Bio-based Nanocomposite Films Research Articles

Physicochemical and optical activity of chitosan based ternary nanocomposites for food packaging applications

Chitosan (CS)-based ternary bionanocomposite materials have applications in the food packaging industry owing to their excellent properties. We fabricated chitosan/polyvinyl alcohol/graphene oxide (CS/PVA/GO) ternary bionanocomposites for food packaging using an environmentally friendly approach involving solution casting and solvent evaporation method. The physiochemical characteristics of the prepared ternary bionanocomposite films were elucidated using FTIR, Raman, XRD, TGA, DSC, FE-SEM, UV–visible, PL, and CD analysis. The viability assay revealed that the bio-based nanocomposite films are superior to native CS and PVA films. Water uptake and porosity of bionanocomposite films were evaluated. Tomatoes (Solanum lycopersicum) were used to evaluate the shelf-life-enhancing capability of the CS/PVA/GO composite. The results indicate that the biocompatible and eco-friendly CS/PVA/GO bionanocomposites are promising for food packaging applications.

Promising nanocomposites for food packaging based on cellulose – PCL films reinforced by using ZnO nanoparticles in an ionic liquid

The fact that most composites consist of polluting synthetic materials has prompted a search for biodegradable replacements based on cellulose fibers and polycaprolactone as potential packaging materials. In this work, we developed a green, efficient approach to rendering hydrophobic polycaprolactone (PCL) compatible with hydrophilic cellulose fibers by using an ionic liquid as a nanowelding agent in the presence of zinc oxide nanoparticles (ZnONPs). Transparent biobased nanocomposite films were thus directly obtained by in situ ring-opening polymerization (ROP) of ε-caprolactone (CL) monomers onto the dissolved cellulose matrix by using the ionic liquid 1-ethyl-3-methylimidazolium acetate ([EMIM]Ac). [EMIM]Ac and ZnONPs were efficiently catalyzed ε-caprolactone ROP under mild conditions. Cellulose-grafted PCL nanocomposite films were obtained by adding variable amounts of CL and ZnONPs to the cellulose matrix. The maximum grafting of 40% was achieved by using 5▒wt% ZnONPs and 70% CL. FTIR spectra confirmed the presence of PCL in the nanocomposites. Also, FE-SEM revealed uniform dispersion of ZnONPs and PCL in the regenerated cellulose matrix, and trapping of nanoparticles in nanofibrils after the cellulose matrix was regenerated. X-ray diffraction (XRD) spectra showed a decreased apparent crystallinity and crystallite size. The XRD results also confirmed that the crystal properties of the nanocomposite films and an all-cellulose composite (ACC) were almost identical. The mechanical, barrier and optical properties of the nanocomposite films were significantly better than those of the ACC film by effect of the incorporation of ZnONPs and PCL especially with 5▒wt% ZnONPs and 70% CL). The nanocomposite films exhibited acceptable antioxidant activity and UV-light barrier properties, so they hold promise for used in food packaging. Nanocomposite films are in fact multifunctional materials with the potential for use in cellulose-based food packaging by virtue of their being transparent and bio-based, and possessing very good water vapor and oxygen barrier properties.

Multifunctional pectin films based on mussel-inspired modified 2D Ag nanosheets for long-lasting antibacterial and enhanced barrier properties

Two-dimensional (2D) silver (Ag) nanosheets are ideal fillers to improve the barrier and antimicrobial properties of bio-based nanocomposite films for food packaging due to their high aspect ratio features and superior bactericidal activity. However, the nano-Ag directly added to the matrix is prone to aggregation, which will weaken its effect. In this study, Ag nanosheets were surface non-covalently functionalized with polydopamine (PDA) formed by dopamine oxidative self-polymerization. The PDA modification improved the dispersibility and biocompatibility of the nanosheets in pectin matrixes and immobilized them, delaying their release rate. The potential of the prepared pectin-based nanocomposite film in food packaging was investigated. Results showed that the composite film containing PDA-modified Ag nanosheets (PDA@Ag) had superior UV resistance and mechanical properties, a more hydrophobic surface with a water contact angle close to 90°. Compared with pure pectin film, the barrier capacity of the film to both water vapor and oxygen was significantly improved. It also exhibited excellent bactericidal efficiency against E. coli and S. aureus. When applied to Agaricus bisporus, the film effectively protected them from UV light, oxygen and microorganisms, thus delaying browning and spoilage, maintaining their texture, color and nutrients, and extended their freshness period up to 6 days.

Bioproduced Polymers Self-Assemble with Graphene Oxide into Nanocomposite Films with Enhanced Mechanical Performance.

Graphene oxide (GO) has recently been highlighted as a promising multipurpose two-dimensional material. However, free-standing graphene oxide films suffer from poor strength and flexibility, which limits scaling-up of production and lifetime structural robustness in applications. Inspired by the relationship between the organic and inorganic components of the hierarchical structure of nacre found in mollusk shells, we have fabricated self-assembled, layered graphene-based composite films. The organic phase of our composite is produced via environmentally friendly and economical methods based on bacterial production of γ-poly(glutamic acid) (PGA). Composite films made of GO, PGA, and divalent cations (Ca2+) were prepared through a slow solvent evaporation method at ambient temperature, resulting in a nacre-like layered structure. These biobased nanocomposite films showed impressive mechanical properties, which resulted from a synergistic combination of hydrogen bonding with the bacterially produced PGA and ionic bonding with calcium ions (Ca2+). The GO/PGA/Ca2+ composite films possessed a high strength of 150 ± 51.9 MPa and a high Young’s modulus of 21.4 ± 8.7 GPa, which represents an increase of 120% and over 70% with respect to pure GO films. We provide rational design strategies for the production of graphene-based films with improved mechanical performance, which can be applied in filtration purification of wastewater in the paper, food, beverage, pigment, and pharmaceuticals industries, as well as for manufacturing of functional membranes and surface coatings.

Green preparation of lignin nanoparticles in an aqueous hydrotropic solution and application in biobased nanocomposite films

Abstract Lignin nanoparticles (LNPs) from lignocellulosic biomass are expected to become promising basic building blocks for various applications in the development of multifunctional nanocomposites. Facile green preparation of LNPs and their application in polyvinyl alcohol (PVA) composite films were studied in this paper. LNPs were produced by performing fractionation of wheat straws at less than 80 °C with a recyclable hydrotropic, aqueous p-toluene sulfonic acid (p-TsOH). The dissolved lignin could be simply separated as LNPs by diluting the spent liquor (SL) to below the minimal hydrotropic concentration (MHC) of 11.5%. The resulting LPNs exhibited an oblate spheroid morphology and a uniform particle size distribution. After introducing the available LNPs into the PVA matrix at 6% loading, the nanocomposite products could block 100 and 95% of UV light at 315 and 400 nm, respectively, and exhibited 80% antioxidant activity. In addition, the respective maximum TS and TM were 59.7 MPa and 2.07 GPa, respectively, which were increases of approximately 36 and 104% compared with those of pure PVA film. The LNPs/PVA nanocomposite films displayed improved UV resistance, mechanical properties, thermal stability and antioxidant activity and could be used as additional multifunctional agents in the fields of biodegradable plastics, tissue engineering and UV-protective biobased materials.

Antibacterial bionanocomposite films based on CaSO4-crosslinked alginate and zinc oxide nanoparticles

Abstract Antibacterial bionanocomposite films (BNCFs) were successfully developed using CaSO4-crosslinked alginate and zinc oxide (ZnO) nanoparticles. The alginate film crosslinked with 1% (w/w) CaSO4 resulted in an increase in thickness (96.64 ± 6.15 μm) and tensile strength (35.15 ± 1.65 MPa), but decreased elongation at break (4.72 ± 0.69%) and water solubility (55.73 ± 1.51%) compared to the pure alginate film (89.00 μm; 24.7 MPa; 8.33%; 78.14%). Incorporation of ZnO into the BNCFs resulted in enhanced mechanical and UV barrier properties. The tensile strength of the BNCF-2.0 (containing 2% ZnO nanoparticles; w/w based on alginate) was 42.23 ± 4.65 MPa, whereas its elongation at break decreased to 2.75 ± 0.53%. BNCF-2.0 also exhibited strong UV-light barrier properties with a slight decrease in transparency. In addition, the BNCFs were effective against both Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria, demonstrating potential as antibacterial bio-based nanocomposite films for food packaging applications.

Barrier and antimicrobial properties of PVA films incorporated with ZnO nanoparticles and stearic acid

The barrier properties of a polymer film is very important for application as packaging material. Moreover, packaging materials with antimicrobial properties give advantages to prolong the shelf life of perishable foodstuff. Polyvinyl alcohol (PVA) is a water-soluble polymer, which has good oxygen barrier properties, but this depends on the humidity, as PVA is sensitive to moisture. The purpose of this study was to assess the characterization of bio-based nanocomposite films of PVA with the addition of ZnO nanoparticles and stearic acid. Bionanocomposite films were prepared by PVA dissolving in distilled and a range of ZnO nanoparticle formulations (and/or stearic acid) was added. Response Surface Methodology data analysis showed all response models qualified as good models with adequate presision (greater than 4). Result revealed that the addition of ZnO nanoparticles and/or stearic acid can reduce the water vapor transmission rate of the resulting film, lower light transmission, as well as results in antimicrobial properties.

Preparation, Characterization and Antibacterial Activity Investigation of Hydrocolloids Based Irish Moss/ZnO/CuO Bio-based Nanocomposite Films

Natural hydrocolloids Irish moss (IM) based ternary bio-based nanocomposite films (BBNCFs), reinforced with ZnO nanorods and foliated CuO were prepared through co-precipitation method. The morphologies and structures of the nanocomposite were characterized by Fourier Transform Infrared Spectroscopy analysis, Scanning Electron Microscopy, Energy-Dispersive X-Ray Spectroscopy and X-Ray Diffraction. Their antibacterial activities were studied using Gram-negative Escherichia coli (E. coli, PTCC 1330) by the plate count method. The nanocomposite films exhibited characteristic antibacterial activity. The synergistic outcome of combined use of more than one antibacterial agent is reflected by enhanced antibacterial activity of the nanocomposite. These IM/ZnO/CuO films could be used as effective bactericidal agents for various industries, particularly the food industry.

Development of bioactive fish gelatin/chitosan nanoparticles composite films with antimicrobial properties

The objective of this work was to develop active bio-based nanocomposite films from fish gelatin (FG) and chitosan nanoparticles (CSNPs) incorporated with Origanum vulgare L. essential oil (OEO). CSNPs were obtained by ionic gelation of chitosan with sodium tripolyphosphate, which presented a spherical morphology with size range of 40–80nm. Remarkable differences in the surface morphology were observed between the control and bioactive nanocomposite films as revealed by SEM and AFM images. FTIR results confirmed that an interaction between polymer matrix and essential oil had occurred, as shown by an increase in the amplitude of peaks at wavenumbers 1242cm−1 and 1451cm−1. Meanwhile, XRD peaks of OEO-containing films were more intense, indicating that the introduction of essential oil into the film matrix induces an increase in crystallinity. TGA analysis demonstrated that the addition of OEO had no impact on thermal stability of the films. Inclusion of OEO in the film matrix resulted in less resistant and more flexible films, with a decrease in water vapor permeability (WVP). The FG/CSNPs bioactive films exhibited distinctive antimicrobial activity against four test food pathogens, namely Staphylococcus aureus, Listeria monocytogenes, Salmonella enteritidis and Escherichia coli.

Preparation of nano cellulose fibers and its application in kappa-carrageenan based film

Bio-based nanocomposite films were successfully developed using nanofibrillated cellulose (NFC) as the reinforcing phase and kappa-carrageenan (KCRG) as the matrix. NFC was successfully synthesis from short stable cotton fibers by chemo-mechanical process. The bionanocomposites were prepared by incorporating 0.1, 0.2, 0.3, 0.4, 0.5, and 1wt% of the NFC into a KCRG matrix using a solution casting method there characterization was done in terms of thermal properties (DSC), morphology (SEM), water vapor transmission rate (WVTR), oxygen transmission rate (OTR), X-ray diffractograms (XRD), and tensile properties. The main conclusion arising from the analysis of the result is that the bionanocomposites containing 0.4wt% of NFC exhibited the highest enhancement in tensile strength it is almost 44% improvement. WVTR and OTR results showed improvement of all nanocomposite film compare to control KCRG film.

Crosslinking as an Efficient Tool for Decreasing Moisture Sensitivity of Biobased Nanocomposite Films

Chitosan-nanoclay bio-hybrid films were successfully crosslinked with glutaraldehyde, genipin and glyoxal. Moisture sensitivity of films decreased as a result of crosslinking which led to improved barrier properties against water vapor and oxygen. Films containing chitosan (6.6 g/m2) with genipin (3.3 g/m2) and nanoclay (6.6 g/m2) had water vapor transmission rate of 72 g × 100 µm/(m2 × 24 h) which was 34% lower as compared to pure chitosan and 30% lower as compared to chitosan/nanoclay without crosslinkers. Glyoxal induced crosslinking resulted in 92% reduction in oxygen transmission rate at 80% relative humidity as compared to pure chitosan films. Oxygen transmission through glyoxal (3.3 g/m2) treated chitosan/nanoclay film was 2.8 cm3 × 100 µm/(m2 × 24 h) which was 53% lower as compared to chitosan/nanoclay without crosslinkers. In addition, nanoclay and especially glyoxal crosslinking prevented the water vapor sorption of chitosan considerably. Crosslinking may be used as an efficient tool for enhancing the exploitability of naturally hydrophilic biopolymers towards new high-value applications, such as food packaging.

Structure and magnetic properties of regenerated cellulose/Fe3O4 nanocomposite films

AbstractCellulose nanocomposites containing high contents of Fe3O4 nanoparticles were successfully prepared with regenerated cellulose films as a matrix and mixture solutions of Fe2+/Fe3+ as precursors. The structure and properties of the magnetic nanocomposite films were investigated with X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and vibrating sample magnetometry. Fe3O4 nanoparticles as prepared were irregular spheres and were homogeneously dispersed in the cellulose matrix. With an increase in the concentration of precursors from 0.2 to 1.0 mol/L, the content of Fe3O4 nanoparticles in the dried nanocomposites increased from 12 to 39 wt %, and the particle diameter increased from 32 to 64 nm. The cellulose nanocomposite films demonstrated superparamagnetic behavior, and their saturation magnetizations were in the range 4.2–21.2 emu/g, which were related to the increase in Fe3O4 nanoparticle content. With increasing nanophase content, the nanocomposite films displayed significantly anisotropic magnetic properties in the parallel and perpendicular directions. This study provided a green and facile method for the preparation of biobased nanocomposite films with high nanophase content and excellent magnetic properties. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009