Biodegradable composites from poly(butylene adipate-co-terephthalate) with carbon nanoparticles: Preparation, characterization and performances.

The development of composites for food packaging that have good mechanical and antimicrobial characteristics is still a major challenge. In applications like food packaging, the usage of poly (butylene adipate-co-terephthalate) (PBAT), which has an adversative effect on the environment and reduces petroleum resources, has grown widespread. The present work reveals PBAT composites reinforced with CNPs at a few percentages up to 5.0 wt %. The PBAT/CNPs composites were produced using the solvent casting method. The results of TGA studies, CNPs significantly enhanced the thermal stability of composites using PBAT. The mechanical strength of the PBAT composites was improved by increasing CNPs concentration. Tensile strength increased from 7.38 to 10.22 MPa, respectively. The oxygen transmission rate (OTR) decreased with increasing the CNPs concentrations. The barrier properties (H2O and O2) of PBAT were improved by the presence of CNPs. WVTR was calculated to be 108.6 ± 1.8 g/m2/day for PBAT. WVTR reduced when CNPs concentration in PBAT increased. The PCN-5.0 film sample had the lowest WVTR value, 34.1 ± 3.1 g/m2/day. For PCN-3.0, WVTR dropped by 45.39%, indicating and even with a 3.0 wt% loading of CNPs in PBAT, the rise is noticeable. Contact angle measurements indicate that PBAT/CNPs composites becomes hydrophobic after reinforcing. Gram-positive (S. aureus) and Gram-negative (E. coli) food-borne pathogenic microorganisms showed enhanced antimicrobial activity against the developed PBAT composites. The carrot pieces preserved their freshness for an extended period of 12 days while packaged in the PBAT/CNPs composite film, indicating that the film is an effective and excellent packaging for food materials.

Degradation of poly(butylene adipate-co-terephthalate) by Stenotrophomonas sp. YCJ1 isolated from farmland soil.

In recent years, poly (butylene adipate-co-terephthalate) (PBAT) has been widely used. However, PBAT-degrading bacteria have rarely been reported. PBAT-degrading bacteria were isolated from farmland soil and identified. The effects of growth factors on the degradation of PBAT and the lipase activity of PBAT-degrading bacteria were assessed. The degradation mechanism was analyzed using scanning electron microscopy, attenuated total reflection Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, X-ray diffraction, and liquid chromatography-mass spectrometry. The results showed that Stenotrophomonas sp. YCJ1 had a significant degrading effect on PBAT. Under certain conditions, the strain could secrete 10.53 U/mL of lipase activity and degrade 10.14 wt.% of PBAT films. The strain secreted lipase to catalyze the degradation of the ester bonds in PBAT, resulting in the production of degradation products such as terephthalic acid, 1,4-butanediol, and adipic acid. Furthermore, the degradation products could participate in the metabolism of YCJ1 as carbon sources to facilitate complete degradation of PBAT, indicating that the strain has potential value for the bioremediation of PBAT in the environment.

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.

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.

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.

Preparation and Antimicrobial Characterization of Poly(butylene adipate-co-terephthalate)/Kaolin Clay Biocomposites.

The biodegradable polymer poly(butylene adipate-co-terephthalate) (PBAT) starts decomposing at room temperature. Kaolin clay (KO) was dispersed and blended into PBAT composites using a solution-casting method. Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to evaluate the structure and morphology of the composite materials. PBAT/kaolin clay composites were studied by thermogravimetric analysis (TGA). The PBAT composite loaded with 5.0 wt% kaolin clay shows the best characteristics. The biocomposites of PBAT/kaolin [PBC-5.0 (37.6MPa)] have a good tensile strength when compared to virgin PBAT (18.3MPa). The oxygen transmission rate (OTR), with ranges from 1080.2 to 311.7 (cc/m2/day), leads the KO content. By including 5.0 wt% kaolin 43.5 (g/m2/day), the water vapor transmission rate (WVTR) of the PBAT/kaolin composites was decreased. The pure PBAT must have a WVTR of 152.4 (g/m2/day). Gram-positive (S. aureus) and Gram-negative (E. coli) food-borne bacteria are significantly more resistant to the antimicrobial property of composites. The results show that PBAT/kaolin composites have great potential as food packaging materials due to their ability to decrease the growth of bacteria and improve the shelf life of packaged foods.

[Application of cutinase in the degradation of biodegradable polyester poly(butylene adipate-co-terephthalate)].

With the environmental pollution caused by waste plastics becoming increasingly serious, biodegradable polyester has become the focus of public attention. Poly(butylene adipate-co-terephthalate) (PBAT) is a biodegradable polyester formed by the copolymerization of aliphatic and aromatic groups, which has excellent performance of both. The degradation of PBAT under natural conditions requires strict environmental conditions and long degradation cycle. To address these shortcomings, this study explored the application of cutinase in PBAT degradation and the impact of butylene terephthalate (BT) content on the biodegradability of PBAT, so as to improve the degradation rate of PBAT. Five Polyester degrading enzymes from different sources were selected to degrade PBAT to pick out the most efficient enzyme. Subsequently, the degradation rate of PBAT materials with different BT content were determined and compared. The results showed that cutinase ICCG was the best enzyme for PBAT biodegradation, and the higher the BT content, the lower the degradation rate of PBAT. Furthermore, the optimum temperature, buffer type, pH, the ratio of enzyme to substrate (E/S) and substrate concentration in the degradation system were determined to be 75 ℃, Tris HCl, 9.0, 0.4% and 1.0% respectively. These findings may facilitate the application of cutinase in PBAT degradation.

Preparation and Performance of Biodegradable Poly(butylene adipate-co-terephthalate) Composites Reinforced with Novel AgSnO2 Microparticles for Application in Food Packaging.

Biodegradable composites with antimicrobial properties were prepared with microparticles of silver stannate (AgSnO2) and poly(butylene adipate-co-terephthalate) (PBAT) and tested for applications in food packaging. The PBAT matrix was synthesized and confirmed by 1H-nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction (XRD). Ultrasonic and coprecipitation methods were used to synthesize AgSnO2. A two-step mixing method and a solvent cast technique were utilized to fabricate the PBAT composites (different weight % of AgSnO2) for packaging foods. Attenuated total reflection-infrared spectroscopy, X-ray photoelectron spectroscopy, XRD, and scanning electron microscopy were used to investigate the formation, structure, and size of the composites. Thermogravimetric analysis and differential thermal calorimetry were used to examine the PBAT/AgSnO2 composites. The best characteristics are exhibited in 5.0 wt. % AgSnO2 loaded PBAT composite. The tensile strength, elongation at break, water vapor transmission rate, and oxygen transmission rate were 22.82 MPa, 237.00%, 125.20 g/m2/day, and 1104.62 cc/m2/day.atm, respectively. Incorporating AgSnO2 enhanced the hydrophobicity of the PBAT materials as evaluated by the water contact angle. The 5.0 wt. % AgSnO2/PBAT film shows a favorable zone of inhibition against the bacteria pathogens S. aureus and E. coli, according to an evaluation of its antimicrobial activity. The weight loss of 5% AgSnO2/PBAT film was 78.4% after eight weeks in the natural soil environments. In addition, the results of food quality studies recommend that AgSnO2/PBAT (5.0 wt. %) film had a longer food shelf life than the neat PBAT and commercial, increasing it from one to 14 days for carrot vegetables.

Strong synergistic toughening and compatibilization enhancement of carbon nanotubes and multi-functional epoxy compatibilizer in high toughened polylactic acid (PLA)/poly (butylene adipate-co-terephthalate) (PBAT) blends.

Different carbon nanotubes (CNTs) contents on high-toughness polylactic acid (PLA)/poly (butylene adipate-co-terephthalate) (PBAT) blends were prepared by one-step melt blending using multifunctional epoxy oligomers (ADR) as reactive compatibilizer. During reactive blending, the PLA or PBAT chains were grafted onto the CNTs by allowing the carboxyl or hydroxyl groups to react with epoxy groups and form a branched CNTs-based copolymer. The branched copolymer at the interface between PLA and PBAT was dispersed through emulsion to improve the polymer-polymer or polymer-nanoparticle entanglement between the molecular chains. Interfacial adhesion, interface layer stability, and system viscoelasticity and compatibility were improved as indicated by rheological curves and dynamic mechanical analysis. The strength and toughness of the sample were simultaneously improved by the addition of CNTs and ADR. The impact strength reached 35.3 kJ/m2, which was approximately 7 times that of the PLA/PBAT blend, and the tensile strength was also increased from 33.6 MPa to 42.8 MPa. The properties of PLA/PBAT blend synergistically modified by ADR and CNTs were obviously better than those of PLA/PBAT blend modified by ADR or CNTs. The toughening synergistic effect of ADR and CNTs on PLA/PBAT was observed with efficiency reaching 3.05. With the further understanding of the toughening mechanism, the branched CNTs-based copolymers and CNTs clusters induce a synergistic effect, which increased the interfacial adhesion and ability of energy dissipation and stress transmission.

Robust multiphase and multilayer starch/polymer (TPS/PBAT) film with simultaneous oxygen/moisture barrier properties.

The demands for bioplastics that provide good barrier properties against moisture and oxygen while simultaneously displaying good physical properties without compromising their biodegradability is ever-increasing. In this work, a multiphase and multilayer film assembly composed of thermoplastic starch (TPS) and its maleated counterpart (MTPS) with poly(butylene adipate-co-terephthalate) (PBAT) was constructed as a suitable barrier film with excellent mechanical properties. The bioplastic film assemblies were fabricated through reactive extrusion, compression molding, and dip-coating process. The incorporation of PBAT co-blend with TPS in the core layer enhanced the multilayer film's interfacial bond. The MTPS/PBAT film assembly provided 86.8% and 74.3% improvement in moisture barrier and oxygen barrier as compared to the baseline TPS and PBAT films, respectively. Overall, the multiphase and multilayer film assembly displayed good mechanical properties in conjuncture with excellent barrier properties indicating their potential as a biodegradable and cost effective alternative to conventional plastics used in the packaging industry.

Properties of Biodegradable Films Based on Poly(butylene Succinate) (PBS) and Poly(butylene Adipate-co-Terephthalate) (PBAT) Blends †,‡.

Compression molded biodegradable films based on poly(butylene succinate) (PBS) and poly(butylene adipate-co-terephthalate) (PBAT) at varying weights were prepared, and their relevant properties for packaging applications are here reported. The melt rheology of the blends was first studied, and the binary PBS/PBAT blends exhibited marked shear thinning and complex thermoreological behavior, due to the formation of a co-continuous morphology in the 50 wt% blend. The films were characterized by infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), mechanical tensile tests, scanning electron microscopy (SEM), and oxygen and water vapor permeability. PBS crystallization was inhibited in the blends with higher contents of PBAT, and FTIR and SEM analysis suggested that limited interactions occur between the two polymer phases. The films showed increasing stiffness as the PBS percentage increased; further, a sharp decrease in elongation at break was noticed for the films containing percentages of PBS greater than 25 wt%. Gas permeability decreased with increasing PBS content, indicating that the barrier properties of PBS can be tuned by blending with PBAT. The results obtained point out that the blend containing 25 wt% PBS is a good compromise between elastic modulus (135 MPa) and deformation at break (390%) values. Overall, PBS/PBAT blends represent an alternative for packaging films, as they combine biodegradability, good barrier properties and reasonable mechanical behavior.

Enhanced compatibility between poly(lactic acid) and poly (butylene adipate-co-terephthalate) by incorporation of N-halamine epoxy precursor.

In this work, a new N-halamine precursor with two epoxy groups, 1,3-bis(2,3-epoxypropyl)-s-triazine-2,4,6-trione (BETT), was synthesized and used to enhance the compatibility between poly(lactic acid) (PLA) and poly (butylene adipate-co-terephthalate) (PBAT). The rheological analysis and GPC indicated that chain extension between PLA and PBAT occurred during the melt-blending in the presence of BETT. The PLA/PBAT chain extensions improved the compatibility between PLA and PBAT and hindered the crystallization of PLA. SEM images showed that PLA/PBAT blend gradually changed from the typical sea-island phase without BETT to a co-continuous structure with increase in amount of BETT. This showed that the interfacial compatibility between PLA and PBAT improved significantly on addition of BETT. Moreover, compared to PLA/PBAT blend, the mechanical properties of PLA/PBAT/BETT blends showed great improvement. Furthermore, the chlorinated PLA/PBAT/BETT sheets displayed excellent antibacterial activities against E. coli (CMCC 44103) and S. aureus (ATCC 6538) cultures, wherein the sheets with 17.5 ± 0.8 µg/cm2 of the active chlorine could kill all inoculated bacteria within 30 min.

Dispersion study of nanofibrillated cellulose based poly(butylene adipate-co-terephthalate) composites.

The production of lower cost bionanocomposites based on nanofibrillated cellulose (NFC) is a promising source to develop the next generation of light weight and high performance materials for a variety of defense, infrastructure and energy applications. In this study, a series of bio-nanocomposites were developed by reinforcing NFC from regenerated wood fiber into poly(butylene adipate-co-terephthalate) (PBAT) by injection molding. The incorporation of NFC in PBAT matrix (0.2-1 wt%) increased the storage modulus (G') and dynamic viscosity (η') as revealed by shear rheology, indicating a percolation threshold around 0.2-0.5 wt% region. DSC analysis showed similar trends with slight improvement of glass transition (Tg) and crystallization temperature (Tc). Percentage crystallinity, as calculated from heat of fusion equation and taking into account 100% crystallized PBAT data improved in overall. This is a fundamental study aimed at understanding the morphological, rheological and thermal evaluation of such nanocomposites for an improved dispersion of NFC as filler in the matrix.