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Blends of poly(lactic acid) (PLA) with poly(propylene carbonate) (PPC) are currently in the phase of intensive study due to their promising properties and environmentally friendly features. Intensive study and further commercialization of PPC-based polymers or their blends, as usual, will soon face the problem of their waste occurring in the environment, including soil. For this reason, it is worth comprehensively studying the degradation rate of these polymers over a long period of time in soil and, for comparison, in phosphate buffer to understand the difference in this process and evaluate the potential application of such materials toward agrochemical and agricultural purposes. The degradation rate of the samples was generally accompanied by weight loss and a decrease in molecular weight, which was facilitated by the presence of PPC. The incubation of the samples in the aqueous media yielded greater surface erosions compared to the degradation in soil, which was attributed to the leaching of the low molecular degradation species out of the foils. The phytotoxicity study confirmed the no toxic impact of the PPC on tested plants, indicating it as a "green" material, which is crucial information for further, more comprehensive study of this polymer toward any type of sustainable application. [ABSTRACT FROM AUTHOR]

The aim of this study was to develop a novel amikacin (AMI) delivery system with prolonged release based on composite electrospun nanofibers of PLA supplemented with AMI-loaded Si nanoparticles of different morphology. The resultant materials were characterized in terms of their physical properties (scanning electron microscopy, Brunauer–Emmett–Teller analysis, thermogravimetric analysis, water contact angle). High-Performance Liquid Chromatography was used to determine the AMI content in the liquid fractions obtained from the release study. The results show that nanofibers of fumed silica exhibited an aggregated, highly porous structure, whereas nanofibers of mesoporous silica had a spherical morphology. Both silica nanoparticles had a significant effect on the hydrophilic properties of PLA nanofiber surfaces. The liquid fractions were investigated to gauge the encapsulation efficiency (EE) and loading efficiency (LE) of AMI, demonstrating 66% EE and 52% LE for nanofibers of fumed silica compared to nanofibers of mesoporous silica nanoparticles (52% EE and 12.7% LE). The antibacterial activity of the AMI-loaded nanofibers was determined by the Kirby–Bauer Method. These results demonstrated that the PLA-based silica nanofibers effectively enhanced the antibacterial properties against the Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae. [ABSTRACT FROM AUTHOR]

This manuscript details the preparation and characterization of a renewable biocomposite material intended as a soil conditioner based on low-molecular-weight poly(lactic acid) (PLA) and residual biomass (wheat straw and wood sawdust). The swelling properties and biodegradability of the PLA-lignocellulose composite under environmental conditions were evaluated as indicators of its potential for applications in soil. Its mechanical and structural properties were characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Results showed that the incorporation of lignocellulose waste material into PLA increased the swelling ratio of the biocomposite by up to 300%. The application of the biocomposite of 2 wt% in soil enhanced its capacity for water retention by 10%. In addition, the cross-linked structure of the material proved to be capable of swelling and deswelling repeatedly, indicating its good reusability. Incorporating lignocellulose waste in the PLA enhanced its stability in the soil environment. After 50 days of the experiment, almost 50% of the sample had degraded in the soil. [ABSTRACT FROM AUTHOR]

A set of renewable and biodegradable hydrogels based on acid whey and cellulose derivatives blended with poly(lactic acid) (PLA) were designed as eco-friendly biopolymeric material for sustainable agricultural applications. The physico-chemical properties of the hydrogel were evaluated using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and rheological measurements. The effect of the whey/polysaccharide/PLA hydrogel on soil quality improvement (water retention study, biodegradability, loading capacity and release of the fertilizers) and the growth pattern of Raphanus sativus and Phaseolus vulgaris has been also studied. The addition of PLA has been found to improve mechanical properties of the hydrogel. The introduction of 20% wt PLA extended decomposition time of hydrogels by 25% which makes the material more stable in the environment and maintaining the soil humidity for longer. The increasing the amount of PLA led to a rise in hydrogel viscosity brought about better entrapment efficiency of the fertilizers (86–92% for KNO 3 and 87–96% for urea, resp.) compared to control (82% for KNO 3 and 85% for urea, resp.). The novel hydrogels with swelling ratio of up to 500% showed potential as a sustainable water reservoir for plants improving water retention capacity of the soil by 30%. • Renewable and biodegradable whey/cellulose derivatives-based hydrogels mixed with low-molecular weight PLA were prepared. • Effect of different PLA content on hydrogel properties was evaluated • The hydrogels demonstrate a high water holding capacity and excellent biodegradability. • Acting as a source of water a nutritive whey agents for plants and for slow release of fertilizers. • Promising alternative to commercial hydrogels based on synthetic polymers. [ABSTRACT FROM AUTHOR]

Exposure to endocrine-disrupting chemicals (EDCs) has been linked to harmful effects in biota due to their widespread chemical persistence. In this paper, we report on the fabrication of electrospun polylactic acid (PLA) based nanofibers functionalized with TiO 2 nanoparticles. The PLA-based TiO 2 nanofibers were further stabilized with the incorporation of halloysite (HNT) particles. The nanofibers were fabricated in varied concentrations of HNT (5, 10, 15%), while TiO 2 was kept at 10% for all the prepared samples. The fabricated samples were evaluated for elimination of synthetic 17α-ethinylestradiol (EE2) hormone as a model EDC pollutant. By using combined adsorptive and photocatalytic processes, the as-prepared samples were evaluated in a continuous flow system under dark and UV-light irradiation for EE2 removal. The best-performing sample with an optimized concentration of PLA/TiO 2 /HNT (85, 10, 5%) was able to eliminate 71.6% of EE2 hormone under UV irradiation at a hormone concentration of 0.1 mg/L. The maximum removal capacity obtained was 1.26 mg/g in 2 h, which best fitted the pseudo-first-order kinetics model. The sample was further utilized for additional experiments by changing experimental parameters, such as contact time, solution pH, and flow rate. To elucidate the actual degradation of the EE2 hormone, LCMS analysis was carried out to monitor the formation of by-products, which indicated that EE2 was fragmented into different potentially benign molecules. Finally, the best-performing sample was utilized for ten cyclic runs under optimized conditions for which the sample maintained sufficiently high degradation without any loss in structural integrity. Overall, the results showed that the developed PLA/TiO 2 /HNT nanofibers have a high potential to target persistent organic pollutants. [Display omitted] • PLA-based nanofibers were functionalized with TiO 2 and HNT nanoparticles. • The as-prepared nanofibers were evaluated using ethinylestradiol hormone. • Elimination of EE2 by tandem synergistic adsorptive and photocatalysis processes. • Reusability of the fibers was determined after ten cyclic operations. • LCMS analysis was carried out to identify the formation of degraded byproducts. [ABSTRACT FROM AUTHOR]

Nanocellulose (NC), a one-dimensional nanomaterial, is considered a sustainable material for water and wastewater purification because of its promising hydrophilic surface and mechanical characteristics. In this regard, nanostructured membranes comprising NC and two-dimensional (2D) nanomaterials emerged as advanced membranes for efficient and sustainable water purification. This article critically reviews the recent progress on NC-2D nanostructured membranes for water and wastewater treatment. The review highlights the main techniques employed to fabricate NC-2D nanostructured membranes. The physicochemical properties, including hydrophilicity, percent porosity, surface roughness, structure, and mechanical and thermal stability, are summarized. The key performance indicators such as permeability, rejection, long operation stability, antifouling, and interaction mechanisms are thoroughly discussed to evaluate the role of NC and 2D nanomaterials. Finally, summary points and future development work are highlighted to overcome the challenges for potential practical applications. This review contributes to the design and development of advanced membranes to solve growing water pollution concerns in a sustainable manner. [Display omitted] [ABSTRACT FROM AUTHOR]

This work describes the preparation of a novel biopolymer hydrogel based on acid whey, cellulose derivatives and polyvinyl alcohol (PVA). The hydrogel was prepared and characterized with the aim of producing an environmentally-friendly soil amendment to increase water retention capacity of the soil. The findings showed considerable swelling properties of the hydrogels depending on the PVA content and crosslinking density. The samples with PVA in a concentration 2.5 % and 5 % were more rigid, the gel fraction increased with a subsequently decrease in their swelling capacity. The hydrogels crosslinked with 15 % of citric acid demonstrated a constant swelling ratio (SR) of around 500 % within 10 swelling/drying cycles. The hydrogels crosslinked with 10 % citric acid and supplemented with 1 % of PVA showed SR of 1000–1400 % caused by less crosslinked polymer network and increased pore volume for water uptake. It was found that hydrogel with a higher gel fraction had a stable structure. Supplementing PVA at 5 % extended the period of decomposition of the hydrogel material by almost 60 % in the soil environment and soil humidity was maintained for longer. Applying 2 % of the hydrogel 5PVA to soil increased the water retention capacity by 19 %. • An environmentally-friendly soil conditioner was prepared for sustainable agricultural applications. • The effect of polyvinyl alcohol on the swelling properties and biodegradability of the hydrogels was evaluated. • Addition of 5 % PVA extended the period of biodegradation of the hydrogel in soil by almost 60 %. • The results show the potential of acid whey to be a source of nutritive whey agents for plants. [ABSTRACT FROM AUTHOR]

Composite materials based on PLA have been studied in depth for many applications, including food packaging. This manuscript describes extensive research conducted on a biodegradable polymer (PLA), inorganic filler (CaCO 3), and polyester-based plasticizer (PEP, based on a copolymer of low-molecular-weight PLA and PEG) prepared under semi-industrial conditions, as applicable for the packaging of hot food. The properties of the composite were achieved by post-processing annealing, notably its thermal stability, thereby permitting contact of the material with hot food. The manner of processing was deemed suitable for deployment at an industrial scale, moreover, the thermal stability of the final product endured, evidencing its applicability for such packaging. Change in the morphology of the structure of the composite material depended on the composition and annealing process, as detailed herein. The effect of the post-production thermal annealing on the molecular weight of samples was studied using the gel permeation chromatography. The thermal properties of the composites were investigated by differential scanning calorimetry, dynamic mechanical analysis, and thermogravimetric analysis. The crystallinity was assessed using X-ray diffraction technique, while mechanical behavior was tested in relation to the given tensile properties, shape stability at high temperature, and permeability by the transmission rates of gas/water vapor. [Display omitted] • PLA composite with CaCO 3 and plasticizer was prepared under semi-industrial conditions with a post-processing annealing. • The properties of the composite depended on the morphology and volume fractions of the crystalline and amorphous regions. • The two additive components and given technological conditions lends shape stability to the composite. • The composite was suitable for contact with hot food or use as packaging for foodstuffs that are heated in microwave ovens. [ABSTRACT FROM AUTHOR]

This study describes the development of a renewable and biodegradable biopolymer-based hydrogel for application in agriculture and horticulture as a soil conditioning agent and for release of a nutrient or fertilizer. The novel product is based on a combination of cellulose derivatives (carboxymethylcellulose and hydroxyethylcellulose) cross-linked with citric acid, as tested at various concentrations, with acid whey as a medium for hydrogel synthesis in order to utilize the almost unusable by-product of the dairy industry. The water uptake of the hydrogel was evaluated by swelling tests under variations in pH, temperature and ion concentration. Its swelling capacity, water retention and biodegradability were investigated in soil to simulate real-world conditions, the latter being monitored by the production of carbon dioxide during the biodegradation process by gas chromatography. Changes in the chemical structure and morphology of the hydrogels during biodegradation were assessed using Fourier transform infrared spectroscopy and scanning electron microscopy. The ability of the hydrogel to hold and release fertilizers was studied with urea and KNO3 as model substances. The results not only demonstrate the potential of the hydrogel to enhance the quality of soil, but also how acid whey can be employed in the development of a soil conditioning agent and nutrient release products. [ABSTRACT FROM AUTHOR]

This study investigated the effect of natural antioxidants inherent to beetroot (Beta vulgaris var. Vulgaris) on the ageing of environmentally friendly plastics. Certain properties were examined in this context, comprising thermal, mechanical, and morphological properties. A visual evaluation of relevant changes in the given polymers (polylactide and polycaprolactone) was conducted during an ageing test in a UV chamber (45 °C, 70% humidity) for 720 h. The films were prepared by a casting process, in which samples with the extract of beetroot were additionally incorporated in a common filler (bentonite), this serving as a carrier for the extract. The results showed the effect of the incorporated antioxidant, which was added to stabilize the biodegradable films. Its efficiency during the ageing test in the polymers tended to exceed or be comparable to that of the reference sample. [ABSTRACT FROM AUTHOR]