LLDPE kinetic properties estimation combining thermogravimetry and differential scanning calorimetry as optimization targets

Alonso, Alain; Lázaro, M.; Lázaro, Pedro; Lázaro, David Rodríguez; Alvear, Daniel

doi:10.1007/s10973-019-08199-4

Cited by 7 publications

(4 citation statements)

References 56 publications

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“…In the case of the PMMA, the obtained TG and DSC curves agrees with executed tests using similar boundary conditions alike this work such as such as [40][41][42] for oxygen content atmosphere and [41][42][43] for non-oxygen content atmosphere tests. As it was quoted above [12,21,34], lower sample mass and slower heating rates lead to decrease the onset temperature of the process (Fig. 3).…”

Section: Pmmasupporting

confidence: 57%

“…As far as TG and DSC results show, the oxygen concentration, initial amount of mass and the heating rate strongly influence the LLDPE decomposition process. For instance, the onset temperature of the process decrease when the oxygen concentration increases, and faster heating rates delay the onset temperature, i.e., it makes that decomposition process takes place at higher temperatures [12,21,34]. If the amount of sample mass decreases, the decomposition process takes place at lower temperatures.…”

Section: Lldpementioning

confidence: 99%

“…Some of these boundary conditions can be determined taking into account other studies in similar conditions from available literature. For instance, in fire engineering non-isothermal heating rates are employed to carry out STA and DSC tests [10][11][12]; the material of the crucible should be chosen in order to avoid the reaction with the sample [13]; or the condition of the sample which is recommended to be in powder for solids as far as possible [1].…”

Section: Introductionmentioning

confidence: 99%

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Self-heating evaluation on thermal analysis of polymethyl methacrylate (PMMA) and linear low-density polyethylene (LLDPE)

Alonso

Lázaro

et al. 2022

J Therm Anal Calorim

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Thermal analysis has been proven to be an efficiently technique to analyse thermal decomposition reactions of different type of materials. This technique is widely used in different fields. Among them, fire science, where polymeric materials are very common, has a particular issue, being the combustion reactions recurrent on these analyses. Thermal analysis has different particularities depending on the studied material. For instance, polymeric materials could undergo different decomposition reactions that are highly dependent on definition of the thermal analysis boundary conditions. The International Confederation for Thermal Analysis and Calorimetry (ICTAC) (Vyazovkin et al. in Thermochim Acta 590:1–23, 2014) and standards (ISO 11358-1. Plastics—Thermogravimetry (TG) of polymers—Part 1: General principles. ISO. 2014; https://www.iso.org/standard/59710.html. Accessed 31 Jan 2022), (ISO 11357-1. Plastics — Differential scanning calorimetry (DSC) — Part 1: General principles. ISO. 2016; https://www.iso.org/standard/70024.html. Accessed 31 Jan 2022) stablish how to set-up these boundary conditions in the thermogravimetric (TG) and differential scanning calorimetry (DSC) standards. As far as initial amount of sample mass is concern, some discrepancies can be found between the standards. For instance, the standards suggest a sample mass between 10 and 100 mg for TG and between 2 and 40 mg for DSC, whereas the ICTAC recommendations suggests that the sample mass times the heating rate should not exceed 100 mg K·min−1 in thermo-oxidative decomposition analysis, which is equivalent to samples masses lower than 10 mg for heating rates of 10 K·min−1, or lower than 5 mg for heating rates of 20 K·min−1. This discrepancy may lead to obtain different results from the tests. Additionally, according to the thermal and thermo-oxidative decomposition of polymers, the ICTAC remarks the influence on the results of the sample thicknesses, carrier gas and heating rates, but it does not analyse the influence of self-heating as it does for the hazardous materials. This work presents a study of the self-heating influence in the thermal decomposition processes of two widely used polymers as poly methyl methacrylate (PMMA) and linear low-density polyethylene (LLDPE). TG/DSC tests are used to evaluate the thermal decomposition processes. Boundary conditions of the tests definition as sample mass, atmospheres, and heating rate are considered to evaluate its influence on the polymers self-heating effect on the thermal decomposition. It also includes how to check if TG/DSC tests follows the theoretical principles of the thermal analysis, or if the results are affected by the self-heating. In the present study, a series of 32 experimental tests has been performed, analysing 16 boundary conditions. These experimental tests allow evaluating the influence of selected boundary conditions on the mass loss, the heat flux, and the materials decomposition reactions. Additionally, we analyse the effect of the boundary conditions on the temperature of the sample. Results show the impact of each different boundary conditions of the self-heating effect, and its influence in the final thermal decomposition measured and they represent an aid to define the suitable conditions to perform TG/DSC test on PMMA and LLDPE, or similar polymer materials. This is done by the evaluation of the influence of the self-heating in parameters as the sample temperature lags defined in [1], the reactions heat fluxes, and the difference between the sample and the programmed temperature. It is also analysed the influence of the auto-ignition temperature in the thermal analysis. It is remarkable the PMMA auto-ignition temperature effect on the TG/DSC results. Finally, some useful recommendations have been defined.

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Section: Pmmasupporting

confidence: 57%

Section: Lldpementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Self-heating evaluation on thermal analysis of polymethyl methacrylate (PMMA) and linear low-density polyethylene (LLDPE)

Alonso

Lázaro

et al. 2022

J Therm Anal Calorim

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“…Finally, curve-fitting optimization methods are very efficient for complex processes involving multiple reactions, but require significant computational effort [27][28][29][30][31][32][33][34][35][36].…”

Section: Introductionmentioning

confidence: 99%

A Simple Direct Method to Obtain Kinetic Parameters for Polymer Thermal Decomposition

et al. 2021

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In a fire, the polymer combustion occurs when gaseous fuels react with oxygen. The heating of a material could force the release of gaseous fuels during thermal decomposition and pyrolysis. The rate of pyrolysis to define the gaseous fuels is usually interpreted by means of the Arrhenius expression and a reaction model expression, which are characterized by an activation energy, a pre-exponential factor, and a reaction order value. Many methods are available for determining kinetic parameters from thermogravimetric experimental data. However, the most challenging issue is achieving an adequate balance between accuracy and simplicity. This work proposes a direct method for determining the kinetic parameters with only a thermogravimetric experiment at a single heating rate. The method was validated with six polymers, and the results were compared with those from similar procedures, such as the Lyon method and generalized direct method. The results achieved using the simpler approach of the proposed method show a high level of accuracy.

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Risk assessment of polyarylether polymerization process

Zhou

Suetor

et al. 2020

J Therm Anal Calorim

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LLDPE kinetic properties estimation combining thermogravimetry and differential scanning calorimetry as optimization targets

Cited by 7 publications

References 56 publications

Self-heating evaluation on thermal analysis of polymethyl methacrylate (PMMA) and linear low-density polyethylene (LLDPE)

Self-heating evaluation on thermal analysis of polymethyl methacrylate (PMMA) and linear low-density polyethylene (LLDPE)

A Simple Direct Method to Obtain Kinetic Parameters for Polymer Thermal Decomposition

Risk assessment of polyarylether polymerization process

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