin and Urbanovici-Segal models have been applied for determining the isothermal crystallization kinetics of virgin poly(ethylene terephthalate) (PET) and PET/poly(methyl methacrylate) (PMMA) blends. The different compositions investigated were PET90/PMMA10, PET75/PMMA25 and PET50/PMMA50 [wt/wt%]. The experimental data was fitted using Solver, a non-linear multi-variable regression program and linearization method. The effect of composition variation of PET/PMMA on parameters like crystallization rate constant and crystallization exponent were investigated. Urbanovici-Segal and Avrami models gave the best fit to the experimental data. Tobin model does not seem to fit the experimental data for the systems under investigation. Experimental results indicated that the crystallization rate constant values increased with decreasing temperatures.

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“…Ramesan and Lee (2008) reported that the addition of PET to perspex was found to accelerate the crystallisation significantly during synthesis. Al‐Mulla and Shaban (2007) investigated the morphology of the blend of perspex and PET using scanning electron microscopy (SEM). Their study revealed that the blend showed a heterogeneous morphology in which the amorphous phase perspex formed spherical particles distributed in the PET matrix.…”

Section: Resultsmentioning

confidence: 99%

“…The thermal degradation of PET was investigated in great depth about 7 decades ago (Al‐Mulla and Shaban, 2007; Avrami, 1941; Williams and Williams, 1999). Hujuri et al (2008) investigated the pyrolysis of PET in the temperature range 25–600°C.…”

Section: Introductionmentioning

confidence: 99%

Kinetic analysis and modelling of thermal degradation of perspex (PMMA) and perspex blend plastic waste

et al. 2012

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The thermal decomposition of pure perspex and a mixture of 50% perspex and 50% poly(ethylene terephthalate; PET) was carried out between 295 and 325°C using a thermogravimetric analyser (TGA) in air and nitrogen (N2) atmosphere. The weight losses of decomposition products were measured during these experiments. The thermal degradation process is slower in inert atmosphere than air, where oxidation reaction expedites the decomposition process. Kinetic rate constants (k), pre‐exponential factor (A) and activation energy (E) for both pure prespex and a blend of perspex/PET were calculated for both air and N2 conditions. The thermal degradation process followed a third‐order reaction in air and second‐order in N2. A second‐order (n = 2) model for the pyrolytic process based on simultaneous reactions was developed using experimental data for pure and blend. The pyrolytic products are gases, liquids, waxes, aromatics and char, which can be ultimately used as raw material and fuel in various applications. It is important to note that the addition of PET to perspex was found to suppress/inhibit the decomposition of perspex compared with pure perspex. Pre‐exponential factor (A) and activation energy (E) values support such an observation. © 2012 Canadian Society for Chemical Engineering

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Degradation kinetics of poly(ethylene terephthalate) and poly (methyl methacrylate) blends

Cited by 15 publications

References 6 publications

Structure-reactivity relationship in pyrolysis of plastics: A comparison with natural polymers

Structure-reactivity relationship in pyrolysis of plastics: A comparison with natural polymers

Isothermal crystallization kinetics of poly(ethylene terephthalate) and poly(methyl methacrylate) blends

Kinetic analysis and modelling of thermal degradation of perspex (PMMA) and perspex blend plastic waste

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