Flynn Wall Ozawa Method Research Articles

Pyrolysis kinetics of new bioenergy feedstock from anaerobic digestate of agro-waste by thermogravimetric analysis

In this study, thermogravimetric and kinetic analysis of digestate from anaerobic co-digestion of dairy manure and dry biomass of Amaranthus retroflexus L. is presented. Thermal decomposition of digestate was studied in the temperature range 40–1000 °C in an inert atmosphere using thermogravimetric and differential scanning calorimetry (TG-DSC) at the heating rates of 5, 10, 15 and 20 °C/min. According to the results of TG/DTG analysis, the thermal decomposition of digestate occurs in three stages: dehydration, devolatilization and decomposition of carbonaceous residue. The devolatilization stage in pyrolysis is a key stage; therefore, it was divided into two steps: I-st step and II-nd step and analyzed in detail. The kinetic parameters were estimated by isoconversion Friedman, OFW (Ozawa-Flynn-Wall) and KAS (Kissinger-Akahira-Sunose) methods and using model-based methods, such as CnB (reaction of n-th order with autocatalysis by product), Bna (expanded Prout-Tompkins equation) and Fn (the reaction of n-th order). For the model-free methods, the average Eα values for the I-st step were 136.3 kJ/mol and for the II-nd step 143.1 kJ/mol. The average Eα values obtained using the CnB, Bna, and Fn models were 105.8 kJ/mol for the I-st step and 145.6 kJ/mol for the II-nd step, i.e. Eα increased by 37.6%. The results of the evaluation of the thermal behavior of digestate from agro-waste indicate a good prospect for the use of biomass as a new bioenergy feedstock. The obtained kinetic parameters are of great importance for the design of pyrolysis reactors.

Gaussian model analysis and thermal decomposition kinetics of nature fibers

The thermal decomposition of the heartwood and sapwood of eight wood species was investigated using dynamic thermogravimetric analysis in this study. To calculate the activation energy of the heartwood and sapwood, four “model-free” methods were used: the Flynn–Wall–Ozawa method, the modified Coats–Redfern method, the Friedman method, and the Kissinger method. Because the activation energy of the heartwood and sapwood was calculated using model-free methods that did not account for the reaction mechanism of the thermal decomposition of the hardwood and sapwood, the Gaussian multi-peak fitting method. The method did account for the reaction mechanism. The activation energy of the heartwood and sapwood was calculated using various methods in order to compare the results obtained by the various methods and, ultimately, to confirm the reliability of the results. The activation energy of the eight wood species' hardwood and sapwood ranged from 120 kJ/mol to 140 kJ/mol. The activation energy of the heartwood was slightly higher than that of the sapwood within the same wood species. Infrared spectrograms of the selected woods revealed that the heartwood had higher absorption peak intensities in the wavelength range of 3100–3500 cm −1 than the sapwood. This indicates that the heartwood, as opposed to the sapwood, requires more energy to sustain the chemical reaction at this stage. This is one of the primary reasons why heartwood has higher apparent activation energy values than sapwood. Furthermore, softwood had a higher activation energy than hardwood. Furthermore, when compared to other model-free methods, the Friedman method was less reliable for studying the kinetics of pyrolysis in the heartwood and sapwood of the eight wood species.

Kinetic Study on The Slow Pyrolysis of Isolated Cellulose and Lignin from Teak Sawdust

This study was conducted to explicate the stages of biomass pyrolysis by using a comprehensive kinetics study. The pyrolysis was performed on teak sawdust and its isolated klason lignin and cellulose. Pyrolysis experiments were carried out on Thermogravimetric Analysis (TGA) with 3 different heating rates at 5, 10, and 20 K min−1. The results were analyzed with 2 model-free methods of Kissinger-Akahira-Sunose (KAS) and Ozawa-Flynn-Wall (OFW), and a model-fitting method of nth-order Distributed Activation Energy Model (DAEM). The model-free kinetics analyses using KAS and OFW methods gave consistent activation energy trends for all samples. In teak sawdust pyrolysis, the activation energy fluctuates with the increase of conversion between 235-252 kJ mol−1. For cellulose, the activation energy increased along with the conversion from 208 to 240 kJ mol−1. Whereas for lignin, the activation energy widely ranges between 80-250 kJ mol−1. Further exploration using the multi-component nth-order DAEM was conducted to provide deeper insight on multistage pyrolysis reaction. The 4 components DAEM successfully provided a satisfying mathematical fit to the experimental data of teak sawdust pyrolysis. The proposed model was able to capture the two stages of lignin pyrolysis. The method that has been demonstrated here gave a broader insight to the application of DAEM in describing lignocellulosic biomass pyrolysis.

Kinetic modelling for pyrolytic degradation of olive tree pruning residues with predictions under various heating configurations

Herein, the aim was to develop an in-depth understanding of the kinetic behaviour of olive tree pruning residue (OTPR), an abundant agricultural waste, during pyrolysis. Thermal analysis at 1, 2, 4, 6 and 10 °C.min−1 was performed using TGA-thermogravimetric analysis, with the results subsequently used to determine the OTPR's kinetic thermal breakdown behaviour. Furthermore, advanced kinetics and technology solutions (AKTS) thermo-kinetic tool was applied to investigate the kinetic behaviour of OTPR and to generate kinetic predictions for various heating configurations. Friedman's method was the main approach used to evaluate the kinetic parameters. For comparison, other established kinetic modelling techniques, such as ASTM-E698 and Flynn-Wall-Ozawa (FWO) methods, were applied. The ASTM-E698 approach yielded an apparent activation energy (Ea) of 172.09 kJ.mol−1, whereas the FWO method yielded an Ea range from 38 to 172 kJ.mol−1. Finally, the differential iso-conversional approach yielded Ea values ranging between 85 and 191 kJ.mol−1. Kinetic predictions were then developed for isothermal, non-isothermal, and stepwise configurations using the kinetic parameters obtained via Friedman’s model. The forecasts shed light on optimising production throughput in a variety of reactor configurations.

Study on Fire Behavior, Thermal Stability and Degradation Kinetics of Thiol-Ene with Poly(aminopropyl/phenyl)silsesquioxane.

In this article, the flame retardant poly(aminopropyl/phenyl)silsesquioxane (PA) was incorporated into thiol-ene (TE), to obtain a flame-retardant thiol-ene (FRTE) composite. The cone calorimeter (CONE) measurement results showed that, compared with neat TE, the peak of heat release rate (PHRR) and total heat release (THR) of FRTE have decreased by almost 23.7% and 14.5%, respectively. Thermogravimetric analysis (TGA) results further confirmed that the flame retardant PA could induce the initial thermal degradation of TE, and increased the amounts of residual char. Moreover, the activation energies of FRTE were calculated through the Kissinger and Flynn–Wall–Ozawa methods. Compared with the neat TE, the activation energies of FRTE were raised by the addition of PA. It indicated that the flame retardant PA promoted cross-linking reactions of TE, to form a compact char layer and retarded further the thermal degradation of the polymer matrix.

Application of Chromatographic and Thermal Methods to Study Fatty Acids Composition and Positional Distribution, Oxidation Kinetic Parameters and Melting Profile as Important Factors Characterizing Amaranth and Quinoa Oils

Amaranth and quinoa are classed as pseudocereals that do not belong to the grass family, meaning they are not technically a grain. Both of them are seeds with tremendous nutritional value; compared to other cereals, they contain much more fat. The aim of the study was to present the parameters characterizing thermal properties of amaranth and quinoa oils, such as: oxidation induction time, oxidation kinetic parameters, and melting profile. In isolated oils, the peroxide value, oxidative stability by the Rancimat test (in 120 °C) and the pressure differential scanning calorimetry (PDSC) method (at 100, 110, 120, 130, 140 °C), fatty acids composition, and their distribution between the triacylglycerol positions were determined. The kinetic parameters of the oxidation process (activation energy, pre-exponential factor, and reaction rate constants) were calculated using the Ozawa–Flynn–Wall method and the Arrhenius equation. To measure the melting profile, the differential scanning calorimetry (DSC) method was used. Both types of seeds are a good source of unsaturated fatty acids. Induction time of oxidation suggests that amaranth oil may have better resistance to oxidation than quinoa oil. The melting characteristics of the oils show the presence of low-melting triacylglycerol fractions, mainly containing unsaturated fatty acids, which means that a small amount of energy is required to melt the fats.

Effect of processing on the stability and electrical properties of pressureless sintered graphene oxide–alumina composites

This paper explores the processing of an alumina matrix composite with a percolating network of graphene oxide (GPO), which exhibits a moderate electric resistivity and a near zero temperature coefficient of resistance. Different formulations of GPO–alumina composites were processed using a water–base blending, and, the pellets were densified by pressureless sintering under Argon flow. Electrical conduction at room temperature was achieved in the 2 wt % GPO–alumina composite sintered at 1400 °C, and, the 3 wt % GPO–alumina composites sintered at 1400, 1550 and 1700 °C. An investigation of the degradation of electrical conductivity was used to identify potential stable operating regimes in which these materials could be used as heaters. Thermogravimetric analysis using the Ozawa–Flynn–Wall method, was used to determine the kinetic parameters of a 3 wt % GPO composite sintered at 1400 °C which, had an activation energy for GPO degradation of 195 ± 68 kJ/mol and, an estimated thermal lifetime of 8.7 ± 0.8 years for a conversion of 0.5 wt % (failure criterion) at an application temperature of 340 °C.

Kinetics and mechanism of low-temperature aluminothermic reduction of manganese tantalate

ABSTRACT The paper studies the kinetics of low-temperature (840–1180 °C) reduction of manganese tantalate (99.4 mass% MnTa2O6, 0.6 mass% Ta2O5, particle size <0.1 mm) with aluminium powder (particle size <0.14 mm) taken in an amount providing a mole ratio of MnTa2O6: Al = 1: 10. Reduction experiments were performed in non-isothermal mode using differential scanning calorimetry at three heating rates. Kinetic analysis of the experimental data was performed by the Friedman and Ozawa–Flynn–Wall methods with optimisation of results by non-linear regression. It is shown that the reduction process corresponds to a combined exothermic peak in the differential scanning calorimetry curve with the temperatures of onset at 890 °C and maxima at 940 and 1032 °C. At 1180 °C, the reduction products are TaAl3, MnAl6–δ, Ta, Mn1+x Al1–x , Mn8.97Al30.03, Mn53.3Al230.8, and Al, while the process can proceed through the formation of intermediate oxides of the Mn x TaO4–y type. The process is represented by a scheme that includes three consecutive steps controlled by nth-order chemical reactions. The mathematical model built based on the obtained data sufficiently describes the rate of low-temperature reduction of manganese tantalate with the excess of aluminium and can be used to optimise the technological modes for producing tantalum alloys.

Valorization of Wet Oily Petrochemical Sludge via Slow Pyrolysis: Thermo-Kinetics Assessment and Artificial Neural Network Modeling

Oily sludge is a hazardous waste stream of oil refineries that requires an effective process and an environment-friendly route to convert and recover valuable products. In this study, the pyrolytic conversion of the wet waste oil sludge was implemented in an autoclave pyrolyzer and a thermogravimetric analyzer (TGA) at 5°C/min, 20°C/min, and 40°C/min, respectively. The kinetic analysis was performed using model-free methods, such as Friedman, Kissenger–Akahira–Sunose (KAS), and Ozawa–Flynn–Wall (OFW) to examine the complex reaction mechanism. The average activation energy of wet waste oil sludge (WWOS) estimated from Friedman, KAS, and OFW methods was 198.68 ± 66.27 kJ/mol, 194.60 ± 56.99 kJ/mol, and 193.28 ± 54.88 kJ/mol, respectively. The activation energy increased with the conversion, indicating that complex multi-step processes are involved in the thermal degradation of WWOS. An artificial neural network (ANN) was employed to predict the conversion during heating at various heating rates. ANN allows complex non-linear relationships between the response variable and its predictors. nH, ΔG, and ΔS were found to be 191.26 ± 2.82 kJ/mol, 240.79 ± 2.82 kJ/mol, and −9.67 J/mol K, respectively. The positive values of ΔH and ΔG and the slightly negative value of ΔS indicate the endothermic nature of the conversion process, which is non-spontaneous without the supply of energy.

Elucidating the bioenergy potential of raw, hydrothermally carbonized and torrefied waste Arundo donax biomass in terms of physicochemical characterization, kinetic and thermodynamic parameters

The present investigation aimed to understand the pyrolysis kinetic behavior of raw Arundo donax (Raw-AD), hydrothermally carbonized Arundo donax (HTC-AD), and torrefied Arundo donax (TOR-AD) in a thermogravimetric analyzer at dynamic heating rates. The physicochemical characterization analysis revealed that fuel properties have been enhanced after hydrothermal carbonization and torrefaction. The characterization techniques such as FE-SEM, EDX, FTIR, and XRD have been used to investigate the biomass surface morphology, inorganic elements, functional groups, and crystallinity. The kinetic parameters were calculated using the model-free methods of Ozawa-Flynn-Wall (OFW), Kissinger-Akahira-Sunose (KAS), and Vyazovkin (VZK), whereas Criado's z(α) master plot was used to elucidate the reaction mechanism. The average activation energy was obtained to be 259.11, 262.53, and 250.13 kJ/mol for Raw-AD, 115.31, 110.39, and 107.26 kJ/mol for HTC-AD, and 243.46, 242.68, and 233.79 kJ/mol for TOR-AD using OFW, KAS, and VZK method respectively. The thermodynamic analysis divulged that pyrolysis proceeded through various reaction mechanisms.

Thermogravimetric analysis of high-density cork granules using isoconversional methods

In the present work thermogravimetric techniques were used to study the thermal degradation of high-density cork granules. Pyrolysis experiments were carried out for four heating ramps (10, 15, 20 and 25 °C.min−1), using nitrogen as the carrier gas. From the differential thermogravimetric (DTG) curves it was seen that degradation mainly occurs from 220 °C to 525 °C for the main components of cork (suberin, lignin, cellulose, and hemicellulose). It was also observed that for temperatures higher than 525 °C and up to 900 °C, lignin continued to decompose. Activation energies were calculated using the data obtained and the two isoconversional methods Kissinger–Akahira–Sunose (KAS) and Flynn–Wall–Ozawa (FWO). For the KAS method, and for degrees of conversion between 0.10 and 0.85, the activation energies varied between 232.2 and 353.0 kJ.mol−1. Using the FWO method and for the same degrees of conversion, the activation energies were in the range of 230.0 to 346.6 kJ.mol−1. These values agree with data provided by other authors, for different lignocellulosic biomass.

Property Prediction of Ag-Filled Isotropic Conductive Adhesive through the Analysis of Its Curing and Decomposition Kinetics

In this study, various thermal analyses were carried out on a self-developed and commerce-oriented Ag-filled isotropic conductive adhesive (ICA) and its unfilled matrix resin through which glass transition temperature (Tg) and thermal endurance could be quantitatively predicted. An autocatalyzed kinetic model was used to describe the curing reaction, which was proven to be in good consistency with the experimental data. The activation energies for the curing reaction of the ICA and the matrix resin were determined to be 68.1 kJ/mol and 72.9 kJ/mol, respectively, which means that the reaction of the ICA was easier to occur than its unfilled matrix resin. As a result, the time–temperature profile could be calculated for any Tg requested based on the kinetic model of curing and the DiBenedetto equation. Further, the thermal decomposition stability of the ICA and its unfilled matrix resin were also studied. The activation energies for the thermal decomposition of the ICA and the matrix resin were calculated to be 134.1 kJ/mol and 152.7 kJ/mol, respectively, using the Ozawa–Flynn–Wall method, which means that the decomposition of ICA was easier to occur. The service life of the resin system at a specific temperature could therefore be calculated with their activation energy. The addition of micro-scale Ag flakes did not change the curing and decomposition mechanisms by much.

Thermogravimetric Analysis and Kinetic Study on Catalytic Pyrolysis of Rice Husk Pellet using Its Ash as a Low-cost In-situ Catalyst

The thermogravimetric behaviors and the kinetic parameters of uncatalyzed and catalyzed pyrolysis processes of a mixture of powdered raw rice husk (RRH) and its ash (RHA) in the form of pellets were determined by thermogravimetric analysis at three different heating rates, i.e., 5, 10, and 20 K/min, from 303 to 873 K. This research aimed to prove that the rice husk ash has a catalytic effect on rice husk pyrolysis. To investigate the catalytic effect of RHA, rice husk pellets (RHP) with the weight ratio of RRH:ARH of 10:2 were used as the sample. Model-free methods, namely Friedman (FR), Kissinger-Akahira-Sunose (KAS), and Flynn-Wall-Ozawa (FWO), were used to calculate the apparent energy of activation(EA). The thermogravimetric analysis showed that the decomposition of RHP in a nitrogen atmosphere could be divided into three stages: drying stage (303-443 K), the rapid decomposition stage (443-703 K), and the slow decomposition stage (703-873 K). The weight loss percentages of each stage for both uncatalyzed and catalyzed pyrolysis of RHP were 2.4-5.7%, 35.5-59.4%, and 2.9-12.2%, respectively. Using the FR, FWO, and KAS methods, the values of for the degrees of conversion (a) of 0.1 to 0.65 were in the range of 168-256 kJ/mol for the uncatalyzed pyrolysis and 97-204 kJ/mol for the catalyzed one. We found that the catalyzed pyrolysis led the to have values lower than those got by the uncatalyzed one. This phenomenon might prove that RHA has a catalytic effect on RHP pyrolysis by lowering the energy of activation.

Thermal Safety Analysis of On-Site Emulsion Explosives Mixed with Waste Engine Oil

The study of the thermal safety of emulsion explosives mixed with waste engine oil is very important for the safety of these types of explosives used in mine blasting. In order to study the thermal safety of emulsion explosives mixed with waste engine oil, thermal safety tests were carried out using a Differential Scanning Calorimeter (DSC), non-isothermal kinetics, and the Flynn–Wall–Ozawa method. The results show that the minor particle impurities in the filtered waste engine oil are mainly combustibles; after adding different amounts of waste engine oil, the activation energy of the emulsion matrix decreases from 110.33 kJ/mol to 75.39 kJ/mol, 74.50 kJ/mol, and 82.23 kJ/mol, and the critical temperature for thermal explosion changes from 194.16 °C to 169.73 °C, 227.47 °C, and 208.78 °C. The addition of waste engine oil reduces the activation energy of emulsion explosives. The waste engine oil is negatively correlated with the activation energy and the thermal explosion reaction temperature of emulsion explosives, and the correlation coefficient is −0.686 and −0.333. The emulsifier is positively correlated with the critical temperature of thermal explosion of emulsion explosives, and the correlation coefficient is 0.251. The small particles in the waste engine oil create a hot spot in the emulsion explosives, which reduces the thermal safety of the emulsion explosives mixed with waste engine oil. The emulsifier reduces the droplet size of the emulsion explosive, improves the oil-water interface strength, and improves the thermal safety of the emulsion explosives mixed with waste engine oil. The thermal safety of emulsion explosives mixed with waste engine oil can be improved by reducing the proportion of the sensitizer and increasing the proportion of the emulsifier.

Effect of lanthanum cerium methionine on the properties of natural rubber

Lanthanum cerium methionine was synthesized using the metathesis method and its molecular formula was confirmed as La0.35Ce0.65Cl3(C5H10NO2S)3·2H2O via Inductively Coupled Plasma Optical Emission Spectrometer, FTIR, and thermogravimetry-differential scanning calorimetry characterization methods. Lanthanum cerium methionine can significantly reduce the activation energy of the vulcanization reaction. The vulcanization kinetics model is used to fit the vulcanization curve of the rubber, and the obtained vulcanization activation energy of lanthanum cerium methionine for rubber is E1 = 76.89 KJ/mol, E2 = 102.36 KJ/mol and E3 = 126.00 KJ/mol. The above value is lower than pristine rubber. The Kissinger method and Flynn–Wall–Ozawa method were used to analyze the activation energy of thermal-oxidative degradation of vulcanized rubber. It was found that the rubber added with lanthanum cerium methionine exhibited higher thermal-oxidative degradation activation energy compared to that of pristine rubber; in addition, it was more difficult to age under the same environment. These results indicated that lanthanum cerium methionine can be not only used as a vulcanization accelerator, but also plays a role in resisting thermal and oxygen aging.

Thermogravimetric analysis kinetic study of Spirulina platensis residue pyrolysis

Bio-oil from microalgae pyrolysis has excellent potential to be developed as a renewable, sustainable, and environmentally friendly energy fuel. Using pyrolysis technology to use the solid waste from microalgae extraction of spirulina platensis as an energy source is a solution for pollution due to biomass extraction. The solid residue is known as Spirulina Platensis Residue (SPR). SPR pyrolysis will produce liquid fuel (bio-oil), gas, and biochar. This paper discusses the study of the pyrolysis kinetics of SPR with Thermogravimetric analysis (TGA) by flowing nitrogen, the settlement method using Kissinger - Akahira - Sunose (KAS) and Flynn -Wall - Ozawa (FWO). The samples were heated at a temperature ranging from 30°C to 1000°C with three different heating levels, namely 10, 30, and 50°C/min yang injected 20 mL/min Nitrogen (N2). The results obtained from the thermal decomposition process show three main stages, namely dehydration, active and passive pyrolysis. The activation energy (Ea) and the pre-exponential factor (A) obtained by the KAS method were around 42.241 kJ/mol, 51.290 kJ/mol, 54.556 kJ/mol, and 61.604 kJ/mol with conversion of 0.2%, 0.3%, 0.4%, while the estimation of activation energy from FWO 48.963 kJ/mol, 58.107 kJ/mol, 61.498 kJ/mol, and 68.457 kJ/mol with conversion of 0.2%, 0.3%, 0.4%, and 0.5% respectively. the kinetic parameter can be described by using this method. The experimental results show that the kinetic parameters obtained from the two methods are slightly different. However, the KAS and FWO methods are quite efficient in explaining the mechanism of the degradation reaction.

Pyrolytic thermal degradation kinetics of pigeon pea stalk (Cajanus Cajan): Determination of kinetic and thermodynamic parameters

This article highlights the pyrolytic thermal degradation behavior of pigeon pea stalk (PPS) at different heating rates (β) ranging from 10 to 40 °C/min in inert nitrogenous atmosphere using the thermogravimetric analysis (TGA). Three isoconversional methods: Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS) and Starink method were used to evaluate the kinetic parameters, including activation energy (Ea) and pre-exponential factor for range of conversion degree (α) 0.1 to 0.9. The highest average value of activation energy for PPS was found 126.24kJmol−1 for FWO method followed by Starink and KAS method as 122.59kJmol −1 and 116.23kJmol −1 respectively. Pre exponential factor (A) and thermodynamic parameters such as change in Gibbs free energy (G), enthalpy (ΔH) and entropy (ΔS) were computed and critically discussed. The average value of ΔH was found as 117.36, 110.95 and 120.97kJmol −1 for FWO, KAS and Starink method, respectively. Whereas, ΔG values were noticed very close to each other (ranges from 302 to 315kJmol −1) and average values of ΔS were − 181, −192 and −185Jmol−1K−1 for OFW, KAS and Starink method, respectively. The difference between average activation energy and value of ΔH was noticed imperceptible (∼5kJmol −1), which is a positive confirmation about the generation of green product from PPS requiring low energy potential. As summary PPS was found to have significant potential to be used as a feedstock for bioenergy production.

Kinetics of Thermolysis of a Low-Temperature Tar in the Presence of a Catalyzer Agent with Deposited Metals

The thermal decomposition of low-temperature coal tar (LTCT) obtained from the coals of Shubarkol Komir JSC of the Republic of Qazaqstan in the presence of nanocatalysts with metal oxides (iron, cobalt and nickel) supported on microsilicate was studied for the first time. Microsilicate acts as a carrier and catalyst. Microsil-icate is a product of the Karaganda silicon plant of “Tau-Ken.temir” LLP. The main chemical component of the original microsilicate is silicon oxide. The individual and chemical phase composition of the microsilicate was determined using X-ray spectral analysis. The particle size of the initial microsilicate and the mixture of microsilicate with metal oxide catalysts (nickel, cobalt, and iron) was determined using a nanosizer. Stages of thermal decomposition of LTCT and a mixture of LTCT with catalysts under conditions of programmed heat-ing up to 640 °С in a nitrogen atmosphere have been established. On the basis of thermogravimetric analysis, the kinetic parameters (activation energy, mass loss rate, and pre-exponential factor) of LTCT pyrolysis and mixture with added catalysts were determined. The modeless integral isoconversion Ozawa–Flynn–Wall method was used to determine the kinetic parameters. The values of the activation energy for the thermal de-struction of the LTCT in the absence and presence of the nanocatalyst ranged from 54.04 to 297.5 kJ/mol. A kinetic compensation effect was revealed, probably due to the multicomponent composition of the LTCT and the influence of added catalysts to the LTCT. The thermogravimetry method showed a high effect of the sup-ported catalysts on the thermal degradation of LTCT. This method was used to determine the values of the ac-tivation energy and the pre-exponential degradation factor for the LTCT and the mixture with catalysts at dif-ferent heating rates, which allows a detailed interpretation of the thermal analysis data. The obtained results of the kinetics of decomposition of LTCT can be used to create a database for mathematical modeling of the process of processing this type of raw material.

Production and Characterization of Palm Oil Based Epoxy Biocomposite by RSM Design

In this research, some physical and chemical properties of the biocomposite obtained from synthesized epoxy modified palm oil (MPO) and epoxy resin have been characterized. The experimental study plan is made according to Response Surface Methodology (RSM) and biocomposites with different MPO rates are obtained. The chemical bond structure of MPO and epoxy biocomposite has been evaluated with Fourier Transform Infrared Spektrofotometre (FTIR). The experimental, and RSM model results obtained, the density of the biocomposite rise as the MPO rate increases. It is determined that the Shore D hardness of the biocomposite is inversely proportional to the MPO rate by mass. The thermal conductivity coefficient and thermal stability also rise with the rate of MPO (wt.%) in the biocomposite. In the thermal degradation experiments of the obtained biocomposite, it is observed that the thermal stability of the composite goes up as the MPO rate rises. Activation energies are calculated using the Flynn Wall Ozawa, Kissinger, and Coats Redfern models. The activation energies calculated for the 9th, 2nd, and 13th experiments according to the Flynn Wall Ozawa method are approximately 139.65, 143.56, and 145.28 kJ/mol, respectively. The function with the highest R2 value has been determined according to the Coats Redfern method, and the deviation in Flynn Wall Ozawa and Kissinger model results was below 7%.

Effects of Organic Based Heat Stabilizer on Properties of Polyvinyl Chloride for Pipe Applications: A Comparative Study with Pb and CaZn Systems.

In this paper, the effects of organic based stabilizers (OBS) are investigated and compared with traditional lead (Pb) and calcium zinc (CaZn) heat stabilizers regarding their processability, mechanical property, and thermal degradation behaviors in rigid PVC pipe applications. In addition, the effects of repeated processing cycles on the degree of gelation and the impact strength of the PVC/OBS, PVC/CaZn, and PVC/Pb are also examined. A repeated processing cycle of those three types of the heat stabilizers up to four cycles was found to increase the degree of gelation and proved no significant effect on the impact strength and heat resistance of the resulting PVC samples. The OBS showed a positive effect on preventing the autocatalytic-typed thermal degradation of the PVC samples. This leads to a longer retention time for the initial color change of the PVC/OBS compared to PVC/Pb or PVC/CaZn systems. This characteristic was related to a more uniform fusion behavior of the PVC/OBS, i.e., the lowest gelation speed and the longest fusion time. The non-isothermal kinetic parameter determined by the Kissinger and Flynn–Wall–Ozawa methods of the dehydrochlorination stage of the PVC/OBS was in satisfactory agreement and continued to compare with the PVC/Pb and PVC/CaZn systems. The results indicated that the OBS might decrease the dehydrochlorination rate of PVC, implying that PVC/OBS was more stable than PVC/Pb and PVC/CaZn systems.