Biopolymer-based Nanocomposites Research Articles

Trends and challenges of biopolymer-based nanocomposites in food packaging.

The ultimate goal of new food packaging technologies, in addition to maintaining the quality and safety of food for the consumer, is to consider environmental concerns and reduce its impacts. In this regard, one of the solutions is to use eco-friendly biopolymers instead of conventional petroleum-based polymers. However, the challenges of using biopolymers in the food packaging industry should be carefully evaluated, and techniques to eliminate or minimize their disadvantages should be investigated. Many studies have been conducted to improve the properties of biopolymer-based packaging materials to produce a favorable product for the food industry. This article reviews the structure of biopolymer-based materials and discusses the trends and challenges of using these materials in food packaging technologies with the focus on nanotechnology and based on recent studies.

Enhancing the Antifungal Activity of Griseofulvin by Incorporation a Green Biopolymer-Based Nanocomposite.

Fungal biofilms have caused several medical problems, resulting in significant morbidity and mortality as well as poor response to antifungal drugs. The current study was designed to evaluate the enhancement of antifungal and anti-biofilm activity of Griseofulvin-loaded green nanocomposite-based biopolymers (Ge-Nco) of glycogen and gelatin against different strains of pathogenic Candida species. The prepared Ge-Nco was characterized using Fourier-transform infrared (FT-IR), X-ray diffraction pattern (XRD), scanning electron microscopy-energy dispersive X-ray (SEM-EDX) and transmission electron microscope (TEM). In addition, the morphology of the mature biofilm and the inhibition of biofilm was monitored and visualized using confocal laser scanning microscopy (CLSM). The minimal inhibitory concentrations (MIC) and (IC50) of Griseofulvin alone and the prepared Ge-Nco against three different strains of Candida sp. were determined according to Clinical and Laboratory Standards Institute (CLSI) method. The effects of Griseofulvin alone and Ge-Nco on the tested Candida sp. biofilm formation were determined by the crystal-violet staining protocol. The biofilm inhibition potential of Ge-Nco against the tested Candida sp. was detected and depicted under CLSM (2.5 D view). The findings depicted that Ge-Nco was prepared in nanometer size (10–23 nm). The observed minimum inhibitory concentration (MIC) of Griseofulvin alone and Ge-Nco against three different Candida sp. were found to be in range 49.9–99.8 μg/mL and 6.24–12.48 μg/mL, respectively. These results provide evidence for implementing efficient antivirulence approaches against three different Candida sp. that would be less likely to foster the emergence of resistance.

Heavy metal removal from polluted water by <i>Nopal cactus</i> biopolymer-based magnetic nanocomposites

Heavy metal removal from polluted water by <i>Nopal cactus</i> biopolymer-based magnetic nanocomposites

An overview of biopolymer-based nanocomposites for optics and electronics

We summarize the recent advances in optics and electronics of biopolymer-based nanocomposites. They are emerging as new materials for high-tech applications, thanks to the sustainability of the matrix and the functionalities of the nanofillers.

The non-enzymatic electrochemical detection of glucose and ammonia using ternary biopolymer based-nanocomposites

Novel biopolymer-based nanocomposites exhibit significant electrocatalytic activity towards glucose and aqueous ammonia detection with high sensitivity and low detection limits.

APPLICATION OF BIO-WASTE MATERIALS IN THE GREEN SYNTHESIS OF COMPOSITES FOR WATER PURIFICATION

Treatment of the polluted water has become an issue of cardinal importance in the framing of the most recent strategies that define the way the environmental engineering and conservation are being looked upon. Adsorption techniques that involve solid adsorbents have been widely practiced to filter out the contaminants from the aqueous contents, and composites of biopolymer have attracted greater attention because they are inherently innocuous to the environment and can be classified as bio-degradable. Biopolymer-based nano-composites in particular have often been proved to be possessing better physical, chemical, and mechanical properties than those of the corresponding biopolymers as such, and also provide the advantages of both counterparts in the composites. This paper details versatile biopolymer-based composites of cellulose extracted from banana peel impregnated with zero-valent iron nanoparticles aimed at the discharge of an organ othiophosphate pesticide from aqueous contents. The prepared composites were characterised by scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and Brunauer–Emmett–Teller analysis. The synthesis of the adsorbents, their intrinsic adsorption characteristics, and effective applications are the focal point of this paper and are subjected to detailed analysis.

Hydroxypropyl methylcellulose-TiO2 and gelatin-TiO2 nanocomposite films: Physicochemical and structural properties

Photocatalytic properties of titanium dioxide (TiO2) have been widely studied. However, its tendency to aggregation in biopolymer-based nanocomposites limits its application for food packaging and has been few studied. The aim of this work was to study the dispersion of TiO2 (0–2 wt%) incorporated in the hydroxypropyl methylcellulose (HPMC-TiO2) and gelatin (gelatin-TiO2) film forming solutions. Particle size and zeta potential of TiO2 nanoparticles were investigated. Nanocomposite films were characterized as to the thickness, moisture content, solubility, color, absorption to the light, relative opacity, morphology, chemical composition, crystallinity, thermal and mechanical properties and water vapor permeability (WVP). TiO2 nanoparticles showed better dispersion in acid medium than water. Moisture content, water solubility and WVP of the gelatin-TiO2 films were influenced by the incorporation of TiO2, while HPMC-TiO2 films were not. The increase of relative opacity of the films as TiO2 was more attenuated for the gelatin-TiO2 films due to lower TiO2 aggregation in gelatin. Morphology, chemical composition, crystallinity and thermal properties of the films evidenced that TiO2 was better dispersed in both matrices at 1 wt%. It was also concluded that TiO2 aggregation generated more biphasic regions in HPMC than generated in gelatin, which caused a microstructural reorganization in the matrices.

Preparation and properties of chitosan/guar gum/nanocrystalline cellulose nanocomposite films

Nanocrystalline cellulose (NCC) has shown great potential for reinforcing nanocomposite systems, particularly in biopolymer-based nanocomposites. In the present work, transparent and biodegradable chitosan (CH)/guar gum (GG)/NCC nanocomposite films were designed and prepared. The effect of NCC loadings on the rheological behavior of the as-prepared nanocomposite suspensions was investigated, the overall properties of the resultant nanocomposite films as a function of various amounts of NCC were determined, and the surface morphology of various nanocomposite films was characterized by scanning electron microscopy (SEM). Results indicated that the increased NCC loadings increased the shear viscosity of the nanocomposite suspensions. Moreover, as expected, the obtained CH/GG/NCC nanocomposite films were found to exhibit improved tensile strength and reduced air permeability in comparison to pure CH/GG films. This work supported the conclusion that NCC was effective in reinforcing the CH/GG composite films, which may be a promising material for food packaging applications.

Silk fibroin/gold nanocrystals: a new example of biopolymer-based nanocomposites

The dispersion of nanoparticles in ordered polymer nanostructures can provide control over particle location and orientation, and pave the way for tailored nanomaterials that have enhanced mechanical, electrical, or optical properties. Here we used silk fibroin, a natural biopolymer, to embed gold nanocrystals (NCs), so as to obtain well-ordered structures such as nanowires and self-assembled triangular nanocomposites.Monodisperse gold NCs synthesized in organic media are mixed to silk fibroin and the obtained nanocomposites are characterized by UV-visible spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (FE-SEM), atomic force microscopy (AFM) and Infrared spectroscopy. The optical properties study of gold NCs and silk-gold nanocomposites shows that the Surface Plasmon band is blue shifted compared to gold NCs. The size and shape of NCs gold superlattices can be well controlled by the presence of silk fibroin giving nanowires and also self-assembled triangular nanocomposites as characterized by TEM, FE-SEM and AFM. The strong interaction between gold NCs and silk fibroin is also revealed by the conformation change of silk protein in presence of gold NCs, as shown by FTIR analysis. The formation of such ordered nanocomposites (gold NCs/silk fibroin) will provide new nanoplasmonic devices.

PLA graphene nanoplatelets nanocomposites: Physical properties and release kinetics of an antimicrobial agent

Abstract Graphene nanoplatelets (GnP) as filler and ciprofloxacin (CFX) as biocide were incorporated via melt-compounding into poly(lactic acid) (PLA) to obtain biopolymer-based nanocomposites with antimicrobial properties. GnP were added with the aim of improving the mechanical properties of the antimicrobial system and tuning the drug release. The obtained systems were mechanically characterized in tensile mode by quasi-static and dynamic mechanical tests. Furthermore, rheological measurements were performed. The morphology of the samples was analyzed through scanning electron microscopy (SEM). Moreover, a mathematical model, i.e. power law model, was used to fit the release data in order to investigate the release mechanism. The results showed that the obtained nanocomposite systems exhibit antimicrobial activity. The incorporation of GnP increased the stiffness of the matrix and allowed to reduce the burst release effect.

Effect of Graphene Nanoplatelets on the Physical and Antimicrobial Properties of Biopolymer-Based Nanocomposites.

In this work, biopolymer-based nanocomposites with antimicrobial properties were prepared via melt-compounding. In particular, graphene nanoplatelets (GnPs) as fillers and an antibiotic, i.e., ciprofloxacin (CFX), as biocide were incorporated in a commercial biodegradable polymer blend of poly(lactic acid) (PLA) and a copolyester (BioFlex®). The prepared materials were characterized by scanning electron microscopy (SEM), and rheological and mechanical measurements. Moreover, the effect of GnPs on the antimicrobial properties and release kinetics of CFX was evaluated. The results indicated that the incorporation of GnPs increased the stiffness of the biopolymeric matrix and allowed for the tuning of the release of CFX without hindering the antimicrobial activity of the obtained materials.

Biosorption of Pb2+, Ni2+ and Cu2+ ions from aqueous solutions by L-cystein-modified montmorillonite-immobilized alginate nanocomposite

In this study, L-cystein-modified montmorillonite (MMT)-immobilized sodium alginate biopolymer-based nanocomposite was synthesized using solution casting method. The synthesized material was characterized by X-ray diffraction, FTIR, TGA-DTG, scanning electron microscopy and transmission electron microscopy techniques. The material was further evaluated for the removal of heavy metal ions like (Pb2+, Ni2+ and Cu2+) from aqueous solutions. The effect of various parameters such as pH, agitation time, initial metal ion concentration, temperature and adsorbent dose on the extent of adsorption was investigated. The equilibrium data obtained by experiments were well analysed by four isotherm models, and the results are well fitted with Langmuir model at 50°C, and a maximum adsorption capacity (qm) 100.00, 111.11 and 125.00 (mg g−1) was obtained for Cu2+, Pb2+ and Ni2+, respectively. Various kinetic equations were applied to kinetic data, and the results are best found to follow pseudo-second-order kinetic model. Thermodynamic parameters of the adsorption process such as the standard Gibbs free energy change (∆G°), standard enthalpy change (∆H°), standard entropy change (∆S°) were calculated, and the result showed that adsorption of heavy metals onto Alg-Cys-MMT is spontaneous and endothermic in nature.

Elaboration and Rheological Investigation of Magnetic Sensitive Nanocomposite Biopolymer Networks

We propose the elaboration and study of rheological properties under continuous magnetic field of magnetic sensitive biopolymer-based nanocomposites. Magnetic iron oxide (maghemite) nanoparticles were synthesized by the polyol process and then functionalized by grafting organic bifunctional ligand for establishing electrostatic bonds between the sodium alginate chains of biopolymer and functionalized nanoparticles. The enhancement of rheological properties at low shear rate of these new magnetic soft nanocomposites was clearly demonstrated by the increase of yield stress and viscoelastic moduli in the linear viscoelastic domain with an increase of applied magnetic field, thus providing new functionality to these soft nanocomposites.

Recent Advances in Biopolymers and Biopolymer-Based Nanocomposites for Food Packaging Materials

Plastic packaging for food and non-food applications is non-biodegradable, and also uses up valuable and scarce non-renewable resources like petroleum. With the current focus on exploring alternatives to petroleum and emphasis on reduced environmental impact, research is increasingly being directed at development of biodegradable food packaging from biopolymer-based materials. The proposed paper will present a review of recent developments in biopolymer-based food packaging materials including natural biopolymers (such as starches and proteins), synthetic biopolymers (such as poly lactic acid), biopolymer blends, and nanocomposites based on natural and synthetic biopolymers. The paper will discuss the various techniques that have been used for developing cost-effective biodegradable packaging materials with optimum mechanical strength and oxygen and moisture barrier properties. This is a timely review as there has been a recent renewed interest in research studies, both in the industry and academia, towards development of a new generation of biopolymer-based food packaging materials with possible applications in other areas.

Biopolymer-based nanocomposites: effect of lignin acetylation in cellulose triacetate films

We have prepared all-biopolymer nanocomposite films using lignin as a filler and cellulose triacetate (CTA) as a polymer matrix, and characterized them by several analytical methods. Three types of lignin were tested: organosolv, hydrolytic and kraft, with or without acetylation. They were used in the form of nanoparticles incorporated at 1 wt% in CTA. Self-supported films were prepared by vapor-induced phase separation at controlled temperature (35–55 °C) and relative humidity (10–70%). The efficiency of acetylation of each type of lignin was studied and discussed, as well as its effects on film structure, homogeneity and mechanical properties. The obtained results are explained in terms of intermolecular filler-matrix interaction at the nanometer scale, for which the highest mechanical resistance was reached using hydrolytic lignin in the nanocomposite.

Synthesis and characterization of a novel chitosan/montmorillonite/hydroxyapatite nanocomposite for bone tissue engineering

Recently, biopolymer-based nanocomposites have been replacing synthetic polymer composites for various biomedical applications. This is often because of the biocompatible and biodegradable behavior of natural polymers. Several studies have been reported pertaining to the synthesis and characterization of chitosan(chi)/montmorillonite(MMT) and chitosan (chi)/hydroxyapatite (HAP) for tissue engineering applications. In the present work, a biopolymer-based novel nanocomposite chitosan/montmorillonite (MMT)/hydroxyapatite (HAP) was developed for biomedical applications. The composite was prepared from chitosan, unmodified MMT and HAP precipitate in aqueous media. The properties of the composites were investigated using x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and thermogravimetric analysis (TGA). Nanomechanical properties were measured using nanoindentation. Cell culture experiments were also conducted in order to ascertain the biocompatibility of the composite. The XRD results indicate that an intercalated structure was formed with an increase in d-spacing of montmorillonite. FTIR studies provide the evidence of molecular interaction among the three different constituents of the composite. AFM images show well-distributed nanoparticles in the chitosan matrix. The composites also exhibit a significant enhancement in nanomechanical property as compared to pure chitosan as well as the chi/HAP and chi/MMT composites. The TGA results indicate that an intercalated nanocomposite was formed with improved thermal properties even compared to chi/MMT composites. The results of cell culture experiments show that the composite is biocompatible and has a better cell proliferation rate compared to chi/HAP composites. This work represents the design of a novel clay–chitosan–hydroxyapatite composite with improved mechanical properties that has potential applications in bone tissue engineering.

All Cellulose Nanocomposites Produced by Extrusion

The aim of this study was to produce biopolymer-based nanocomposites using extrusion as an industrially adaptable manufacturing process, and to study how this production process influenced the structure and properties of the nanocomposites produced. Cellulose nanowhiskers (CNWs) were prepared and used as nanoreinforcement in two different biopolymers, polylactic acid (PLA) and cellulose acetate butyrate (CAB). The CNWs were added to PLA and CAB in order to improve the thermal and mechanical properties of these polymers. Two different preparation methods of CNWs were used; isolation by sulfuric acid hydrolysis and isolation by hydrochloric acid hydrolysis. Different feeding procedures were used and evaluated during compounding. The CNW suspension was either freeze-dried and dry-mixed with the polymer prior the extrusion, or fed as a suspension directly into the extruder during compounding. However, the CNW suspension required modification in order to prevent re-aggregation of the whiskers as the dispersing medium was removed and to uniformly disperse the whiskers in the polymer matrix. In order to improve the dispersion of the CNWs in the matrix, a surfactant and a water soluble polymer were used for PLA, and a plasticizer was used for CAB. No major improvements in mechanical or thermal properties were seen for the PLA/CNW nanocomposites, either because of degradation of the matrix or poor dispersion of the whiskers. The material system of CAB/CNW was more successful and showed great improvements in mechanical and thermal properties. This study demonstrated that it is possible to produce nanocomposites by pumping a suspension of CNWs into the extruder during compounding, but compatibility between the CNWs and the matrix is required.