Biodegradable Composite Films Research Articles

Preparation and Characteriztion of Biodegradable Composite Films from Poly (vinyl alcohol) and Natural Proteins for Food and other Packaging Applications

Packaging materials provide a means to preserve, protect, merchandise, market and distribute foods. Synthetic polymers are widely and massively used to make packaging materials for diverse applications.The environmental issues due to the non-degradability of the polymer packaging material wastes demands biodegradable and environmental friendly polymers for these applications. Hence increasing research is focussed to manufacture packaging materials from biodegr-adeable synthetic and natural polymers.The present study involves fabrication of biodegradable composite polymer films by solution casting from natural biopolymers such as whey and soy proteins, and synthetic biocompatible polymer such as poly(vinyl alcohol) using UV light, glutaraldehyde etc as croslinkers, and glycerol as a plasticizes. The prepared films were evaluated for their tensile strength, water vapour permeability, thermal stability, biodegradability, structure, morphology etc. The tensile strength in terms of breaking load and % elongation measured on non standard dimension of the films were in the range 1.6 -4.7 kgf and 75-400 % respectively. Thermogravimetric studies indicated that polymer films were sufficiently thermostable for packaging uses. Soil burial test and X-ray diffraction studies of the films indicated that they were biodegradable and predominantly amorphous respectively. Glutaraldehyde crosslinked composite polymer films were found to have improved antimicrobial properties compared to the uncrosslinked film. The water vapour permeability of the fabricated films were within the acceptable range of values (5.208 -7.81 g/cm2h * 10-5 ) reported for typical biopolymer films used in packaging applications. The fabricated composite polymer films may be exploited for commercial packaging applications.

Thermally stable, enhanced water barrier, high strength starch bio-composite reinforced with lignin containing cellulose nanofibrils

Lignin containing cellulose nanofibrils (LCNF) were obtained by mechanically fibrillating unbleached tree bark after alkaline extraction and used as a reinforcement in thermoplastic starch (TPS) to develop novel biodegradable composite films. With the addition of 15 wt % LCNF, the tensile strength and modulus of the composites increased by 319 % and 800 % compared to neat TPS films, respectively. The crystalline property of cellulose and the high interaction between TPS and LCNF improved the mechanical property of the composite films. The composite film Tonset and Tmax were 263.1 °C and 316.5 °C, respectively, compared to 250.5 °C and 297.3 °C for neat TPS. The composite films also showed higher water barrier property. Experimental results showed that LCNF features a high lignin content. Lignin, a natural polymer, contains hydrophobic and aromatic groups and, thus, can increase the water barrier property and thermal stability of TPS/LCNF composite films.

Characterization of Aloe vera-banana starch composite films reinforced with curcumin-loaded starch nanoparticles

Abstract Interest in developing biodegradable composite films that can incorporate bioactive substances and have and active role in food packaging, has been growing in the last decades. Curcumin, known for its antimicrobial and antioxidant activity has been proposed as an active molecule that can be incorporated into biodegradable films. This work proposes the development and characterization of composite films made from banana starch and Aloe Vera gel incorporated with curcumin-loaded native and acetylated starch nanoparticles. The effect of the curcumin-loaded nanovehicles in the mechanical, barrier, and thermal properties of the composite films was studied. In this sense, the study noted that inclusion of highly hydrophobic curcumin leads to a reduction of the film’s water vapor permeability while enhancing the film’s tensile strength. Finally, this paper reports the release profiles of curcumin from the composite film in different food simulants, observing that it is possible to control curcumin release in different foodstuffs by changing the characteristics of the nanovehicles incorporated.

Facile fabrication of cellulose composite films with excellent UV resistance and antibacterial activity

Research on biodegradable cellulose composite film with unique properties is of significance to alleviate current dependency on petroleum-based polymers, and to promote highly efficient utilization of lignocellulosic biomass. Lignin nanoparticles (LNPs) have been considered as a promising material for high value-added products. In this study, LNPs were prepared from corncob lignin via anti-solvent precipitation method, and then characterized by FTIR, TGA, AFM, and NMR. The CNF@CLNPs composite film was fabricated by blending CLNPs with CNF. The results showed that the CLNPs had an average diameter of about 118 nm, meanwhile the main structures and properties of corncob lignin were maintained. The CNF@CLNPs composite film exhibited a high ultraviolet resistance, and a good antibacterial activity against both Escherichia coli and Staphylococcus aureus. It is expected that the CNF@CLNPs composite film would have potential applications in outdoor materials and food packaging.

Potential of using multiscale corn husk fiber as reinforcing filler in cornstarch-based biocomposites

In this study, biodegradable composite films were prepared by using thermoplastic cornstarch matrix and corn husk fiber as a reinforcing filler. The composite films were manufactured via a casting technique using different concentrations of husk fiber (0–8%), and fructose as a plasticizer at a fixed amount of 25% for starch weight. The Physical, thermal, morphological, and tensile characteristics of composite films were investigated. The findings indicated that the incorporation of husk fiber, in general, enhanced the performance of the composite films. There was a noticeable reduction in the density and moisture content of the films, and soil burial assessment showed less resistance to biodegradation. The morphological images presented a consistent structure and excellent compatibility between matrix and reinforcement, which reflected on the improved tensile strength and young modulus as well as the crystallinity index. The thermal stability of composite films has also been enhanced, as evidenced by the increased onset decomposition temperature of the reinforced films compared to neat film. Fourier transform infrared analysis revealed increasing in intermolecular hydrogen bonding following fiber loading. The composite materials prepared using corn husk residues as reinforcement responded to community demand for agricultural and polymeric waste disposal and added more value to waste management.

Preparation of chitosan/zinc oxide/Melissa officinalis essential oil nano-composite film and evaluation of physical, mechanical and antimicrobial properties by response surface method

The use of biodegradable films for releasing antimicrobials into food packaging is an active packaging type in the food industry. In this study, an antibacterial film was produced based on the chitosan biopolymer, in which zinc oxide (ZnO) particles (0, 1 and 3% (W/V)) and Melissa essential oil (0, 0.25 and 0.5% (W/V)) were used for the enhancement of the biopolymer properties based on the central composite design (CCD). Physical, color, antimicrobial and mechanical properties including tensile strength (TS) and strain to break (STB), FT-IR, XRD and surface morphology of chitosan/Melissa essential oil/ZnO (CS/MEO/ZnO) film were investigated. The results of surface morphology showed that the sizes of zinc oxide particle in the polymer structure are in the nanometer size (40–80 nm). Increasing the concentration of zinc oxide nanoparticles and Melissa essential oil increased the TS of films and reduced water solubility and water vapor permeability (WVP). The results of color analysis showed that by increasing the concentration of zinc oxide, opacity was increased. Increasing the concentration of Melissa essential oil increased the transparency of film samples. The results of antimicrobial properties showed that increasing the concentration of zinc oxide and Melissa essential oil increased the antibacterial properties of composite film. The overall result of this study showed that the resulting composite film can be used as a new antimicrobial biodegradable composite film in food packaging industry.

Effect of nanosilica and neem tree oil on antimicrobial, thermal, mechanical and electrical insulate of biodegradable composite film

In this present investigation, the antimicrobial, mechanical and electrical insulation behaviour of neem oil and nanosilica modified biodegradable polybutylene adiple Co-terephthalate composite films were studied. The principal aim of this present investigation was to study the antimicrobial, mechanical and electrical properties of neem tree oil reinforced nano silicon oxide added polybutylene adiple Co-terephthalate composite films for food packing and electronic part packing industries. Neem oil of 5 and 10 wt% and nanosilica of 1 and 3 wt% were reinforced with PBAT thermoplastic and made as a film for further analysis. The FT-IR spectral analysis revealed that the effective blending of neem oil with PBAT was achieved in 10 wt% without any precipitations and phase extinguishing. The anti-microbiological results showed that the addition of 10 wt% of neem seed oil and 3 wt% of nanosilica into PBAT thermoplastic improved the antimicrobial resistance than virgin PBAT. Similarly, the TGA graph revealed that adding 10 wt% of neem oil along with 3 wt% of nanosilica greatly improved the mass decomposition stability. The SEM morphology of BPAT/neem bio blend shows homogeneous mixture and uniform dispersion of nanosilica on matrix. The mechanical results revealed that adding 10 wt% of neem into PBAT polymer reduces its cross linking density and mechanical properties, whereas further addition of nanosilica of 3 wt% improved the tensile strength and percentage of elongation. The dielectric results showed that addition of non-polar neem oil and nanosilica in PBAT bio polymer did not alter the dielectric properties. These antimicrobial, thermal and mechanically strengthened dielectric unaltered PBAT thermoplastic polymers are highly preferred in food packing industries, electronic goods packing and medical engineering where high resistance to microbiological activates are required.

Development of biodegradable composite chitosan-based films incorporated with xylan and carvacrol for food packaging application

Abstract This paper presents an experimental study on the development of uniform and homogeneous composite chitosan based flexible films containing various amount of xylan from 0 to 25 wt percent and carvacrol. The influence of the addition of xylan on the composite films was evaluated by measuring the tensile strength, moduli and elongation at break. The tensile strength and moduli of composite films containing 20 wt. % increase considerably by 73.9% and 66.8%, respectively. The elongation at break also increases considerably with the addition of xylan, the maximum value of 4.5% was obtained with film containing 8 wt.% xylan. Thermogravimetric analysis (TGA) indicates that the addition of xylan reduces the rate of degradation and shifts the thermal degradation peak from 290.7 to 276.8 °C for the film containing 20 wt.% xylan. Investigation on the antibacterial activity showed that Tetracycline reference control is effective in controlling the growth the bacteria while the incorporation of carvacrol in chitosan xylan composite is not effective.

Eco-compatible cassava starch films for fertilizer controlled-release

As an attempt to tackle the environmental issues derived from the use of non-degradable plastic and fertilizers overuse, such as irreversible soil pollution, this work focuses on the development of a fertilizer controlled-release, bio-based and biodegradable composite films for agricultural applications. Cassava starch and bagasse composite materials containing urea as active compound and plasticizer were prepared to achieve this purpose, analyzing their properties and stability during storage. Moreover, their biodegradation rate and urea release in soil were also assessed. Films were based on cassava starch with cassava bagasse particles as reinforcing agent and urea contents ranging from 0 to 50 wt% with respect to starch content. Urea proved to be an effective plasticizer of the matrix and films became more flexible with storage time. In addition, the material biodegradation rate in soil increased with urea content. Films with 50 wt% urea content showed a total weight loss of 57% and 95% release of the active compound after 15 days. The results indicate that this approach is adequate for the design of eco-compatible starch-based composite materials for urea dosage in soil based on cassava starch and bagasse.

Comparative study of polystyrene/chemically modified wheat straw composite for green packaging application

The recalcitrant nature of native wheat straw (WS) biomass results from cellulose, lignin, hemicellulose and some amount of protein embedded together in a composite structure causing poor adhesion to a polymer matrix composite. Adequate pre-treatment can curtail the recalcitrance structure of WS and enhance the susceptible cellulose area to synthesize a green composite. This paper examined the effect of various chemical pre-treatment procedures in improving surface morphology of wheat straw. Moreover, polystyrene (PS), PS (60 wt%)/native WS (40 wt%), PS (60 wt%)/NaOH-treated WS (40 wt%), PS (60 wt%)/HCl-treated WS (40 wt%), and PS (60 wt%)/H2SO4-treated WS (40 wt%) composite films were prepared using solution casting method. The changes in crystalline structure, hydrophobicity, water vapor migration rate, and thermal and mechanical stabilities of synthesized bio-composites were examined. From the results it can be concluded that the alkali-treated WS is highly compatible with the PS and can be used to synthesize a biodegradable composite film for various industrial green packaging applications.

A novel nanosilica‐supported ultraviolet absorber for the preparation of robust biodegradable plastic film with high ultraviolet aging resistance

A novel type of nanosilica‐supported ultraviolet absorber (SiO2‐N‐0) was successfully prepared by chemically grafting 2,4‐dihydroxybenzophenone (UV‐0) onto the surface of nanosilica (SiO2) with the aid of a coupling agent via a sol–gel method, which was confirmed by Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, and thermogravimetric analysis. SiO2‐N‐0 was then incorporated into poly(butylene adipate‐co‐terephthalate) (PBAT) to fabricate biodegradable composite film with a casting method. As expected, SiO2‐N‐0 was homogeneously dispersed in PBAT matrix, leading to higher mechanical strength and lower water vapor transmission of PBAT/SiO2‐N‐0 film than those of PBAT/SiO2/UV‐0 film. More importantly, because of its low migration and volatility, SiO2‐N‐0 endowed PBAT film with excellent aging resistance under ultraviolet radiation than did the corresponding low molecular ultraviolet absorber UV‐0. Taken together, these results suggest that thus prepared PBAT/SiO2‐N‐0 composite film may find many applications, especially as biodegradable agricultural mulch film. POLYM. COMPOS., 40:4154–4161, 2019. © 2019 Society of Plastics Engineers

Biobased Cellulose Nanofibril-Oil Composite Films for Active Edible Barriers.

Low-concentration oil-in-water emulsions stabilized by cellulose nanofibrils (CNFs) extracted from primary plant cell wall materials are used to prepare thin biobased CNF–oil composite films by solvent casting. Flexible, transparent, and biodegradable composite films are obtained, with increased thermal stability (up to 300 °C) as the oil concentration increases. Examination of the microstructure demonstrates a clear dependency on the oil content, as a multilayered structure where the oil phase trapped between two layers of CNFs is appreciated at high oil concentrations. The embedded oil significantly influences the mechanical and wetting properties of the films, confirming their potential for use in packaging systems. Encapsulation of curcumin in the composite films leads to an increased antioxidant (up to 30% radical scavenging activity) and antimicrobial activity, inhibiting the growth of foodborne bacteria such as Escherichia coli. The resulting composite films show promising results in the field of active packaging for applications in the food, pharmaceutical, and cosmetic industries.

Development of black and biodegradable biochar/gutta percha composite films with high stretchability and barrier properties

It is necessary to develop biodegradable composite films for reducing environmental pollution. Black and biodegradable biochar/gutta percha composite films were developed by adding different contents of biochar (0, 2, 4, 6 and 8%, w/w) into the gutta percha matrix. The results showed that the biochar effectively improved the hydrophobicity and mechanical properties compared with the control film. Moreover, the biochar/gutta percha composite films showed high stretchability and barrier properties. In particular, the 2% BC film had the highest tensile strength (18.3 MPa) and elongation at break (280.4%) and the lowest water vapor permeability value (0.09 × 10−9 g/m/h/Pa) at 34% relative humidity. However, the melting enthalpy (ΔHm) and crystallinity decreased. In addition, these composite films exhibited little electromagnetic interference shielding with a reflection loss up to −1.79 dB at 8.2 GHz. Finally, the composite films were more biodegradable than PE film after 60 days in soil.

Mechanical and physical properties of regenerated biomass composite films from lignocellulosic materials in ionic liquid

As an important sustainable source of biomass, lignocellulosic materials are highly recalcitrant to biotransformation, which limits their use and prevents economically viable conversion into value-added products. Ionic liquids (ILs) have emerged as attractive solvents for lignocellulosic biomass pretreatment in the production of biochemical feedstocks. In this work, a mixture of wood powder and waste paper was dissolved in the ionic liquid 1-allyl-3-methylimidazolium chloride ([AMIM]Cl). Composite films were made from the regenerated lignocellulosic materials in [AMIM]Cl by adjusting the ratio of the raw materials. The physical and mechanical properties of biomass composite films were determined by optical microscopy (OM), Fourier transform infrared (FTIR) spectra, X-ray diffraction (XRD), and tensile strength tests. The results indicated that lignocellulosic materials were dissolved in [AMIM]Cl by destroying inter- and intramolecular hydrogen bonds between lignocelluloses. With increasing waste paper cellulose content, the dissolution of the fir powder in [AMIM]Cl was accelerated, and the tensile strength and elongation at break of the composite films increased. The rate of dissolution initially rose rapidly with increasing content of waste paper cellulose content, but the rate leveled off when the content was above 40%. This research highlights new opportunities for biodegradable composite films made from waste biomass.

Halloysite nanotubes as nanocarriers for plant herbicide and its controlled release in biodegradable polymers composite film

The active ingredients of eupatorium adenophora spreng (AIEAS) as botanical herbicide were first loaded in halloysite nanotubes (HNTs) with the amount of 7.26 wt%, and then the AIEAS-loaded HNTs (HNTs-AIEAS) were further incorporated into poly(vinyl alcohol)/starch composites (PVA/ST, with the weight ratio of 80/20) to prepare a dual delivery system for AIEAS. The AIEAS loaded in HNTs showed much slower release from PVT/ST film through soil layer than free AIEAS. For example, after ten times of leaching in water, the total release amount of AIEAS from PVA/ST film with HNTs-AIEAS was only 31.7%, while this value reached 61.3% in PVA/ST film with free AIEAS. Moreover, HNTs-AIEAS could significantly improve the erosion resistance of PVA/ST film, which only reinforced the film skeleton, thus delaying the release of herbicide, but also significantly prolonged the service life of PVA/ST/HNTs-AIEAS composites film as biodegradable agricultural mulch film.

Preparation and characterization of cellulose nanofibrils from coconut coir fibers and their reinforcements in biodegradable composite films

Coconut waste husks were effectively utilized in this study as a promising cellulose source for production of purified coir cellulose (PCC) after multiple treatments, e.g., ultrasonic-assisted solvent immersion, alkaline treatment, bleaching, etc. As to upgrade the self-value of coir cellulose based products and further broaden their applications in light of biorefinery, coir cellulose nanofibrils (CCNF) with an average diameter of 5.6 ± 1.5 nm were prepared by selection of a milder TEMPO-mediated oxidation system (TEMPO/NaClO/NaClO2, pH = 4.8) accompanied by subsequent ultrasonic treatment. The cellulose nanofibrils were comprehensively characterized in terms of their functional groups, crystallinity, morphology, and thermal stability. The potential reinforcement of CCNFs as a filler for biodegradable PVA based films was investigated and the main properties including tensile strength, elongation at break, and thermal stability of CCNF/PVA composite films were significantly enhanced especially when 3% of CCNF (based on dry film weight) was applied.

Tough, strong, and biodegradable composite film with excellent UV barrier performance comprising soy protein isolate, hyperbranched polyester, and cardanol derivative

Tough and biodegradable soy protein isolate film with excellent UV barrier performance by hyperbranched polyester, and cardanol derivative.

Neem leaves extract based seaweed bio-degradable composite films with excellent antimicrobial activity for sustainable packaging material

Seaweed-based biodegradable films were studied with incorporation of different concentrations of neem (Azadirachta indica) leaf extract. The films were fabricated via a hot casting method and were subjected to physical, mechanical, and morphological examinations to investigate the effect of the neem extract reinforcement in the edible film. There was moderate improvement in the tensile strength, contact angle values, and elongation at break values, while the water vapour permeability was reduced with the addition of neem leaves extract beyond 5 w/w %. Analysis of the morphology of the fabricated films confirmed that there was good dispersion of the neem leaves extract in the seaweed matrix films, which resulted in the enhanced mechanical strength of the fabricated films. Moreover, the fabricated composite films showed excellent antimicrobial activity towards both Gram-positive bacterium subclasses (coccus and bacillus), which is highly desirable for the packaging material in the current scenario. So far, this is the first report on neem leave based seaweed films with enhanced antimicrobial activity, which makes them suitable for sustainable packaging application. The experiments showed that the seaweed-based film incorporated with neem leaves extract has potential application as an active packaging material due to its enhanced mechanical properties and antimicrobial activity.

Physical properties and structural characterization of starch/polyvinyl alcohol/graphene oxide composite films

The starch/polyvinyl alcohol/graphene oxide composite film was prepared by casting method by adding GO to starch/PVA matrix. The effects of GO with different concentrations on the performance of the composite film were studied. With the increase of GO concentration, the thickness increased, the tensile strength increased first and then decreased. When the concentration of GO reached 2 mg/ml, the tensile strength was 25.28 MPa reaching the maximum. The increase of GO concentration caused the enhancement of film's moisture resistance. Through FTIR, SEM and TGA analysis, it was found that the addition of GO did not change the composition of the film, but it could change the phenomenon of matrix agglomeration and improve the thermal stability of the film. The preparation of composite films by adding GO could improve the properties, expand the application of nanomaterials in the food packaging field, and expand the research of biodegradable composite films.

Hydroxypropyl starch‐based films reinforced by incorporation of alkalized microcrystalline cellulose

Environment friendly and biodegradable composite films comprised of alkalized microcrystalline cellulose (MCC) and hydroxypropyl starch (HPS) have been developed by a solution casting method. The particle sizes and crystal structure of alkalized MCC have been investigated by Laser Diffraction Particle Size Analyzer and X‐ray diffraction. The surface morphology of MCC/HPS films have been observed by scanning electron microscopy. Meanwhile, the enhanced thermal stability has been confirmed by thermogravimetric analysis and Differential scanning calorimetry. Incorporating alkalized MCC into HPS, composite films show raised glass transition temperature (increased by 13.31%), strengthened mechanical properties (increased by 13.72%), and reduced water vapor permeation (reduced by 75.27%). As‐prepared alkalized MCC/HPS composite films could not only be employed as an most promising candidate for developing green food packaging materials, but also endow themselves with substitute for petroleum plastic products while concomitantly promoting the development of sustainable materials. POLYM. COMPOS., 40:E856–E864, 2019. © 2018 Society of Plastics Engineers