Biocomposite Films Research Articles

S-nitrosoglutathione functionalized polydopamine nanoparticles incorporated into chitosan/gelatin hydrogel films with NIR-controlled photothermal/NO-releasing therapy for enhanced wound healing

Nitric oxide (NO) has aroused wide interest in the treating infected wounds due to its characteristic functionalities. However, its utilization is limited due to its volatile properties, high reactivity, direct potential toxicity, and byproducts of NO donors limited its application. Herein, endogenously NO donor S-nitrosoglutathione (GSNO) was connected covalently to polydopamine nanoparticles (PDA-GSNO NPs) to minimize the loss of NO in aqueous medium. Meanwhile, near-infrared (NIR)-controlled NO release and photothermal therapy (PTT) was obtained through the photothermal conversion by PDA. Then chitosan (CS)/gelatin (GE) biocomposite hydrogel films with preferable biocompatibility, surface hydrophilicity, hydroabsorptivity, and mechanical adhesive properties were constructed. By embedding PDA-GSNO NPs into the films, a multifunctional wound dressing was fabricated. Under NIR light irradiation, the combination of PTT, NO-releasing, and CS antibacterial agents can strengthen the in vitro antimicrobial efficacy and in vivo wound healing activities. Meanwhile, the obtained wound dressing presented good biocompatibility. This work outlines an approach for combating bacterial infections and demonstrating the possibility for synergistic NO-releasing wound healing.

High-Performance Biocomposite Polyvinyl Alcohol (PVA) Films Modified with Cellulose Nanocrystals (CNCs), Tannic Acid (TA), and Chitosan (CS) for Food Packaging

Polyvinyl alcohol (PVA) has been widely applied in industries for its low cost, nontoxicity, biodegradability, and renewable advantages. However, its unstable structure may not meet some strong physical and mechanical needs. In order to enhance the performances of the PVA film, cellulose nanocrystals (CNCs), tannic acid (TA), and chitosan (CS), working as a reinforcer, a crosslinker, and an antimicrobial agent, respectively, were introduced into the PVA matrix. The results indicated that CNCs, TA, and CS were evenly distributed and cohesively incorporated within the PVA matrix, which contributed to the good mechanical properties and thermal stabilities of biocomposite PVA films. Besides, the addition of TA remarkably improved the antiultraviolet and antioxidant capabilities of PVA films, although the light transmittance declined slightly. It was also observed that the pure PVA film and PVA reinforced with CNCs were incapable of protecting against bacteria, while the ones with CS had prominent antibacterial properties to Escherichia coli and Staphylococcus aureus. Overall, the resulting film presented a high potential utilization as a food packaging material for its outstanding physical and mechanical performances.

Bioactive Pectin-Murta (Ugni molinae T.) Seed Extract Films Reinforced with Chitin Fibers.

This study investigated the biocomposite pectin films enriched with murta (Ugni molinae T.) seed polyphenolic extract and reinforced by chitin nanofiber. The structural, morphological, mechanical, barrier, colorimetric, and antioxidant activity of films were evaluated. The obtained data clearly demonstrated that the addition of murta seed extract and the high load of chitin nanofibers (50%) provided more cohesive and dense morphology of films and improved the mechanical resistance and water vapor barrier in comparison to the control pectin film. The antioxidant activity ranged between 71% and 86%, depending on the film formulation and concentration of chitin nanofibers. The presented results highlight the potential use of chitin nanofibers and murta seed extract in the pectin matrix to be applied in functional food coatings and packaging, as a sustainable solution.

Properties of Biocomposite Film Based on Whey Protein Isolate Filled with Nanocrystalline Cellulose from Pineapple Crown Leaf.

Among the main bio-based polymer for food packaging materials, whey protein isolate (WPI) is one of the biopolymers that have excellent film-forming properties and are environmentally friendly. This study was performed to analyse the effect of various concentrations of bio-based nanocrystalline cellulose (NCC) extracted from pineapple crown leaf (PCL) on the properties of whey protein isolate (WPI) films using the solution casting technique. Six WPI films were fabricated with different loadings of NCC from 0 to 10 % w/v. The resulting films were characterised based on their mechanical, physical, chemical, and thermal properties. The results show that NCC loadings increased the thickness of the resulting films. The transparency of the films decreased at higher NCC loadings. The moisture content and moisture absorption of the films decreased with the presence of the NCC, being lower at higher NCC loadings. The water solubility of the films decreased from 92.2% for the pure WPI to 65.5% for the one containing 10 % w/v of NCC. The tensile strength of the films peaked at 7% NCC loading with the value of 5.1 MPa. Conversely, the trend of the elongation at break data was the opposite of the tensile strength. Moreover, the addition of NCC produced a slight effect of NCC in FTIR spectra of the WPI films using principal component analysis. NCC loading enhanced the thermal stability of the WPI films, as shown by an increase in the glass transition temperature at higher NCC loadings. Moreover, the morphology of the films turned rougher and more heterogeneous with small particle aggregates in the presence of the NCC. Overall, the addition of NCC enhanced the water barrier and mechanical properties of the WPI films by incorporating the PCL-based NCC as the filler.

Influence of Ulluco Starch Concentration on the Physicochemical Properties of Starch-Chitosan Biocomposite Films.

This work aimed to prepare ulluco starch (US)/chitosan (Ch) edible films and evaluate the effect of the concentration of US on their physicochemical properties. The use of edible films is a means of adding value to the ulluco crop and evaluating the viability of using new sources to produce packaging materials. Different samples were prepared at different US concentrations (2%, 3%, 4%, and 5% w/v) and a fixed chitosan concentration (1.5% w/v); then, samples were analyzed, considering their physical, mechanical, and thermal properties. The US/Ch edible films showed an increase in solubility from 17.5% to 21.7%, swelling power (SP) from 38.9% to 267%, tensile strength (TS) from 3.69 MPa to 10.7 MPa, Young modulus (YM) from 18.0 Pa to 652 Pa, and thermal stability as the US concentration increased. However, samples with low US concentrations showed higher elongation at break (EB) (36.6%) and better barrier properties (WVP) (5.61 × 10−11 g/m s Pa). The films evaluated in this work presented good physical, mechanical, and barrier properties, revealing their potential as packaging material ensuring food security, and demonstrating the technological potential of US.

Mechanical and antibacterial properties of ZnO/chitosan bio-composite films

Abstract In the current study, ZnO/chitosan bio-composite films were produced via solution-casting method. Two different ZnO powders, micrometer (d50 ≅ 1.5 μm) and nanometer sized (d50 ≅ 100 nm), were used to investigate the effect of ZnO particle size and concentration (0, 2, and 8% w/w of chitosan) on the mechanical and antibacterial properties of the ZnO/chitosan bio-composite films. The incorporation of the ZnO powders into the chitosan film resulted in an increase in the tensile strength (TS) and a decrease in the elongation at break (EB) values. Mechanical test results revealed that TS and EB properties were considerably affected (p < 0.05) by the concentration and particle size of the ZnO reinforcement. Disc diffusion method demonstrated good antibacterial activities of bio-composite films containing high amount of ZnO (8% w/w of chitosan) against Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, and Bacillus subtilis. The growth-limiting effect of the films was more pronounced for S. aureus and K. pneumoniae. Due to enhanced TS and imparted antibacterial activity of the produced ZnO/chitosan bio-composite films, these materials are promising candidates for applications such as food packaging, wound dressing, and antibacterial coatings for various surfaces.

Use of Biochar as Filler for Biocomposite Blown Films: Structure-Processing-Properties Relationships.

In this work, biocomposite blown films based on poly(butylene adipate-co-terephthalate) (PBAT) as biopolymeric matrix and biochar (BC) as filler were successfully fabricated. The materials were subjected to a film-blowing process after being compounded in a twin-screw extruder. The preliminary investigations conducted on melt-mixed PBAT/BC composites allowed PBAT/BC 5% and PBAT/BC 10% to be identified as the most appropriate formulations to be processed via film blowing. The blown films exhibited mechanical performances adequate for possible application as film for packaging, agricultural, and compost bags. The addition of BC led to an improvement of the elastic modulus, still maintaining high values of deformation. Water contact angle measurements revealed an increase in the hydrophobic behavior of the biocomposite films compared to PBAT. Additionally, accelerated degradative tests monitored by tensile tests and spectroscopic analysis revealed that the filler induced a photo-oxidative resistance on PBAT by delaying the degradation phenomena.

Preparation and Characterization of Chinese Leek Extract Incorporated Cellulose Composite Films.

This study aimed to prepare microcrystalline cellulose (MCC) films with good mechanical properties via plasticization using a Chinese leek (CL, Allium tuberosum) extract. The microstructure, crystal structure, mechanical properties, barrier ability, and thermal properties of the films were investigated. The chemical structure analysis of CL extract showed the existence of cellulose, lignin, and low-molecular-weight substances, such as polysaccharides, pectins, and waxes, which could act as plasticizers to enhance the properties of MCC:CL biocomposite films. The results of scanning electron microscopy and atomic force microscopy analyses indicated the good compatibility between MCC and CL extract. When the volume ratio of MCC:CL was 7:3, the MCC:CL biocomposite film exhibited the best comprehensive performance in terms of water vapor permeability (2.11 × 10–10 g/m·s·Pa), elongation at break (13.2 ± 1.8%), and tensile strength (24.7 ± 2.5 MPa). The results of a UV absorption analysis demonstrated that the addition of CL extract improved the UV-shielding performance of the films. Therefore, this work not only proposes a facile method to prepare MCC films with excellent mechanical properties via plasticization using CL extract but also broadens the potential applications of MCC films in the packaging area.

Development of Multifunctional Pullulan/Chitosan-Based Composite Films Reinforced with ZnO Nanoparticles and Propolis for Meat Packaging Applications.

Pullulan/chitosan-based multifunctional edible composite films were fabricated by reinforcing mushroom-mediated zinc oxide nanoparticles (ZnONPs) and propolis. The ZnONPs were synthesized using enoki mushroom extract and characterized using physicochemical methods. The mushroom-mediated ZnONPs showed an irregular shape with an average size of 26.7 ± 8.9 nm. The combined incorporation of ZnONPs and propolis pointedly improved the composite film’s UV-blocking property without losing transparency. The reinforcement with ZnONPs and propolis improved the mechanical strength of the pullulan/chitosan-based film by ~25%. Additionally, the water vapor barrier property and hydrophobicity of the film were slightly increased. In addition, the pullulan/chitosan-based biocomposite film exhibited good antioxidant activity due to the propolis and excellent antibacterial activity against foodborne pathogens due to the ZnONPs. The developed edible pullulan/chitosan-based film was used for pork belly packaging, and the peroxide value and total number of aerobic microorganisms were significantly reduced in meat wrapped with the pullulan/chitosan/ZnONPs/propolis film.

Preparation and Characterization of Polyethylene Biocomposites Reinforced by Rice Husk: Application as Potential Packaging Material

The development of biodegradable materials as food packaging material is important not only due to the reduction in environmental pollution but also because of an improvement in the functionality. Rice husk-reinforced biopolymers have offered a possible solution to waste-disposal problems associated with traditional petroleum-derived plastics. Rice husk-reinforced low density polyethylene (LDPE)-based biocomposites have been of great interest for their use as food packaging material. In this work, the LDPE/RH biocomposites with different rice husk (RH) content (10, 20, 30, 40 and 50 wt.%) were prepared by the melt mixing process in a laboratory Brabender mixer. The effect of RH content on the physical, thermal and mechanical properties of LDPE was investigated. More importantly, this work aimed to research the biodegradation of the LDPE/RH biocomposites as well as their effect on ‘Granny Smith’ apples’ respiration. The results showed that the incorporation of RH into the LDPE decreased the thermal stability of LDPE, increased water vapour permeability and water absorption, and increased the degree of crystallinity. The incorporation of RH increased the biodegradability of LDPE as well as the postharvest quality of ‘Granny Smith’ apples. The addition of RH in LDPE film significantly decreased fruit respiration and increased firmness as compared to LDPE film. The composting results showed that after the LDPE/RH biocomposite films were biodegraded for 21 days, the biocomposite films with the highest content of rice husks were the most degraded.

Effects of hectorite loading on tear properties and biodegradability of thermoplastic starch films

Development of bio-based polymers can reduce human dependence on fossil fuel and move to a sustainable material resource. In this work, thermoplastics starch (TPS) films were produced by plasticization process, in which the crystalline structure of the starch granules was destroyed and reformed by water and glycerine through mechanical stirring and heating process. Hectorite was employed as filler to reinforce the TPS films. The hectorite was subjected to ultrasonication process for reducing the size and aggregation of particles. The ultrasonicated hectorite was added into the TPS solution to produce the TPS/hectorite bio-composite by film casting method. The TPS films with hectorite loading in the range of 1% to 5% were prepared. The morphology, tear strength and soil biodegradability of the TPS/hectorite bio-composite films were studied by altering the loading of hectorite incorporated into the TPS films. Results showed that the TPS/hectorite bio-composite films have higher tear strength compared to the pure TPS films. The tear strength of the bio-composite films slightly increased with hectorite content 1% and 2%. However, as the filler loading increased to 3%, there was a drastic increase of the tear strength. The maximum tear strength value was achieved by the TPS film when 4% hectorite filler was employed. The TPS/4% hectorite (ultrasonicated) has the lowest rate of soil biodegradation due to its lower moisture uptake and greatest interface interaction between starch and hectorite, inhibiting diffusion of bacteria into the films.

Cassava starch-chitosan-sorghum micro-fibrillated cellulose biocomposite wrapping film to prevent COVID-19 outspread

To prevent virus spreading, the corpse or the coffin of COVID-19 patients need to be wrapped in plastic. Low-density polyethylene (LDPE), a crude oil-based wrapping plastic, is difficult to decompose in nature after use. In this study, biocomposite wrapping film was developed from cassava starch and chitosan, with the addition of sorghum Micro-Fibrillated Cellulose (MFC) by levels of 1%, 2%, 3%, 4% and 5%. Cassava starch (raw starch) was modified by acetic anhydride to produce acetylated cassava starch (acetylated starch) which is less hydrophilic thus enhance the compounding ability with LDPE. The sorghum MFC was obtained from sorghum fibers after following processes: soda pulping, bleaching and fibrillation with a super grinder. The addition of 1% sorghum MFC into raw starch-chitosan increased the tensile strength and modulus of elasticity by 33% and 17%, respectively. On the other hand, the addition of 2% sorghum MFC into acetylated starch-chitosan increased the elongation by 38%. Wrapping film needs to have good elongation ability so that it can be stretched during application. Based on elongation characteristic, acetylated cassava starch-chitosan with addition of 2% sorghum MFC can be developed to be a candidate for biocomposite wrapping film to prevent COVID-19 outspread.

Effect of graphene nanoplatelet addition on the electrical conductivity of poly(hydroxybutyrate-co-hydroxyvalerate) biocomposites

Poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) is one of the most promising biodegradable polymers used in many applications due to its biodegradability and non-toxicity. However, the usage of PHBV in electronic, biomedical, and biosensor applications has been limited due to its poor electrical properties. This study shows a simple method of producing and enhancing the electrical conductivity of PHBV-based biocomposites by adding graphene nanoplatelet (GNP) as a conductive filler. The biocomposite films were prepared using the solvent casting method, consist of five GNP loading (0-5 wt. %). The prepared PHBV/GNP biocomposites show enhanced electrical conductivity compared to neat PHBV. PHBV/GNP biocomposite with 5 wt. % filler loading exhibits the highest electrical conductivity at 3.83 × 10−3 S/cm. Higher crystalline regions in the PHBV/GNP biocomposites have facilitated the transfer of electrons between PHBV, resulting in the formation of conductive biocomposites, as evident from X-ray diffraction (XRD) characterization.

Mechanical Properties of Thermoplastic Starch Biocomposite Films with Hybrid Fillers

Thermoplastic starch (TPS) was studied extensively to replace conventional plastic in packaging application. In this study, granule corn starch was first plasticized with water and glycerol to form TPS films and two different fillers were incorporated with TPS to form hybrid biocomposite films (TPSB). Two different fillers: Microcrystalline cellulose (MC) and Nano bentonite (NB) fixed at 1: 4 ratios in various loading (1wt%-6wt%) were incorporated in TPS to study effect of hybrid fillers on the mechanical properties of TPSB films. The effect of different loading of MC/NB on TPSB films was investigated through the structural, morphological and mechanical testing. Fourier Transform Infrared Spectroscopy (FTIR) shows TPS matrix and hybrid fillers are highly compatible due to hydroxyl bonding and verified through the shifting of spectra band. Scanning Electron Microscope (SEM) showed even distribution of fillers in the matrix of TPS. The TPSB films exhibited significant improvement 40% in elongation at break compared to pure TPS films. In this study, 5wt% is best loading of the hybrid fillers to incorporated in TPSB films as it achieved the highest value of tensile strength (8.52MPa), Young’s Modulus (42.0 MPa) and elongation at break (116.3%). Generally, previous studies showed flexibility of TPS composite films reduced with incorporating filler, however in this study, the flexibility TPSB show significant improvement compared to previous studies and exhibit promising potential in dry food packaging application.

Propolis green biofilm for the immobilization of carbon nanotubes and metallic ions: Development of redox catalysts

• A new green thin biofilm based on propolis is proposed. • The propolis biofilm has presented high-capacity to immobilize CNTs. • The biocomposite has increased the electrical conductivity of the base electrode. • A green electrochemical device was used for synthesis of catalysts. Greener materials have been used in the construction of electrochemical devices, becoming one of the main strands of this scientific development area. Thin films based on natural and renewable sources, such as propolis, allow the development of biocomposites. Hence, we have proposed the use of a thin film based on propolis for the stable and homogeneous immobilization of carbon nanotubes (CNTs), which increased the electrical conductivity of the base electrode (glassy carbon electrode) by almost 500 thousand times. The CNTs/propolis biofilm proportion was optimized by multivariate analysis, providing a decrease in the number of experiments, the demand for reagents, and analysis time. The biocomposite thin film was used for the spontaneous preconcentration and anchoring of metal ions, and the electrochemical synthesis of redox mediators and catalysts. This qualifies the proposed strategies for the development of eco-friendly electrochemical devices.

Thermoplastic sago starch nanocomposites wound dressing fortified with antibiotic-modified HNT

Starches were reported to promote wound healing. However, the hydrophilicity of starch help absorbs the exudates from the wounds during the healing process, but it also enables a bacterial infection that slows the healing process. Halloysite nanotubes (HNT) are attracting many biological technologies because of their high loading capacity and biocompatibility. This paper investigates the modified HNT as a carrier for antimicrobials agent in wound healing materials. Halloysite was modified by dispersing it with chloramphenicol solution using a magnetic stirring method. Thermoplastic sago Starch (TPSS)/modified HNT (MHNTs) biocomposite films of different compositions (0.25, 0.5, 0.75 and 1 wt. % HNT) were then developed using the solution casting method. SEM revealed that modified HNT shows good dispersion on the TPSS matrix. With the introduction of modified HNT, the FTIR peaks of TPSS have altered at the peak of 3693.21 cm-1 and 1040.05 cm-1. In addition, modified HNT reduced the water absorption rate of the TPSS films. Furthermore, modified HNT showed good resistance to bacterial culture and significantly reduced the biodegradability rate of TPSS compared to pristine HNT. From the findings, HNT can be a potential carrier for antibacterial agents to withstand bacterial attacks.

Development and Characterization of Alginate Based Biocomposite Films Reinforced by Gracilaria Powder

The edible film is a thin sheet that functions as a coating or packaging material on foods that may be eaten simultaneously as packaged products. The ingredient that is often used is alginate made from seaweed. The advantage of using seaweed as a bioplastic material is that it can be produced in a large quantity, low price, and is non-toxic; it can also produce bioplastic that resembles conventional plastic. The experimental method with two components of Completely Randomized Factorial Design was employed in this study (CRFD), the concentration of Gracilaria seaweed powder with four levels (0%, 0.5%, 1%, 1.5%, and 1%) and concentration of alginate with three levels (1%, 1.25%, dan 1.5%). The result showed that the concentration of seaweed powder and concentration of alginate that used in the making of the edible film had a significant effect on the quality of the edible film on all parameters, which is thickness, moisture content, tensile strength, elongation, water vapor transmission rate, water-solubility, color, opacity and surface morphology. There is an interaction between the concentration of seaweed powder and concentration of alginate at the significant effect on the quality of the edible film, which is a concentration of seaweed powder at the level of 1.5% and concentration of alginate at the level of 1.5%. The film has a the thickness of 0.25mm, moisture content of 6.94%, tensile strength of 54.29 Mpa, elongation of 3.26%, the water solubility of 64.41%, water vapor transmission rate of 3242 g/cm2/24 h, and opacity of 81.7%.

A comparative investigation of gelatinized and regenerated starch composites reinforced by microfibrillated cellulose

This research demonstrated a novel and ecofriendly method for producing regenerated starch (RS)/microfibrillated cellulose (MFC) composite films with a nearly 1.4-fold improvement in tensile strength than traditional gelatinized starch (GS) films. Pure starch was dissolved in 14 wt% urea/4 wt% sodium hydroxide (NaOH) solution at 0 °C. Then, RS films and their biocomposite films containing MFC were prepared by dialyzing and solution-casting method. Results showed that the tensile strength and elongation at break of RS increased by 44.8% and 82.4%, compared with that of GS film, respectively. Owing to the adequate dispersion, lower viscosity-average molecular weight, higher amylose content, lower crystallinity and smaller crystal grain size, RS/MFC composite films exhibited significantly improved mechanical properties. The novel strategy used in this study will be helpful in preparing regenerated starch materials with excellent mechanical properties and biodegradability as alternatives to petrochemical plastics for the development of sustainable materials.

Structural and Morphological Properties of Wool Keratin and Cellulose Biocomposites Fabricated Using Ionic Liquids.

In this study, the structural, thermal, and morphological properties of biocomposite films composed of wool keratin mixed with cellulose and regenerated with ionic liquids and various coagulation agents were characterized and explored. These blended films exhibit different physical and thermal properties based on the polymer ratio and coagulation agent type in the fabrication process. Thus, understanding their structure and molecular interaction will enable an understanding of how the crystallinity of cellulose can be modified in order to understand the formation of protein secondary structures. The thermal, morphological, and physiochemical properties of the biocomposites were investigated by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), and X-ray scattering. Analysis of the results suggests that both the wool keratin and the cellulose structures can be manipulated during dissolution and regeneration. Specifically, the β-sheet content in wool keratin increases with the increase of the ethanol solution concentration during the coagulation process; likewise, the cellulose crystallinity increases with the increase of the hydrogen peroxide concentration via coagulation. These findings suggest that the different molecular interactions in a biocomposite can be tuned systematically. This can lead to developments in biomaterial research including advances in natural based electrolyte batteries, as well as implantable bionics for medical research.

Effect of cashew shell biomass synthesized cardanol oil green compatibilizer on flexibility, barrier, thermal, and wettability of PLA/PBAT biocomposite films

Effect of cashew shell biomass synthesized cardanol oil green compatibilizer on flexibility, barrier, thermal, and wettability of PLA/PBAT biocomposite films