Non-biodegradable Polymers Research Articles

Interrelation of macroscopic mechanical properties and molecular scale thermal relaxation of biodegradable and non-biodegradable polymers

Comparative analysis of macroscopic mechanical properties of a biodegradable polymer polypropylene carbonate (PPC) is carried out concerning two most commonly used, non-biodegradable synthetic polymers-high-density polyethylene (HDPE) and linear-low density polyethylene (LLDPE). Responses of the films of these polymers when subjected to mechanical and thermal stresses are analyzed. Response to tensile stress reveals the highest elongation at break (EB) in PPC films (396 ± 104 mm), compared to HDPE (26 ± 0.5 mm) and LLDPE (301 ± 143 mm), although the elastic modulus (YM) of PPC is around 50 ± 6 MPa, 3-fold lesser than LLDPE (YM = 153 ± 7 MPa) and 6-fold lesser than HDPE (YM = 305 ± 32 MPa). The plastic deformation response of PPC is intermediate to that of HDPE and LLDPE; initial strain softening is followed by strain hardening in LLDPE, a plateau region in PPC, and prolonged strain softening in HDPE. Crystalline domains in HDPE produce restriction on molecular motion. Crystallinity abruptly decreases by 70% in HDPE following a thermal quench, showing the possibility of free chain molecular mobility during plastic deformation. High correlation among Raman modes for all polymers reveals cooperative relaxation processes after thermal quench; C-C stretching modes and C-H bending, CH2wagging modes have Pearson's correlation coefficient 0.9. The integrated peak intensity and width of the C-C stretching Raman mode is 3-fold higher in PPC than HDPE after a thermal quench, showing enhanced molecular mobility and contributing modes in PPC. The peak width of this mode shows a strong negative correlation of -0.7 with the YM and a strong positive correlation of 0.6 with EB, showing that higher amorphicity leads to enhanced molecular mobility and EB at the cost of YM. This study reveals importance of molecular-scale response in governing the macroscopic properties of polymers.

Alternative and Emerging Mulch Technologies for Organic and Sustainable Agriculture in the United States: A Review

Plastic mulches made from nonbiodegradable polymers (e.g., polyethylene) provide an essential service in commercial horticultural production systems by enhancing crop productivity through weed suppression, soil moisture conservation, and moderating soil and canopy temperature conditions. Plastic mulches are particularly important in organic agriculture because weed management options are limited. Nevertheless, there is increasing concern about addressing the negative environmental impacts of plastic mulch waste. Soil-biodegradable plastic mulch (BDM) films that are designed to biodegrade in soils after incorporation are promising alternatives to nonbiodegradable plastic mulch. However, although the US organic standards technically permit the use of BDM films, no commercially available products meet National Organic Program (NOP) requirements for 100% biobased content and 90% degradation after 2 years following soil incorporation (7 Code of Federal Regulations, section 205.2). Other concerns about biodegradable film mulches include high perceived cost, esthetics, and uncertainties regarding the impacts of soil incorporation. New mulch technologies have emerged to diversify sustainable mulch options and overcome barriers associated with BDM film use in organic production. The objective of this study was to provide an overview of alternative and emerging mulch technologies, with an emphasis on biodegradable mulches, including water-based sprayable mulches such as hydromulch and foam mulch, and biobased agrotextiles. Information about how these mulch technologies contribute to organic and sustainable agriculture is provided, along with definitions, opportunities, challenges, and recommended areas for future research.

Repeated Mechanical Recycling of Biodegradable Polymers: PLA Exhibits Less Deterioration than PBAT/PLA Blend.

Biodegradable polymers have been extensively researched as alternatives to non-biodegradable fossil-based polymers. Although they reduce environmental impact, their production competes with land needed for food crops. Therefore, exploring their reuse and recycling is essential for enhancing their circular economy and sustainability. This study evaluated the recyclability of commercially available biodegradable polymers, poly (lactic acid) (PLA) and its blend with poly (butylene adipate co-terephthalate) (PBAT), across three cycles of mechanical recycling. Each cycle simulates plastic production, shelf-life, washing, and reprocessing stages. Samples were analysed after molding, ageing, and washing for each cycle using Differential Scanning Calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), tensile testing, and rheological analysis to track changes in crystallization, chemical structure, viscosity, and mechanical behaviors. Results indicated that both PLA and PBAT/PLA (55/45wt.%) blend showed a rise in crystallinity () due to the annealing effect of the ageing and washing. No changes in FTIR spectra and were detected after one recycling cycle, indicating stability. After three reprocessing cycles, second heating crystallinity rose from 2% to 13% for PLA and from 2% to 12% for PBAT/PLA (45 wt% PLA), indicating morphological changes from degradation and molecular weight reduction. Despite higher crystallinity and a more moderate decline in complex viscosity and storage modulus than PLA, PBAT/PLA showed reduced mechanical properties, with a 90% drop in elongation at break and nearly 50% in stress at break, highlighting the need for interventions to control PBAT degradation. PLA maintained strong mechanical properties, demonstrating its potential as a compostable recyclable material.

Excited State Bond Homolysis of Vanadium(V) Photocatalysts for Alkoxy Radical Generation.

Advancements in photocatalysis have transformed synthetic organic chemistry, using light as a powerful tool to drive selective chemical transformations. Recent approaches have focused on metal-halide ligand-to-metal charge transfer (LMCT) photoactivated bond homolysis reactions leveraged by earth-abundant elements to generate valuable synthons for radical-mediated cross-coupling reactions. Of recent utility, oxovanadium(V) LMCT photocatalysts exhibit selective alkoxy radical generation from aliphatic alcohols upon blue light (UVA) irradiation under mild conditions. The selective photochemical liberation of alkoxy radicals is valuable for applying late-stage fragmentation approaches in organic synthesis and depolymerization strategies for nonbiodegradable polymers. Steady-state and time-resolved spectroscopy were used to assign the electronic structure of three well-defined V(V) photocatalysts in their ground and excited states. We assign the excited state for this transformation at earth-abundant vanadium(V), interrogating the electronic structure using static UV-visible absorption, ultrafast transient absorption, and electron paramagnetic resonance spectroscopy coupled to computational approaches. These findings afford assignments of the short-lived excited state intermediates that dictate selective homolytic bond cleavage in metal alkoxides, illustrating the valuable insight gleaned from fundamental investigations of the molecular photochemistry responsible for light-escalated chemical transformations.

Materials based on biodegradable polymers chitosan/gelatin: a review of potential applications.

Increased mass manufacturing and the pervasive use of plastics in many facets of daily life have had detrimental effects on the environment. As a result, these worries heighten the possibility of climate change due to the carbon dioxide emissions from burning conventional, non-biodegradable polymers. Accordingly, biodegradable gelatin and chitosan polymers are being created as a sustainable substitute for non-biodegradable polymeric materials in various applications. Chitosan is the only naturally occurring cationic alkaline polysaccharide, a well-known edible polymer derived from chitin. The biological activities of chitosan, such as its antioxidant, anticancer, and antimicrobial qualities, have recently piqued the interest of researchers. Similarly, gelatin is a naturally occurring polymer derived from the hydrolytic breakdown of collagen protein and offers various medicinal advantages owing to its unique amino acid composition. In this review, we present an overview of recent studies focusing on applying chitosan and gelatin polymers in various fields. These include using gelatin and chitosan as food packaging, antioxidants and antimicrobial properties, properties encapsulating biologically active substances, tissue engineering, microencapsulation technology, water treatment, and drug delivery. This review emphasizes the significance of investigating sustainable options for non-biodegradable plastics. It showcases the diverse uses of gelatin and chitosan polymers in tackling environmental issues and driving progress across different industries.

Comparative degradation behavior of polybutylene succinate (PBS), used PBS, and PBS/Polyhydroxyalkanoates (PHA) blend fibers in compost and marine–sediment interfaces

Amid increasing concerns over microplastic pollution and the persistence of nonbiodegradable polymers in the ocean, this study evaluates the biodegradability of polybutylene succinate (PBS)-based fishing gear under different conditions: pristine PBS fibers, PBS fibers utilized in fishing (PBS_used), and PBS fibers blended with 10% polyhydroxyalkanoate (PHA). By simulating compost and marine–sediment interface environments with reference to ISO 14855 and ISO 19679 standards, respectively, we aimed not only to assess the degradation performance of these fibers but also to examine the physical and chemical property changes pre and postdegradation. PBS, PBS_used, and PBS/PHA (9:1) fibers exhibited degradation rates of 31.9%, 35.5%, and 39.5% in compost environments, and 20.3%, 22.1%, and 25.9% at the seawater–sediment interface, respectively. Through comprehensive physicochemical analyses involving molecular weight measurement, field emission–scanning electron microscope, Fourier transform infrared spectroscopy, tensile property evaluation, and thermogravimetric analysis, the degradation behavior of PBS-based fibers depending on the degradation environment was compared. This study suggests that PBS-based fishing gear can biodegrade under various conditions encountered in the actual fishing sector, thereby preventing ghost fishing and mitigating the issue of abandoned, lost, or otherwise discarded fishing gear.

Towards Sustainable Packaging Using Microbial Cellulose and Sugarcane (Saccharum officinarum L.) Bagasse.

The high consumption of packaging has led to a massive production of waste, especially in the form of nonbiodegradable polymers that are difficult to recycle. Microbial cellulose is considered a biodegradable, low-cost, useful, ecologically correct polymer that may be joined with other biomaterials to obtain novel characteristics and can, therefore, be used as a raw material to produce packaging. Bagasse, a waste rich in plant cellulose, can be reprocessed and used to produce and reinforce other materials. Based on these concepts, the aim of the current research was to design sustainable packaging material composed of bacterial cellulose (BC) and sugarcane bagasse (SCB), employing an innovative shredding and reconstitution method able to avoid biomass waste. This method enabled creating a uniform structure with a 0.10-cm constant thickness, classified as having high grammage. The developed materials, particularly the 0.7 BC/0.3 SCB [70% (w/w) BC plus 30% (w/w) SCB] composite, had considerable tensile strength (up to 46.22 MPa), which was nearly thrice that of SCB alone (17.43 MPa). Additionally, the sorption index of the 0.7 BC/0.3 SCB composite (235.85 ± 31.29 s) was approximately 300-times higher than that of SCB (0.78 ± 0.09 s). The packaging material was also submitted to other analytical tests to determine its physical and chemical characteristics, which indicated that it has excellent flexibility and can be folded 100 times without tearing. Its surface was explored via scanning electron microscopy, which revealed the presence of fibers measuring 83.18 nm in diameter (BC). Greater adherence after the reconstitution process and even a uniform distribution of SCB fibers in the BC matrix were observed, resulting in greater tear resistance than SCB in its pure form. The results demonstrated that the composite formed by BC and SCB is promising as a raw material for sustainable packaging, due to its resistance and uniformity.

Biodegradable Poly (L-Lactic acid) Fibrous Membrane with Ribbon-Structured Fibers and Ultrafine Nanofibers Enhances Air Filtration Performance.

Here, the poly (l-lactic acid) (PLLA) membrane with multi-structured networks (MSN) is successfully prepared by electrospinning technology for the first time. It is composed of micron-sized ribbon-structured fibers and ultrafine nanofibers with a diameter of tens of nanometers, and they are connected to form the new network structure. Thanks to the special fiber morphology and structure, the interception and electrostatic adsorption ability for against atmospheric particulate matter (PM) are significantly enhanced, and the resistance to airflow is reduced due to the "slip effect" caused by ultrafine nanofibers. The PLLA MSN membrane shows excellent filtration performance with ultra-high filtration efficiency (>99.9% for PM2.5 and >99.5% for PM0.3) and ultra-low pressure drop (≈20Pa). It has demonstrated filtration performance that even exceeds current non-biodegradable polymer materials, laying the foundation for future applications of biodegradable PLLA in the field of air filtration. In addition, this new structure also provides a new idea for optimizing the performance of other polymer materials.

Effect of UV-induced crosslink network structure on the properties of polylactic acid/polybutylene adipate terephthalate blend

Over the past few decades, biobased polylactic acid (PLA) has emerged as the most promising option to replace some of the fossil-based and nonbiodegradable polymers due to environmental concerns. In this study, a flexible polymer, polybutylene adipate terephthalate (PBAT) was blended with PLA to improve the toughness and flexibility of PLA, and the PLA/PBAT blend was further UV-induced to form crosslink structure. The results show that the flexibility and toughness of PLA could be significantly enhanced when PBAT was introduced, and the compatibility of PLA and PBAT could be enhanced by the development of a crosslink structure. Especially, the elongation at break and unnotched impact strength of ABT-UV30 (PLA/PBAT/triallyisocyanurate (TAIC) exposed to ultraviolet (UV) light for 30 min) was increased to 3.9 and 8.4 times of neat PLA. The glass transition temperature (Tg) of PLA was increased from 63.4 to 72.9 °C as the radiation duration was prolonged to 60 min. The melting point temperature of PBAT was also increased gradually until it eventually coincided with that of PLA. The thermalgravimetric analyzer thermograms show that a moderate amount of UV radiation can improve the thermal stability of the sample while an excessive amount of UV radiation can reduce the degradation temperature.

Construction of Tough Hydrogel Cross-Linked via Ionic Interaction by Protection Effect of Hydrophobic Domains.

Most hydrogels have poor mechanical properties, severely limiting their potential applications, and numerous approaches have been introduced to fabricate more robust and durable examples. However, these systems consist of nonbiodegradable polymers which limit their application in tissue engineering. Herein, we focus on the fabrication and investigate the influence of hydrophobic segments on ionic cross-linking properties for the construction of a tough, biodegradable hydrogel. A biodegradable, poly(γ-glutamic acid) polymer conjugated with a hydrophobic amino acid, l-phenylalanine ethyl ester (Phe), together with an ionic cross-linking group, alendronic acid (Aln) resulting in γ-PGA-Aln-Phe, was initially synthesized. Rheological assessments through time sweep oscillation testing revealed that the presence of hydrophobic domains accelerated gelation. Comparing gels with and without hydrophobic domains, the compressive strength of γ-PGA-Aln-Phe was found to be six times higher and exhibited longer stability properties in ethylenediaminetetraacetic acid solution, lasting for up to a month. Significantly, the contribution of the hydrophobic domains to the mechanical strength and stability of ionic cross-linking properties of the gel was found to be the dominant factor for the fabrication of a tough hydrogel. As a result, this study provides a new strategy for mechanical enhancement and preserves ionic cross-linked sites by the addition of hydrophobic domains. The development of tough, biodegradable hydrogels reported herein will open up new possibilities for applications in the field of biomaterials.

Xanthan gum/Guar gum-based 3D-printed scaffolds for wound healing: production, characterization, and biocompatibility screening

Biodegradable and eco-sustainable medical devices represent an urgent need to face up to the increasing pollution associated to plastic device wastes. The present study aimed to develop semisolid extruded 3D (SSE-3D)-printed medical devices using mixtures of Xanthan gum (XG) and Guar gum (GG) as a green alternative to non-biodegradable synthetic polymers. The final purpose is to prepare biocompatible, biodegradable, and sterilizable implantable scaffolds with pro-regenerative and wound-healing properties. Inks prepared with 12 % w/v XG/GG (50:50) and blended with citric (CA), succinic (SA), or tartaric acid (TA) possessed suitable rheological profiles and allowed the 3D printing of porous scaffolds with high precision and structural control. Steam-heat sterilization triggered the cross-linking through ester bond formation (confirmed by ATR-FTIR and CP/MAS 13C-NMR). The scaffold crosslinked with SA had reproducible porosity (SEM and pycnometer), maintained the initial shape after 7 days swelling in PBS pH 7.4 and subjected to compression cycles (texturometer analysis), showed good cytocompatibility and hemocompatibility, and promoted angiogenesis in ovo in a chorioallantoic membrane model, evidencing tissue integration without toxicity. Furthermore, these scaffolds attenuated collagenase activity by trapping divalent ions (Ca2+ and Zn2+). Hence, by coupling angiogenic and anticollagenase activity, XG/GG scaffolds are promising candidates for wound healing and pro-regenerative applications.

Characterizations on a GRAS Electrospun Lipid-Polymer Composite Loaded with Tetrahydrocurcumin.

Electrospun/sprayed fiber films and nanoparticles were broadly studied as encapsulation techniques for bioactive compounds. Nevertheless, many of them involved using non-volatile toxic solvents or non-biodegradable polymers that were not suitable for oral consumption, thus rather limiting their application. In this research, a novel electrospun lipid-polymer composite (ELPC) was fabricated with whole generally recognized as safe (GRAS) materials including gelatin, medium chain triglyceride (MCT) and lecithin. A water-insoluble bioactive compound, tetrahydrocurcumin (TC), was encapsulated in the ELPC to enhance its delivery. Confocal laser scanning microscopy (CLSM) was utilized to examine the morphology of this ELPC and found that it was in a status between electrospun fibers and electrosprayed particles. It was able to form self-assembled emulsions (droplets visualized by CLSM) to deliver active compounds. In addition, this gelatin-based ELPC self-assembled emulsion was able to form a special emulsion gel. CLSM observation of this gel displayed that the lipophilic contents of the ELPC were encapsulated within the cluster of the hydrophilic gelatin gel network. The FTIR spectrum of the TC-loaded ELPC did not show the fingerprint pattern of crystalline TC, while it displayed the aliphatic hydrocarbon stretches from MCT and lecithin. The dissolution experiment demonstrated a relatively linear release profile of TC from the ELPC. The lipid digestion assay displayed a rapid digestion of triglycerides in the first 3-6 min, with a high extent of lipolysis. A Caco-2 intestinal monolayer transport study was performed. The ELPC delivered more TC in the upward direction than downwards. MTT study results did not report cytotoxicity for both pure TC and the ELPC-encapsulated TC under 15 μg/mL. Caco-2 cellular uptake was visualized by CLSM and semi-quantified to estimate the accumulation rate of TC in the cells over time.

Valorisation of Agricultural Residue Bio-Mass Date Palm Fibre in Dry-Blended Polycaprolactone (PCL) Bio-Composites for Sustainable Packaging Applications

Abstract Purpose This study experimentally developed and characterised dry-blended Polycaprolactone (PCL)/date palm fibre biodegradable composites for sustainable packaging applications. Date palm fibres are collected from date palm trees as by-products or waste materials. They will be valorised in bio-composite application to promote fibre-based sustainable packaging items over their non-biodegradable synthetic polymer based conventional packaging products. In the dry-blending process, fibre and polymer are mixed with a shear mixer, while, in a melt-blending process, an extruder is used to extrude fibre/polymer blends after applying heating and high shear pressure to melt and mix polymer with fibres. Dry-blending process offers many comparative advantages, such as less equipment, steps, cost, process degradation, energy consumption and hence, lower harmful environmental emissions; while, a proper fibre/polymer mixing is a challenge and it needs to be achieved properly in this process. Therefore, it is important to understand the effects of dry-blending process on manufacturing of PCL/date palm fibre bio-composites for packaging applications, before promoting the dry-blending as a suitable alternative to the melt-blending process. Methods Short chopped fibres were grinded as powders and dry-blended at a ratio of (0 − 10%) (w/w) with PCL polymer using hand and a shear mixer for 30 min, following a compression moulding process to produce bio-composite samples. Tensile, water contact angle, SEM, TGA, DSC and DMA tests and analysis were conducted. The dry-blended PCL/date palm fibre composites’ properties were compared with reported melt-blended samples’ results found in literature. Results Dry-blended samples showed an increase in tensile modulus values (up-to 20%) with fibre inclusion and these values were found close to the melt-blended samples in the literature. Tensile strength and strain values were reduced which could be related to the poor fibre/polymer interface. Fibre addition affected the thermal, thermo-mechanical and crystallisation processes in PCL polymer matrix. Conclusion Dry-blending is capable of producing bio-composites with a very comparable properties to melt-blended counterparts, although a more details study is needed to conduct in future. The results of this study, could be used carefully to design dry-blended PCL/date palm fibre bio-composites for possible packaging applications. The irregular fibre distribution in dry-blended samples could be improved in different ways which should be investigated in future. Graphical Abstract

Production of Polyhydroxyalkanoates by Bacteria Isolated from the Gut of the Larvae of African Palm Weevil (Rhynchophorus phoenicis)

The indispensability of plastics in everyday life has made the search for environmentally sustainable alternatives to these nonbiodegradable polymers more earnest. Polyhydroxyalkanoates (PHAs) are a class of biodegradable, biocompatible plastics comprising of polyesters of R-hydroxyalkanoic acids. They are accumulated intracellularly as polymeric granules upon cultivating several gram-positive and gram-negative bacteria in nutrient-limiting conditions. Hence, the objective of this paper is to investigate the production of polyhydroxyalkanoates by bacteria isolated from the gut of the larvae of African Palm Weevil (Rhynchophorus phoenicis) using agricultural-waste substrates. Two bacteria isolated from the gut of polystyrene-fed R. phoenicis larvae were utilized for the production of PHA using brewery waste, bean hull, cassava peel and palm pith, as substrates. The bacteria were identified as Lysinibacillus macriodes and Pantoea dispersa. Isolate P. dispersa accumulated PHAs ranging from 0.89- 1.44 g/L from agricultural waste and 4.24 g/L from glucose, equivalent to 30.8%-46.7% and 71.9% yields respectively. L. macrolides, accumulated PHAs ranging from 1.11-1.50 g/L from agricultural waste and 3.89 g/L from glucose equivalent to 40.4%-48.1% and 69.2% yields respectively. The isolates can be desirable candidates for PHAs production under optimized conditions.

Bio-Polyethylene and Polyethylene Biocomposites: An Alternative toward a Sustainable Future.

Polyethylene (PE), a highly prevalent non-biodegradable polymer in the field of plastics, presents a waste management issue. To alleviate this issue, bio-based PE (bio-PE), derived from renewable resources like corn and sugarcane, offers an environmentally friendly alternative. This review discusses various production methods of bio-PE, including fermentation, gasification, and catalytic conversion of biomass. Interestingly, the bio-PE production volumes and market are expanding due to the growing environmental concerns and regulatory pressures. Additionally, the production of PE and bio-PE biocomposites using agricultural waste as filler materials, highlights the growing demand for sustainable alternatives to conventional plastics. According to previous studies, addition of ≈50% defibrillated corn and abaca fibers into bio-PE matrix and a compatibilizer, results in the highest Young's modulus of 4.61 and 5.81GPa, respectively. These biocomposites have potential applications in automotive, building construction, and furniture industries. Moreover, the advancement made in abiotic and biotic degradation of PE and PE biocomposites is elucidated to address their environmental impacts. Finally, the paper concludes with insights into the opportunities, challenges, and future perspectives in the sustainable production and utilization of PE and bio-PE biocomposites. In summary, production of PE and bio-PE biocomposites can contribute to a cleaner and sustainable future.

Synthesis of eco-friendly multifunctional dextran microbeads for multiplexed assays

There has been an increasing demand for simultaneous detection of multiple analytes in one sample. Microbead-based platforms have been developed for multiplexed assays. However, most of the microbeads are made of non-biodegradable synthetic polymers, leading to environmental and human health concerns. In this study, we developed an environmentally friendly dextran microbeads as a new type of multi-analyte assay platform. Biodegradable dextran was utilized as the primary material. Highly uniform magnetic dextran microspheres were successfully synthesized using the Shirasu porous glass (SPG) membrane emulsification technique. To enhance the amount of surface functional groups for ligand conjugation, we coated the dextran microbeads with a layer of dendrimers via a simple electrostatic adsorption process. Subsequently, a unique and efficient click chemistry coupling technique was developed for the fluorescence encoding of the microspheres, enabling multiplexed detection. The dextran microbeads were tested for 3-plex cytokine analysis, and exhibited excellent biocompatibility, stable coding signals, low background noise and high sensitivity.

Cellulose Nanofiber as Mask/Personal Protective Equipment Surface Agent for Enhanced Anti-Bacterial Performance

The utilization of face-covering masks as an extended form of personal protective equipment has led to exponential waste measures during the COVID-19 pandemic, with estimations of up to 7200 tons of medical-type waste daily. A primary cause of this waste is surgical layered disposable masks that are constructed by melt-blown nonwovens usually made of non-biodegradable thermoplastic polymers like polypropylene. To increase widespread sustainable options to the public, commercialized or do-it-yourself-based fabric masks serve as a solution, but their resistance to harmful molecules is less than that of the medical-grade masks due to the fabric structure that leaves space for penetration. This project examines a water-soluble dispersion composed of cellulose nanofiber and polyvinyl alcohol, as a spray agent capable of treating the mask fabric surface to promote protection and sustainability against harmful aerosol particles. Cellulose nanofiber spray is also low-cost and biocompatible and could allow multi-use through home laundering. Polyvinyl alcohol was chosen as the water-soluble bonding system and polymer matrix to effectively adhere cellulose nanofiber onto the mask surface. This project follows the biomimic concept of dragonfly wings having uneven nanopillar surfaces to trap and rip bacterial membranes, as the spray decreases the water droplet contact angle on fabric surface, resulting in an increase in adhesion for incident bacteria and/or viruses.

Optimizing slurry preparation for improved mechanical and physical characteristics of nata de coco-based edible packaging

Conventional plastic food packaging, primarily composed of non-biodegradable synthetic polymers, has been a significant environmental concern. To address this issue, this study proposes the use of nata de coco (NDC) as an eco-friendly, edible alternative for food packaging, aiming to optimize NDC-based packaging to enhance both food safety and packaging quality. The study also seeks to improve the solubility of NDC edible packaging when mixed with food. To achieve this, NDC was processed into a slurry using different preparation techniques: kitchen blender (B), blender-hand mixer (BM), blender-sieve (BS), and blender-food chopper (BFC). Furthermore, the BFC treatment achieved the highest water solubility at 96.85% and demonstrated a tensile strength 19.35% greater than the B treatment. In assessing the practical application, the shelf-life of red ginger powder packaged in NDC sachets was estimated. Impressively, the highest shelf-life was recorded at 8 °C, lasting 331.74 days. The development of this bacterial-resistant, edible, sustainable packaging offers a viable substitute for the environmental effects of traditional plastic packaging.

Dynamically bonded cellulose nanocrystal hydrogels: Structure, rheology and fire prevention performance

Flame retardant composite hydrogels offer many advantages over conventional flame retardants, such as high water-retention capacity, enhanced fire resistance, and mechanical tunability. Herein, we developed flame-retardant dynamic covalent hydrogels using wood-derived cellulose nanocrystals (CNCs) crosslinked with boronate ester bonds, addressing environmental and health issues associated with the presence of non-biodegradable synthetic polymer and/or inorganic nanoparticle components in the existing systems. Our rheological investigation shows a liquid-to-soft-solid transition of CNC dispersions with tunable network elasticity ranging between ≈ 0.2 kPa to 3.5 kPa and an immediate self-healing ability. Coating pine wood with these hydrogels delayed ignition by about 30 s compared to native wood, and achieved a remarkable limiting oxygen index of 64.5 %. Also, the increased borax content of the gels was found to decrease and delay the first peak of the heat release rate up to 40 s, causing an increase in the fire retardancy index by 277 %. We correlate the microstructure and rheological behavior with the fire prevention mechanisms for the rational design of sustainable fire-retardant materials, and the results showcased a circular use of plant-based dynamic gels to prevent wood fires, even after drying- a feature lacking in conventional hydrogels.

Epoxidized Olive Oil as a Sustainable Plasticizer to Polylactic Acid

The consumption of synthetic, non-biodegradable polymer plastics has drawn attention to growing environmental concerns, prompting the development of other materials, particularly bio-based materials. Biopolymer-based biocomposite materials are plasticized to improve their ductility. In this study, five distinct weight ratios of biopolymers (PA/EOO), 90 wt.%, 80 wt.%, 70 wt.%, 60 wt.%, and 50 wt.% were employed as plasticizers for poly-lactic acid (PA) in a fluid molding process. The mechanical, thermal stability, and morphological characteristics of the blends were each examined using a viscometer measurement (R.V.), tensile properties (TP), a scanning electron microscope (SEM), and a thermogravimetric analyzer (TGA). All composite materials (PA/EOO) mixtures show notable improvements in mechanical properties and excellent thermal stability when compared to pure PA. The maximum PA/EOO elongation at break was around 213 % when the PA/EOO mix was 80 wt %. Attractive morphological results from composite materials (PA/EOO) blends showed that EOO was compatible with PA and that the resulting composite material (PA/EOO) was thought to be an ecologically beneficial mixture because it contained vegetable oil.