Adipate Terephthalate Research Articles

FDM 3D Printing and Properties of WF/PBAT/PLA Composites

Fused deposition molding (FDM) is a commonly used 3D printing method, and polylactic acid (PLA) has become one of the most important raw materials for this technology due to its excellent warping resistance. However, its mechanical properties are insufficient. Polybutylene adipate terephthalate (PBAT) is characterized by high toughness and low rigidity, which can complement the performance of PLA. The biodegradable polymers produced by blending the two have thus been used to replace petroleum-based plastics in recent years, but the high cost of the blends has limited their wide applications. Introducing plant fibers into the blends can not only maintain biodegradability and improve the overall performance of the plastics but also reduce their costs greatly. In this study, the PBAT/PLA blends with a mass ratio of 70/30 were selected and mixed with wood flour (WF) to prepare ternary composites using a FDM 3D printing technique. The effects of WF dosage on the mechanical properties, thermal properties, surface wettability, and melt flowability of the composites were investigated. The results showed that the proper amount of WF could improve the tensile and flexural moduli of the composites, as well as the crystallinity and hydrophobicity of the printed specimens increased with the content of WF, while the melt flow rate decreased gradually. Compared to PBAT/PLA blends, WF/PBAT/PLA composites are less costly, and the composite containing 20 wt.% WF has the best comprehensive performance, showing great potential as raw material for FDM 3D printing.

Thermoplastic starch/poly(butylene adipate-co-terephthalate) blown film with maltol and ethyl maltol preserving cake quality: Morphology and antimicrobial function

Maltol (MT) and ethyl maltol (EM) are flavoring compounds that release vapors into headspace, exerting antimicrobial effects and extending food shelf-life. This study investigated biodegradable films for packaged bakery quality. Biodegradable films (40 % polybutylene adipate terephthalate and 60 % thermoplastic starch) were produced via extrusion for films with varying MT and EM contents (1, 3, and 5 %). Scanning electron microscopy revealed smoother and more homogeneous film cross-sections with MT/EM, indicating reduced surface wrinkling. Fourier-transform infrared spectroscopy analysis suggested modified OH and CH stretching due to hydrogen bonding between TPS and EM/MT. The XRD pattern showed sharp MT crystallization, modifying crystal polymorphs of starch and PBAT. EM and MT films exhibited against Staphylococcus aureus after 24 h. Moreover, EM/MT films effectively delayed fungal growth in butter cake, inhibiting mold growth in butter cake more than twofold. These findings suggest that volatile compounds like MT/EM have promising potential for incorporation into PBAT/TPS films, creating active bakery packaging.

Mechanistic insight into interactive effect of microplastics and arsenic on growth of rice (Oryza sativa L.) and soil health indicators

Microplastics (MPs) pollution has recently become a major concern for agroecosystems. The interplay between MPs, and heavy metal(loid)s in the soil can intensify the risks to plant growth and human health. The current study investigated the interactive effects of arsenic (As) and biodegradable and petroleum-based conventional MPs on rice growth, As bioavailability, soil bacterial communities, and soil enzyme activities. As-contaminated soil (5 mg kg−1) was treated with conventional MPs i.e., polystyrene (PS) and polyethylene (PE) and biodegradable MPs i.e., polylactic acid (PLA) and polybutylene adipate terephthalate (PBAT) at 0.1 % and 1 % rates. In a pot experiment, rice plants were cultivated in soil co-contaminated with As and MPs. PLA-MPs exhibited significant interactions with As, increasing its bioavailability and impairing rice plant growth by enhancing plant oxidative stress. The results illustrated that T2 treatment (PLA-MPs @ 1 % + As 5 mg kg−1) significantly decreased the root and shoot lengths, root and shoot dry weights as well as the rates of photosynthesis, transpiration, intercellular CO2, and stomatal conductance in rice plants. Biodegradable PLA-MPs @ 1 % resulted in increased uptake of As in rice roots, stems, and leaves by 13.4 %, 38.9 %, and 20.6 %, respectively. In contrast, conventional PE-MPs @ 1 % showed contradictory results with As uptake declined by 2.2 %, 5.1 %, and 9.9 % in rice roots, stem and leaves. Soil enzyme kinetics showed that biodegradable MPs increased the activities of soil catalase, dehydrogenase, and phytase enzymes, whereas both conventional PS and PE-MPs decreased their activities. Moreover, As and PLA-MPs combined stress altered soil bacterial communities by increasing the relative abundance of Protobacteria, Acidobacteria, Chloroflexi, and Firmicutes phyla by 49 %, 29 %, 82 %, and 57 %, respectively. This study provides new insights into MPs-As interactions in soil-plant system and ecological risks associated with their coexistence.

Optimizing mechanical and environmental degradation performance of polybutylene adipate terephthalate by adjusting polyvinyl alcohol content

Biodegradable plastics offer a promising alternative to traditional plastics in agriculture, particularly where rapid and controlled degradation is required. This study investigates the properties and degradation behavior of blends of Polybutylene Adipate Terephthalate (PBAT) and Polyvinyl Alcohol (PVA). Mechanical testing revealed that incorporating PVA significantly enhanced both tensile and flexural strengths. For example, pure PBAT had a tensile strength of 14.51 MPa, while the 20PBAT/80PVA blend achieved 53.48 MPa. However, higher PVA content led to reduced elongation at break and fracture toughness. Water immersion tests showed that PVA dissolution and PBAT degradation caused notable reductions in mechanical properties after 5 days, with blends containing 80 % PVA exhibiting an 80.1 % weight loss, and the 40PBAT/60PVA blends showing a 41.75 % weight loss after 30 days. Soil degradation experiments confirmed that the degradation rate increased with higher PVA content. These results highlight the superior degradation performance of PBAT/PVA blends and demonstrate that adjusting the PVA content effectively modulates both degradation rates and mechanical properties. This offers valuable insights for the development of environmentally friendly materials.

Analysis of forensic polymer samples using double shot pyrolysis gas chromatography – Mass spectrometry

Polymers are present in many different products, such as paints, plastics, and rubbers, which are routinely encountered in forensic casework. Comparison of such samples involves an initial visual examination followed by comparison of the chemical compositions of the exhibits. Techniques such as Fourier transform infrared spectroscopy (FTIR) and pyrolysis gas chromatography – mass spectrometry (PyGC-MS) have been reported for determining the chemical compositions of polymers in forensic samples. Double-shot pyrolysis gas chromatography – mass spectrometry (DS-PyGC-MS) is an extension of single-shot pyrolysis gas chromatography – mass spectrometry (SS-PyGC-MS) which is the current PyGC-MS method used in most forensic laboratories. DS-PyGC-MS involves a preliminary thermal desorption GC-MS step, followed by the pyrolysis GC-MS step, with this second step being analogous to SS-PyGC-MS. The pyrolyser furnace operates at a lower temperature during the thermal desorption step, allowing low volatility compounds, such as additives, to be thermally desorbed and detected, minimising interference from the polymeric component of the sample. This pilot study analysed four different polymeric substrates, commonly encountered in forensic casework, by DS-PyGC-MS. The substrates chosen were tyre rubber, road cones, cling film, and shotgun wads. The aim was to investigate whether more chemical information was generated by DS-PyGC-MS compared to SS-PyGC-MS, potentially providing increased discrimination of such samples. Qualitative results showed that tyre rubber and road cones were ideal substrates for DS-PyGC-MS. A wide range of additives were detected in these samples in the thermal desorption step, which were not detected using SS-PyGC-MS. All of the rubber tyres (n=5) and road cones (n=6) were able to be uniquely distinguished using DS-PyGC-MS. Some additional compounds were detected in the thermal desorption analysis of shotgun wads (n=4), providing increased discrimination compared to SS-PyGC-MS. For the cling film samples analysed (n=7) the polyethylene-based cling films (n=6) could not be distinguished from each other, with no compounds detected in the thermal desorption step. The other cling film sample contained a mixture of polylactic acid (PLA) and polybutylene adipate terephthalate (PBAT) and could easily be distinguished from the polyethylene-based cling films using either SS- or DS-PyGC-MS, or other common analytical methods such as Fourier transform infrared spectroscopy (FTIR). This pilot study has demonstrated that DS-PyGC-MS has the potential to provide more comprehensive chemical composition information for some polymeric substrates and is a promising method for the forensic comparison of polymer evidence.

Transport of reduced PBAT microplastics in saturated porous media: Synergistic effects of enhanced surface energy and roughness

Microplastic (MP) pollution presents significant global environmental challenges, exacerbated by reduction aging processes in anoxic environments, thereby increasing environmental risks and potential threats to human health. However, the mechanisms underlying the transport of reduced MPs remain poorly understood. In this study, laboratory-scale column experiments were conducted to investigate the transport behavior of polybutylene adipate terephthalate (PBAT), a common biodegradable MPs, and its reduced products obtained through the aging process mediated by two typical reducing agents, NaBH4 and Na2S, under varying conditions (ionic strength (IS), divalent cations, and low molecular weight organic acids (LMWOAs)). The results indicated that reduction aging improved the hydrophilicity of PBAT by increasing the surface roughness (roughness factor increased from 1.300 to 1.642) and surface energy (from 51.80 to 107.03 mN m−1), thereby increasing the mobility of reduced PBAT (with recovery rate increased from 53.77 % to 63.18 %). Increased IS decreased the mobility of reduced PBAT by decreasing the surface negative charge density. Divalent cations inhibited the mobility of both pristine and reduced PBAT in porous media, with pristine PBAT, containing more oxygen functional groups, exhibiting stronger inhibition. Furthermore, LMWOAs promoted the retention of reduced PBAT in porous media, which was dependent on the type of LMWOAs. This study revealed the alterations in MPs properties caused by reduction aging and their effects on transport mechanisms, offering new insights into the transport behavior and environmental risks of reduced MPs.

Different mulch films, consistent results: soil fauna responses to microplastic

Agricultural activities contribute to plastic pollution, with unintentional introduction and intentional use of plastic mulch films leading to the accumulation of microplastic particles in soils. The lack of removal techniques and scarce information on the effects on soil organisms, especially for biodegradable mulch films, necessitate an assessment of potential effects. This study aimed to elucidate the effects of mulch film microplastic on soil fauna by investigating reproduction output and subcellular responses before and after recovery from exposure. Two common soil organisms, Folsomia candida and Eisenia fetida, were exposed to petroleum-based polyethylene (PE) and biodegradable polylactic acid/polybutylene adipate terephthalate (PLA/PBAT) microplastic for 28 days, according to OECD guidelines 232 and 222, respectively. Juvenile numbers revealed no polymer- or concentration-dependent effects on E. fetida and F. candida reproduction after exposure to up to 5 and 10 g/kgdw soil, respectively. To provide a more sensitive and early indication of sublethal effects, subcellular responses in E. fetida were analyzed. Glutathione S-transferase (GST) activity increased with rising microplastic concentration; however, catalase (CAT), acetylcholine esterase (AChE) activity, and reactive oxygen species (ROS) did not differ from control levels. Further, the more environmentally relevant PE polymer was chosen for in-depth assessment of subcellular response after 28-day microplastic exposure and subsequent 28 days in uncontaminated soil with E. fetida. No significant differences in biomarker activity and stress levels were observed. We conclude that mulch film–derived microplastic did not adversely affect earthworm and collembolan species in this scenario, except for a slight induction in the detoxification enzyme glutathione S-transferase.

Interfacial compatibilization of fully biodegradable polylactic acid/polybutylene adipate terephthalate blends for improved mechanical and physical performance

Environmental problems, such as plastic pollution and global warming, are motivating researchers worldwide to seek sustainable biodegradable polymers that would replace the nonbiodegradable ones. Polylactic acid (PLA) has emerged as one of the most promising alternatives due to its superior mechanical and thermal qualities compared to other types of biopolymers. However, PLA has some inherent deficiencies such as its brittleness and rigidity, which limit its further use. This study investigates the toughening effect of different amounts of polybutylene adipate terephthalate (PBAT) on PLA, and the compatibilization effect of ADR, a chain extender, on the PLA/PBAT blends. The results indicate that PBAT can significantly enhance the flexibility and toughness of PLA. PLA and PBAT can react with ADR to form PLA-g-PBAT copolymers thereby increasing the compatibility of these two polymers. The tensile strength, elongation at break and impact strength of the PLA/PBAT/ADR blends are all increased due to the increased compatibility. The chain extension reaction can promote the formation of a better crystalline structure in the PLA/PBAT blends, which leads to the increase of the Tm of PLA. Besides, the hydrophilicity of PLA can be adjusted by blending with PBAT, and the hydrophilicity of the blends with blend ratios of 75:25, 50:50 and 25:75 can also be enhanced after the addition of ADR.

The Impact of Water on Polylactide – Polybutylene Adipinate Terephthalate Blends

Mixing in the melt followed by pressing, blends of polylactide — polybutylene adipate terephthalate of various compositions were obtained. The content of polybutylene adipate terephthalate in blends was 10, 20 and 30 wt. %. The effect of water on film samples at a temperature of 22 ± 2°C for 270 days was studied. After exposure to water, a change in morphology was detected: turbidity of the samples and the appearance of defects. The thermophysical characteristics before and after hydrolytic degradation were determined by differential scanning calorimetry. A decrease in the cold crystallization temperature in pure polylactide and with a low content of polybutylene adipate terephthalate, and the disappearance of the cold crystallization peak at a content of 20 and 30 wt. % of polybutylene adipate terephthalate were shown. The degree of crystallinity of polylactide after exposure to water tended to increase. Changes in the chemical structure of mixed samples were monitored by IR spectroscopy.

Biodegradation of poly(butylene adipate terephthalate) and poly(vinyl alcohol) within aquatic pathway

Understanding the environmental fate of biodegradable plastics in aquatic systems is crucial, given the alarming amount of plastic waste and microplastic particles transported through aquatic pathways. In particular, there is a need to analyze the biodegradation of commercialized biodegradable plastics upon release from wastewater treatment plants into natural aquatic systems. This study investigates the biodegradation behaviors of poly(butylene adipate terephthalate) (PBAT) and poly(vinyl alcohol) (PVA) in wastewater, freshwater, and seawater. Biodegradation of PBAT and PVA assessed through biochemical oxygen demand (BOD) experiments and microcosm tests revealed that the type of aquatic system governs the biodegradation behaviors of each plastic, with the highest biodegradation rate achieved in wastewater for both PBAT and PVA (25.6 and 32.2 % in 30 d, respectively). Plastic release pathway from wastewater into other aquatic systems simulated by sequential incubation in different microcosms suggested that PBAT exposed to wastewater and freshwater before reaching seawater was more prone to degradation than when directly exposed to seawater. On the other hand, PVA displayed comparable biodegradation rate regardless of whether it was directly exposed to seawater or had passed through other environments beforehand. Metagenome amplicon sequencing of 16S rRNA genes revealed distinct community shifts dependent on the type of plastics in changing environments along the simulated aquatic pathway. Several bacterial species putatively implicated in the biodegradation of PBAT and PVA are discussed. Our findings underscore the significant influence of pollution routes on the biodegradation of PBAT and PVA, highlighting the potential for wastewater treatment to facilitate rapid degradation compared to direct exposure to pristine aquatic environments.

Towards Sustainable Production of Polybutylene Adipate Terephthalate: Non-biological Catalytic Syntheses of Biomass-derived Constituents.

Renewable chemicals, which are made from renewable resources such as biomass, have attracted significant interest as substitutes for natural gas- or petroleum-derived chemicals to enhance the sustainability of the chemical and petrochemical industries. Polybutylene adipate terephthalate (PBAT), which is a copolyester of 1,4-butanediol (1,4-BDO), adipic acid (AA), and dimethyl terephthalate (DMT) or terephthalic acid (TPA), has garnered significant interest as a biodegradable polymer. This study assesses the non-biological production of PBAT monomers from biomass feedstocks via heterogeneous catalytic reactions. The biomass-based catalytic routes to each monomer are analyzed and compared to conventional routes. Although no fully commercialized catalytic processes for direct conversion of biomass into 1,4-BDO, AA, DMT, and TPA are available, emerging and promising catalytic routes have been proposed. The proposed biomass-based catalytic pathways toward 1,4-BDO, AA, DMT, and TPA are not yet fully competitive with conventional fossil fuel-based pathways mainly due to high feedstock prices and the existence of other alternatives. However, given continuous technological advances in the renewable production of PBAT monomers, bio-based PBAT should be economically viable in the near future.

Microplastics and biochar interactively affect nitrous oxide emissions from tobacco planting soil

Biochar application to amend acidified tobacco-soils can enhance tobacco quality and reduce nitrous oxide (N2O) emissions. Microplastics from agricultural mulch are commonly found in cash-crop farmland soils and, together with biochar, affect soil N2O emissions. In this study, we applied three types of microplastics (polyethylene, PE; polylactic acid, PLA; polybutylene adipate terephthalate, PBAT) and rice biochar alone or in combination to acidified tobacco planting soil in central China to investigate their effects on soil N2O emissions, soil chemical properties, nitrogen-cycle-related functional genes, and microbial functional diversity during a 35-day laboratory incubation period. Significant increases in N₂O emissions were observed with PE and PLA, which raised emissions by 15.96 % and 21.52 %, respectively. Additionally, different microplastics affected soil N₂O emissions through distinct regulatory pathways. Co-application of microplastics and biochar suppressed N2O emissions compared to microplastics alone. Biochar mitigates N2O emissions mainly by increasing the abundance of the nosZ gene. It can remediate soil contaminated by microplastics and reduce their negative impacts on the soil environment. This study provides deeper insight into the effects of microplastics on soil nitrogen cycling and biochar-mitigated remediation of microplastic-contaminated soil.

Application of biohybrid membranes for arsenic and chromium removal and their impact on pollutant accumulation in soybean (Glycine max L.) seedlings.

Chromium and arsenic are among the priority pollutants to be controlled by regulatory and health agencies due to their ability to accumulate in food chains and the harmful effects on health resulting from the ingestion of food contaminated with metals and metalloids. In the present work, four biohybrid membrane systems were developed as alternatives for the removal of these pollutants, three based on polyvinyl alcohol polymeric mesh (PVA, PVA-magnetite, PVA L-cysteine) and one based on polybutylene adipate terephthalate (PBAT), all associated with bioremediation agents. The efficiency of the bioassociation process was assessed through count methods and microscopy. The removal capacity of these systems was evaluated in synthetic liquid medium, both in the absence and in the presence of soybean (Glycine max L.) seedlings. The content of chromium and arsenic was also analyzed in aerial and hypogeous tissues of seedlings grown on contaminated solid substrate. PVA and PVA-magnetite biohybrid membranes showed the highest removal rates, between 57 and 75% of the initial arsenic content and more than 80% of the initial chromium content after 48h of treatment, when evaluated in synthetic liquid media with initial concentrations of 2.5ppm of pentavalent arsenic and 5ppm of hexavalent chromium, both in presence and absence of seedlings. PVA and PBAT promoted a significant reduction of arsenic translocation to the aerial parts, generally edible, of this crop of agronomic interest. The systems tested showed a high potential for biotechnological applications in matrices affected by the presence of arsenic and chromium.

Modified nanoporous zeolites on a biodegradable polymer film with excellent hydrophobicity, ethylene gas adsorption, and antibacterial activity through surface charge accumulation

The high specific surface area and large pore volume of nanoporous zeolites (NZs) were utilized to impart a biodegradable polymer film with superhydrophobicity, ethylene gas adsorption capability, and active antibacterial activity. NZs were synthesized by using organic silanes via a sol–gel method. They were then dispersed on a biodegradable blended PPP [poly(lactic acid) (PLA)/poly butylene succinate (PBS)/poly butylene adipate terephthalate (PBAT)] film to enhance its mechanical properties and control water repellent. The hydrophobicity of the organic silanes on the zeolite surface gradually increased according to their length. The film prepared by utilizing octadecyltriethoxysilane (ODTES) was superhydrophobic with a contact angle 142.6°. The porous structure of the PPP with attached ODTES-NZs impeded the release of accumulated charges generated through friction, thereby yielding excellent output voltage when applying friction periodically. The output performance of the PPP-ODTES-NZs film was measured to be 723 V when a positive charge was injected into the film, which was about 3.1 times higher than the output performance of the PPP film without surface modification. The accumulated positive charges provided excellent antibacterial efficacy against externally introduced bacteria. Our approach of attaching ODTES-NZs to a blended polymer provides a multifunctional biodegradable film (ethylene gas adsorption, water repellent, and antibacterial activity via positive charge accumulation) with excellent food-storage capability.

Adsorption behavior and mechanism of different types of (aged) microplastics for napropamide in soils

The role of microplastics (MPs) as pollutant carriers and their influence on the fate of organic pollutants has received considerable attention. However, the impacts of MPs on the adsorption of amide herbicides in soil, have not been investigated. In this study, non-biodegradable (polyethylene, PEM) and biodegradable (polybutylene adipate terephthalate, PBATM) MPs were aged by exposure to one month of ultraviolet irradiation. The impacts of MPs on the adsorption of napropamide (Nap) in two agricultural soils (black soil [BS] and fluvo-aquic soil [CS]) were investigated through batch experiments. The findings suggested that the adsorption of Nap onto PEM was mainly governed by physical processes, while, chemical mechanisms, should not be overlooked on PBATM. With the addition of 0.2% MPs, the maximum adsorption capacity (Qm) and adsorption distribution coefficient (KF) of soil containing PEM (soil-PEM) were higher than that of soil-PBATM, however, the Qm and KF values of soil-PBATM for Nap were higher when the addition of MPs was 2%. After UV aging, the increased specific surface area of MPs led to an increased adhesion of soil particles. These were attributed to the different surface properties and concentrations of different (aged) MPs, resulting in differences in the inhibition effect by soil particles. The adhesion of soil particles was confirmed by X-ray photoelectron spectroscopy. Additionally, regardless of the addition of MPs, the Qm values of BS for Nap were higher than those for CS. In summary, MPs can alter the adsorption of Nap in soil, influencing both its mobility within the soil ecosystem and the environmental risk.

Production of conductive microfibers based on Polybutylene adipate terephthalate and graphite using a 3D printed electrospinning system and their application as electrochemical dopamine sensor

The use of fibers has intensified in the application of technological and industrial devices and systems, due to their characteristics such as mechanical resistance, elasticity, and a wide range of morphological configurations. In this sense, conductive microfibers based on graphite powder (GP) and the polylactic acid/ Polybutylene adipate terephthalate polymeric blend were developed through the electrospinning technique using a new 3D printer automatized collector. The obtained microfibers were characterized and used in the manufacture of an electrochemical sensor for the determination of dopamine, which presented a linear range of 0.5 to 20 μmol L−1 with a limit of detection of 0.008 μmol L−1. The sensor was applied for the detection of dopamine in a human serum sample and had a recovery range of 85.5 to 101.0 %. Therefore, conductive microfibers manufactured by electrospinning have potential as a material for the development of electrochemical sensors.

Effect of fiber orientation on the mechanical properties of a biodegradable composite made from lyocell‐fiber reinforced polybutylene adipate terephthalate

AbstractPolymer waste in the environment is a more and more serious problem for nature. Therefore, the industry is increasingly interested in the use of materials that are biodegradable. Polybutylene adipate terephthalate (PBAT) belongs to the group of biodegradable polymers, but this polymer often does not have the desired properties for many uses. Therefore, this polymer is often mixed with other biodegradable polymers to form blends with suitable properties. An alternative is, to change the polymer's properties with the addition of fibers. The aim of the present work is to use lyocell fibers to improve the mechanical properties of PBAT. Lyocell is an eco‐friendly cellulose fiber that is biodegradable. The lyocell fibers were embedded into a PBAT matrix in the form of a woven fabric, with different orientations of the fabric warp yarns to the long axis of composites. Consequently, composites with a warp yarn orientation of 0°, ±22.5°, ±45°, ±67.5°, and 90° were prepared. The mechanical properties were characterized by quasi‐static tensile testing and also by dynamic mechanical analysis. The elastic modulus as a function of warp yarn orientation was modeled with the modified rule‐of‐mixture theory and with the theory of elasticity.

Multigenerational toxicity of microplastics derived from two types of agricultural mulching films to Folsomia candida

Degradation and fragmentation of mulching films represents an increasing source of microplastics (MPs, plastic particles 1 μm to 5 mm in size) to agricultural soils. MPs have been shown to affect many soil invertebrates, including springtails. However, these studies typically use test materials representing less environmentally relevant particle types, such as pristine uniform MPs, which do not represent the large range of particle sizes and morphologies found in the field. This study aimed at providing insight into the adverse effects of MPs originating from agricultural mulching films, by using artificially aged MPs derived from both biodegradable (starch-polybutadiene adipate terephthalate (PBAT)) blend, as well as conventional (linear low-density polyethylene (LLDPE)) plastic polymers. The soil dwelling springtail Folsomia candida was exposed to these MPs for five generations in order to elucidate population effects due to possible reproduction toxicity, endocrine disruption, mutagenesis or developmental toxicity. F. candida were exposed to 0, 0.0016, 0.008, 0.04, 0.2, 1, 2, 3, 4 and 5 % (w/w dry soil) MPs in Lufa 2.2 soil, which includes concentrations within the range of environmental relevance. Juveniles produced at each concentration were transferred to the next generation, with the parental, F2 and F4 generations being exposed for four weeks and F1 and F3 generations for five weeks. No concentration-dependent effects on F. candida survival or reproduction were observed in exposures to either of the MPs, in any of the generations. These results suggest that the particular MPs used in this study, derived from mulching films used on agricultural soils, may not be potent toxicants to F. candida, even after long-term exposure and at elevated concentrations.

Reactively Processed Poly(butylene adipate terephthalate) Composite–Based Multilayered Films with Improved Properties for Sustainable Packaging Applications: Structural Characterization and Biodegradation Mechanism

AbstractIn this study, it is attempted to enhance the properties and biodegradability of poly(butylene adipate terephthalate) (PBAT) using nanocomposite technology to meet the demand for sustainable packaging applications. Two nanoclays containing PBAT composites are reactively processed and integrated into the multilayered films. Reactive processing facilitates the dispersion and distribution of nanoclay particles in the PBAT matrix. The multilayered films comprising reactively processed PBAT composites exhibited a 24.5%–31.5% reduction in the oxygen transmission rate and improved dimensional stability and tensile properties. Moreover, the degradability of the multilayered film comprising reactively processed PBAT composites reached 82% in 180 days. In contrast, a neat PBAT film of similar thickness attained only 53% degradation in the same period. The biodegradation mechanism is proposed based on the topology of the disintegrated films studied using scanning electron microscopy, chemical bond vibrations determined by Fourier‐transform infrared spectroscopy, and structural evolution by small‐ and wide‐angle X‐ray scattering (SWAXS). The SWAXS analysis is used to understand the changes in the degree of crystallinity, long‐range periodic order, and crystalline and amorphous layer thickness of the multilayered films before and after degradation. Such multilayered films can find applications where packaging or biomedical devices cannot be recycled.

Multilayer Film Comprising Polybutylene Adipate Terephthalate and Cellulose Nanocrystals with High Barrier and Compostable Properties.

In the present study, a multilayer, high-barrier, thin blown film based on a polybutylene adipate terephthalate (PBAT) blend with polyhydroxyalkanoate (PHA), and composed of four layers including a cellulose nanocrystal (CNC) barrier layer and an electrospun poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) hot-tack layer, was characterized in terms of the surface roughness, surface tension, migration, mechanical and peel performance, barrier properties, and disintegration rate. The results showed that the film exhibited a smooth surface. The overall migration tests showed that the material is suitable to be used as a food contact layer. The addition of the CNC interlayer had a significant effect on the mechanical properties of the system, drastically reducing the elongation at break and, thus, the flexibility of the material. The film containing CNCs and electrospun PHBV hot-tack interlayers exhibited firm but not strong adhesion. However, the multilayer was a good barrier to water vapor (2.4 ± 0.1 × 10-12 kg·m-2·s-1·Pa-1), and especially to oxygen (0.5 ± 0.3 × 10-15 m3·m-2·s-1·Pa-1), the permeance of which was reduced by up to 90% when the CNC layer was added. The multilayer system disintegrated completely in 60 days. All in all, the multilayer system developed resulted in a fully compostable structure with significant potential for use in high-barrier food packaging applications.