Renewable and recyclable polymeric materials for food packaging: A new open special issue in Materials

“Renewable and Recyclable Polymeric Materials for Food Packaging” is a new open Special Issue of Materials that will publish original and review papers on new scientific and applied research, and the articles it contains will make a contribution to the discovery and understanding of biodegradable and recyclable materials, their functional properties, characterization and applications

Recent advancements in the application of new monomers and membrane modification techniques for the fabrication of thin film composite membranes: A review

Thin film composite (TFC) membranes have been experiencing significant modifications recently aiming to improve their structure, properties and separation efficiency. One of the promising modifications to tailor the membranes more efficient is changing the materials used. m-phenylene diamine (MPD), piperazine (PIP), and trimesoyl chloride (TMC) are the most common monomers used to fabricate TFC membranes. Recent studies have introduced several alternatives to these traditional monomers showing significant contribution of these monomers to the physicochemical properties of the membranes (e.g., surface roughness, hydrophilicity, cross-linking density, chemical structure) as well as membranes\u27 separation efficiency. Emergence of more favorable functional groups such as carboxylic and amine groups due to the new materials integration facilitates the polymerization process and is beneficial to the membrane properties. Here, a critical review on the new interfacial polymerization monomers applied for reverse osmosis (RO) and nanofiltration (NF) membranes fabrication is presented. The membrane molecular structure and fabrication mechanism are investigated in details. This is followed by a review of the recent surface modification methods including grafting, coating and additive incorporating into the thin layer of membranes. The application of alternative monomers to MPD, PIP and TMC are investigated and the benefits of using these monomers or co-monomers are discussed

Harnessing the power of neural networks for the investigation of solar-driven membrane distillation systems under the dynamic operation mode

Accurate modeling of solar-driven direct contact membrane distillation systems (DCMD) can enhance the commercialization of these promising systems. However, the existing dynamic mathematical models for predicting the performance of these systems are complex and computationally expensive. This is due to the intermittent nature of solar energy and complex heat/mass transfer of different components of solar-driven DCMD systems (solar collectors, MD modules and storage tanks). This study applies a machine learning-based approach to model the dynamic nature of a solar-driven DCMD system for the first time. A small-scale rig was designed and fabricated to experimentally assess the performance of the system over 20 days. The predictive capabilities of two neural network models: multilayer perceptron (MLP) and long short-term memory (LSTM) were then comprehensively examined to predict the permeate flux, efficiency and gain-output-ratio (GOR). The results showed that both models can efficiently predict the dynamic performance of solar-driven DCMD systems, where MLP outperformed the LSTM model overall, especially in the prediction of efficiency. Additionally, it was indicated that the accuracy of the models for the prediction of GOR can be significantly improved by increasing the size of the dataset

Acute Severe Pancreatitis in Pregnancy Masquerading as Partial Hemolysis Elevated Liver enzymes Low Platelet (HELLP) Syndrome

Introduction: Acute severe pancreatitis may result in biochemical abnormalities resembling those seen in Hemolysis Elevated Liver enzymes Low Platelet (HELLP) Syndrome. Case Presentation: A 17-year-old female with 27 weeks of gestation presented mild acute pancreatitis. Based on the criteria of persistent Systemic Inflammatory Response Syndrome (SIRS) she subsequently developed severe pancreatitis. Bilirubin 2.2 mg/dL, lactate dehydrogenase 2171 IU/L and platelet of 53000 mm3 after 48 hours of the onset of pain, also indicated the possibility of partial HELLP syndrome. However, the results of the differential diagnosis ruled out the presence of Disseminated Intravascular Coagulation (DIC), Thrombotic Thrombocytopenic Purpura (TTP), Systemic Lupus Erythematosus (SLE) and Anti phospholipids syndrome. We terminated her pregnancy due to the above-mentioned diagnoses and postponed the cholecystectomy. Conclusions: Termination of pregnancy was performed as it would save the patient’s life in either deteriorated acute severe pancreatitis or HELLP. Keywords: Pancreatitis; Syndrome; Pregnanc

Experimental investigation of temperature polarisation by capturing the temperature profile development over DCMD membranes

Temperature polarisation (TP) is a major drawback limiting the global acceptance of membrane distillation (MD) technology. TP is typically quantified using a dimensionless index known as Temperature Polarisation Coefficient (TPC). TPC has significant limitations, whereby it cannot be used to compare different MD configurations or design conditions, nor to analyse the TP phenomenon along the membrane. In this research, the temperature profile over and along a lengthy DCMD membrane has been measured under various operational conditions, where its impact on TP has been explored for the first time. A specialised DCMD membrane cell was manufactured to capture temperature profiles, both along and over the membrane surfaces, using miniature thermocouples. The effects of flow rate and feed temperature were investigated on the temperature profiles. The results showed that the extent of TP was not constant along the membrane, and that the temperature profile was not symmetrical across the feed and permeate side, predominantly due to the effects of the inlet and outlet on the flow. The TPC value calculated using the conventional method was not able to accurately reflect the TP phenomenon along the membrane, indicating TPC to be an ineffective tool to study TP along the membrane

Thermo-Responsive Hydrophilic Support for Polyamide Thin-Film Composite Membranes with Competitive Nanofiltration Performance

Poly(N-isopropylacrylamide) (PNIPAAm) was introduced into a polyethylene terephthalate (PET) nonwoven fabric to develop novel support for polyamide (PA) thin-film composite (TFC) membranes without using a microporous support layer. First, temperature-responsive PNIPAAm hydrogel was prepared by reactive pore-filling to adjust the pore size of non-woven fabric, creating hydrophilic support. The developed PET-based support was then used to fabricate PA TFC membranes via interfacial polymerization. SEM–EDX and AFM results confirmed the successful fabrication of hydrogel-integrated non-woven fabric and PA TFC membranes. The newly developed PA TFC membrane demonstrated an average water permeability of 1 L/m2 h bar, and an NaCl rejection of 47.0% at a low operating pressure of 1 bar. The thermo-responsive property of the prepared membrane was studied by measuring the water contact angle (WCA) below and above the lower critical solution temperature (LCST) of the PNIPAAm hydrogel. Results proved the thermo-responsive behavior of the prepared hydrogel-filled PET-supported PA TFC membrane and the ability to tune the membrane flux by changing the operating temperature was confirmed. Overall, this study provides a novel method to fabricate TFC membranes and helps to better understand the influence of the support layer on the separation performance of TFC membranes

Thermo-responsive hydrophilic support for polyamide thin-film composite membranes with competitive nanofiltration performance

Poly(N-isopropylacrylamide) (PNIPAAm) was introduced into a polyethylene terephthalate (PET) nonwoven fabric to develop novel support for polyamide (PA) thin-film composite (TFC) membranes without using a microporous support layer. First, temperature-responsive PNIPAAm hydrogel was prepared by reactive pore-filling to adjust the pore size of non-woven fabric, creating hydrophilic support. The developed PET-based support was then used to fabricate PA TFC membranes via interfacial polymerization. SEM–EDX and AFM results confirmed the successful fabrication of hydrogel-integrated non-woven fabric and PA TFC membranes. The newly developed PA TFC membrane demonstrated an average water permeability of 1 L/m2 h bar, and an NaCl rejection of 47.0 % at a low operating pressure of 1 bar. The thermo-responsive property of the prepared membrane was studied by measuring the water contact angle (WCA) below and above the lower critical solution temperature (LCST) of the PNIPAAm hydrogel. Results proved the thermo-responsive behavior of the prepared hydrogel-filled PET-supported PA TFC membrane and the ability to tune the membrane flux by changing the operating temperature was confirmed. Overall, this study provides a novel method to fabricate TFC membranes and helps to better understand the influence of the support layer on the separation performance of TFC membranes

Green synthesis of nanomaterials for smart biopolymer packaging: Challenges and outlooks

There are several physical and chemical methods for synthesizing nanomaterials, while the most appropriate techniques involve using green chemistry and eco-friendly material. Recently, green synthesized materials for different applications have gained attention as a result of their environmental friendliness and cost-effectiveness. Applying green synthesized nanoparticles (NPS) in food packaging has been extensively investigated. Biopolymers require filler to enhance the optical, barrier, thermal, antimicrobial, and mechanical properties of packaging. Biopolymer packaging incorporated with green synthesized NPs is expected to simultaneously enhance performance while reducing environmental damage. The current review article focuses on biopolymer films with bio (green)-synthesized nanomaterials and their effectiveness in reducing the negative environmental implications of synthetic packaging. It also covers the general concepts of green synthesis of NPs, their production methods, their performance, and characterization, and discusses the potential, performance and recent developments of bio-nanocomposite films/coatings in biodegradable food packaging. Recent reports and trends provide more insight into the impact of green synthesized nanomaterials on food packaging. Graphical Abstract: [Figure not available: see fulltext.]

Encapsulation of orange peel oil in biopolymeric nanocomposites to control its release under different conditions

Orange peel oil (OPO) is one of the most common flavorings used in the food industry, but it is volatile under environmental conditions (the presence of light, oxygen, humidity, and high temperatures). Encapsulation by biopolymer nanocomposites is a suitable and novel strategy to improve the bioavailability and stability of OPO and its controlled release. In this study, we investigated the release profile of OPO from freeze-dried optimized nanocomposite powders as a function of pH (3, 7, 11) and temperature (30, 60, and 90 °C), and within a simulated salivary system. Finally, its release kinetics modelling was performed using experimental models. The encapsulation efficiency of OPO within the powders, along with the morphology and size of the particles, were also evaluated by an atomic force microscopy (AFM) analysis. The results showed that the encapsulation efficiency was in the range of 70–88%, and the nanoscale size of the particles was confirmed by AFM. The release profile showed that the lowest and the highest release rates were observed at the temperatures of 30 and 90 °C and in the pH values of 3 and 11, respectively, for all three samples. The Higuchi model provided the best model fitting of the experimental data for the OPO release of all the samples. In general, the OPO encapsulates prepared in this study showed promising characteristics for food flavoring applications. These results suggest that the encapsulation of OPO may be useful for controlling its flavor release under different conditions and during cooking

Tuning the physicochemical, structural, and antimicrobial attributes of whey-based poly (L-Lactic Acid) (PLLA) films by Chitosan Nanoparticles

Recently, the research and innovation to produce raw materials from microbial processes has gained much attention due to their economic and environmental impacts. Lactic acid is a very important microbial product due to its wide application in the food, pharmaceutical, cosmetic, and chemical industries. In the current study, poly (L-lactic acid) (PLLA) was produced by the ring opening polymerization (ROP) technique of L-lactic acid recovered from whey fermentation, and was used for the production of nanocomposites films reinforced with chitosan nanoparticles (CNPs) (average diameter ca. 100–200 nm). Three different CNPs concentrations, namely 1, 3, and 5% w/w, were tested, and their influence on the physical, mechanical, thermal, antibacterial and structural attributes of PLLA film was assessed. The results showed that the addition of CNPs up to 3% caused a significant improvement in water vapor permeability, appearance, tensile strength and elongation at break. The antibacterial properties of nanocomposites followed a dose-depended pattern as a result of CNPs addition. Therefore, the best inhibitory effects on Escherichia coli and Staphylococcus aureus was made by the addition of 5% of CNPs and lower dosages slightly affected the growth of pathogens or didn\u27t cause any inhibitory effects (in 1% of CNPs). It can be concluded that the incorporation of CNPs into the PLLA matrix allows to improve the structural, thermal, physical, mechanical and antibacterial properties of the polymer, generating promising systems for food packaging and biomedical applications