Thermal Degradation Characteristics Research Articles

Physico-chemical and thermal degradation characteristics of marine red macroalgae for sustainable packaging applications

This study aims to examine the characteristics of Eucheuma cottonii, Gracilaria verrucosa, and Acanthophora spicifera red macroalgae. Eucheuma cottonii showed an average particle size of 58 μm, while Gracilaria verrucosa and Acanthophora spicifera were 84 μm and 72 μm, respectively. Besides, Eucheuma cottonii presented the lowest band of hydroxyl groups, exhibiting the formation of greater intermolecular hydrogen bonds. The red macroalgae biopolymer films were fabricated via a solvent-casting technique. The optimum performance was achieved from Eucheuma cottonii macroalgae with the tensile strength, puncture resistance, and contact angle reached 27.38 MPa, 6.72 N, and 72.58°, respectively. The increase in storage time for six months resulted in a slight decrease in the water barrier and film transparency. It appears feasible to use these red macroalgae as promising sustainable marine biomasses for practical use in eco-friendly packaging materials since the red macroalgae films showed good mechanical, water barrier, and biodegradability properties.

ВПЛИВ ВУГЛЕЦЕВИХ НАНОТРУБОК НА ТЕРМІЧНУ СТІЙКІСТЬ ТА ТЕРМОМЕХАНІЧІ ВЛАСТИВОСТІ ЕПОКСИДНОГО ПОЛІМЕРУ ЕД-20

The thermal stability and thermomechanical properties of an epoxy composite based on ED-20 epoxy oligomer cured with a polyaniline complex doped with tetrafluoroboric acid (PAn-BF3) The thermal stability and thermomechanical properties of an epoxy composite made from the ED-20 epoxy oligomer, cured with a polyaniline complex doped with tetrafluoroboric acid (PAn-BF3), were examined using differential thermogravimetry (DTG) and thermomechanical analysis (TMA).were investigated using differential thermogravimetry (DTG) and thermomechanical analysis (TMA). Multi-walled carbon nanotubes (MWCNTs) with unmodified (MWNT) and phenyl diazonium tetrafluoroborate-modified surfaces (mMWNT) were used as fillers. At the final stages of thermal degradation at T > 600 °C, the nature of the thermogravimetric curves and the conversion characteristics of polymer thermal degradation are virtually independent of the nature and mass of carbon nanotubes in the composite. At the initial stages of the process, including the region of rapid degradation, the conversion and temperature characteristics of thermal degradation indicate the influence of the nature of carbon nanotubes on the process. While in the case of pristine (unmodified) MWCNTs, the temperature of the onset of polymer mass loss Tp is practically independent of the MWCNT content, in the case of modified mMWNTs, mass loss of the composite is observed at significantly lower temperatures. An increase in the mMWNT content to 2.5 wt% causes a further decrease in the temperature Tp. The reduction in the thermal stability of epoxy composites filled with mMWNTs is chemical. It is associated with the thermal desorption of the modifier - phenyl diazonium tetrafluoroborate from the surface of MWCNTs. The results of the thermomechanical analysis of the studied epoxy polymer composites show that the introduction of a nanoscale filler leads to a significant improvement in the thermomechanical stability of the polymer matrix. This is shown by an increase in the glass transition temperature (Tg), the temperature of the polymer transition to a highly elastic state (Thes), and the high elasticity modulus. This effect is most significant for composites containing 2.5 wt.% carbon nanotubes.

Combined kinetic analysis of thermal degradation characteristics and reaction mechanism of thin intumescent fire-retardant coating of steel structure

To determine the thermal kinetic triplets and elucidate the reaction mechanism of thin intumescent fire-retardant coatings (IFR) of steel structures, one efficient combined kinetic approach was implemented in this study. Thermogravimetric experiments were conducted in air atmosphere at four heating rates, and the whole IFR thermal degradation process was divided into two stages. The average activation energy values derived by model-free methods were 78.9 kJ/mol and 175.16 kJ/mol for Stage I (0<α < 0.2) and Stage II (0.2<α < 0.9), respectively. Furthermore, the linear Coats-Redfern (CR) and non-linear Masterplots models were applied to identify the possible reaction mechanism. It was found that the F3/2 mechanistic model was better suited to the main thermal degradation process. Then model reconstruction based on the F3/2 mechanism model was performed. The results showed that the reconstructed model had a strict linear relationship in the independence analysis and KCE analysis, along with a good agreement between the theoretical and experimental results. The current study provided new insights into the systematic thermal degradation mechanism of IFR, and the proposed kinetic model would be helpful for the thermal protection prediction for steel structure during fire.

Thermal degradation of capsaicin and dihydrocapsaicin: Mechanism and hazards of volatile products

Food safety issues have become unprecedentedly notable. To ensure the safe use of capsaicin (CAP) and dihydrocapsaicin (DHCAP) in the food sector, their thermal degradation characteristics was examined for the first time through thermogravimetric analysis (TGA) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) analysis. The second major phase occurred within the temperature range of 265–425 ℃, leading to substantial weight reductions of 96.13 % for CAP and 92.76 % for DHCAP. Thermodynamic parameters, calculated using the Flynn–Wall–Ozawa (FWO), Kissinger–Akahira–Sunose (KAS), and Coats–Redfern (C–R) methods, indicated that the thermal decomposition of both CAP and DHCAP was non-spontaneous and followed an F1 mechanism (−ln(1−α)). The pyrolysis of CAP and DHCAP released several volatile compounds, including CAP, DHCAP, Z-9-octadecenamide, octadecanamide, 9-decenenitrile, nonanenitrile, and 8-methylnonanoic acid. These compounds may pose certain toxicological risks and potential hazards to human health. The pyrolytic pathways for CAP and DHCAP are likely to involve the cleavage of alkyl C-N and/or amide bonds, as well as processes of deamidation and demethylation. Therefore, it is prudent to avoid heating food containing CAP and DHCAP above 265 ℃ during culinary preparation.

Improved thermomechanical and rheological properties of polypropylene composites with thermomechanical pulp for injection molding

AbstractMaterial extrusion and injection molding are prevalent in polymer processing, but wood fiber‐reinforced polymer composites offer eco‐friendly alternatives for industries like automotive, and aviation. Our study explores biocomposites using bleached chemi‐thermomechanical pulp (BCTMP) and polypropylene (PP). BCTMP is rich in cellulose and hemicellulose and quite hydrophilic, while PP's hydrophobic structure creates a disconnect to creating a composite of the two. Traditional methods add costly coupling agents like maleic anhydride polypropylene (MAPP) in an attempt to enhance the adhesion properties of wood‐plastic composites. However, it is worth noting that even in the presence of MAPP, PP maintains its high hydrophobicity and low surface energy, despite exhibiting considerable heterogeneity. Further complexity arises from the thermal degradation characteristics of BCTMP during the melting processing of PP. Our proposed method involves premixing via cryo and planetary ball milling. This boosts PP and BCTMP adhesion, enhancing dispersion quality and mechanical properties without needing coupling agents. Moreover, the premixing of BCTMP and PP forms a thermal buffer layer around BCTMP, minimizing its thermal degradation during processing. This process also ensures even distribution of BCTMP into PP, resulting in a 200% rise in Young's modulus with 30 wt% BCTMP without compromising ultimate tensile strength.Highlights Exploration of biocomposites using bleached chemi‐thermomechanical pulp (BCTMP) and polypropylene (PP) thorough injection molding Implementation of premixing to enhance PP/BCTMP adhesion without coupling agents Premixing reduces thermal degradation of BCTMP, enhances dispersion, and improves mechanical properties Achieving a 200% increase in Young's modulus with 30% BCTMP incorporation, while maintaining ultimate tensile strength

Research on the pyrolysis mechanism of tobacco based on low temperature torrefaction

The temperature range of 100–220 °C is known to cause the volatilization of some volatile components and the pyrolysis of some unstable components in tobacco. However, there is a lack of research on the pyrolysis mechanism of tobacco at this temperature range. To address this gap, the present study employed an innovative cascade pyrolysis method based on stepwise heating to analyze the composition of tobacco's rapid pyrolysis products within this temperature range. The analysis was conducted at intervals of 30 °C. The study summarized the release characteristics of organics at different temperatures and analyzed the representative substances of various organic families. In addition, considering that tobacco has a unique composition compared to most biomass, the same five temperature points as they do in the cascade pyrolysis process were selected to torrefy the tobacco samples. These temperatures are lower than the conventional torrefaction temperatures typically used for biomass pretreatment. Multiple techniques were used to systematically analyze the composition, functional group structure, and thermal degradation characteristics of tobacco torrefied at different temperatures. Subsequently, the effect of torrefaction temperature on the release performance of products from tobacco pyrolysis at 650 °C was also studied. The results of this study not only contribute to a more comprehensive understanding of the pyrolysis mechanism of tobacco but also provide theoretical support for cigarette processing and tobacco waste utilization.

Catalyst-free construction of biomass-based robust and flame-retardant polyurethane foams

This study introduces a green synthesis method for the preparation of flame-retardant biobased polyurethane foams (PUFs) without the use of catalysts. The approach involves the design and utilization of two cardanol-based hydroxyalkyl benzoxazines (CHBzs) capable of self-catalytic foaming through the action of their oxazine rings. Additionally, tris(hydroxymethyl)phosphine oxide (THPO) is incorporated as both a crosslinking agent and a flame-retardant additive during the foaming process to enhance the physical properties and flame retardancy of the resulting PUFs. The thermodynamic performance, compressive strength, and flame-retardant properties of the synthesized foams are analyzed. Furthermore, the morphology of the combustion residues is investigated to understand the combustion process. The results demonstrate that the addition of THPO significantly improves the flame-retardant performance and thermal degradation characteristics of bio-based flame-retardant PUFs. This green synthesis approach offers a promising strategy for the development of sustainable and flame-retardant PUF materials.

Thermal degradation behavior and kinetics of porous polymer based on high functionality components

AbstractTwo kinds of porous polymer were prepared based on high functionality components. Thermogravimetric analysis (TGA) is used to compare the thermal degradation behavior and kinetics of these two materials. The thermogravimetric tests of rigid polyurethane foam (H‐RPUF) and polyurea aerogel (H‐PUA) were carried out in nitrogen atmosphere at different heating rates. The thermal degradation characteristics of the porous polymer were obtained. The apparent activation energy (Ea) of thermal degradation of the porous polymer was investigated by model‐free methods. The results showed that the thermal degradation temperature and ash content of H‐RPUF were higher than those of H‐PUA, and the volatile content was lower. With the rise of heating rate, thermal hysteresis effect of the two porous polymer was relatively high, while the release amount of volatiles was unchanged. For the Kissinger method, Ea of H‐PUA and H‐RPUF was 212.8 kJ mol−1 and 157.4 kJ mol−1, respectively. According to Starink method, the average activation energy of H‐PUA and H‐RPUF was 220.2 kJ mol−1 and 107.2 kJ mol−1, respectively. Obtained by Flynn‐Wall‐Ozawa model, the average activation energy of H‐PUA and H‐RPUF was 219.0 kJ mol−1 and 111.5 kJ mol−1, respectively. The data obtained from the three models all show that Ea of thermal degradation of H‐PUA is higher than that of H‐RPUF, and it is less likely to decompose.

Assessing the degradation profiles of a thermoresponsive polyvinyl alcohol (PVA)‐based hydrogel for biomedical applications

AbstractPrimary challenges associated with the design and success of polymeric biomedical devices are generally related to the control of the biomaterial in terms of degradability characteristics, sufficient processability characteristics, and required mechanical strength that may be altered during sterilization or manufacturing procedures. Polyvinyl alcohol‐based thermoresponsive biomaterials provide a distinct advantage for biomedical applications as their physiochemical properties can be easily modified according to their desired use. In this work, we evaluated the thermal degradation characteristics of a polyvinyl alcohol (PVA)/polyethylene glycol (PEG)/polyvinylpyrrolidone (PVP) hydrogel that undergoes a steam sterilization autoclave cycle at 121°C to induce fluid‐like behavior. FTIR was used to characterize the evolution of the area of the carbonyl region between 1800 and 1525 cm−1. The carbonyl area increased at temperatures beyond 121°C which were used to accelerate the onset of degradation during both thermal oxidation and pyrolysis. The change in the carbonyl region was shown to correlate with respect to both temperature and time of exposure. The carbonyl region increased significantly in the presence of oxygen at temperatures above 150°C. Despite showing signs of thermal degradation at temperatures exceeding 150°C, our biomaterial was shown to be stable at 121°C during thermal degradation testing. Furthermore, bulk property analysis showed the hydrogel's mechanical and swelling properties were preserved even after being subject to multiple autoclave cycles beyond what would be experienced during a sterilization or clinical procedure.

Investigation of the evolved pyrolytic products and energy potential of Bagasse: experimental, kinetic, thermodynamic and boosted regression trees analysis

This study explored bagasse's energy potential grown using treated industrial wastewater through various analyses, experimental, kinetic, thermodynamic, and machine learning boosted regression tree methods. Thermogravimetry was employed to determine thermal degradation characteristics, varying the heating rate from 10 to 30 °C/min. The primary pyrolysis products from bagasse are H2, CH4, H2O, CO2, and hydrocarbons. Kinetic parameters were estimated using three model-free methods, yielding activation energies of approximately 245.98 kJ mol−1, 247.58 kJ mol−1, and 244.69 kJ mol−1. Thermodynamic parameters demonstrated the feasibility and reactivity of pyrolysis with ΔH ≈ 240.72 kJ mol−1, ΔG ≈ 162.87 kJ mol−1, and ΔS ≈ 165.35 J mol−1 K-1. The distribution of activation energy was analyzed using the multiple distributed activation energy model. Lastly, boosted regression trees predicted thermal degradation successfully, with an R2 of 0.9943. Therefore, bagasse's potential as an eco-friendly alternative to fossil fuels promotes waste utilization and carbon footprint reduction.

Cure kinetics and thermal degradation characteristics of epoxy/polyetheramine systems

Cure kinetics and thermal degradation characteristics of epoxy/polyetheramine systems

Microporous Polyurethane Elastomer’s Comprehensive Properties Affected by Flame Retardant EG/APP

The mechanical characteristics, creep resistance, fatigue resistance, and other comprehensive properties of flame retardants/microporous polyurethane elastomers (FRs/MPUE) have not been systematically researched. Because of this, we used expandable graphite (EG) and ammonium polyphosphate (APP) to conduct this study on FRs/MPUE composites. The thermal degradation and flame retardant characteristics, tensile strength, compressive creep, and dynamic and static stiffness ratio of FRs/MPUE were studied. The findings demonstrated that the optimum synergistic flame retardant effect occurred when the ratio of EG to APP was 2:1. The LOI of MPUE reached 30.5%. The vertical combustion grade achieved V-0. The stage of thermal decomposition was the most stable. However, compared with pure MPUE, the tensile strength was slightly decreased, and the compressive creep and dynamic and static stiffness ratio were slightly increased. The MPUE’s LOI value was more than or equal to 26% when the EG to APP ratio was 2:1 to 1:2. The tensile strength was basically the same as that of pure MPUE. The compression creep was less than 5%, which met the B1 flame retardant requirements and creep resistance performance indicators of floating floor vibration-damping pads.

Ultra-high molecular weight EPDM composites via crossover curing agents: Stabilized crosslink network structure and performance properties

This study investigates the impact of various crosslinking systems, such as those based on sulfur, peroxide, and their hybrid combinations, on the thermal degradation characteristics of ethylene propylene diene rubber (EPDM). During aerobic degradation, polymer networks undergo reversible physical and irreversible chemical changes. There are two kinds of irreversible chemical changes that may occur: chain scission reactions and crosslinking events. The impact of these reactions on the characteristics of the elastomer is antagonistic. When measuring the properties of an elastomer as it ages, most standard characterization techniques reveal the aggregate impact of two reactions. This work employs a straightforward approach based on compression set measurements to distinguish between the scission and crosslinking events that occur during thermal aging. This work has analyzed hybrid crosslinked materials using this method and demonstrated their remarkable thermal stability, as evidenced by their ability to maintain equilibrium between scission and crosslinking reactions. The stability of performance characteristics, such as tensile strength and crosslink density, in hybrid-cured samples during thermal aging supports the aforementioned. Furthermore, the investigation also delves into the potential of hybrid curing systems using crossover curing agents instead of coagents, which are multifunctional additives, to augment the durability of performance characteristics over an extended period of thermal aging.

Synergistic co-combustion of carbon-rich fraction from coal gasification fine slag and corncob char: Performance, mechanism, kinetics, and thermodynamics

Coal gasification fine slag (FS) is a coal-based solid waste with high carbon content, and landfill-based disposal causes water-soil-gas composite pollution. Co-combustion is a common method of solid waste thermal disposal, and corn cob is used as an auxiliary fuel for co-combustion because of its energy density and ease of handling and processing. In this paper, the thermal degradation characteristics, interaction mechanism, kinetics, and thermodynamics of co-combustion RC (carbon-rich fraction obtained by flotation) and CC (corncob char) were studied. The results showed that physicochemical properties suggested that RC and CC will complement and promote each other in the combustion process. The addition of CC reduced the RC ignition temperature and improved the overall combustion performance. The interaction effect was mainly due to metal catalysis, the effect of the porous carbon structure, the thermal effect, and the hindering effect of ash. The activation energy was reduced due to the blending of RC-CC, and the activation energy was lowest (132.19 kJ/mol) when the RC adding ratio was 60%. The co-combustion process was controlled by the F3 model (chemical third-order reaction kinetics), and it was a typical gas-solid phase reaction with a progressive process from the outsides toward the insides. Thermodynamic analysis showed that the co-firing process was an extremely complex multi-stage reaction. The results of this study provide a theoretical reference for the synergistic resource utilization of coal gasification fine slag and waste biomass.

Acrylonitrile Butadiene Styrene/Thermoplastic Polyurethane Blends for Material Extrusion Three-Dimensional Printing: Effects of Blend Composition on Printability and Properties.

Blend filaments of acrylonitrile butadiene styrene (ABS) and thermoplastic polyurethane (TPU) were prepared at different weight ratios, i.e., 100:0, 70:30, 50:50, 30:70, and 0:100, for FDM printing; the prepared filaments, with an average diameter of 2.77 ± 0.19 mm, were encoded as A100, A70T30, A50T50, A30T70, and T100, respectively. The properties and printability of the filaments were thoroughly investigated. The blend composition, as well as the printing parameters, were optimized to obtain the FDM-printed objects with a well-defined surface structure and minimized warpages. The glass transition temperatures of ABS and TPU in the blends were not much altered from those of the parent filaments, whereas the thermal degradation characteristics of the blend filaments still fell between those of the neat filaments. The fractured surfaces of the filaments, observed by SEM, appeared smoother when higher amounts of TPU integrated; the smoothest surface of the ABS-based filament was found in A30T70, indicating the well-compatible blend characteristic. This was also confirmed by its rheological behavior examined by a parallel plate rheometer at 225 °C. Not only was the printability of the filaments improved, but also the warpages of the 3D-printed specimens were decreased when increasing amount of TPU was incorporated into the filaments. Among the printed objects, the A30T70 specimen exhibited the evenest surface morphology with the lowest surface roughness value of 32.9 ± 13.2 nm and the most uniform and consistent linear printing structure when being fabricated at the nozzle temperature of 225 °C and the printing bed temperature of 60 °C. However, the incorporation of TPU into the filaments markedly cut down both strength and modulus values of the fabricated materials up to about half but assisted the printed articles to absorb more energy, demonstrating that this polymer served as a good and effective toughener for ABS.

Thermal-degradation characteristics of mechanically nanofibrillated bleached pulps from hardwood and softwood

Nanofibrillated cellulose (NFC) consists of ultrafine cellulose structures in which the fibrils can have widths in the range from about 5 to 100 nm. NFC has been studied and developed in the paper industry, using bleached pulp from wood as the raw material. One of the issues in the application of NFC is their heat resistance to thermal degradation. The production process of NFC results in a decrease in their pyrolysis temperature during the nanofibrillation of bleached pulp; however, the details behind the reason and mechanisms are still unclear. In this study, NFC was prepared from bleached hardwood and softwood pulp by mechanical nanofibrillation using a grinder, and the pyrolysis behavior was investigated. For both bleached pulps, a decrease in the pyrolysis temperature was observed after nanofibrillation. The results suggest that the decrease in the pyrolysis temperature from nanofibrillation is not due to damage of the crystalline cellulose by nano fibrillation, but the damage of the hemicellulose components in the surface of the cellulose microfibrils or the interface between the crystalline cellulose and hemicellulose. If the hemicellulose on the surface of crystalline cellulose could be removed from the NFC, then the decrease in the pyrolysis temperature could be suppressed.

Insights into pyrolysis of pearl millet (Pennisetum glaucum) straw through thermogravimetric analysis: Physico-chemical characterization, kinetics, and reaction mechanism

Millets and millet crop residues are gaining increasing attention. Present work provides insights into thermal degradation characteristics, pyrolysis indices, kinetic triplets, and thermodynamic parameters for pearl millet straw (PMS) pyrolysis. Pyrolysis indices revealed suitability of higher heating rates for PMS in terms of enhanced pyrolysis performance and shorter reaction time. Combined approach, encompassing model-free methods and model-based method, i.e. distributed activation energy model (DAEM) was employed to study kinetics. Average activation energy through Kissinger-Akahira-Sunose, Flynn-Wall-Ozawa, Friedman, Starink, Vyazovkin, and DAEM was found to be 189.61, 190.84, 192.71, 187.84, 193.33, and 191.08 kJ/mol, respectively. Statistical analysis through ANOVA using Tukey test demonstrated insignificant deviation for obtained activation energies. Kinetic compensation effect was employed to determine pre-exponential factor. Master plots revealed prevalence of random nucleation (R1 and R2) for α < 0.5 and diffusion (D1) and power law (P2) models for α > 0.5. Thermodynamic parameters revealed endothermic, non-spontaneous, and high degree of randomness for PMS pyrolysis.

Thermal degradation and flame spread characteristics of epoxy polymer composites incorporating mycelium

Although bioderived flame retardants are environmentally sustainable and less toxic, their impact on the thermal stability and flammability of polymers remains poorly understood. In this study, we assessed the influence of mycelium on the thermal stability and flame spread characteristics of epoxy through thermogravimetric analysis, Fourier transform infrared spectroscopy, the UL94 flammability test, and scanning electron microscopy. We observed a decrease in the maximum mass loss rate temperature when mycelium was incorporated into epoxy, indicating an earlier onset of thermal degradation. The inclusion of mycelium increased char yields above 418 °C due to mycelium’s inherent char-forming ability. However, mycelium did not alter the thermal degradation pathway of epoxy. Furthermore, according to the UL94 test results, the incorporation of mycelium reduced the flame spread rate compared to that of neat epoxy. These findings contribute to our understanding of the interaction between bioderived flame retardants and polymers paving the way for the development of more sustainable fireproofing materials.

Fabrication, Characterization, and In Vitro Cytotoxicity Assessment of Tri-Layered Multifunctional Scaffold for Effective Chronic Wound Healing.

Chronic wounds have been a global health risk that demands intensive exploration. A tri-layered biomaterial scaffold has been developed for skin wounds. The top layer of the scaffold is superhydrophobic, and the bottom layer is hydrophilic, both of which were electrospun using recycled expanded polystyrene (EPS) and monofilament fishing line (MFL), respectively. The intermediate layer of the scaffold comprised hydrogel by cross-linking chitosan (CS) with polyethylene glycol. The surface morphology, surface chemistry, thermal degradation, and wettability characteristics of each layer of the scaffold were examined. Also, the antibacterial activity and in vitro cytotoxicity study on the combined tri-layered scaffold were assessed against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Data revealed exceptional water repellency of the heat-treated electrospun top superhydrophobic layer (TSL) with a high-water contact angle (WCA) of 172.44°. A TSL with 15 wt% of micro-/nano-inclusions had the best thermal stability above 400 °C. The bottom hydrophilic layer (BHL) displayed a WCA of 9.91°. Therapeutically, the synergistic effect of the combined tri-layered scaffold significantly inhibited bacteria growth by 70.5% for E. coli and 68.6% for S. aureus. Furthermore, cell viability is enhanced when PEG is included as part of the intermediate CS hydrogel layer (ICHL) composition.

Thermal conversion performance, kinetic mechanism, and products of electric vehicle lithium battery diaphragms

The proliferation of waste lithium batteries is on the rise; however, the thermal treatment attributes of these batteries are largely overlooked, and the conversion mechanism of lithium battery separators remains unclear. This study marks the first comprehensive to compare the thermal degradation characteristics, kinetic parameters and mechanisms, thermal degradation products, and degradation pathways of polypropylene (PP) and polyethylene (PE) lithium battery diaphragms. The pyrolysis temperatures for the PP and PE were 340–500 and 440–530 °C, respectively. PP and PE exhibited average activation energies of 65.19–73.04 and 207.62–209.40 kJ/mol, respectively. At 600–800 °C, the yields of PP and PE pyrolysis gases and gasoline products increased with increasing temperature, while the yields of diesel and paraffin products decreased. The most dominant products generated from the pyrolysis of PP and PE were olefins, and the amount of olefin products from PE increased with increasing pyrolysis temperature. CH3 fracture was the first reaction step that occurred during PP pyrolysis. Our study provides useful information for industrial recycling, disposal, and utilization of electric vehicle lithium battery separators as well as data on the pyrolysis behaviours and transformation mechanisms of polyolefin wastes.