Effects of starch filling on physicochemical properties, functional activities, and release characteristics of PBAT-based biodegradable active films loaded with tea polyphenols.

In this work, the modification of poly(butylene adipate-co-terephthalate) (PBAT) was combined with the development of active packaging films. PBAT, starch, plasticizer, and tea polyphenols (TP) were compounded and extrusion-blown into thermoplastic starch (TPS)/PBAT-TP active films. Effects of TPS contents on physicochemical properties, functional activities, biodegradability, and release kinetics of PBAT-based active films were explored. Starch interacted strongly with TP through hydrogen bonding and induced the formation of heterogeneous structures in the films. With the increase in TPS contents, surface hydrophilicity and water vapor permeability of the films increased, while mechanical properties decreased. Blending starch with PBAT greatly accelerated degradation behavior of the films, and the T30P70-TP film achieved complete degradation after 180 days. As TPS contents increased, swelling degree of the films increased and TP release were improved accordingly, resulting in significantly enhanced antioxidant and antimicrobial activities. This work demonstrated that filling starch into PBAT-based active films could achieve different antioxidant and antimicrobial activities of the films by regulating film swelling and release behavior.

Fabrication and Characterization of PLA/PBAT Blends, Blend-Based Nanocomposites, and Their Supercritical Carbon Dioxide-Induced Foams.

In this study, a twin-screw extruder was used to fabricate poly(lactic acid) (PLA)/poly(butylene adipate-co-terephthalate) (PBAT) blends and blend-based nanocomposites with carbon nanotube (CNT) or nanocarbon black (CB) as nanofillers. The fabricated samples were subsequently treated with supercritical carbon dioxide (scCO2) to fabricate the corresponding foams. Bi-phasic morphology and selective distribution of CNTs or CBs in the PBAT phase were observed in the blends/composites through scanning electron microscopy. After the scCO2 treatment, the selective foaming of the PBAT phase in the prepared blends/composites was confirmed. The cellular structure of PBAT phase in scCO2-treated blends is similar to the size/shape of PBAT domains in untreated blends or treated neat PBAT foam. The addition of CNTs or CBs in the blends led to a slight reduction in cell size of the foamed PBAT phase, demonstrating CNT/CB-induced cell nucleation. Differential scanning calorimetry (DSC) results showed that CNTs and CBs played as nucleating agents and increased the initial crystallization temperature up to 14 °C compared with neat PBAT for PBAT in different composites during cooling. The scCO2 treatment induced the bimodal stability of PBAT crystals in different samples, which melted mainly in two temperature regions in DSC studies. Thermogravimetric analyses revealed that compared with parent blends, the addition of CNTs or CBs increased the temperature at 80 wt.% loss (degradation of PBAT portion) up to 6 °C. The electrical resistivity decreased by more than six orders of magnitude for certain CNT- or CB-added composites compared with the parent blends. The hardness of the blends slightly increased after forming the corresponding composites and then declined after the scCO2 treatment.

Characterization, hazard identification, and risk assessment of volatile organic compounds in Poly(butylene adipate-co-terephthalate)-based food contact articles.

The chemical safety of poly (butylene adipate-co-terephthalate) (PBAT) based food contact articles (FCAs) has aroused increasing toxicological concerns in recent years, but the chemical characterization and associated risk assessment still remain inadequate as it fails to elucidate the distribution pattern and discern the potential genotoxic and carcinogenic hazards of the identified substances. Herein, the volatile organic compounds (VOCs) in 50 batches of PBAT-based FCAs of representative categories and 10 batches of PLA and PBAT pellets were characterized, by which 237 VOCs of 10 chemical categories were identified and exhibited characteristic distribution patterns in the chemical spaces derived from their molecular descriptors. Chemical hazards associated with the identified VOCs were discerned by a hazard-driven classification scheme integrating hazard-related knowledge from multiple publicly available sources, and 34 VOCs were found to bear genotoxic or carcinogenic hazards and to feature higher average molecular weight than the other VOCs. Finally, the Risk and hazard quotient (HQ) calculated as the metrics of risk suggested that all identified VOCs posed acceptable risks (Risk<10-4 or HQ < 1), whereas oxolane, butyrolactone, N,N-dimethylacetamide, 2-butoxyethanol, benzyl alcohol, and 1,2,3-trichloropropane posed non-negligible (Risk>10-6) genotoxic or carcinogenic risk and thus should be of prioritized concern to promote the chemical safety of PBAT-based FCAs.

Reactive extrusion fabrication of thermoplastic starch with Ca2+ heterodentate coordination structure for harvesting multiple-reusable PBAT/TPS films.

Creating multiple-reusable PBAT/TPS (PT) films presents a novel solution to reduce carbon emissions from disposable packaging, addressing challenges like the high creep of PBAT and the glycerol migration of TPS. Consequently, adopting reactive extrusion to fabricate reversible cross-linking TPS with high shape memory performance, low migration, and homogeneous dispersion in PBAT matrix was a fascinating strategy. Herein, starch, glycerol and CaCl2 (calcium chloride) were extruded to fabricate TPS-Ca with Ca2+ heterodentate coordination structure and confirmed by XPS, 1H NMR and temperature-dependent FTIR. The results of DMA, dynamic rheology, flow activation energy and SEM revealed that TPS-Ca exhibited significant temperature-sensitive reversible properties and robust melt flow capability, enabling micro-nano scale dispersion in PBAT. Noteworthy, PBAT/TPS-Ca (PT-Ca) would recover 100 % length within 20 s by microwave heating after being loaded under the hygrothermal environment. Meanwhile, the migration weight of glycerol decreased from 2.5 % to 1.2 % for the heat-moisture-treated PBAT/TPS (HPT) and PBAT/TPS-Ca (HPTCa). Remarkably, the tensile strength and elongation at the break of HPT-Ca increased to 20.0 MPa and 924 %, respectively, due to reduced stress concentration sites in the phase interface. In summary, our study provides a streamlined strategy for fabricating multiple-reusable PT, offering a sustainable solution to eliminate carbon emissions linked to disposable plastic.

Regioselective enzymatic depolymerization of aromatic-aliphatic polyester revealed by computational modelling.

Poly(butylene adipate-co-terephthalate) (PBAT) is widely utilized in the production of food packaging and mulch films. Its extensive application has contributed significantly to global solid waste, posing numerous environmental challenges. Recently, enzymatic recycling has emerged as a promising eco-friendly solution for the management of plastic waste. Here, we systematically investigate the depolymerization mechanism of PBAT catalyzed by cutinase TfCutSI with molecular docking, molecular dynamics simulations, and quantum mechanics/molecular mechanics calculations. Although the binding affinities for acid ester and terephthalic acid ester bonds are similar, a regioselective depolymerization mechanism and a "chain-length" effect on regioselectivity were proposed and evidenced. The regioselectivity is highly associated with specific structural parameters, namely Substrate@O4-Met@H7 and Substrate@C1-Ser@O1 distances. Notably, the binding mode of BTa captured by X-ray crystallography does not facilitate subsequent depolymerization. Instead, a previously unanticipated binding mode, predicted through computational analysis, is confirmed to play a crucial role in BTa depolymerization. This finding proves the critical role of computational modelling in refining experimental results. Furthermore, our results revealed that both the hydrogen bond network and enzyme's intrinsic electric field are instrumental in the formation of the final product. In summary, these novel molecular insights into the PBAT depolymerization mechanism offer a fundamental basis for enzyme engineering to enhance industrial plastic recycling.

Eco-Friendly Poly (Butylene Adipate-co-Terephthalate) Coated Bi-Layered Films: An Approach to Enhance Mechanical and Barrier Properties.

In this research work, a coated paper was prepared with poly (butylene adipate-co-terephthalate) (PBAT) film to explore its use in eco-friendly food packaging. The paper was coated with PBAT film for packaging using hot pressing, a production method currently employed in the packaging industry. The coated papers were evaluated for their structural, mechanical, thermal, and barrier properties. The structural morphology and chemical analysis of the coated paper confirmed the consistent formation of PBAT bi-layered on paper surfaces. Surface coating with PBAT film increased the water resistance of the paper samples, as demonstrated by tests of barrier characteristics, including the water vapor transmission rate (WVTR), oxygen transmission rate (OTR), and water contact angle (WCA) of water drops. The transmission rate of the clean paper was 2010.40 cc m-2 per 24 h for OTR and 110.24 g m-2 per 24 h for WVTR. If the PBAT-film was coated, the value decreased to 91.79 g m-2 per 24 h and 992.86 cc m-2 per 24 h. The hydrophobic nature of PBAT, confirmed by WCA measurements, contributed to the enhanced water resistance of PBAT-coated paper. This result presents an improved PBAT-coated paper material, eliminating the need for adhesives and allowing for the fabrication of bi-layered packaging.

Biodegradable Nanocomposites Based on Blends of Poly(Butylene Adipate-Co-Terephthalate) (PBAT) and Thermoplastic Starch Filled with Montmorillonite (MMT): Physico-Mechanical Properties.

Poly(butylene adipate-co-terephthalate) (PBAT) is widely used for production of biodegradable films due to its high elongation, excellent flexibility, and good processability properties. An effective way to develop more accessible PBAT-based bioplastics for wide application in packaging is blending of PBAT with thermoplastic starch (TPS) since PBAT is costly with prices approximately double or even triple the prices of traditional plastics like polyethylene. This study is focused on investigating the influence of TPS/PBAT blend ratio and montmorillonite (MMT) content on the physical and mechanical properties and molecular mobility of TPS-MMT/PBAT nanocomposites. Obtained TPS-MMT/PBAT nanocomposites through the melt blending process were characterized using tensile testing, dynamic mechanical thermal analysis (DMTA), and X-ray diffraction (XRD), as well as solid-state 1H and 13C NMR spectroscopy. Mechanical properties demonstrated that the addition of TPS to PBAT leads to a substantial decrease in the tensile strength as well as in the elongation at break, while Young's modulus is rising substantially, while the effect of the MMT addition is almost negligible on the tensile stress of the blends. DMTA results confirmed the formation of TPS domains in the PBAT matrix. With increasing TPS content, mobility of starch-rich regions of TPS domains slightly increases. However, molecular mobility in glycerol-rich regions of TPS domains in the blends was slightly restricted. Moreover, the data obtained from 13C CP/MAS NMR spectra indicated that the presence of TPS in the sample decreases the mobility of the PBAT chains, mainly those located at the TPS/PBAT interfaces.

Poly(butylene adipate-co-terephthalate)/Polylactic Acid/Tetrapod-Zinc Oxide Whisker Composite Films with Antibacterial Properties.

Biodegradable composite films comprising of poly(butylene adipate-co-terephthalate) (PBAT), polylactic acid (PLA), and tetrapod-zinc oxide (T-ZnO) whisker were prepared by a melt-extrusion and blow molding process. The effect of the incorporation of the T-ZnO whisker (1 to 7 wt.%) in the PBAT/PLA blend film was studied systematically. The composite films with an optimal T-ZnO whisker concentration of 3 wt.% exhibited the highest mechanical (tensile strength ~32 MPa), rheological (complex viscosity~1200 Pa.s at 1 rad/s angular frequency), and gas barrier (oxygen permeability~20 cc/m2·day) properties, whereas the composite films with 7 wt.% T-ZnO whiskers exhibited the highest antibacterial properties. The developed composite films can find potential application as antibacterial food packaging materials.

Isolation, characteristics, and poly(butylene adipate-co-terephthalate) (PBAT) degradation mechanism of a marine bacteria Roseibium aggregatum ZY-1.

Marine microorganisms have been reported to degrade microplastics. However, the degradation mechanisms are still poorly understood. In this study, a bacterium Roseibium aggregatum ZY-1 was isolated from seawater, which can degrade poly(butylene adipate-co-terephthalate) (PBAT). The PBAT-PLA(polylactic acid, PLA) films, before and after degradation, were characterized by scanning electron microscope (SEM) and Fourier transform infrared spectrometer (FTIR), the weight loss rate and water contact angle were measured. The results indicate that ZY-1 colonized on PBAT-PLA film, changed the functional groups and decreased water contact angle of PBAT-PLA film. Moreover, liquid chromatography mass spectrometry (LC-MS) analysis reveales that PBAT was degraded into its oligomers (TB, BTB) and monomers (T, A) during 10 days, and adipic acid (A) could be used as a sole carbon source. The whole genome sequencing analyses illustrate the mechanisms and enzymes such as PETase, carboxylesterases, arylesterase (PpEst) and genes like pobA, pcaBCDFGHIJKT, dcaAEIJK, paaGHJ involved in PBAT degradation. Therefore, the R. aggregatum ZY-1 will be a promising candidate of PBAT degradation.

Development of cinnamon essential oil-loaded PBAT/thermoplastic starch active packaging films with different release behavior and antimicrobial activity.

The poly (butylene adipate-co-terephthalate)/thermoplastic starch (PBAT/TPS) active packaging films containing cinnamon essential oil (CEO) were fabricated by melting blending and extrusion casting method. The effects of TPS content (0 %, 10 %, 20 %, 30 %, 40 % and 50 %) on the properties of the films and their application in largemouth bass preservation were studied. As TPS content increased from 0 % to 50 %, the water vapor permeability increased from 7.923 × 10-13 (g•cm/(cm2•s•Pa)) to 23.967 × 10-13 (g•cm/(cm2•s•Pa)), the oxygen permeability decreased from 8.642 × 10-11 (cm3•m/(m2•s•Pa)) to 3.644 × 10-11 (cm3•m/(m2•s•Pa)), the retention of CEO in the films increased. The release rate of CEO from the films into food simulant (10 % ethanol) accelerated with increasing TPS. The films exhibited different antibacterial activity against E. coli, S. aureus, and S. putrefaciens. It was closely related with the release behavior of the CEO. The films containing CEO could efficiently inhibit the decomposition of protein and the growth of microorganisms in largemouth bass. It showed that the higher TPS in the films, the better inhibitory effect. This study provided a new idea for developing PBAT/TPS active films with different release behavior of active agents and different antibacterial activity for food packaging.

Highly impact toughened and excellent flame-retardant polylactide/poly(butylene adipate-co-terephthalate) blend foams with phosphorus-containing and food waste-derived flame retardants.

Green polymeric foams are an important research topic for sustainable development. In this study, a natural multifunctional flame-retardant additive based on food waste was developed and evaluated for its ability to replace the commercial additives tricresyl phosphate (TCP) and trioctyl phosphate (TOP) in a polylactide/poly(butylene adipate-co-terephthalate) (PLA/PBAT) foam. A series of blend foams with additives were prepared by melt extrusion. According to the results, the blend foam with 20 phr of TCP showed the best combination of impact toughness and flame retardancy. TCP, however, poses health and environmental risks. Therefore, natural flame retardants (NFRs) were used to partially replace the commercial flame retardant (CFR). A combination of TCP and soybean residue (SB) produced an impact toughened and flame-retardant blend foam. When compared to the neat PLA/PBAT foam, the impact toughness of the best sample was increased by about 256 %. The optimal foam showed excellent flame resistance with a V-0 UL-94 rating and a high LOI value (31.8 %). SB has the potential to partially replace TCP as flame retardant and could be used in a broad range of PLA/PBAT foam applications.

A reactive compatibilization with the compound containing four epoxy groups for polylactic acid/poly(butylene adipate-co-terephthalate)/thermoplastic starch ternary bio-composites.

How to effectively improve the poor interfacial adhesion between polylactic acid/poly(butylene adipate-co-terephthalate) (PLA/PBAT) matrix and thermoplastic starch (TPS) is still a challenge. Therefore, this work aims to introduce a convenient method to enhance the performance of PLA/PBAT/TPS blend by melt reactive extrusion. Here, using 4,4'-methylene-bis(N,N-diglycidyl-aniline) (MBDG) containing four epoxy groups as a reactive compatibilizer, and respectively using 1-methylimidazole (MI) or triethylenediamine (TD) as a catalyzer, serial PLA/PBAT/TPS ternary bio-composites are successfully prepared via melt reactive extrusion. The results showed that, under the catalysis of organic base, especially MI, the epoxy groups of MBDG can effectively react with hydroxyl and carboxyl groups of PLA/PBAT and hydroxyl groups in TPS to form chain-expanded and cross-linked structures. The tensile strength of the composites is increased by 20.0 % from 21.1 MPa, and the elongation at break is increased by 182.4 % from 17.6 % owing to the chain extension and the forming of cross-linked structures. The molecular weight, thermal stability, crystallinity, and surface hydrophobicity of the materials are gradually improved with the increase of MBDG content. The melt fluidity of the composites is also improved due to the enhancement of compatibility. The obtained PLA/PBAT/TPS materials have the potential to be green plastic products with good properties.

Enhanced Mechanical Properties of Polylactic Acid/Poly(Butylene Adipate-co-Terephthalate) Modified with Maleic Anhydride.

An increase in plastic waste pollution and the strengthening of global environmental policies have heightened the need for research on biodegradable plastics. In this regard, polylactic acid (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) are notable examples, serving as alternatives to traditional plastics. In this study, the compatibility and mechanical properties of PLA/PBAT blends were improved by the chemical grafting of maleic anhydride (MAH). In addition, qualitative analyses were conducted, dynamic mechanical properties were investigated, and the structure and mechanical characteristics of the blends were analyzed. With an increase in the MAH concentration, the grafting yield of the blends increased, and significantly improved the compatibility of the PLA/PBAT blend, with an ~2 and 2.9 times increase in the tensile strength and elongation at break, respectively. These findings indicate that the modified PLA/PBAT blend demonstrates potential for applications that require sustainable plastic materials, thereby contributing to the development of environmentally friendly alternatives in the plastics industry.

Enhanced Biodegradation Rate of Poly(butylene adipate-co-terephthalate) Composites Using Reed Fiber.

To enhance the degradability of poly(butylene adipate-co-terephthalate) (PBAT), reed fiber (RF) was blended with PBAT to create composite materials. In this study, a fifteen day degradation experiment was conducted using four different enzyme solutions containing lipase, cellulase, Proteinase K, and esterase, respectively. The degradation process of the sample films was analyzed using an analytical balance, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). The PBAT/RF composites exhibited an increased surface hydrophilicity, which enhanced their degradation capacity. Among all the enzymes tested, lipase had the most significant impact on the degradation rate. The weight loss of PBAT and PBAT/RF, caused by lipase, was approximately 5.63% and 8.17%, respectively. DSC analysis revealed an increase in the melting temperature and crystallinity over time, especially in the film containing reed fibers. FTIR results indicated a significant weakening of the ester bond peak in the samples. Moreover, this article describes a biodegradation study conducted for three months under controlled composting conditions of PBAT and PBAT/RF samples. The results showed that PBAT/RF degraded more easily in compost as compared to PBAT. The lag phase of PBAT/RF was observed to decrease by 23.8%, while the biodegradation rate exhibited an increase of 11.8% over a period of 91 days. SEM analysis demonstrated the formation of more cracks and pores on the surface of PBAT/RF composites during the degradation process. This leads to an increased contact area between the composites and microorganisms, thereby accelerating the degradation of PBAT/RF. This research is significant for preparing highly degradable PBAT composites and improving the application prospects of biodegradable green materials. PBAT/RF composites are devoted to replacing petroleum-based polymer materials with sustainable, natural materials in advanced applications such as constructional design, biomedical application, and eco-environmental packaging.

Insights into the enhanced mechanism of electron beam pretreatment on application performance for poly (butylene adipate-co-terephthalate)/acetylated cellulose composite plastics.

In this work, we developed a strategy to construct poly (butylene adipate-co-terephthalate) (PBAT) composite plastics with excellent mechanical properties, superior thermal stability and enhanced biodegradability by combining acetylated celluloses (ECs) mediated by electron beam irradiation (EBI), which works as a toughening agent. With findings, the EBI pretreatment assisted with acetylation was applied to develop ECs materials with a higher degree of acetylation than acetylation alone. The pretreated ECs with increased hydrophobicity tended to decrease the chance of self-aggregation and enhanced the interfacial compatibility and adhesion with PBAT in PBAT/ECs composite plastics. Thus, PBAT/ECs composite plastics exhibited a smoother and more uniform surface structure during preparation and offered higher tensile strength, water vapor transmission rate, water absorption rate, thermal stability and degradation rate, and lower elongation at a break during application. On top of that, the PBAT/ECs composite plastics were characterized by a series of methods containing Fourier transform infrared spectroscopy and X-ray diffraction, indicating that these properties are mainly caused by the acetylation of hydroxyl groups from cellulose and carboxyl groups of PBAT. The work is expected to expand the application scope of PBAT and cellulose and provide an attainable solution for a biodegradable substitute for traditional plastics.

Improving the compatibility and toughness of sustainable polylactide/poly(butylene adipate-co-terephthalate) blends by incorporation of peroxide and diacrylate.

Polylactide/poly(butylene adipate-co-terephthalate) (PLA/PBAT) blends were compatibilized using dicumyl peroxide (DCP) and poly(ethylene glycol) 600 diacrylate (PEG600DA) through a one-step melt-blending process. The compatibility and performance of these blends were subsequently characterized. The results showed that grafts formed "in situ" effectively improved the compatibility and interfacial adhesion between PLA and PBAT phases. Melt viscosity and elasticity of both the PLA/PBAT/DCP and PLA/PBAT/DCP/PEG600DA blends evinced significant increases. Compared to PLA alone, both cold and melt crystallization abilities of the PLA/PBAT/DCP/PEG600DA blends were enhanced, with crystallinities increasing by 5 % - 10 %. Furthermore, the thermal stability, as well as hydrophobicity and oleophobicity of the compatibilized blends improved. In comparison with PLA, the elongation at break and notched impact strength for the PLA/PBAT/DCP/PEG600DA (60/40/0.1/4) blend achieved increases of 290 % and 44.23 kJ/m2, corresponding to improvements of 279 % and 1457 %, respectively. The toughening effect was substantially influenced by the ductile matrix (either a co-continuous phase or a flexible PBAT matrix) in addition to the strong interfacial adhesion and fine phase domain. These eco-friendly blends exhibit considerable potential for packaging articles and 3D printing products owing to their excellent mechanical properties and enhanced melt rheology.

Comparison of anaerobic digestion of starch- and petro-based bioplastic under hydrogen-rich conditions.

To identify an economically viable waste management system for bioplastics, thermoplastic starch (TPS) and poly(butylene adipate-co-terephthalate) (PBAT) were anaerobically digested under hydrogen (H2)/carbon dioxide (CO2) and nitrogen (N2) gas-purged conditions to compare methane (CH4) production and biodegradation. Regardless of the type of bioplastics, CH4 production was consistently higher with H2/CO2 than with N2. The highest amount of CH4 was produced at 307.74 mL CH4/g volatile solids when TPS digested with H2/CO2. A stepwise increased in CH4 yield was observed, with a nominal initial increment followed by accelerated methanogenesis conversion as H2 was depleted. This may be attributed to a substantial shift in the microbial structure from hydrogenotrophic methanogen (Methanobacteriales and Methanomicrobiales) to heterotrophs (Spirochaetia). In contrast, no significant change was observed with PBAT, regardless of the type of purged gas. TPS was broken down into numerous derivatives, including volatile fatty acids. TPS produced more byproducts with H2/CO2 (i.e., 430) than with N2 (i.e., 320). In contrast, differential scanning calorimetry analysis on PBAT revealed an increase in crystallinity from 10.20 % to 12.31 % and 11.36 % in the H2/CO2- and N2-purged conditions, respectively, after 65 days of testing. PBAT surface modifications were characterized via Fourier transform infrared spectroscopy and scanning electron microscopy. The results suggest that the addition of H2/CO2 can enhance the CH4 yield and increase the breakdown rate of TPS more than that of PBAT. This study provides novel insights into the CH4 production potential of two bioplastics with different biodegradabilities in H2/CO2-mediated anaerobic digestion systems.

Synergistic Effects of 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-Based Derivative and Modified Sepiolite on Flame-Retarded Poly (Ethylene Oxide)-Poly (Butylene Adipate-Co-Terephthalate) Composites.

A 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO)-based derivative (PN-DOPO) combined with aluminium phosphates-coated sepiolite (Sep@AlPO4) was used to improve the flame retardance, thermal stability and mechanical performances of poly (ethylene oxide) (PEO)/poly (butylene adipate-co-terephthalate) (PBAT) blends. The synergistic effects of PN-DOPO and Sep@AlPO4 on flame-retarded PEO/PBAT composites were systematically discussed. Results indicated that introducing 5 wt% Sep@AlPO4 with 10 wt% PN-DOPO into PEO/PBAT achieved a V-1 rating for the UL-94 test and increased the limiting oxygen index value to 23.7%. Moreover, the peak heat release rate (p-HRR), average HRR and total heat release values of PEO/PBAT/PN10%/Sep5% composites decreased by 35.6%, 11.0% and 23.0% compared with those of PEO/PBAT, respectively. Thermogravimetric analysis (TGA) results confirmed that PN-DOPO/Sep@AlPO4 enhanced the initial thermal stability and char yield of PEO/PBAT matrix, and TGA/Fourier transform infrared spectrometry results revealed that the composites exhibited the characteristic absorption peaks of phosphorous-containing groups and an increase in gas-phase volatiles during thermal degradation. The morphological structures of the residues indicated that PN-DOPO and Sep@AlPO4 mixtures produced a more dense and continuous char layer on the composite surface during burning. Rheological behaviour revealed that higher complex viscosity and modulus values of PEO/PBAT/PN-DOPO/Sep@AlPO4 sample could also promote the crosslinking network structure of condensed phases during combustion. Furthermore, the PEO/PBAT/PN-DOPO/Sep@AlPO4 composites exhibited superior elongation at break and flexural performance than the PEO/PBAT system. All results demonstrated that the PEO/PBAT system modified with PN-DOPO/Sep@AlPO4 showed remarkable flame retardance, and improved thermal stability and mechanical properties, indicating its potential application in areas requiring fire safety.