Thermogravimetric Fourier Transform Infrared Spectroscopy Research Articles

Thermo‐oxidative degradation behavior of poly(vinyl chloride) insulation for new and overloaded wires via TG‐FTIR

AbstractWhen a poly(vinyl chloride) (PVC) wire experiences overload failure, the internal structure of the insulation changes to become overloaded insulation and the fire hazard changes. In this study, the thermo‐oxidative degradation behavior of new and overloaded PVC insulation materials was analyzed using coupled thermogravimetric‐Fourier transform infrared spectroscopy (TG‐FTIR). The thermo‐oxidative degradation results show that the first two stages of thermo‐oxidative degradation of PVC insulation are important stages for measuring fire hazard. In addition, the onset temperature of thermo‐oxidative degradation of overloaded PVC insulation was increased. The activation energies of the first two stages of the overloaded PVC insulation increased by 7.7% and 27.0%, respectively, compared to the new PVC insulation. And the reaction mechanism is changed. The FTIR results indicate that the increased amount of volatile organic compounds and CO2 generated during the pyrolysis of the overloaded PVC insulation may result in the generation of more heat and smoke during combustion, thus increasing the fire hazard.

High fire-safety epoxy thermosets with a macromolecular phosphorus-nitrogen containing flame retardant at a low loading

In this article, a macromolecular phosphorus-nitrogen containing flame retardant defined as PDPSB was incorporated into epoxy resins (EP). The fire safety, flame-retardant mechanism and mechanical properties of EP/PDPSB thermosets were systematically investigated. The EP-5 sheets containing 5 wt% PDPSB passed V-0 level in the vertical burning tests (UL-94) with a high limiting oxygen index (LOI) value of 30.9%. The results of cone calorimeter tests (CCT) revealed that both the emission of heat and smoke for EP/PDPSB thermosets was substantially suppressed. Compared to pure EP, the values for peak of heat release rate (PHRR), total heat release (THR) and total smoke production (TSP) of EP-5 were dropped by 19.4%, 31.5% and 33.0%, respectively. Remarkably, the char residue mass of EP-5 was enhanced by 87.7%. The maximum smoke density (Ds, max) was slashed by 18.9%. Furthermore, the tensile, flexural and charpy impact strength of EP-5 were maintained to 97.3%, 95.1% and 86.9%, respectively. The investigation of flame-retardant mechanism demonstrated PDPSB exerted flame retardant effect both in condensed and gaseous phase by the scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDX), X-ray photoelectron spectra (XPS), laser Raman spectra (LRS) and thermogravimetric-Fourier transform infrared spectroscopy (TG-FTIR). As PDPSB was a one-component multifunctional additive renowned for its exceptional efficiency, it was anticipated to facilitate the advancement of high-performance epoxy thermosets via researching on EP/PDPSB thermosets.

The nitrogen transformation behavior based on the pyrolysis products of wheat straw

In order to provide basic design parameters for the industrial pyrolysis process, the transformation behavior of nitrogen was investigated using wheat straw as raw material. The distributions of nitrogen in pyrolysis char, oil and gas were obtained and the nitrogenous components in the products were analyzed systematically by X-ray photoelectron spectroscopy (XPS), pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and thermogravimetric-Fourier transform infrared spectrometry (TG-FTIR). The nitrogen distribution ranges of the pyrolysis char, oil and gas were 37.34% − 54.82%, 32.87% − 40.94% and 10.20% − 28.83%, respectively. More nitrogen was retained in char at lower pyrolysis temperature and the nitrogen distribution of oil was from rise to decline with increasing temperature. The most abundant N-containing compounds in three phase products were pyrrole-N, amines and HCN, respectively. In addition, the transformation mechanism of nitrogen from wheat straw to pyrolysis products was concluded.

Catalytic co-pyrolysis of cabbage waste and plastics with Ni/ZSM-5 catalysis to produce aromatic-rich oil

This study investigates the selective production of aromatics through the co-pyrolysis of cabbage waste and plastics followed by catalytic reforming with Ni-modified ZSM-5. Co-pyrolysis significantly improves the inflection point (a parameter for determining thermal stability) to 251.3 °C from 232.7 °C. This process also enhances the relative yield of olefins and phenols, which are precursors for aromatic production to 25.46 and 17.23 respectively, up from 13.87 to 12.05. Furthermore, catalytic pyrolysis elevates the relative yield of aromatics to 53.4, as confirmed by Thermogravimetric Analysis (TGA) and Thermogravimetric-Fourier Transform Infrared Spectroscopy (TG-FTIR) analyses. GC-MS confirms the enhanced formation of valuable chemical precursors via co-pyrolysis such as phenols and olefines to 18.67 % and 22.13 % leading to a 63.81 % selective yield of aromatics in the final oil with 10Ni/ZSM-5. Ni modification of ZSM-5 is influential in decreasing PAH formation (7.26 % from 20.37 %), indicating that this two-step process is an effective method for transforming waste into high-quality bio-oil with enriched aromatic content.

Enhancing bio-based chemical production and reducing pollutants emission through the synergistic effect of ZSM-5/CaO during hydrogen-deficient biomass pyrolysis

The study proposed the use of ZSM-5/CaO as a catalyst to simultaneously improve the quality of pyrolytic products and reduce pollutants emission during the pyrolysis of hydrogen-deficient biomass, specifically cabbage waste (CW). Variables such as pyrolysis temperature and catalysts, including 5% ZSM-5, 5% CaO and 10% ZSM-5/CaO, significantly affected biomass conversion, yield, and products composition. Thermogravimetric-Fourier transform infrared spectroscopy (TG-FTIR) analysis shows that the catalysts (5% ZSM-5, 5% CaO and 10% ZSM-5/CaO) reduced pollutants emission and increased value-added chemicals production by 24.96%, 28.5%, 17.39% and 75.04%, 71.5%, 82.1%, respectively compared to non-catalytic process as 34.18% and 65.82%. Moreover, these catalysts enhanced the relative yield of olefins, aromatics, and phenols to 23.5, 21.6, 27.6% for 5wt.%ZSM-5; 20.8, 18.7, 23.3% for 5wt.%CaO; 30.7, 38.6, 41.3% for 10wt.%ZSM-5/CaO, compared to the non-catalytic process' yield of 15.7, 10.7, 19.3%. Py/GC–MS analysis confirms that these catalysts also decreased PAH and oxygenates production to 13.5, 15.3% for 5wt.%ZSM-5; 11.8, 9.1% for 5wt.%CaO; 5.2, 4.7% for 10wt.%ZSM-5/CaO, in contrast to the non-catalytic process' 26.2, 28.7%. This confirms the synergistic effect of ZSM-5/CaO for upgrading bio-based chemicals and reducing pollutants emission.

Kinetic Analysis of Thermal Decomposition of Polyvinyl Chloride at Various Oxygen Concentrations

PVC plastic products are common combustible substances seen in fires, but their thermal degradation behavior under different oxygen concentrations has not been adequately studied. The thermal degradation behavior of PVC materials in atmospheres with different oxygen concentrations was analyzed via thermogravimetric–Fourier transform infrared spectroscopy (TG-FTIR). The TG results show that the thermal degradation process of PVC under a non-oxygenated atmosphere occurred in two stages, and the activation energies of the two stages were 130–175 KJ mol−1 and 230–320 KJ mol−1, respectively; under the oxygenated atmosphere, the thermal degradation process occurred in three stages. The activation energies of the three stages were 130–175 KJ mol−1, 145–510 KJ mol−1 and 75–190 KJ mol−1, respectively. And the reaction mechanism of the second stage of thermal degradation was changed from D-ZLT3 to En by the higher oxygen concentration. Infrared spectroscopy (FTIR) was used to analyze the pyrolysis process of PVC in the non-oxygenated atmosphere, and the eight major components were as follows, in descending order according to amount released: C-H stretching > HCl > C-Cl stretching > H2O > CO2 > C-H bending > C-H aliphatic bending > CH2. For the reaction of PVC at an oxygen concentration of 7%, the nine major components, in descending order according to amount released, were as follows: CO2 > HCl > H2O > CO > C-H stretching > C-Cl stretching > C-H aliphatic bending > C-H bending > CH2. For PVC reactions at oxygen concentrations of 14% and 21%, the five major components, in descending order according to amount released, were CO2 > HCl > CO > C-Cl stretching > H2O.

Pyrolysis of food waste digestate residues for biochar: Pyrolytic properties, biochar characterization, and heavy metal behaviours

The current work has examined the pyrolytic properties, product formation mechanisms, biochar properties, and heavy metal (HMs) safety of biochar during food waste digestate residue (DR) pyrolysis. The results have shown that DR pyrolysis proceeded in five stages. The kinetic model for Stages 1, 3 and 4 was the simple reaction order model, the one-dimensional diffusion model for Stage 2, and the three-dimensional (Jander) diffusion model for Stage 5. Based on thermogravimetric-Fourier transform infrared spectrometry (TG-FTIR) and pyrolysis–gas chromatography-mass spectrometry (Py-GCMS) analysis, the volatile components of the DR pyrolysis were mainly produced by the Maillard, decarboxylation, and deamination reactions as H2O, CH4, CO2, CO, phenol, CO (anhydride/ketone/aldehyde), C-O and NH3. While there were six main components of the pyrolysis oil, that is, amines and amides, nitriles, N-hybrid compounds, oxides, and sulfides. Appropriate aromatic properties were observed in the prepared biochar, and the biochar obtained at a pyrolysis temperature of 700 °C had a relatively high specific surface area. The HMs results showed that the HMs in biochar obtained from DR pyrolysis at 400, 500, 600, 700, and 800 °C were predominantly in the oxidizable and residual fractions. The toxicity characteristic leaching procedure (TCLP) tests and the potential ecological risk indices for HMs have indicated a high safety profile for biochar. This work has elucidated the formation process of DR pyrolysis products and the physicochemical properties and safety of biochar. It has also provided an outlet for the application of biochar, which provides a strong contribution to promoting resource use of DR.

Thermoplastic polyurethane composite modified by piperazine pyrophosphate: Flame retardancy, thermal stability and combustion properties

In this work, flame retarded thermoplastic polyurethane (TPU) composites were fabricated by introducing a novel flame retardant piperazine pyrophosphate. The flame retardany, thermal stability and combustion performance were systematically investigated. Flame retardant tests confirmed that thermoplastic polyurethane/piperazine pyrophosphate (TPU/PAPP) composites showed LOI of 27.5 vol% without any melt dripping when only 5 wt% PAPP was added. micro-combustion calorimetry (MCC) test implied that PAPP significantly suppressed heat release of TPU/PAPP composites. 10 wt% of PAPP endow PHRR1 and THR values TPU/PAPP10 decreased by 67.0% and 35.1% compared with TPU. Thermogravimetric-Fourier transform infrared spectroscopy (TG-FTIR) showed that PAPP significantly inhibited the release of toxic and combustible gases. The char residue investigation showed that TPU/PAPP composites formed compact char residue, which was able to effectively inhibit the heat and mass transmission in combustion. Based on the investigation, the work mechanism of PAPP in TPU/PAPP composites was proposed.

A novel composite coating containing P/N/B and bio-based compounds for flame retardant modification of polyester/cotton blend fabrics

Herein, a novel composite coating containing P/N/B and bio-based compounds was developed and applied to the flame-retardant finishing of polyester/cotton (T/C) blend fabrics. The flame-retardant coating was prepared with a combination of triethanolamine borate, diethylenetriamine pentamethylene phosphonic acid and calcium alginate. The combined characterization of scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) proved that the coating system has been successfully processed to the surface of T/C blend fabrics. The results of limiting oxygen index (LOI), horizontal flammability test (HFT) and vertical flammability test (VFT) showed that the P/N/B/Ca-T/C blend fabrics obtained good flame retardancy and exhibited excellent char-forming ability. Meanwhile, the thermal stability and combustion behavior of the blend fabrics before and after coating were evaluated by thermogravimetric (TG) and cone calorimetry tests. Obviously, the flame-retardant coating transformed the thermal degradation process of T/C blend fabrics and suppressed their heat and smoke release during combustion. Furthermore, Fourier transform infrared (FTIR) spectroscopy of char layers and thermogravimetric-Fourier transform infrared spectroscopy (TG-IR) analysis indicated that the composite coating exerted flame retardancy to T/C blend fabrics in both the condensed and gas phases.

Mechanical, Thermal Stability, and Flame Retarding Properties of Phosphorus-Modified PET Blended with DOPO-POSS.

In this study, an antidroplet flame retardant system based on FRPET (phosphorus-containing copolyester) is constructed with DOPO-POSS (polyhedral oligomeric silsesquioxane containing DOPO) as an additive flame retardant. It is demonstrated that DOPO-POSS has good dispersibility at a lower amount. When the amount of DOPO-POSS is 9 wt %, the residual char of DOPO-POSS/FRPET at 700 °C increases to 23.56 from 18.16% of FRPET, and the maximum thermal weight loss rate also reduces. What is more is that the limiting oxygen index increases to 33 from 26% of FRPET. The flame burning time is shortened to 4.95 from 20.8 s, the phenomenon of self-extinguishing of the fire occurs, and the vertical combustion level is increased from V-2 to V-0. Compared with FRPET, the peak of the heat release rate decreases by 66.0%, the total heat release decreases by 32.4%, the flame retardancy index (FRI) reaches an excellent value, and the condensed-phase products significantly improve. The Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDX), thermogravimetric-FTIR (TG-FTIR), and pyrolysis-gas chromatograph/mass spectrometry (Py-GC/MS) results indicate that DOPO-POSS contributes to the formation of char layers and decomposes to generate free radicals with a quenching effect. In a word, DOPO-POSS is an effective radical trapper and charring agent for PET and exerts a flame retardancy effect in gaseous and condensed phases simultaneously.

The effects of alkali metals and alkaline earth metals on the mechanism of N-containing gases production during glutamic acid pyrolysis

Biomass contains Alkali and Alkaline Earth Metals (AAEMs) which, during the pyrolysis process of biomass, can affect the production of harmful gases such as NH3, HCN and HNCO. In this study, the effect of AAEMs on the mechanisms of amino acid pyrolysis was analysed with a combination of Thermogravimetric- Fourier Transform Infrared Spectroscopy (TG-FTIR) experiments and Density Functional Theory (DFT) calculations. Moreover, the four most abundant metals in biomass (K, Ca, Na and Mg) were selected, and glutamic acid (Glu), which accounts for the largest proportion of plant proteins, was studied. The results showed that all four metal chlorides had an inhibitory effect on the production of N-containing gases, while promoted the char formation. Sodium was the most effective in reducing the yields of NH3, HCN and HNCO. The alkaline earth metals (Ca and Mg) could influence the temperature range for gas release. Diketopiperazines (DKP) were produced from the pyrolysis of amino acids, and the precursor of HCN and HNCO. This study explained the effect of AAEMs on nitrogen conversion mechanisms during biomass pyrolysis and provided theoretical support for controlling the nitrogen element transfer.

Comprehensive study of thermal degradation behavior of carbon fiber flexible sucker rods: Product characteristics, kinetics and thermodynamics

Carbon fiber flexible sucker rods (CFSR) are important as an essential component of oilfield extraction and their potential energy resource after decommissioning is very important. This research presents a detailed examination of the pyrolysis kinetic triplets and product characterization of CFSR that used a thermogravimetric analyzer (TGA), thermogravimetric-Fourier transform infrared spectroscopy (TG-FTIR) and gas chromatograph-mass spectrometer (GC-MS). The results revealed that the CFSR reaction interval was between 240 and 550 °C. Model fitting and the Criado method were used to determine the reaction control mechanism, and the average activation energies obtained by four model-free methods were 201.52(FWO), 201.93(KAS), 217.96(FM), and 202.29(Starink) kJ/mol. The byproducts consist mainly of acids, aromatics and hydrocarbons. In addition, the regenerated carbon fibers have a smooth surface and almost no residual resin as the temperature climbs to 600 °C. The results of the study facilitate the process optimization of carbon fiber composites and provide theoretical guidance and data support for subsequent development and utilization.The results of the study facilitate the process optimization of carbon fiber composites and provide theoretical guidance and data support for subsequent development and utilization.

Systematic study on dynamic pyrolysis behaviors, products, and mechanisms of weathered petroleum-contaminated soil with Fe2O3

Weathered petroleum-contaminated soil (WPCS) with a high proportion of heavy hydrocarbons is difficult to remediate. Our previous research demonstrated that Fe2O3-assisted pyrolysis was a cost-effective technology for the remediation of WPCS. However, the pyrolysis behaviors, products, and mechanisms of the WPCS with Fe2O3 are still unclear. In this study, a combination of Thermogravimetric–Fourier transform infrared spectroscopy (TG-FTIR) and pyrolysis gas chromatography/mass spectrometry (Py-GC/MS) techniques were used to explore these pyrolysis characteristics. The thermal desorption/degradation of light and heavy hydrocarbons in the WPCS mainly occurred at 200–400 °C and 400–550 °C, respectively. The activation energy of thermal reaction of heavy hydrocarbons was decreased in the presence of Fe2O3 during the WPCS pyrolysis processes. In the process, the released inorganic gaseous products were mainly H2O and CO2, while the released organic gaseous compounds were primarily cycloalkanes, alkanes, acids/esters, alcohols, and aldehydes. Compared with the WPCS pyrolysis without Fe2O3, the yields of gaseous products released during the WPCS pyrolysis with Fe2O3 were reduced significantly, and some gaseous products were even not detected. This phenomenon was contributed by the following two reasons: 1) heavy hydrocarbons in the WPCS were more easily transformed into coke in the presence of Fe2O3 during pyrolysis; 2) some released gaseous products were reacted with Fe2O3 and fixed on the soil particles. Therefore, the WPCS pyrolysis with Fe2O3 can effectively reduce the burden of tail gas treatment. Criado method analysis results suggested that the reaction mechanism of heavy hydrocarbons during the WPCS pyrolysis with Fe2O3 was rendered as the synergic effects of diffusion, order-based, and random nucleation and growth reactions.

PREPARATION OF IRON- REDUCED GRAPHENE OXIDE/ EPOXY RESIN COMPOSITE AND ITS FLAME RETARDANCY AND THERMAL STABILITY

In order to reduce flammability, smoke release and enhance thermal stability of epoxy resin (EP), iron powder is mixed with graphene oxide/ epoxy resin (GO/EP) composite by mechanical blending. The combustion performance of composite material is investigated through limiting oxygen index (LOI), Underwriters Laboratory (UL)-94 test, and cone calorimeter test (CCT). Thermogravimetric-Fourier transform infrared spectroscopy (TG-FTIR) and scanning electron microscope (SEM) are also used to explore the mechanism of flame retardancy and smoke suppression. Results show that, with the addition of 0.5% mass fraction of GO and the corresponding iron powder combination (EP3 sample), the LOI value can achieve 32.5% while reaching the UL-94 V0 rating. Compare with EP0, the peaks of heat release rate, smoke production rate, and smoke factor values of EP3 are decreased by 42%, 60%, and 50%, respectively. The char and TG-FTIR data of EP3 reveal that it has a more compact structure, good thermal stability, and produce fewer toxic gases and smoke. Reduction of GO could inhibit the degradation of EP, and iron catalyzes the formation of carbonaceous char on the surface. Thus, the thermal stability and flame retardancy of EP are improved significantly. This study provides a suitable way to prepare graphene/EP composites that contain iron catalyst and can be extended to the industrial manufacture of flame retardant polymer composites. Keywords: iron powder; epoxy resin; graphene oxide; flame retardant; thermal stability

Research on the co-pyrolysis of coal gangue and coffee industry residue based on machine language: Interaction, kinetics, and thermodynamics

Co-pyrolysis technology of urban solid waste and biomass has broad application prospects in alleviating energy crisis and environmental pollution. In this study, thermogravimetric-Fourier transform infrared spectroscopy (TG-FTIR) was used to study the co-pyrolysis characteristics of coal gangue (CG) and coffee industry residue (CIR). CG and CIR were uniformly mixed according to the mass ratios of 1: 0, 7:3, 5:5, 3:7, and 0:1. Then the samples were heated and pyrolyzed in an atmosphere with a nitrogen flow rate of 60 mL/min. As the proportion of CG increased, the comprehensive pyrolysis index (CPI) showed an exponential decrease. FTIR detected that the gas produced by pyrolysis of CG-CIR contained hydroxyl compounds, hydrocarbons, CO2, CO, Phenols, and NH3. CG-CIR co-pyrolysis had obvious interaction. By using Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) methods, the relationship between activation energy (Eα) and kinetic parameters and conversion degree was studied. Principal component analysis (PCA) was used to determine the principal reaction of CG-CIR pyrolysis. ANN 21 was the best model for predicting the pyrolysis of CG-CIR.

Fire performance of piperazine phytate modified rigid polyurethane foam composites

Using phytic acid (PA) and piperazine (Pi) as raw materials, piperazine phytate (PA‐Pi) was fabricated by simple ionic reaction. Furthermore, A series of rigid polyurethane foam/piperazine phytate (RPUF/PA‐Pi) composites were prepared by one‐step water‐blown technology. Thermogravimetric (TG) results showed that the addition of PA‐Pi improved the thermal stability of RPUF/PA‐Pi composites at high temperature. At 700°C, RPUF/PA‐Pi20 exhibited the highest carbon residue of 25.8 wt%. Cone calorimetry and smoke density tests suggested that PA‐Pi could reduce the heat and smoke release during combustion process of the composites, thus reducing their fire hazard. Thermogravimetric‐Fourier transform infrared spectroscopy (TG‐FTIR) indicated that PA‐Pi significantly inhibited the release of toxic gases (isocyanate compounds, aromatic compounds, CO and HCN) and flammable gases (hydrocarbons and esters) during the decomposition process of RPUF/PA‐Pi composites, effectively improving fire performance of the composites. Scanning electron microscope (SEM), Raman and Fourier transform infrared spectroscopy (FTIR) were used to characterize the carbon residue of RPUF/PA‐Pi composites. The results showed that PA‐Pi could promote the formation of dense carbon layer of composites and effectively prevented heat and mass transfer in the combustion process.

Research on the fire safety effect of thermoplastic polyurethane elastomer based on sodium fumarate

AbstractSodium fumarate (SF, C4H3NaO4), as a low‐cost and environment‐friendly additive, has been applied as the fire safety agent to investigate the flame retardancy and smoke suppression property in thermoplastic polyurethane elastomer (TPU). A series of tests were carried out, including limiting oxygen index (LOI), cone calorimeter test (CCT), smoke density test (SDT), and thermogravimetric/Fourier transform infrared spectroscopy (TG‐IR). The results proved that the addition of SF can significantly improve the fire safety property of TPU. Remarkably, in the case of the sample containing 2.0 wt% SF, LOI was raised up to 27.5 compared with 21.0 of pure TPU. The CCT results showed that pHRR, THR, TSR, and SF values decreased by 60.1%, 17.0%, 44.6%, and 66.4%, respectively, while the residual mass increased from 3.0% to 12.3% compared with pure TPU. The digital photographs displayed a more compact and intense carbon layer after the addition of SF. The SDT results indicated SF has increased the luminous flux and reduced Ds values, implying the improvement of the smoke suppression property of TPU. TG and TG‐IR results showed that the addition of SF has promoted the char forming process and reduced the release of CO2 and other volatile compounds. All results of tests illustrated that SF has considerable fire safety effect on TPU. Through the analysis of the results of this experiment, it will make a significance in the aspect of fire safety of polymer.

Effects of torrefaction on the formation and distribution of dioxins during wood and PVC pyrolysis: An experimental and mechanistic study

Dioxins reduction is crucial for the pyrolysis of municipal solid waste (MSW). In this work, torrefaction was employed as a pretreatment for inhibiting the synthesis of dioxins. A mixture of poplar and polyvinyl chloride (PVC) was used as the model MSW and provided the polycyclic aromatic hydrocarbon (PAH) source and chlorine sources, respectively. A torrefaction-pyrolysis experiment was performed in a tubular furnace system, and the weight loss and chlorine release (mainly in the form of hydrogen chloride) were evaluated. The dioxins distribution in the products were detected by high-resolution mass spectrometry (HR-MS). Thermogravimetric Fourier transform infrared spectroscopy (TG-FTIR) was employed to clarify the chlorination of PAHs. The results showed that torrefaction could reduce 98.63 % of the total amount of dioxins and reduce 99.09 % of the toxic equivalent of volatile dioxins. Since torrefaction cut the Cl participation of MSW (from PVC) by 86.94 %, the overall reaction process was simplified, and the temperature of the maximum conversion rate was increased. In addition, the analysis of the functional groups indicated that most dioxins during pyrolysis was synthesized from 200 ℃ to 400 ℃. This research demonstrated a significant emission reduction, which effected by torrefaction, and provided a new idea for dioxins clean pyrolysis of MSW.

Thermodynamics, kinetics, gas emissions and artificial neural network modeling of co-pyrolysis of sewage sludge and peanut shell

The co-pyrolysis characteristics of sewage sludge (SS) and peanut shell (PS) under nitrogen atmosphere were studied by thermogravimetric – Fourier transform infrared spectrometry (TG-FTIR) and artificial neural network (ANN). The proportion of PS in the experimental samples is 0, 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100%. The experiments were performed at three heating rates of 5 °C/min, 7 °C/min and 10 °C/min. The variation of sample mass with temperature and gas emission were detected in this paper. SS and PS in the co-pyrolysis experiment have a synergistic effect in terms of mass loss at 335 °C ∼ 500 °C. Gases generated by pyrolysis of the mixture of SS and PS include H2O, CH4, CO2, CO, phenol and NH3. The functional groups detected in the experiment include CO and C O. Apparent activation energy E was obtained by two non-isothermal kinetic analysis methods (Flynn–Wall–Ozawa and Kissinger–Akahira–Sunose). The artificial neural network method was used to predict the relationship between the mass loss of pyrolysis experiments and the change of temperature. The best ANN model (ANN21) for predicting SS and PS pyrolysis was identified.

Supramolecular Poly(cyclotriphosphazene) Functionalized Graphene Oxide/Polypropylene Composites with Simultaneously Improved Thermal Stability, Flame Retardancy, and Viscoelastic Properties

AbstractA novel crosslinkable supramolecular poly(cyclotriphosphazene) functionalized graphene oxide (FGO) is synthesized and melt‐processed with polypropylene (PP), which results in a PP composite with simultaneously improved flame retardancy, smoke‐suppression, and thermal and viscoelastic properties. The cone‐calorimetry test results reveal that the peak heat‐release rate and total heat release of the composite (2 wt% FGO) are reduced by 39.7% and 29.9%, respectively, compared to those of the neat PP. Meanwhile, the total smoke released and total smoke production of PP are significantly (42.7% and 34.9%, respectively) reduced after composite formation with 2 wt% FGO. Similarly, the PP/FGO composite shows an improved maximum weight loss temperature of 392.4 °C, compared to that of neat PP (361.4 °C). Thermogravimetric Fourier‐transform infrared spectroscopy (TG‐FTIR) analysis further confirms that the composite reduces the evolution of the flammable components and toxic gases, especially CO gas, indicating that the FGO significantly decreases the fire hazards of the PP. The thermomechanical and melt‐rheological analyses reveal that the composite has higher mechanical stiffness and viscoelastic properties than the neat polymer. In summary, FGO is shown to have potential as an advanced additive to obtain PP composites with multifunctional properties; however, higher FGO loading would be needed to improve UL‐94 rating from V‐2 to V‐0.