Thermal Degradation Mechanism Research Articles

Elucidate the Thermal Degradation Mechanism of Y6‐Based Organic Solar Cells by Establishing Structure‐Property Correlation

AbstractOrganic solar cells (OSCs) achieved performance booming benefiting from the emerging of non‐fullerene acceptors, while inadequate device stability hampers their further application. At present, the prevalent belief attributes the inevitable thermal degradation of OSC device to morphological instability caused by excessive phase separation and crystallization in the active layer during device operation. However, it is inapplicable for state‐of‐art Y6‐based devices which strongly degrade before large‐scale morphology change. Herein, an alternative degradation mechanism is elucidated wherein molecular orientation change and demixing induced performance degradation in Y6‐based devices. Distinct from IT‐4F‐based counterpart, Y6‐based devices suffer severe thermal degradation dominated by open‐circuit voltage (VOC) and fill factor (FF) losses. The VOC loss is attributed to molecular orientation transition of polymer donors from edge‐on to face‐on, leading to a strong built‐in potential reduction and increase in non‐radiative loss due to energy level shifting. As for FF decay, discontinuous acceptor phases result in electron mobility decrease by over orders of magnitude, originating from the increased molecular stacking and phase separation. This work reveals the thermal degradation mechanism for Y6‐based devices and correlates the photoelectric properties with morphology instability, which will offer guidance for improving the stability of high‐performance OSCs.

Exploring the structure, characteristics, and thermal degradation of composites comprising thermoplastic polyolefin and graphene oxide under high-temperature dynamic shear conditions

Dynamic high-temperature shear aging tests were conducted on thermoplastic polyolefin (TPO)/graphene oxide (GO) composite materials using a Hakke torque rheometer. The study employed ATR-FTIR, DSC, SEM, oxygen performance testing, and TGA to analyze the structure, properties, thermal degradation behavior, kinetics, and mechanisms of TPO/GO composites. The results demonstrated that the high-temperature dynamic shear thermal oxidative aging of TPO/GO composite materials establishes a dual protective mechanism, incorporating physical (intercalation oxygen resistance) and chemical (inorganic oxygen resistance) effects. This can be attributed to the polar surface and honeycomb structure of GO, as well as the shear-induced more uniform physical distribution of GO within TPO. Consequently, TPO/GO composite materials exhibit significantly enhanced resistance to dynamic shear thermal oxidative aging compared to TPO alone.

Catalyst residues severely impact the thermal stability and degradation mechanism of polycarbonates: How to turn a flaw into an opportunity

Three poly(cyclohexene carbonates) with molecular weights ranging from 4.9 to 9.4 kg/mol were synthesized from cyclohexene oxide and CO2 using macrocyclic phenolate dimetallic catalysts and purified by conventional purification procedure. A decrease in thermal stability of approximately 100 °C was observed in comparison to poly(cyclohexene carbonates) with similar molecular weights synthesized using salen metal catalysts. This decrease derives from the presence of traces of dimetallic catalyst which is able to promote the depolymerisation of poly(cyclohexene carbonate) to CO2 and cyclohexene oxide in contrast to the usual backbiting mechanism that leads to cyclic carbonate. The onset of the degradation can be precisely tuned by changing the amount of residual dimetallic catalyst or including species with functional groups that can reduce the availability of the catalytic centers. Therefore, the possibility of controlling the thermal stability of poly(cyclohexene carbonates) by varying the concentration of the catalyst and the surrounding chemical environment paves the way for the use of these polymers as components in self-sacrificial materials of interest for advanced applications.

Polymerization behaviors and properties of benzoxazine resins based-on meta-substituted anilines

The molecular structure of benzoxazine is closely related to its polymerization activity and the properties of its polymer. In this work, benzoxazines were successfully synthesized from phenol, paraformaldehyde and meta-substituted anilines. Their polymerization behaviors were discussed by non-isothermal differential scanning calorimetry (DSC). Moreover, the thermal properties of corresponding polybenzoxazines were evaluated using DSC and thermogravimetric analysis. The results showed that the electron-withdrawing substituent increased the polymerization temperature while the electron-donating substituent lowered the polymerization temperature. The glass transition temperature decreased for polybenzoxazine with electron-donating substituent but elevated for polybenzoxazine with electron-withdrawing substituent. Besides, the thermal stability and thermal degradation mechanism of polybenzoxazine were significantly affected by the substituent. This work supplied further insight in the structure-property relationship of benzoxazine resin.

An assessment of the role of nanosilica in thermal/thermo‐oxidative degradation mechanism of poly(lactic acid)/polybutylene adipate terephthalate blend nanocomposites

AbstractAs a packaging materials candidate, based on a polylactic acid/ polybutylene adipate terephthalate (PLA/PBAT) blends (90/10 and 75/25 wt/wt) containing 1, 3, and 5 phr hydrophilic (HPL) and hydrophobic (HPB) nanosilica (NS) particles in the presence of a multifunctional epoxide compatibilizer were prepared by melt mixing, in a twin‐screw extruder. Scanning electron microscopic studies confirmed a matrix‐droplet morphology with finer dispersed domains at higher NS content. Energy dispersive spectroscopy mapping also indicated uniform dispersion of NS in blends, with some agglomerates at higher content of nanoparticles. Moreover, transmission electron microscope was applied to study the impact of nanofillers' localization on the systems' morphology. It was observed that NS particles localized at the PLA‐PBAT interface. In addition, thermogravimetric analysis (TGA) was used to investigate thermal stability and thermal degradation kinetics. Data indicates that hydrophobic NS improved thermal stability. The activation energy of degradation was calculated using several techniques of data modeling, including Friedman, Flynn‐Ozawa‐Wall, and Kissinger‐Akahira‐Sunose models. Among blend nanocomposites, 75/25 blend containing 5 phr HPB NS had the maximum degradation activation energy, suggesting that this sample had the most resistance to heat degradation. The intensity of the TGA/FTIR peaks of the evolved products was found to be correlated with the activation energy. The Criado's technique was also used to investigate the changes in the thermal degradation mechanism.

Pr doped La2Zr2O7 TBCs by EB-PVD: Thermal property, morphology and degradation mechanism

Pr doped La2Zr2O7 (LPZ) TBCs have been deposited by electron beam physical vapor deposition. This work concentrates on the thermophysical properties and microstructure evolution of LPZ/YSZ duplex TBCs before and after thermal cyclic so as to probe into the merit and the application feasibility. The thermal expansion, thermal conductivity and phase structure have been measured and analyzed in comparison to other classical TBCs materials. Typical feathery microstructure and intra-columnar gaps did not provide desired thermal cyclic counts for LPZ/YSZ TBCs. Two principal categories of degradation mechanism limited the cyclic lifetime. The first principal degradation mode is the pulverization of LPZ after thermal cyclic due to the Pr rare earth elements modification in lanthanum Zirconates. Pr instability created the pulverization degradation mode instead of spalling. The second degradation mode is the cracks extension paralleled to interface inside TGO due to the brittle spinel generated by excessive oxidation. This study of thermal properties and degradation mechanism might offer thought and inspiration for other advanced TBCs.

Study on surface grafting of hydroxyapatite and its influence on the properties of urea-formaldehyde resin

Urea formaldehyde (UF) is the most widely used resin in the wood composite board industry. UF has formaldehyde emission, which is harmful to the environment and human health. In this paper, hydroxyapatite (HAP) was surface modified by silane coupling agent (HAP-KH). And hydroxyapatite/urea formaldehyde resin (HAP-UF) was prepared by adding different amounts of HAP-KH. The optimal amount of HAP-KH was determined by wet shear strength and formaldehyde release. The degradation performance and degradation kinetics of the resin were also studied. The results show that the addition of HAP-KH can improve the wet shear strength of plywood and reduce the release of formaldehyde. The optimal content of HAP-KH was 3%, and the formaldehyde emission of plywood reached the lowest level of 0.35 mg L−1, 52.32% lower than that of the control resin. The wet shear strength was 1.14 MPa, 14.4% higher than that of the control resin. HAP-KH had no significant effect on the thermal stability of UF resins. However, HAP-KH has a significant effect on the thermal degradation mechanism of UF resins. The most likely kinetics mechanism models for UF and HAP-UF are G(a) = [−ln(1−α)]2 and G(a) = [−ln(1−α)]3, respectively.

Non-isothermal crystallization and thermal degradation studies on nylons 7,10 and 10,7 as isomeric odd-even and even-odd polyamides

Aliphatic polyamides (nylons) show a remarkable variability in terms of crystallographic structures, polymorphic transitions and crystal morphology despite all polymers of this family have a simple constitution that is based on amide groups and polymethylene segments. Nylons derived from diamines and dicarboxylic acids having different parity (e.g., even or odd) have peculiar characteristics due to the difficulty of establishing an optimal hydrogen-bonding geometry when molecular chains adopt a typical all trans conformation. In this work, two isomeric odd-even (nylon 7,10) and even-odd (nylon 10,7) polyamides with the same methylene/amide ratio have been studied. Specifically, crystallization kinetics have been evaluated from calorimetric data, while thermal degradation mechanisms from thermogravimetric analysis. Classical methods (e.g., Avrami) together with isoconversional analyses have been considered for crystallization studies, being found significant differences between both nylons in terms of nucleation and activation energies. The isoconversional analyses of the non-isothermal crystallization allowed to determine the temperature dependence of both the crystal growth and the overall crystallization rate that points out the slower crystallization process of nylon 10,7. Isoconversional methods (integral and differential) were applied to evaluate thermal degradation. The mechanism was similar for both nylons (e.g., A3/2 and A1.8 for nylons 7,10 and 10,7, respectively), although a remarkable difference was determined for the corresponding activation energies (175 and 210 kJ/mol for nylons 7,10 and 10,7, respectively).

Depolymerization of PMMA-Based Dental Resin Scraps on Different Production Scales

This research explores the depolymerization of waste polymethyl methacrylate (PMMAW) from dental material in fixed bed semi-batch reactors, focusing on three production scales: laboratory, technical and pilot. The study investigates the thermal degradation mechanism and kinetics of PMMAW through thermogravimetric (TG) and differential scanning calorimetry (DSC) analyses, revealing a two-step degradation process. The heat flow during PMMAW decomposition is measured by DSC, providing essential parameters for designing pyrolysis processes. The results demonstrate the potential of DSC for energetic analysis and process design, with attention to standardization challenges. Material balance analysis across the production scales reveals a temperature gradient across the fixed bed negatively impacting liquid yield and methyl methacrylate (MMA) concentration. Reactor load and power load variables are introduced, demonstrating decreased temperature with increased process scale. The study identifies the influence of temperature on MMA concentration in the liquid fraction, emphasizing the importance of controlling temperature for efficient depolymerization. Furthermore, the research highlights the formation of aromatic hydrocarbons from the remaining char, indicating a shift in liquid composition during the depolymerization process. The study concludes that lower temperatures below 450 °C favor liquid fractions rich in MMA, suggesting the benefits of lower temperatures and slower heating rates in semi-batch depolymerization. The findings contribute to a novel approach for analyzing pyrolysis processes, emphasizing reactor design and economic considerations for recycling viability. Future research aims to refine and standardize the analysis and design protocols for pyrolysis and similar processes.

Startified thermal degradation in blue InGaN quantum well structures: P-GaN growth temperature and its influence on quantum well optical properties

Thermal degradation in blue InGaN multi-quantum well (MQW) structures induced by varying high p-GaN growth temperature and the subsequent influence on the optical properties of MQW are investigated. The results indicate that higher p-GaN growth temperatures improve p-GaN layer contact quality, but may lead to an optical property degradation of InGaN MQWs. A stratified thermal degradation mechanism is observed. The degradation primarily affects the upper quantum barrier layers and results in indium desorption and re-evaporation, where elevated p-GaN growth temperatures may induce more indium segregation and decomposition than in lower layers of MQW. In extreme conditions, such as 1060℃, indium atoms in lower layers escape, causing partial lattice structure corruption and severe degradation in MQW structure, which is also more distinctive in the upper layers.

Accelerated degradation of photovoltaic modules under a future warmer climate

AbstractSolar photovoltaic (PV) module deployment has surged globally as a part of the transition towards a decarbonized electricity sector. However, future climate change presents issues for module degradation due to prolonged exposure to outdoor conditions. Here, we identify key degradation mechanisms of monocrystalline‐silicon (mono‐Si) modules and empirically model their degradation modes under various climate scenarios. Modules tend to degrade faster due to the thermal degradation mechanism. We estimate that the weighted average degradation rate will increase up to 0.1%/year by 2059. On assessing the impacts of module degradation on future PV power generation and levelized cost of energy, we project up to 8.5% increase in power loss that leads to ~10% rise in future energy price. These results highlight the need to climate‐proof PV module design through careful material selection and improvements in the module manufacturing process. In particular, we recommend the use of heat dissipation techniques in modules to prevent degradation due to overheating.

Thermal decomposition kinetics and mechanism of poly(ethylene 2,5-furan dicarboxylate) Nanocomposites for food packaging applications

Poly(ethylene 2,5-furan dicarboxylate) (PEF) based nanocomposites containing different nanoparticles like Ag, TiO2, ZnO, ZrO2 Ce-Bioglass, have been synthesized via in-situ polymerization techniques targeting food packaging applications. Zeta potential measurements showed an increase in the negative zeta potential value due to an increase in the surface charge density of the nanocomposites. Thermogravimetric analysis results proved that, except PEF-ZnO nanocomposite, all the other nanocomposites exhibited good resistance to thermal degradation without serious mass loss until 330 °C. Thermal decomposition kinetic analysis and the dependence of activation energy on the degree of conversion (α), indicated that the presence of ZnO nanoparticles influences, the degradation mechanism of PEF. In contrast, the presence of Ce-Bioglass nanoparticles leads to a slower degradation process, contributing to the enhanced resistance to thermal degradation of the PEF-Bioglass nanocomposite. The thermal degradation mechanism of PEF nanocomposites analyzed by pyrolysis‒gas chromatography/mass spectrometry (Py-GC/MS) indicated that the primary thermal degradation mechanism for the studied nanocomposites was β-hydrogen bond scission, while to a lesser extent, α-hydrogen bond scission products were noted in PEF-TiO2 and PEF-ZrO2 nanocomposites.

Recent advances and challenges in thermal stability of PVA‐based film: A review

AbstractFood packaging film is being developed using biodegradable polymers to prolong the shelf life of foods and address the environmental damage caused by non‐biodegradable plastics. Poly(vinyl alcohol) (PVA) is a biodegradable polymer with outstanding characteristics and can be easily shaped into a film. However, PVA‐based film still faces several obstacles that seriously restrict its practical application in the food packaging industry, particularly its low thermal stability limits the film process method. The growing preference demand for PVA‐based films with enhanced thermal stability in food packaging can be attributed to their advantageous characteristics, including commendable temperature resistance, safety, versatile processing capabilities, and prolonged shelf life. It is critical to comprehend the difficulties with PVA thermal degradation behavior and mechanism, and how to address this problem. In this review, we provide strategies for improving the thermal stability of PVA film including modification with environmentally friendly polymers, nanoparticles, and crosslinking agents. Also, the current challenges, and the potential for future advancements in the thermal stability of PVA and its composites are proposed. The new insight into the relationship between PVA based film processing and thermal properties of materials are expected to provide a valuable guide for developing PVA films with high thermal stability.

Biomass characterization and solvent extraction as tools to promote phenol production from urban pruning

Nowadays, leaves, bark, and branches are generated from the tree-pruning process in urban places, where their management is a problem because of the necessity of disposal. These wastes are lignocellulosic biomasses with poor properties for use in biofuel production, but with interesting projections for building block products such as phenol compounds. Therefore, extensive biomass characterization of urban pruning from Liquidambar styraciflua L. was developed to evaluate its composition as a tool for phenol production through thermal processing, in which solvent extraction is a complementary tool for selectivity improvement. The results showed high lignin content in bark and leaves at 45 and 28 %, respectively, compared with that in branches (14 %). Additionally, high extractives in leaves (14 %) could be an additional source of phenols. The lignin units were analyzed by Raman dispersion, revealing p–hydroxyphenyl (H) units in the bark, guaiacyl (G) units in the bark and leaves, and syringyl (S) units only in the branches. Furthermore, the micropyrolysis coupled with gas chromatography/mass spectrometry assay realized at 600 °C showed high presence of phenolic compounds in the three biomass investigated, where a high phenol concentration was identified in leaves, probably due to the S unit degradation during pyrolysis. With these results, an assay for bio-oil production was performed in a low-temperature pyrolysis reactor using leaves as feedstock, reaching a low bio-oil yield with high water content favored for the high inorganic content of leaves (13 %). The produced bio-oil was used for liquid–liquid extraction evaluation, where 1-octanol and methyl isobutyl ketone were identified as interesting solvents for catechol and phenol extraction, respectively. This article presents the challenge of characterizing each part of urban trees, which could be a tool to promote the use of urban pruning by studying the thermal degradation mechanism to implement processes for high-value products, such as phenols produced from L. styraciflua L.

Preparation of carbon nanotube-filled bismuth/tin green nanocomposites and their efficient catalytic activity in the thermal decomposition of ammonium perchlorate

The practical utility of bismuth and tin compounds, as promising green combustion catalysts, is constrained by their substantial particle agglomeration. Herein, a straightforward ultrasonication-assisted method was reported to incorporate bismuth and tin compounds into the inner spaces of carbon nanotubes (CNTs), affording CNTs-confined bismuth (tin) compounds. The as-prepared nanocomposites were structurally completely characterized. The electrochemical property investigations showed that the introduction of bismuth and tin compounds increases the catalytic active sites of carbon nanotubes and inhibits nanoparticle agglomeration effectively. The theoretical calculations revealed that synergistic effects between Bi2O3 and carbon nanotubes can improve the efficiency of electron transfer in the Bi(NO3)3@A-CNTs(M1) composite. The evaluation results of the combustion catalytic performance of the nanocomposites on ammonium perchlorate (AP) pyrolysis suggested that adding 5 wt.% Bi(NO3)3@A-CNTs(M1) and DBT@A-CNTs(M1) (DBT = Dibutyltin dichloride) in AP brought about a more concentrated thermal decomposition process, advancing the peak of AP in the high-temperature decomposition stage from 420.4 ℃ to 328.9 and 325.9 ℃, respectively, and boosting its heat release from 976.42 J·g−1 to 2251.2 J·g−1 and 2452.03 J·g−1, respectively. The studies on the thermal degradation mechanism of AP, probed by thermal decomposition kinetics, in-situ solid FTIR and TG-FTIR-MS, concluded that the electron transfer from the critical steps ClO4− to NH4+ and O2 to O2− is accelerated by the interaction of the in-situ formed Bi2O3 nanoparticles and carbon nanotubes, boosting the relative contents of more stable gases, and ultimately promoting AP pyrolysis. A tentative catalytic thermal degradation mechanism of AP is finally proposed.

Hydrophobic fouling-resistant electrospun nanofiber membranes from poly(vinylidene fluoride)/polyampholyte blends.

This study reports the fabrication of non-woven fibrous membranes from electrospinning blended solutions of PVDF with polyampholytes in N,N-dimethylformamide and methanol. Polyampholytes are macromolecules that have both positive and negative charged units in different side groups attached to the backbone. In this study, we used a random polyampholyte amphiphilic copolymer (r-PAC) synthesized by co-polymerizing a hydrophobic monomer in addition to the positive and negative charged monomer units, to reduce the fouling propensity of PVDF electrospun membranes while preserving its inherent hydrophobicity. Blends of PVDF/r-PAC were electrospun across the full range of compositions from 0/100 to 100/0. Scanning electron microscopic analysis showed formation of beaded fibers with average fibril diameters from 0.09-0.18 μm. The variation in the fiber diameters is caused by the change in surface charge density, dynamic viscosity of the solution, and the instability of the Taylor cone. Bead formation was observed in the mats electrospun from less viscous solutions. Wide angle X-ray scattering showed that electrospun fibers of PVDF crystallized into the electro-active β and γ crystal phases, whereas polyampholytes were amorphous. Thermogravimetry showed that the PVDF/r-PAC blends have a multi-step thermal degradation mechanism while PVDF homopolymer showed single-step thermal degradation. Sessile drop contact angle measurements confirmed that fibers possess high hydrophobicity and super-oleophilicity. Adsorptive fouling experiments with a fluorescently labeled protein confirmed that the fiber mats obtained from the PVDF/r-PAC blends resist protein adsorption, exhibiting highly enhanced fouling resistance compared to the fibers obtained from homopolymer PVDF.

Thermal stability and degradation mechanism of C60 fullerene‐based polymers

AbstractIn this paper, the thermal stability and degradation mechanisms of C60 fullerene‐based polymers, obtained by click polymerization between dialkyne‐substituted C60 derivative monomers and 1,3,5‐tris(dodecyloxy)benzene‐based diazide comonomers, were evaluated. The activation energy of the fullerene polymer C60P2 with an ethylene spacer, determined under peak degradation rate conditions, was lower than that of the counter polymer C60P1 with a methylene spacer, suggesting lower thermal stability of C60P2. The combined technique of thermogravimetric analysis—mass spectroscopy and Fourier transform infrared spectroscopy revealed that the thermal decomposition onset of the analyzed samples is accompanied by CC cleavage of the dodecyloxyside chain groups, followed by the decomposition of the 1,2,3‐triazole, dicarboxylate and benzoate moieties. It was found that no thermal decomposition of the fullerene carbon cage occurs up to 670°C. Molecular modeling with Hyperchem software version 7.5 confirmed that C60P1 is more thermally stable than C60P2.

A Review on the Adiabatic Shear Banding Mechanism in Metals and Alloys Considering Microstructural Characteristics, Morphology and Fracture

The current review work studies the adiabatic shear banding (ASB) mechanism in metals and alloys, focusing on its microstructural characteristics, dominant evolution mechanisms and final fracture. An ASB reflects a thermomechanical deformation instability developed under high strain and strain rates, finally leading to dynamic fracture. An ASB initially occurs under severe shear localization, followed by a significant rise in temperature due to high strain rate adiabatic conditions. That temperature increase activates thermal softening and mechanical degradation mechanisms, reacting to strain instability and facilitating micro-voiding, which, through its coalescence, results in cracking failure. This work aims to summarize and review the critical characteristics of an ASB’s microstructure and morphology, evolution mechanisms, the propensity of materials against an ASB and fracture mechanisms in order to highlight their stage-by-stage evolution and attribute them a more consecutive behavior rather than an uncontrollable one. In that way, this study focuses on underlining some ASB aspects that remain fuzzy, allowing for further research, such as research on the interaction between thermal and damage softening regarding their contribution to ASB evolution, the conversion of strain energy to internal heat, which proved to be material-dependent instead of constant, and the strain rate sensitivity effect, which also concerns whether the temperature rise reflects a precursor or a result of ASB. Except for conventional metals and alloys like steels (low carbon, stainless, maraging, armox, ultra-high-strength steels, etc.), titanium alloys, aluminum alloys, magnesium alloys, nickel superalloys, uranium alloys, zirconium alloys and pure copper, the ASB propensity of nanocrystalline and ultrafine-grained materials, metallic-laminated composites, bulk metallic glasses and high-entropy alloys is also evaluated. Finally, the need to develop a micro-/macroscopic coupling during the thermomechanical approach to the ASB phenomenon is pointed out, highlighting the interaction between microstructural softening mechanisms and macroscopic mechanical behavior during ASB evolution and fracture.

A numerical model to prevent the thermal degradation of CFRPs at extreme heating rates – The laser processing of CF/PEEK

This study proposes a coupled thermal-chemical numerical model for preventing the thermal degradation of carbon fibre (CF) reinforced polymers at extreme heating rates. Its applicability is demonstrated in a laser-heating case study of CF-reinforced poly-ether-ether-ketone (CF/PEEK). The kinetic parameters of the PEEK matrix, derived from thermogravimetric analysis at conventional heating rates, are introduced in the model and an extrapolation approach is applied to investigate the laser heating of CF/PEEK. The results show that the model captures the heating rate effect on the decomposition of the material, and is used to identify the processing conditions that can reach high temperatures without triggering the thermal degradation mechanisms of the PEEK matrix. Then, a multi-technique experimental investigation takes place to identify the processing conditions that first trigger the thermal degradation mechanisms of CF/PEEK in the examined laser-heating case study. Interestingly, a good agreement is found between the experimental and numerical investigations which validates the model and the applied extrapolation approach.

Kinetic modeling of thermal degradation of TDI/MDI-based flexible polyurethane foam under nitrogen and air atmospheres with Shuffled Complex Evolution algorithm: Insights from TG-FTIR analysis

This study investigates the thermal degradation mechanisms and kinetics of TDI/MDI-based flexible polyurethane foam (FPUF) under nitrogen and air atmospheres, employing thermogravimetric (TG) analysis in conjunction with TG-FTIR technique. The information gleaned from these analysis is used to construct kinetic model based on model-free approaches coupled with the Shuffled Complex Evolution optimization algorithm. The results uncovered the five-step complex thermal degradation process of TDI/MDI-based FPUF compared to TDI-based or MDI-based polyurethane in both atmospheres. In nitrogen atmosphere, this involve the dissociation of TDI- and MDI-based urethane bonds, breakage of recombined urea bonds, random chain scission of polyol, and further degradation of incompletely pyrolyzed solid products. In air atmosphere, the process emcompasses dissociation of TDI- and MDI-based urethane linkages, accelerated oxidation of polyol chains, consumption of urea groups, and combustion of partially oxidized intermediates. This work also emphasizes the limitations of solely relying on TG tests for kinetic modeling, necessitating the integration of TG tests and TG-FTIR technique to obtain a comprehensive understanding of degradation mechanisms. The significance of the acquired insights lies in their potential to reshape the design of thermo-chemical reactors, resulting in heightened resource recovery, diminished environmental impact, and a stride towards a circular economy within the polyurethane industry.