Kinetic of thermal degradation of low-density and high-density polyethylene by non-isothermal thermogravimetry

Sinfrônio, F. S. M.; Santos, José Carlos Oliveira; Pereira, Luiza G.; Souza, A. G.; Conceição, Marta Maria da; Fernandes, Valter J.; Fonseca, V. M.

doi:10.1007/s10973-005-0072-4

Cited by 54 publications

(19 citation statements)

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“…1A) started at temperatures of 388.0, 395.0 and 396.4 8 Cinnitrogen atmosphere at aheating rate of 6, 9and 12 8 C/min, respectively. The reaction was almost complete at 495.0, 499.6 and 508.6 8 C. The same trend for HDPE was observed by other researchers (Kayacan and Dogan, 2008;Sinfronio et al, 2005;Encinar and Gonzalez, 2008). Similar TG curves ( Fig.…”

Section: R Esults and Discussionsupporting

confidence: 87%

Thermal and Tensile Behavior of HD-PE Films Containing Iron (III) Acetylacetonate after UV Irradiation

Kiryakova

Mihaleva

Atanassov

et al. 2014

International Polymer Processing

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The thermal, tensile and other properties of high density polyethylene films containing iron (III) acetylacetonate as pro-oxidant additive have been studied after exposure to UV irradiation for up to 300 h. The effect of photooxidation on polyethylene films with and without pro-oxidant was estimated by Fourier transform infrared spectroscopy, X-ray diffraction analysis, Differential scanning calorimeter measurements and the tensile properties. It was observed that UV irradiation had almost no effect on the melting temperature of the different samples. After exposure, the degree of crystallinity increased from 69 %t o7 2% for the initial polyethylene samples without pro-oxidant additive and by 3% for the samples containing iron (III) acetylacetonate. It was found that the increase in the carbonyl index of initial HDPE was not significant even after 60 he xposure to UV irradiation while samples with pro-oxidant suffered substantial degradation still for 35 h. It was observed that the decrease of the tensile strength is more pronounced for the samples with pro-oxidant under irradiation for 60 to 70 h. The films containing pro-oxidant lose * 90 % of its initial elongation at break after 35 he xposure. 2E xperimental MaterialsPowdery high density polyethylene (HDPE), product of Lukoil-Neftochim Co., Burgas, Bulgaria, with melting temperature 130 8 C, melt index 0.16 g/10 min (190 8 C, 2.160 kg) and density 0.948 g/cm 3 was used for the preparation of the films. The pro-oxidant -i ron acetylacetonateF e(acac) 3 with chemical formula Fe(C 5 H 7 O 2 ) 3 ,m elting temperature 180 -183 8 C, molar weight 353.17 g/mol and density 5.24 g/cm 3 ,product of Merck, Germany. Sample PreparationThe compositions containing 2mmol/kg Fe(acac) 3 were mixed with HDPE and homogenized in al aboratory mixer Carl Hanser Verlag, Munich Intern. Polymer Processing XXIX (2014) 5

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Section: R Esults and Discussionsupporting

confidence: 87%

Thermal and Tensile Behavior of HD-PE Films Containing Iron (III) Acetylacetonate after UV Irradiation

Kiryakova

Mihaleva

Atanassov

et al. 2014

International Polymer Processing

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“…Although several variants of constitutive equations have been proposed for the viscoelastic and viscoplastic behavior of semi-crystalline polymers that reveal an acceptable agreement with observations, these models share common shortcomings: (i) they disregard thermally-induced evolution of microstructure of HDPE in the vicinity of a-relaxation point (in the interval of temperatures between 60 and 80°C), and (ii) their application to fitting observations results in rather high values of the apparent activation energy of solid polyethylene (in the interval between 100 and 200 kJ/mol) which substantially exceed those for polyethylene melts [20-30 kJ/mol (Bin Wadud and Baird, 2000)] and are close to the activation energies for thermal degradation of high-density polyethylene [ranging between 200 and 300 kJ/ mol (Sinfronio et al, 2005;Marazzato et al, 2007)]. …”

Section: Introductionmentioning

confidence: 75%

Thermo-viscoelastic and viscoplastic behavior of high-density polyethylene

Drozdov

Yuan

2008

International Journal of Solids and Structures

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a b s t r a c tObservations are reported on high-density polyethylene in uniaxial tensile tests with constant strain rates and relaxation tests at various temperatures ranging from 25 to 90°C. A constitutive model is derived for the nonlinear viscoelastic and viscoplastic behavior of semi-crystalline polymers at three-dimensional deformations. Adjustable parameters in the stress-strain relations are found by fitting the experimental data. It is demonstrated that (i) the model correctly approximates the observations and (ii) material parameters are independent of strain rate and change consistently with temperature.

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“…Several investigations on the thermal degradation kinetics of polymer nano-composites based on HDPE have been reported by various authors [10][11][12][13]. Chrissafis et al [14] reported thermal degradation of HDPE/SiO 2 nano-composites, and confirmed their enhanced thermal stability.…”

Section: Introductionmentioning

confidence: 93%

Thermogravimetric kinetics of degradation of HDPE based MWCNTs reinforced composites

Rajeshwari

Dey

2014

Int J Plast Technol

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High Density Polyethylene (HDPE) reinforced multiwalled carbon nanotubes (MWCNTs) composites with MWCNTs loading between 0.0011 and 0.0044 volume fractions are fabricated by melt mixing. The prepared nano-composites are investigated by thermo-gravimetric analyzer (TGA) under nitrogen atmosphere at various heating rates. TGA thermograms indicate only a marginal enhanced thermal stability and no significant mass loss occurs up to~400°C. Thermal degradation kinetics of HDPE/MWCNTs nano-composites has been examined in light of five different analytical methods, viz., Coats-Redfern (CR) integral model fitting approach, 'iterative' based CR(modified) approach, integral form of the rate equation (i.e. FWO and KAS), the differential iso-conversional based method of Friedman. The CR integral model fitting based on 14 different kinetic models are analyzed for TGA data for multiple heating rates. Our analysis indicates that the degradation mechanism of the present nano-composites follows diffusion control (D2, D3 and D4) and first order reaction (F1) mechanisms. The apparent activation energy (E a ) as a function of conversion rate (α) estimated by CR (modified), FWO, KAS and FR methods are all in fair agreement with each other and confirms decrease in E a with increased loading of MWCNTs. The pre-exponential factor (A) calculated also decreases with MWCNTs concentration in HDPE. Activation energy (E a ) for different conversion rate (α) calculated by iso-conversional methods (CR(modified), FWO, KAS and FR) indicates contributions from at least two different degradation mechanisms, namely, diffusion controlled (D2, D3, D4) and first order reaction (F1), which are consistent with the findings of Coats-Redfern (CR) integral model.

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Kinetic of thermal degradation of low-density and high-density polyethylene by non-isothermal thermogravimetry

Cited by 54 publications

References 0 publications

Thermal and Tensile Behavior of HD-PE Films Containing Iron (III) Acetylacetonate after UV Irradiation

Thermal and Tensile Behavior of HD-PE Films Containing Iron (III) Acetylacetonate after UV Irradiation

Thermo-viscoelastic and viscoplastic behavior of high-density polyethylene

Thermogravimetric kinetics of degradation of HDPE based MWCNTs reinforced composites

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