Thermal Degradation Of Polypropylene Research Articles

Kinetics and fuel properties of the oil obtained from the pyrolysis of polypropylene over cobalt oxide

In this study pyrolysis of polypropylene (PP) was performed with and without cobalt oxide from 355 to 445 °C in inert conditions in an indigenously manufactured furnace. No oil was produced from non-catalytic reaction; however, the catalytic reaction resulted in production of oil in sufficient quantity. Optimum conditions for the maximum oil yield were explored and 100 min reaction time, 430 °C temperature and 5% of catalyst in continuous flow of nitrogen were observed as the most appropriate conditions for maximum oil production. Gas chromatography-mass spectrometry (GC-MS) of the obtained oil was performed for determining the composition of the oil. Moreover, fuel properties of the oil were examined and found comparable with commercial fuel. Furthermore, thermal degradation of polypropylene with and without cobalt oxide catalyst was performed in a thermobalance under nitrogen environment in the temperature ranging from 30 to 600 °C at temperature programmed rate of 5, 10, 15 and 20 °C/min. Using Kissinger-Akahira-Sunnose (KAS) kinetic model, the average activation energy (Ea) of non-catalytic reaction was found to be 83.14 kJ/mol, while in the presence of cobalt oxide the average Ea was observed as 63.55 kJ/mol. It was observed from the comparison of both the results that use of cobalt oxide has not only reduced Ea but also resulted in the production of oil having resemblance with fuel grade oil. Hence, cobalt oxide was found to be an efficient catalyst for the conversion of polypropylene into valuable products and the study performed on model polypropylene can be extended to polypropylene waste on industrial scale.

PICNIK: A python package with isoconversional computations for non-isothermal kinetics

Isoconversional computations are widely-used methods to determine activation energies for thermally stimulated processes. pICNIK (python Isoconversional Computations for Non-Isothermal Kinetics) is an open-source module designed with the purpose of being a seed to a complete Python package to facilitate kinetic computations. It is object oriented with two classes: DataExtraction and ActivationEnergy. Five isoconversional methods were implemented: Friedmann's method, the Kissinger-Akahira-Sunose method, Ozawa-Flynn-Wall method, Vyazovkin and advanced Vyazovkin. This module allows to compute the activation energy from thermogravimetric data in minutes and the results can be exported as spreadsheet format or comma separated values files instead of traditional tedious and time consuming data processing. The module was validated with simulated data and two study cases: vaporization of n-decane and the thermal degradation of polypropylene. Program summaryProgram Title: pICNIKCPC Library link to program files:https://doi.org/10.17632/dpwtnmjpj5.1Developer's repository link:https://github.com/ErickErock/pICNIKCode Ocean capsule:https://codeocean.com/capsule/0740039Licensing provisions: MITProgramming language: PythonNature of problem: Numerical determination of the parameters of the Arrhenius function and the reaction model under the isoconversion hypothesis.Solution method: A Python module with implemented isoconversional methods. The algorithms implemented include several computations such as linear regressions, numerical integration and differentiation, and minimizing functions, all over several data sets.Additional comments including restrictions and unusual features: The initial data processing is focused on thermogravimetry and may not work for calculating conversion to other properties. However, the object-oriented implementation allows to overcome this limitation easily. Methods for calculating the Arrhenius pre-exponential factor and the reaction model remain to be implemented. It is a small module conceived to be further developed by the community. Another limitation of the code is that it does not include a graphical interface.

Effect of Various Carbon Nanotubes Contents on Surface Resistance and Thermal Degradation of Polypropylene/ Polyamide 6/Glass Fiber Composite

The composite samples containing commercially available carbon nanotubes (CNTs), polypropylene (PP), polyamide 6/glass fiber composite (PA6/GF, 50%/50%) were prepared. They were (x%CNTs)/PP/(PA6/GF) (x/80/20, x% is the percentage of CNTs in the obtained composites, where x=0, 1, 2, 3, 4, 5, 6, respectively.). PA6/GF (50%/50%) and PP samples were also made as control. Surface resistance and thermal degradation for all the samples were measured. According to the resulting data, it is found that, with the increasing of carbon nanotubes contents, the surface resistance for the composite samples decreased, while the initial decomposition temperature increased. The result may be helpful to choose proper carbon nanotubes contents for antistatic and anti-degradation polymeric materials.

Thermal decomposition kinetics and lifetime prediction of a PP/PLA blend supplemented with iron stearate during artificial aging

In this work, the effect of iron stearate (IS) on the thermal degradation of polypropylene (PP)/poly (lactic acid) (PLA) blend compatibilized by polypropylene-grafted-maleic anhydride during artificial aging for 21 days at 70 °C, with sampling every 7 days has been investigated. The thermogravimetric (TG) analysis revealed a two-stage degradation process for the blends (with and without IS), which corresponded to each polymer in the blends. For each degradation stage, the decomposition temperature shifts to a lower value for the system that contains IS. Broadly, the kinetic modeling proved that the activation energy (Ea) decreases with the addition of IS and the artificial aging progress. Moreover, the decomposition mechanisms are dependent on the incorporation of IS and artificial aging. Besides, the lifetimes of the investigated samples were assessed at different failure temperatures using the obtained kinetic triplets. Both IS and artificial aging progress reduce significantly the lifetimes of the PP/PLA blends.

Effect of Phosphorus-Based Flame Retardants and PA6 on the Flame Retardancy and Thermal Degradation of Polypropylene

ABSTRACTThe investigation mainly focuses on the effect of polyamide 6 (PA6) and phosphorus based flame retardants (FRs) on improving the flame retardancy of polypropylene (PP). The flame retardant properties have been studied by limiting oxygen index, vertical burning test tests and cone calorimeter testing. The results demonstrate that PA6 and FRs can greatly improve the flame-retardant and thermal properties of PP. It’s found that the addition of PA6/APP/FRs can promote the formation of stable intumescent char layers. Those indicate that the flame retardancy of PA6/APP/FRs/PP composites is improved by the condensed-phase action of PA6/APP/FRs.

Crystallization, mechanical properties and thermal stability of cockleshell-derived CaCO3 filled polypropylene

This study discusses the potential of utilizing waste cockleshell derived-CaCO3 (CS) as filler in polypropylene (PP). Mineral fillers were prepared from cockleshell-derived CaCO3 and used to fill polypropylene. The composites were prepared by melt blending and fabricated by injection and compression molding techniques. The effects of filler on crystal structure, crystallization and thermal degradation characteristics of filled polypropylene composites were elucidated. The cockleshell filler promoted the formation of the β-crystalline phase in PP, which improved the rigidity and toughness of the composites. However, stearic acid treatments on the filler would significantly affect the nucleation process and therefore hindered crystallization. Acceleration in thermal degradation of PP was also noted with increasing filler loading.

Effect of morphology on the permeability, mechanical and thermal properties of polypropylene/SiO2 nanocomposites

Spherical silica nanoparticles with 20 and 100 nm diameters and organic-template layered silica nanoparticles synthesized by the sol-gel method were melt blended with a polypropylene (PP) matrix in order to study and quantify their effect on the oxygen and water vapor permeability and mechanical and thermal behavior. With regard to barrier properties, the spherical nanoparticles barely increased the oxygen permeability at low loads (≤10 wt%); meanwhile the layered nanoparticles dramatically increased it even at low loading (<5 wt%) probably due to the percolation effect. The changes in water vapor permeability were similar to those in oxygen permeability. The repulsive interaction between nanoparticles and PP forms interconnecting voids where the gas permeates. Tensile stress–strain tests showed that the composites present up to a 56% increase in the elastic modulus with spherical nanoparticles at 20 wt%, while layered nanoparticles show a decrease probably due to agglomerations and voids. Thermogravimetric analysis under inert conditions showed that the nanoparticles improved the PP thermal degradation process through the adsorption of volatile compounds on their surface, where the smaller spherical nanoparticles show the greatest stabilization. © 2015 Society of Chemical Industry

Flame-Retardant and Thermal Degradation Mechanism of Caged Phosphate Charring Agent with Melamine Pyrophosphate for Polypropylene

An efficient caged phosphate charring agent named PEPA was synthesized and combined with melamine pyrophosphate (MPP) to flame-retard polypropylene (PP). The effects of MPP/PEPA on the flame retardancy and thermal degradation of PP were investigated by limiting oxygen index (LOI), vertical burning test (UL-94), cone calorimetric test (CCT), and thermogravimetric analysis (TGA). It was found that PEPA showed an outstanding synergistic effect with MPP in flame retardant PP. When the content of PEPA was 13.3 wt% and MPP was 6.7 wt%, the LOI value of the flame retardant PP was 33.0% and the UL-94 test was classed as a V-0 rating. Meanwhile, the peak heat release rate (PHRR), average heat release rate (AV-HRR), and average mass loss rate (AV-MLR) of the mixture were significantly reduced. The flame-retardant and thermal degradation mechanism of MPP/PEPA was investigated by TGA, Fourier transform infrared spectroscopy (FTIR), TG-FTIR, and scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDXS). It revealed that MPP/PEPA could generate the triazine oligomer and phosphorus-containing compound radicals which changed the thermal degradation behavior of PP. Meanwhile, a compact and thermostable intumescent char was formed and covered on the matrix surface to prevent PP from degrading and burning.

Phosphorous antioxidants against polypropylene thermal degradation during rotational molding‐kinetic modeling

ABSTRACTPhosphorous antioxidants efficiency against molten polypropylene (PP) thermal oxidation was assessed during isothermal ageing and processing by rotational molding. During isothermal ageing, experimental data were compared to the ones calculated on the basis of a kinetic model. Phosphonite is more effective than phosphite. Both phosphite and phosphonite decompose hydroperoxide and prevent initiation of oxidation reactions. However, phosphonite hydrolysis product acts as a radical chain terminator and blocks propagation reactions. Kinetic constants of stabilization reactions were evaluated and discussed. Further, this kinetic modeling was coupled to a thermal software, able to predict polymer temperature evolution during rotational molding and the degradation critical temperature (DCT) of different stabilized PP. A DCT of 235°C was obtained for PP stabilized with phosphonite and hindered phenol against 215°C for PP stabilized with phosphite and the same phenol. This difference of 20°C, corresponding to 5 min more heating is significant to optimize rotational molding. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41285.

Transportation Fuels From Catalytic Co-pyrolysis of Plastic Wastes With Petroleum Residues: Evaluation of Catalysts by Thermogravimetric Analysis

Thermal or catalytic pyrolysis processes have attracted much attention for the conversion of plastic wastes to a mixture of their basic hydrocarbons, which can be valuable either as fuels or as raw chemicals. Especially catalytic pyrolysis has the advantage over non-catalytic pyrolysis as the process can be tailored to produce much useful transportation fuels such as gasoline and diesel oils. The effect of different catalysts on the thermal degradation of polypropylene (PP) and its copyrolysis with petroleum vacuum residue (VR) has been studied by thermogravimetric analysis (TGA). TGA experiments were used to compare the activity of different catalysts towards PP degradation alone and mixture with VR. All the hydrocracking (HC) catalysts enhanced the copyrolysis of PP/VR mixtures. The reaction rates were found to increase with catalyst fraction, acidity, and a reduction in the catalysts particle size. The temperatures of onset, T on , of maximum-rate, T max , and of end, T end , of the degradation also shifted to lower values. Among HC catalysts, it seems that Z-713 performed better at all three weight fractions; Z-713 reduced both T 1% and T 99% better than others. On the other hand, the FCC catalyst (RCD-8) performed poorly for the degradation of PP. Various titania based catalysts prepared in our laboratory performed well. The number of acid sites and catalyst pore size along with impregnation with transition metals such as W/Ni and Ni/Mo are found as the key factors for the energy efficient conversion of polymers and VR to liquid hydrocarbons. The results will help in our ongoing study on conversion of waste plastics into feed stocks for chemicals and transportation fuels.

Morphology−performance relationship of polypropylene−nanoclay composites processed by shear controlled injection moulding

A nanoclay based masterbatch was mixed with polypropylene (PP) and injection moulded by conventional (CIM) and shear controlled orientation (SCORIM) injection moulding techniques. The aim was to correlate the morphologies induced by SCORIM and CIM processing with the thermal, mechanical and fracture performance of thick PP/nanoclay mouldings. In SCORIM, two extreme shear levels were applied by changing processing conditions. A complete characterization is reported, and statistical analysis was carried out to obtain a relationship between moulding properties. Nanoclay acted as a polymer morphology director, and in combination with SCORIM it induced the formation of the γ polymorph of PP. The nanoclay has a strong positive effect on the thermal degradation of PP under an oxidative atmosphere, due to the barrier effect of clay and the physico-chemical adsorption of volatile degradation products on the silicates, but there were no differences between processing techniques. SCORIM samples of neat PP showed nonlinear brittle behaviour, while nanocomposites exhibited quasi-stable behaviour induced by a large deformation capability of the skin. Although fracture initiates at practically the same loading levels, the overall propagation energy values varied with processing conditions. Statistical analysis indicates that the decrement of the core region achieved by SCORIM processing, the differences between skin and core and the PP γ phase induced by the presence of nanoclay are responsible for the toughening of SCORIM PP/nanoclay mouldings. © 2013 Society of Chemical Industry

Waste polypropylene plastic conversion into liquid hydrocarbon fuel for producing electricity and energies

Thermal degradation of polypropylene (PP) waste plastic is batched process studied for the purpose of converting waste PP into liquid hydrocarbon fuel and useful chemicals. The stainless steel reactor is used for conversion to fuel; this reactor chamber has a diameter of 6 inches, height of 18 inches and a temperature input capacity of 500°C. The temperature of 150–370°C was used for PP conversion into fuel. We have also used 1 kg PP waste plastic for conversion into fuel and HZSM-5 catalyst of 5% by preference was used by total weight of sample. Yield percentages obtained from PP to fuel are 92%, 2% light gas and 6% residue. Experimental finish time was 5.25 hours. By gas chromatograph/mass spectrometry instrumental analysis, the PP to fuel carbon range is found to be C3‒ C25, and the low sulfur level is detected by the American Society for Testing and Materials (ASTM) test method to be<1.0 ppm.

Catalytic performances of kaoline and silica alumina in the thermal degradation of polypropylene

Polypropylene was cracked thermally and catalytically in the presence of kaoline and silica alumina in a semi batch reactor in the temperature range 400–550°C in order to obtain suitable liquid fuels. The dependencies between process temperatures, types of catalyst, feed compositions and product yields of the obtained fuel fractions were found. It was observed that up to 450°C thermal cracking temperature, the major product of pyrolysis was liquid oil and the major product at other higher temperatures (475–550°C) are viscous liquid or wax and the highest yield of pyrolysis product is 82.85% by weight at 500°C. Use of kaoline and silica alumina decreased the reaction time and increased the yield of liquid fraction. Again the major pyrolysis product in catalytic pyrolysis at all temperatures was low viscous liquid oil. Silica alumina was found better as compared to kaoline in liquid yield and in reducing the reaction temperature. The maximum oil yield using silica alumina and kaoline catalyst are 91% and 89.5% respectively. On the basis of the obtained results hypothetical continuous process of waste polypropylene plastics processing for engine fuel production can be presented.

Kinetic Analysis of Thermal Degradation of Polypropylene Using a Modified Gompertz Model

A new method, called modified Gompertz model, was proposed to interpret solid state decomposition. To verify the validity of this new model, the thermal degradation of polypropylene (PP) was performed and the results of curves fitting of thermogravimetry (TG) and derivative thermogravimetrical (DTG) from the Gompertz model were compared with those obtained from the traditional general model. The Arrhenius kinetic parameters used in the general model were derived from three traditional methods (i.e., Friedman, Freeman-Carroll, and Ozawa methods). For the Arrhenius parameters calculation, the heating temperature range was set from 298 to 1073 K and three different heating rates of 5, 10, and 15 K/min were selected. The sum of square errors (SSE) and the coefficient of determination ( r2 ) were calculated for all simulated data obtained from the modified Gompertz model and the general model. Statistical results show that all SSE values obtained from the modified Gompertz model are much smaller than those fr...

The origins of volatile oxidation products in the thermal degradation of polypropylene, identified by selective isotopic labeling

Making use of polypropylene samples that are selectively labeled with carbon-13 at each of the three unique positions within the repeating unit, we are conducting mass spectral analyses of the volatile organic oxidation products that are produced when the polymer is subjected to elevated temperature in the presence of air. By examination of both the parent and fragmentation ion peaks in the mass spectrum, we are able to identify the positioning of the C-13 labels within the volatile compounds, and thereby map each compound onto its site of origin from within the macromolecular structure of polypropylene. Most of the organic oxidation products are remarkably specific in terms of their genesis from the polymer. The structural results are discussed in terms of the oxidation chemistry of the macromolecule.

PP and PBT composites filled with sepiolite: Morphology and thermal behaviour

In this paper, we present the first attempt to correlate structure and thermal properties of sepiolite based composites. Composites were prepared in a Brabender internal mixer with 3 wt.% of pristine or organically modified sepiolites in two different polymer matrices, polypropylene (PP) and poly (butylene terephthalate) (PBT). Characterization of the materials was performed by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). A nucleating action was found in both polymeric matrices. Furthermore, PP-composites showed interesting features in the polymer crystalline structure. A linear correlation between T ONSET and the intensity ratio of PP-composites diffraction peaks (I/II) could be observed. Despite a catalytic effect induced by pristine sepiolite on PP thermal degradation, this drawback could be reduced by sepiolite surface modification. Moreover, higher stability towards thermoxidation was achieved. On the other end, the thermal behaviour of PBT was not affected by the presence of sepiolite.

Solid phase microextraction to concentrate volatile products from thermal degradation of polymers

Solid phase microextraction (SPME) was used to analyse the products evolved in the thermal degradation of polypropylene (PP) which was used as a model polymer. The degradation was performed under nitrogen at 470 °C using polydimethylsiloxane and carboxen/polydimethylsiloxane as the fibres for the product pre-concentration. The evolved degradation products were identified by infrared spectroscopy (FTIR) and gas chromatography/mass spectroscopy (GC/MS). More than 30 evolved products associated with alkenes (61.0%), alkanes (33.0%) and alkadienes (4.3%), were identified. In agreement with the literature, evolved products such as 2,4-dimethyl-1-heptene, n-pentane, 2-pentene, propylene, 2-methyl-1-pentene, 2,4,6-trimethyl-1-nonene, etc., were detected from the polypropylene thermal degradation. The results suggest that the SPME technology offers important factors such as, rapid analysis and great efficiency in the pre-concentration of evolved products from the thermal degradation of polymers.

Specific Features of Thermal Degradation of Polypropylene in the Presence of Magnesium Hydroxide

Specific features of thermal oxidative degradation of polypropylene and its composite with Mg(OH)2 were studied by pyrolytic gas chromatography-mass spectrometry and thermal gravimetric analysis.

Thermal stability of PP with acetylated sisal fiber: Romero Garc�a kinetic method

This work deals the effect of acetylated and non-acetylated sisal fiber 011 thermal degradation of polypropylene. Applying the R-G method at constant conversion levels of 0.1, 0.3, 0.5, 0.7 and 0.9 to thermograms of the ”PP/untreated sisal fiber” blend, E, values of 99, 213, 224, 187, and 145 kJ/mol were obtained, whereas they were 99, 299, 255, 205, 154 kJ/mol for the “PP/treated sisal fiber” blend. On the other hand, with the R-G method at constant temperature, activation energies within the range of 156-417 kJ/mol were obtained for the “PP/treated sisal fiber” blend and within the range of 126-344 kJ/mol for the “PP/untreated sisal fiber” blend. Additionally, the method establishes as dominant the following decomposition mechanisms: three-dimension limiting surface reaction between both phases, diffusion in two and three dimeiisions and first-order random nucleation and nuclei growth.

Semiquantitative analysis of the thermal degradation of polypropylene

AbstractThe pyrolysis product distributions of polypropylene (PP) were observed, and the experimental data were semiquantitatively analyzed by computer simulation with the Molic mouse method. Studies by many researchers on PP decomposition and experimental results achieved in this study were examined. The product distributions were classified into three types of hydrocarbon products: 3n, 3n + 1, and 3n + 2 (n = monomer unit). The ratio showed the characteristic tendency, and the thermal degradation of PP appeared to include very complicated scission paths. The Molic mouse method, which was applied to the analysis of the thermal rearrangement and decomposition of poly(phenylene ether), was used to simulate the experimental results. After several steps by which the proper model was constructed, the scission probabilities to generate 2 × 3n, 3n + 1 and 3n + 2, 3n and 3n + 1, 3n and 3n + 2, C9, and C15 hydrocarbons were successfully calculated to be 0.25, 0.67, 0.47, 0.35, 1.0, and 0.33, respectively. This meant that the scission process of PP was very simple except for the C9 and C15 generation paths, for which the cyclic compounds were stable intermediates. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1465–1472, 2003