Studies on methylcellulose/pectin/montmorillonite nanocomposite films and their application possibilities

Ecologically sustainable biodegradable polymers fabricated from banana peel pectin reinforced with silver zeolite nanoparticles (Ag/zeolite NPs)

In the present investigation, the formulation and thorough assessment of biodegradable composite films were conducted, utilizing pectin extracted from banana peel in conjunction with synthesized silver zeolite nanoparticles. The evaluation of physical properties, microstructural investigation, mechanical characteristics, and barrier properties was done providing valuable insights into various attributes of the film. The amalgamation of silver zeolite nanoparticles with the extracted pectin from banana peel results in biodegradable composite films exhibiting distinct physical, mechanical, barrier, and thermal properties. Optimal mechanical characteristics were recorded in films containing 0.75 % Ag-ZY, demonstrating a tensile strength of 43.22 ± 0.12 MPa and a Young's modulus of 829.61 ± 0.71 MPa, while the elongation at break exhibited a decline as the filler concentration escalated. The barrier properties were enhanced with the integration of Ag-ZY. At a concentration of 0.75 % Ag-ZY, the water vapor transmission rate (WVTR) and water vapor permeability (WVP) reached their lowest measurements. The thermal stability increased, with the glass transition temperature (Tg) increasing from 70.31 °C in the baseline film to 135.53 °C when 0.75 % Ag-ZY was added. These results elucidate that the incorporation of 0.75 % silver zeolite nanoparticles into banana peel pectin films significantly improved mechanical, barrier, and thermal properties.

Enhanced ocular retention and intraocular pressure-lowering efficacy of hydrophobic microspheres for glaucoma treatment

Glaucoma eye drops often suffer from low bioavailability due to rapid drug release and poor ocular retention. This study aimed to address these challenges by developing betaxolol hydrochloride-loaded mesoporous silica polyacrylic resin microspheres (BH@MCM-41 MPs) and comparing their safety, ocular retention, and intraocular pressure (IOP)-lowering efficacy with previously reported betaxolol hydrochloride-loaded montmorillonite polyacrylic resin microspheres (BH@MMT MPs), BH solution, and commercially available Betoptic®. Both BH@MCM-41 MPs and BH@MMT MPs demonstrated sustained drug release over 12 h and good biocompatibility. The impact of physicochemical particle characteristics on micro-interactions with tear film mucins and corneal epithelial cells was investigated. BH@MCM-41 MPs exhibited significantly higher mucin-binding capacity compared to BH@MMT MPs, with approximately double the binding at mucin concentrations over 0.4 mg·mL-1. Rose Bengal assays indicated a more hydrophobic surface for BH@MCM-41 MPs, with a binding constant (K) of 88.51, compared to 69.84 for BH@MMT MPs. In addition, these positively charged microspheres demonstrated prolonged precorneal retention, with BH@MCM-41 MPs achieving 58.17 minutes, compared to 44.49 minutes for BH@MMT MPs. Tear pharmacokinetics further confirmed the extended precorneal residence time of these formulations. Ex vivo corneal permeation studies revealed that the hydrophobic surface of BH@MCM-41 MPs enhanced interaction with corneal epithelial cells, promoting drug release and permeation. The area under the IOP reduction curve (AUC0-36h) for BH@MCM-41 MPs was 1.2-fold greater than for BH@MMT MPs, and significantly higher than for the BH solution and Betoptic. These findings suggest that BH@MCM-41 MPs offer enhanced efficacy for sustained glaucoma treatment through improving precorneal retention.

Structural and physicochemical properties of porous starch effected by different microwave involved stages under enzymatic hydrolysis

Microwave-assisted enzymatic hydrolysis is an effective method to shorten the preparation time of porous starch. This study aims to investigate the effect of microwave treatment before/during/after enzymatic hydrolysis on the properties of porous starch. The results showed that the physicochemical properties of the porous starch obtained by microwave-assisted enzymatic hydrolysis were improved. All the samples were typical A-type crystal shapes, and the basic internal structures were the same. Among the samples, the porous starch obtained by microwave treatment during enzymatic hydrolysis (MDEPS) had the largest pore area, the highest number of pores, and significantly improved adsorption capacity, with oil and water absorption rates increased from 84.32 % to 103.1 % and 115 % to 170 % (P < 0.05), respectively. These results demonstrated that microwave treatment during enzymatic hydrolysis has great potential as a green and efficient method for preparing porous starch.

Unleashing the potential of water-insoluble Cu2+-crosslinked chitosan nanocomposite film for enhanced antibacterial and flame-retardant properties

Chitosan (CS) has received widespread attention in various fields due to its excellent antimicrobial properties, inherent biodegradability and biocompatibility. However, the water swelling property of chitosan films reduces their performance and becomes a major obstacle for their practical application. Herein, we develop a water-insoluble montmorillonite/chitosan nanocomposite film (CS/MMT-Cu) with anti-bacterial and fire-retardant properties via Cu2+-crosslinking technique. Cu2+ ions are coordinated with amino and hydroxyl groups to crosslink the chitosan chains and bind to the montmorillonite (MMT) via electrostatic forces. As a result, the content of MMT has a significant effect on the mechanical and flame-retardant properties of CS/MMT-Cu films, in which the maximum tensile strength and finite oxygen index are 30.6 MPa and 40.5 %, respectively. In addition, the CS/MMT-Cu films exhibit good anti-bacterial properties. Overall, the prepared CS/MMT-Cu films have a broad application prospect in various fields, such as flame-retardant material, packaging and coatings.

Preparation, characterization, antimicrobial evaluation, and grape preservation applications of polyvinyl alcohol/gelatin composite films containing zinc oxide@quaternized chitosan nanoparticles

This study employed a precipitation method to synthesize zinc oxide@quaternised chitosan nanoparticles (ZnO@QAC NPs) containing different concentrations of zinc oxide, namely ZnO@QAC-2, ZnO@QAC-4, and ZnO@QAC-6. Subsequently, these nanoparticles were incorporated into matrices consisting of gelatine (Gn) and polyvinyl alcohol (PVA) separately, which were prepared by casting to form a biodegradable film. We assessed the physicochemical properties of ZnO@QAC NPs and physicochemical characteristics, antioxidant properties, antimicrobial activity and grape preservation efficacy of the film. Compared to the control group, the films showed a reduction in water vapor permeability by >9.38 %, an increase in tensile strength by over 51.95 %, over 70 % scavenging of ABTS free radicals, and good biocompatibility. Additionally, the antimicrobial activity of the films containing ZnO@QAC-6 increased by 37.6 %. In the grape preservation experiment, the weight loss of grapes wrapped in ZnO@QAC-2 film was reduced by 40.13 % on day 15 compared to unwrapped grapes. These results demonstrate that ZnO@QAC/PVA/Gn films have considerable potential for food packaging applications.

Sustainable Doped Carbon Dots as Antioxidant and Nanocarrier for Therapeutic Cargos

Aside from their fluorescence sensing capabilities, carbon dots doped with heteroatoms show tremendous promise as nanocarriers for medicinal compounds and as antioxidants. We present a method for producing carbon dots from chitosan and lemon extract (CLCDs) using a one-step hydrothermal coupling synthesis. The as-synthesized CLCDs exhibited remarkable colloidal stability, antioxidant behavior, cytocompatibility, and nanocarrier for drug molecules. The nanoparticles was analyzed using advanced techniques such as Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), fluorescence spectroscopy, electron paramagnetic resonance (EPR) spectroscopy, and transmission electron microscopy (TEM) to determine the precise composition of their surface. In order to evaluate the drug transport properties of CLCDs, their surfaces were further modified with anticancer drug compounds. The drug release behavior was studied against physiologically simulated fluids and at different pH environments showing better delayed response in acidic condition. The plausible mechanistic pathways have been confirmed after fitting the results into Higuchi, Weibull and Korsmeyer-Peppas models. The goodness of fit was more than 95% for the Korsmeyer-Peppas model, with the release mechanism supported by anomalous transport. Moreover, the radical scavenging activity of CLCDs was also confirmed at low levels (1 mg/mL) which could be inferred > 85% efficacy against mostly employed testing agents (DPPH, ABTS, and hydroxyl radicals). Thus, the prepared CLCDs could be used as suitable nanovector in payload delivery with prominent antioxidant activity and low toxicity against living cell lines.

Essential oil-loaded biopolymeric particles on food industry and packaging: A review

Essential oils (EOs) are liquid extracts derived from various parts of herbal or medicinal plants. They are widely accepted in food packaging due to their bioactive components, which exhibit remarkable antioxidant and antimicrobial properties against various pathogenic and food spoilage microorganisms. However, the functional efficacy of EOs is hindered by the high volatility of their bioactive compounds, leading to rapid release. Combining biopolymers with EOs forms a complex network within the polymeric matrix, reducing the volatility of EOs, controlling their release, and enhancing thermal and mechanical stability, favoring their application in food packaging or processing industries. This study presents a comprehensive overview of techniques used to encapsulate EOs, the natural polymers employed to load EOs, and the functional properties of EOs-loaded biopolymeric particles, along with their potential antioxidant and antimicrobial benefits. Additionally, a thorough discussion is provided on the widespread application of EOs-loaded biopolymers in the food industries. However, research on their utilization in confectionery processing, such as biscuits, chocolates, and others, remains limited. Further studies can be conducted to explore and expand the applications of EOs-loaded biopolymeric particles in food processing industries.

Silicon-containing nanomedicine and biomaterials: materials chemistry, multi-dimensional design, and biomedical application

The invention of silica-based bioactive glass in the late 1960s has sparked significant interest in exploring a wide range of silicon-containing biomaterials from the macroscale to the nanoscale. Over the past few decades, these biomaterials have been extensively explored for their potential in diverse biomedical applications, considering their remarkable bioactivity, excellent biocompatibility, facile surface functionalization, controllable synthesis, etc. However, to expedite the clinical translation and the unexpected utilization of silicon-composed nanomedicine and biomaterials, it is highly desirable to achieve a thorough comprehension of their characteristics and biological effects from an overall perspective. In this review, we provide a comprehensive discussion on the state-of-the-art progress of silicon-composed biomaterials, including their classification, characteristics, fabrication methods, and versatile biomedical applications. Additionally, we highlight the multi-dimensional design of both pure and hybrid silicon-composed nanomedicine and biomaterials and their intrinsic biological effects and interactions with biological systems. Their extensive biomedical applications span from drug delivery and bioimaging to therapeutic interventions and regenerative medicine, showcasing the significance of their rational design and fabrication to meet specific requirements and optimize their theranostic performance. Additionally, we offer insights into the future prospects and potential challenges regarding silicon-composed nanomedicine and biomaterials. By shedding light on these exciting research advances, we aspire to foster further progress in the biomedical field and drive the development of innovative silicon-composed nanomedicine and biomaterials with transformative applications in biomedicine.

TiO2 loaded on glycidol functionalized poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) nanobiocomposite film for photocatalytic and antibacterial activities

The rapid acceleration of industrialization and urbanization has exacerbated water pollution, which is primarily caused by the presence of highly toxic, non-biodegradable contaminants in industrial waste and effluents. In response to this urgent issue, a novel nanobiocomposite film with titanium dioxide (TiO2) loaded onto a poly(3-hydroxybutyrate-co-18 mol% 3-hydroxyhexanoate) (18PHBH) matrix was developed to serve as an effective dual-function material with photocatalytic and antibacterial properties. Through Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR), Diffuse reflectance ultraviolet-visible (DRUV-Vis), Scanning Electron Microscope (SEM), and X-ray diffraction (XRD) analyses, the physicochemical properties of the TiO2/Gly/18PHBH nanobiocomposite film were exhaustively characterized, revealing effective TiO2 loading and uniform distribution on the film's surface. The film exhibited extraordinary photocatalytic degradation of methylene blue (MB) dye, with the 5TiO2/Gly/18PHBH film demonstrating the greatest efficiency. In addition, antibacterial testing revealed that the film was effective against 99.8 % of Staphylococcus aureus and 96.9 % of Pseudomonas aeruginosa. These results demonstrate the potential of polyhydroxyalkanoate-based films as exceptional nanoparticle matrices and position the 5TiO2/Gly/18PHBH film as a versatile candidate for applications in photocatalysis and antibacterial interventions, providing innovative solutions to critical environmental challenges.

Fabrication and characterization of waste fish scale-derived gelatin/sodium alginate/carvacrol loaded ZIF-8 nanoparticles composite films with sustained antibacterial activity for active food packaging

An environmental-friendly composite films containing waste fish scale-derived gelatin (FSG), sodium alginate (SA) and carvacrol loaded ZIF-8 (CV@ZIF-8) nanoparticles were designed and fabricated to develop active food packaging materials capable of sustained antibacterial activity. The microstructure and physicochemical properties of the FSG/SA/CV@ZIF-8 composite films were investigated. The incorporation of CV@ZIF-8 into FSG/SA matrix significantly enhanced the UV-light blocking and the elongation at break, improved water resistance and reduced water vapor permeability, and improved the thermal stability of composite film. The FSG/SA/CV@ZIF-8 film not only exhibited strong antioxidant activity with DPPH radical scavenging rate of 92.35 %, but also showed the satisfactory and long-acting antibacterial ability against E. coli and S. aureus due to slow release of CV from composite film. Strawberry preservation experiment revealed that FSG/SA/CV@ZIF-8 film decelerated the texture deterioration and retarded the growth of spoilage microorganism, resulting in the prolonged shelf-life of 8 days under ambient condition, indicating its promising application prospect in food preservation packaging.

Preparation of a pH-responsive chitosan-montmorillonite-nitrogen-doped carbon quantum dots nanocarrier for attenuating doxorubicin limitations in cancer therapy

Despite its widespread usage as a chemotherapy drug in cancer treatment, doxorubicin (DOX) has limitations such as short in vivo circulation time, low solubility, and poor permeability. In this regard, a pH-responsive chitosan (CS)- montmorillonite (MMT)- nitrogen-doped carbon quantum dots (NCQDs) nanocomposite was first developed, loaded with DOX, and then incorporated into a double emulsion to further develop the sustained release. The incorporated NCQDs into the CS-MMT hydrogel exhibited enhanced loading and entrapment efficiencies. The presence of NCQDs nanoparticles in the CS-MMT hydrogel also resulted in an extended pH-responsive release of DOX over a period of 96 h compared to that of CS-MMT-DOX nanocarriers at pH 5.4. Based on the Korsmeyer-Peppas model, there was a controlled DOX release at pH 5.4, while no diffusion was observed at pH 7.4, indicating fewer side effects. MTT assay showed that the cytotoxicity of DOX-loaded CS-MMT-NCQDs hydrogel nanocomposite was significantly higher than those of free DOX (p < 0.001) and CS-MMT-NCQDs (p < 0.001) on MCF-7 cells. Flow cytometry results demonstrated that a higher apoptosis induction achieved after incorporating NCQDs nanoparticles into CS-MMT-DOX nanocarrier. These findings suggest that the DOX-loaded nanocomposite is a promising candidate for the targeted treatment of cancer cells.

Pharmaceutical and drug delivery applications of pectin and its modified nanocomposites

Due to their natural availability, biocompatibility, biodegradability, nontoxicity, flexibility, as well as improved structural and functional characteristics, pectin and pectin-based nanocomposites have become an interesting area of numerous researchers. Pectin is a polysaccharide that comes from plants and is used in a variety of products. The significance of pectin polysaccharide and its modified nanocomposites in a number of applications has been shown in numerous reviews. On their uses in pharmaceutical and medication delivery, there are, however, few review publications. The majority of papers on pectin polysaccharide do not structure their explanations of drug distribution and medicinal application. The biological application of pectin nanocomposite is also explained in this review, along with a recent publication. As a result, the goal of this review was in-depth analysis to summarize biological application of pectin and its modified nanocomposites. Due to their exceptional physicochemical and biological characteristics, pectin and its nanocomposites are remarkable materials for medicinal applications. In addition to enhancing the immune system, controlling blood cholesterol, and other things, they have been shown to have anticancer, antidiabetic, antioxidant, anti-inflammatory, immunomodulatory, and antibacterial properties. Because of their biocompatibility and properties that allow for regulated release, they have also received a lot of interest as drug carriers in targeted drug delivery systems. They have been used to administer medications to treat cancer, inflammation, pain, Alzheimer's, bacteria, and relax muscles. This review found that pectin and its derivatives have better drug delivery efficiency and are viable candidates for a wide range of medicinal applications. It has been advised to conduct further research on the subject of toxicity in order to produce commercial formulations that can serve as both therapeutic agents and drug carriers.

Preparation and characterization of polyvinyl alcohol-piperic acid composite film for potential food packaging applications

Piperic acid, a natural product-based derivative, has been used with polyvinyl alcohol for the first time to form polymer composite films for its suitable modification in physicochemical and antimicrobial properties. Initially, piperic acid was synthesized from piperine, a natural alkaloid extracted from black pepper (Piper nigrum). The solvent casting method was used for the synthesis of PVA-piperic acid composite films. The films were characterized by various spectral and microscopic techniques like UV-visible spectroscopy, FT-IR, SEM, XRD, and TGA. The antibacterial activity was shown by these polymer composites of piperic acid against Gram-positive Staphylococcus aureus (S. aureus-ATCC8738P) and Gram-negative Escherichia coli (E. coli-ATCC8739) was worthwhile. The antifungal activity of the composite films was evaluated by the food poisoning technique. Percentage mycelial growth inhibition was found maximum against Fusarium solani than Aspergillus and Penicillium. The water vapour and oxygen barrier properties are enhanced with the incorporation of increased content of piperic acid. Also, enhancement in the tensile strength of PVA/PA composite film was observed, while elongation at break shows decreased trend with the addition of piperic acid. The surface properties of polymer composite films were determined by contact angle measurements. Contact angle shows a considerable increase in these films when compared to virgin PVA film. It was increased by 56.1° in 15 mL composite film containing a higher concentration of piperic acid than virgin PVA.

Transdermal therapeutic system: Study of cellulose nanocrystals influenced methylcellulose-chitosan bionanocomposites

Over the past few years, there is a drive toward the fabrication and application of bio-based non-cytotoxic drug carriers. Cellulose nanocrystals (CNCs) have gotten immense research attention as a promising bioderived material in the biomedical field due to its remarkable properties. The delivery of analgesic and anti-inflammatory drug, ketorolac tromethamine (KT) by transdermal route is stipulated herewith to fabricate suitable transdermal therapeutic systems. We have synthesized CNCs from jute fibers and aim to develop a non-cytotoxic polymer-based bionanocomposites (BNCs) transdermal patch, formulated with methylcellulose (MC), chitosan (CH), along with exploration of CNCs for sustained delivery of KT, where CNCs act as nanofiller and elegant nanocarrier. CNCs reinforced MCCH blends were prepared via the solvent evaporation technique. The chemical structure, morphology, and thermal stability of the prepared bionanocomposites formulations were studied by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), TGA, DSC, DMA, and SEM. The In vitro drug release studies were executed using Franz diffusion cells. The BNC patches showed in-vitro cytocompatibility and the drug release study revealed that BNC containing 1 wt% CNCs presented the best-sustained drug release profile. The bioderived CNCs appear to enhance the BNCs drug's bioavailability, which could have a broad prospect for TDD applications.

Composites of cellulose nanocrystals in combination with either cellulose nanofibril or carboxymethylcellulose as functional packaging films

Cellulose nanocrystals (CNC) were mixed with either cellulose nanofibril (CNF) or carboxymethylcellulose (CMC) in variable proportions (0/100, 20/80, 40/60, 50/50, 60/40, 80/20 and 100/0) to obtain cast films with acceptable barrier and mechanical properties as replacements for food packaging plastics. Both CNF and CMC improved tensile strength, elongation, UV opacity, air resistance, hydrophobicity (WCA-water contact angle), water vapor transmission rate (WVTR) and oxygen impermeability in pure CNC. WVTR and oxygen permeability were strongly dependent on relative humidity (RH). Interestingly, the greatest effect on WVTR was observed at RH = 90% in films containing CMC in proportions above 60%. CMC- and CNF-containing films had oxygen impermeability up to an RH level of 80% and 60%, respectively. The previous effects were confirmed by food packaging simulation tests, where CMC-containing films proved the best performers. The composite films studied were biodegradable-which constitutes a major environmental related advantage-to an extent proportional to their content in CMC or CNF.

Preparation of the Heterogeneous Saponified Poly(Vinyl Alcohol)/Poly(Methyl Methacrylate-Methallyl Alcohol) Blend Film

For the first time, poly(vinyl alcohol) (PVA)/poly(methyl methacrylate-methallyl alcohol) (P(MMA-MAA)) (9:1, 7:3, 5:5) blend films were made simultaneously using the saponification method in a heterogeneous medium from poly(vinyl acetate) (PVAc)/poly(methyl methacrylate) (PMMA) (9:1, 7:3, 5:5) blend films, respectively. The surface morphology and characteristics of the films were investigated using optical microscopy (OM), atomic force microscopy (AFM), X-ray diffractometer (XRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Moreover, the effect of the PVAc content on the degree of saponification (DS) of the PVAc/PMMA films were evaluated and revealed that the obtained DS value increased with the increase in PVAc content in the PVAc/PMMA blend films. According to the OM results, the saponified films demonstrated increased surface roughness compared with the unsaponified films. The AFM images revealed morphological variation among the saponified PVAc/PMMA blend films with different mass ratios of 9:1, 7:3, and 5:5. According to the DSC and TGA results, all blend film types exhibited higher thermal property after the saponification treatment. The XRD and FTIR results confirmed the conversion of the PVAc/PMMA into PVA/P(MMA-MAA) films. Thus, our present work may give a new idea for making blend film as promising medical material with significant surface properties based on hydrophilic/hydrophobic strategy.

Novel Biocomposite Films Based on High Methoxyl Pectin Reinforced with Zeolite Y for Food Packaging Applications

Pectin is a natural biopolymer with broad applications in the food industry and it is suitable to prepare edible films to prolong food shelf-life. However, the main limitation of pectin-based films is their poor mechanical and barrier properties. Zeolite Y is a hydrophobic clay that can be used as film reinforcement material to improve its physicochemical and mechanical properties. In this work, the influence of high methoxyl citrus and apple pectin on physicochemical properties of biopolymer films modified with zeolite Y (0.05–0.2 wt%) was investigated. The films were characterized by FTIR, TGA, WAXD, mechanical analysis, and water vapor permeability analysis, and a potential film application is presented. The WAXD and FTIR analysis demonstrated that the strongest interaction between pectin chains and zeolite Y occurred when citrus high methylated pectin was used. Adding 0.2 wt% of zeolite Y into citrus high methylated pectin matrix enhanced the tensile strength by 66%, thermal stability by 13%, and water vapor barrier by 54%. In addition, fruit shelf-life test was performed, where strawberries were sealed in film. It was shown that sealed strawberries maintained a better color and healthy appearance than the control treatment after 7 days at 10 °C. This study enabled the development of biocomposite films with improved properties for potential application in food packaging.

The Use of Montmorillonite (MMT) in Food Nanocomposites: Methods of Incorporation, Characterization of MMT/Polymer Nanocomposites and Main Consequences in the Properties

BACKGROUND

The clay Montmorillonite (MMT) is among the nanofillers more frequently used in food packaging. The uniform dispersion of nanoparticles in polymers confers considerable improvement of mechanical, thermal, optical, and/or barrier properties in polymer/clay nanocomposites.

OBJECTIVE

The aim is to ascertain the state of the art of the use of MMT for packaging purposes, with special emphasis on food applications.

METHODS

A literature review was carried out through recent papers and patents that focused on the incorporation of MMT in polymers.

RESULTS

This review emphasizes the interaction of MMT with polymers and their levels of incorporation in the nanocomposites. This work also highlights the analytical methodologies used for the characterization of the polymer/clay nanocomposites and the main consequences of the fillers in the properties of nanocomposites. Challenges remain about increasing the compatibility between clays and biopolymers to promote their utilization in food packaging. New strategies for immobilization of oxides, enzymes, essential oils, and other bioactive compounds are needed.

CONCLUSION

MMT-based composite materials are promising to be used in intelligent and active packaging.

Preparation and characterization of carboxymethyl cellulose-based composite films reinforced by cellulose nanocrystals derived from pea hull waste for food packaging applications

Pea hull is a renewable, readily available and abundant agricultural waste whose high-value utilization deserves more attentions. This work aimed at the isolation of cellulose nanocrystals (CNC) from pea hull and evaluation its reinforcement capability for carboxymethyl cellulose (CMC) film. The obtained CNC displayed needle-like shapes with length of 81-286 nm, diameter of 8-21 nm, aspect ratio of 16 and crystallinity index of 0.77. The effects of CNC content on the morphologies, optical, mechanical, water vapor barrier and thermal properties of CMC/CNC films were investigated. SEM images showed that the CNC was evenly distributed in the CMC matrix to form homogenous films when the content of CNC was ≤5 wt%. The CMC/CNC composite films showed improved UV barrier, mechanical strength, water vapor barrier and thermal stability. Compared with pure CMC film, an increase of 50.8% in tensile strength and a decrease of 53.4% in water vapor permeability were observed for 5 wt% CNC-reinforced composite film. Furthermore, 5 wt% CNC-reinforced composite film was used for red chilies packaging, which is very effective at reducing weight loss and maintaining vitamin C compared with uncoated red chilies. These results indicated that the CMC/CNC composite film may have promising application potential as edible food packaging material.

Preparation and physicochemical properties of antioxidant chitosan ascorbate/methylcellulose composite films

Polysaccharide-based biodegradable films have been considered as the promising candidates for food packaging industry instead of petroleum-based packaging materials. Here, we reported a class of edible composite films based on chitosan ascorbate and methylcellulose prepared by mixing different ratios (1,0, 4:1, 2:1, 1:1, 1:2, 1:4, and 0:1) of the biopolymers using the casting technique. Their physicochemical properties as well as the DPPH radical scavenging ability and reducing power were investigated. All physicochemical properties and antioxidant activities were significantly affected by the chitosan ascorbate/methylcellulose ratio in the matrix. The increases in tensile strength and elongation at break values, maximum decomposition temperatures, whitish index, compactness, moisture content, and a reduction in water vapor permeability were observed as the proportion of methylcellulose increased in the matrix. But the composite films containing a greater proportion of chitosan ascorbate exhibited the better barrier properties against UV-vis light and the stronger DPPH radical scavenging effect and reducing power. The chitosan ascorbate/methylcellulose composite films with interesting physicochemical properties and strong antioxidant action showed the potential value as biodegradable and edible biomaterials for food packaging.

The Study of Zeolitic Imidazolate Framework (ZIF-8) Doped Polyvinyl Alcohol/Starch/Methyl Cellulose Blend Film

ZIF-8 nanoparticle-doped polyvinyl alcohol (PVA)-S-MC films were prepared via casting method. The effect of different concentrations of ZIF-8 on the physical properties and structural characterization of the films were investigated. The results indicated that ZIF-8 could increase the water resistance and mechanical property of the membrane. Through FTIR, scanning electron microscope (SEM), atomic force microscope (AFM), and TGA analysis, it was found that ZIF-8 changed the phenomenon of macromolecule agglomeration and improved the thermal stability of the membrane. The breathable behavior of the film was also studied through oxygen permeability and water vapor permeability analysis. The result illustrated that the breathability of the film improved significantly by adding ZIF-8. The maximum reached when the weight ratio of ZIF-8 was 0.01 wt %. The property expands the application of PVA/starch blend film in the postharvest technology of fruits and vegetables.

Safely Dissolvable and Healable Active Packaging Films Based on Alginate and Pectin

Extensive usage of long-lasting petroleum based plastics for short-lived application such as packaging has raised concerns regarding their role in environmental pollution. In this research, we have developed active, healable, and safely dissolvable alginate-pectin based biocomposites that have potential applications in food packaging. The morphological study revealed the rough surface of these biocomposite films. Tensile properties indicated that the fabricated samples have mechanical properties in the range of commercially available packaging films while possessing excellent healing efficiency. Biocomposite films exhibited higher hydrophobicity properties compared to neat alginate films. Thermal analysis indicated that crosslinked biocomposite samples possess higher thermal stability in temperatures below 120 °C, while antibacterial analysis against E. coli and S. aureus revealed the antibacterial properties of the prepared samples against different bacteria. The fabricated biodegradable multi-functional biocomposite films possess various imperative properties, making them ideal for utilization as packaging material.

A Review of the Synthesis and Applications of Polymer–Nanoclay Composites

Recent advancements in material technologies have promoted the development of various preparation strategies and applications of novel polymer–nanoclay composites. Innovative synthesis pathways have resulted in novel polymer–nanoclay composites with improved properties, which have been successfully incorporated in diverse fields such as aerospace, automobile, construction, petroleum, biomedical and wastewater treatment. These composites are recognized as promising advanced materials due to their superior properties, such as enhanced density, strength, relatively large surface areas, high elastic modulus, flame retardancy, and thermomechanical/optoelectronic/magnetic properties. The primary focus of this review is to deliver an up-to-date overview of polymer–nanoclay composites along with their synthesis routes and applications. The discussion highlights potential future directions for this emerging field of research.

Synthesis of methylcellulose/cellulose nano-crystals nanocomposites: Material properties and study of sustained release of ketorolac tromethamine

Non-toxic nanocomposites based bio-films obtained from methylcellulose (MC) can reduce environmental problems associated with synthetic polymers. A new facile route for the isolation of cellulose nano-crystals (CNC) from jute waste is successfully utilized here. The fabrication of CNC reinforced MC nanocomposites by film casting technique and the studies of the effect of CNC on the properties of the MC based nanocomposites have been reported. The synthesized nanocomposites have shown improved UV resistance, mechanical, barrier, and thermal properties. FTIR results established the physicochemical compatibility between the drug, MC and CNC in nanocomposites. In vitro permeation studies performed by using Franz diffusion cell revealed diffusion mediated sustained drug release from the devices due to the presence of interaction between MC and CNC through H-bonding, electrostatic interaction between the hydrophilic polymer/CNC chains with the drug and the formation of tortuous path. The nanocomposites can be used for edible packaging and transdermal drug delivery.

Effect of Morphology and Size of Halloysite Nanotubes on Functional Pectin Bionanocomposites for Food Packaging Applications

Pectin bionanocomposite films filled with various concentrations of two different types of halloysite nanotubes were prepared and characterized in this study as potential films for food packaging applications. The two types of halloysite nanotubes were long and thin (patch) (200-30 000 nm length) and short and stubby (Matauri Bay) (50-3000 nm length) with different morphological, physical, and dispersibility properties. Both matrix (pectin) and reinforcer (halloysite nanotubes) used in this study are considered as biocompatible, natural, and low-cost materials. Various characterization tests including Fourier transform infrared spectroscopy, field emission scanning electron microscopy, release kinetics, contact angle, and dynamic mechanical analysis were performed to evaluate the performance of the pectin films. Exceptional thermal, tensile, and contact angle properties have been achieved for films reinforced by patch halloysite nanotubes due to the patchy and lengthy nature of these tubes, which form a bird nest structure in the pectin matrix. Matauri Bay halloysite nanotubes were dispersed uniformly and individually in the matrix in low and even high halloysite nanotube concentrations. Furthermore, salicylic acid as a biocidal agent was encapsulated in the halloysite nanotubes lumen to control its release kinetics. On this basis, halloysite nanotubes/salicylic acid hybrids were dispersed into the pectin matrix to develop functional biofilms with antimicrobial properties that can be extended over time. Results revealed that shorter nanotubes (Matauri Bay) had better ability for the encapsulation of salicylic acid into their lumen, while patchy structure and longer tubes of patch halloysite nanotubes made the encapsulation process more difficult, as they might need more time and energy to be fully loaded by salicylic acid. Moreover, antimicrobial activity of the films against four different strains of Gram-positive and Gram-negative bacteria indicated the effective antimicrobial properties of pectin/halloysite functionalized films and their potential to be used for food packaging applications.