Films For Packaging Applications Research Articles

Poly(lactic acid) (PLA)/poly(butylene succinate adipate) (PBSA) films with Micro fibrillated cellulose (MFC) and cardanol for packaging applications

Micro Fibrillated Cellulose (MFC) has emerged as a promising component in film formulations due to its unique barrier prope.rties. In this study, to best of our knowledge, cardanol, a biobased plasticizer derived from cashew processing, was employed for the first time, as a dispersing aid for MFC, during a liquid assisted extrusion technique with a Poly(lactic acid) (PLA)/Poly(butylene succinate adipate) (PBSA) blend. The aim of the work is the production of PLA/PBSA/MFC films for packaging applications. The addition of different MFC amount was investigated (added at 0.5, 0.75 and 1 wt.% concentrations). The results obtained are very interesting, in fact from one hand Cardanol improved the compatibility between PLA and PBSA and avoided the MFC agglomeration. On the other hand, micro fibrillated cellulose ensured a stable film blowing and the achievement of enhanced barrier properties, seal ability and mechanical resistance. In particular, the best result was obtained with an MFC content of 0.75 wt.% for which a good compromise in terms of films ductility, barrier properties and seal ability was achieved.

A comparison study on effects of polyglycerols on physical properties of alginate films

The water solubility and brittleness of unplasticized sodium alginate (SA) films hinder their widely application. Glycerol (GLY), the most commonly used plasticizer, is compatible with alginate due to the formation of hydrogen bonding owing to the hydroxyl functional groups. However, GLY is a small water-soluble molecule, and the resulting leaching problem may lead to decline in mechanical properties of SA films. Aimed at better plasticizers for alginate (ALG) films, this work focuses on the effects of polymerization degree of polyglycerol on physical properties of ALG films. The cross-sectional morphology, crystallinity, mechanical and thermal properties, water solubility, water content and barrier property of ALG films plasticized with GLY, triglycerol (TG) and decaglycerol (DG) were characterized and discussed. Results illustrated that owing to the long molecular chains of TG and DG and their strong interactions with ALG matrix, the plasticized films possessed better mechanical properties, higher water content and lower water solubility. Moreover, it was worth mentioning that even after water treatment, the mechanical properties of ALG-TG and ALG-DG films were superior than that plasticized with GLY. The results of this study were believed to provide particular insights into the plasticization mechanism and the improvement in performance of SA films in packaging applications.

The influence of cassava starch on the properties of PLA/PBS/SCG films for packaging applications

ABSTRACT Fresh fruits and vegetables are perishable products with active metabolism during the post-harvest period; the proper packaging can extend shelf life. The objective of this research has been interested to produce bio-composite film packaging for fresh fruits and vegetables based on poly (lactic acid); PLA, poly butylene succinate; PBS, and natural filler (modified spent coffee grounds; SCG, and cassava starch; ST) by using blow film extruder. The bio-composite film varied in the weight percentage of ST at 0, 5, and 10%wt. control content of PBS at 5%wt. and SCG at 5%wt. The mechanical properties of the PLA blending with PBS can improve % Elongation of the biocomposite film. The cassava starch acts as a nucleating agent present in the cold crystallization temperature was decreased and the degree of crystallinity increased, as well as induced chain mobility, presented in a slight decrease of the glass transition temperature. The SCG and ST particles have a good distribution in the biopolymer phase, the film color was present in light-brown color because of the brown color of SCG particle. The addition of natural filler can improve the UV-light barrier properties, reduce costs, and increase the degradability rate of the film. The WVTR of the biocomposite film was increased with the amount of natural filler added. However, all the biocomposite films presented a water contact angle around 72–75°, this result is essential for the film to apply in a higher humidity environment. The food simulants with aqueous at 40°C and 4°C, 10% ethanol and 3% acetic acid for 10 days were present, the overall migration was less than 10 mg/dm2. The final product from biocomposite film can evaluate the food safety, UV-protection and prolong the shelf-life of fresh vegetables.

Improved barrier properties of biodegradable PBAT films for packaging applications using EVOH: Morphology, permeability, biodegradation, and mechanical properties

AbstractOxygen transmission rate (OTR) and water vapor transmission rate (WVTR) of poly(butylene adipate‐co‐terephthalate) (PBAT) were improved by poly(ethylene‐co‐vinyl alcohol) (EVOH). PBAT/EVOH blends at varying amounts of EVOH were prepared through melt mixing and characterized by OTR, WVTR, SEM, DSC, FTIR, biodegradation in soil, hydrolytic degradation, and tensile tests. EVOH considerably improved the barrier properties of PBAT, example, 77% reduction in OTR and 40% reduction in WVTR at 50 wt% EVOH. Four models of Maxwell, Higuchi, Chiew & Glandt, and Levy were used to evaluate morphology and mechanism of transmission. A high elongation at break of 730% was observed for PBAT/EVOH blends up to 20 wt% EVOH but after that it severely dropped to 350% due to limited compatibility between the two polymers. Limited hydrogen bonding between PBAT and EVOH was observed by FTIR. EVOH accelerated the hydrolytic degradation of PBAT due to its high‐water absorption capacity. This was not observed for biodegradation in soil suggesting that EVOH may retard microbial activity. After 540 h of hydrolytic degradation, the melting point and crystallization temperature of remaining PBAT increased by 5 and 10°C due to more degradation in adipate rubbery domains and less degradation in terephthalate hard segments.

Eco-friendly flaxseed mucilage biofilms fabricated by gamma irradiation

Abstract With looming the global energy crisis and environmental problems Biodegradable green blends based on natural resources and biodegradable polymers have increasingly attracted many researches interest due to their advantages of low cost, use of renewable resource, and biodegradability. In this study, flaxseed mucilage (FM) was extracted with distilled water and utilised to make films with varying ratios of polyvinyl alcohol (PVA) and chitosan (Cs). Gamma irradiation was used as green method to improve the performance of the produced films. Then the films were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), UV–vis spectrophotometry and XRD analysis. The tensile measurements, moisture content were used to evaluate the films’ qualities. When flaxseed mucilage is mixed with PVA/Cs blend, it forms films that are less resistive, less rigid, and more flexible, improves mechanical properties and thermal stability. Films containing mucilage and PVA/Cs blend exhibited a compact and homogeneous structure under SEM, confirming the FTIR spectra that suggested a chemical interaction between these three biopolymers. Based on all above properties of the developed films, it can be envisaged to use these films for packaging applications.

Investigation of Potential Use of Soybean Protein Isolate–Chinese Bayberry Tannin Extract Cross-Linked Films in Packaging Applications

The possibility of using commercial bayberry tannin (BT) from a Chinese source as a cross-linker and functional additive to develop soybean protein isolate (SPI)-based films was explored in this study by using the solvent casting method. In particular, the impacts of BT loading on the tensile strength, microstructure, thermal stability, water resistance and antioxidant capacity were fully investigated. The results reveal that SPI incorporated with BT yielded a phenolic–protein hybrid whose relevant films exhibited an improvement in tensile strength of around two times greater compared with native SPI as a result of the formed interactions and covalent cross-links, which could be proven using FTIR spectroscopy. The introduction of BT also led to the compact microstructure of SPI–BT films and enhanced the thermal stability, while the water vapor permeability was reduced compared with the control SPI film, especially at high loading content of tannin. Additionally, the use of BT significantly promoted the antioxidant capacity of the SPI-based films according to DPPH radical scavenging assay results. On this basis, Chinese bayberry tannin is considered a promising natural cross-linker and multifunctional additive that can be dedicated to developing protein-derived films with antioxidant activity for food packaging applications.

Effect of neem gum on water sorption, biodegradability and mechanical properties of thermoplastic corn starch-based packaging films

ABSTRACT Cornstarch (CS) is an inexpensive and widely available material that can be easily moulded into thermoplastic starch (TPS) films when mixed with the plasticising agent glycerol (CS- Gly). However, its applications in the packaging sector are limited due to its brittleness and high-water solubility. To enhance the functional characteristics of the CS- Gly films in packaging applications, it was blended with neem gum at the concentrations of 0.3 and 0.9% (w/w). The tensile strength, elongation percentage, water sorption and biodegradability efficacy of the blended cornstarch films (CS-Gly-NG) were analysed. The tensile strength of the blended film improved by 1.1-fold compared with CS-Gly (24.49 ± 0.72 MPa) when the natural gum additive was used at 0.30% (w/w). However, once the natural gum content was raised to 0.9% (w/w), the TS of the film decreased to 21.28 ± 1.75 MPa, whereas the resistance to water solubility improved to a greater extent. Moreover, the biodegradability test showed that the blended films (64-69 wt %) disintegrated more rapidly than the CS-Gly film (17.3%) in a setting akin to the natural environment. Therefore, this blended film (CS-Gly-NG) can be used as an alternative to the commercially available non-biodegradable polyethene films and will have a positive impact on the environment.

High-Performanced Hemicellulose Based Organic-Inorganic Films with Polyethyleneimine.

For the high-value utilization of hemicellulose-based composite films, the poor film-forming and mechanical properties of hemicellulose-based composite films must be surmounted crucially. Based on this, hemicellulose-based organic-inorganic composite films with good mechanical properties were prepared from quaternized hemicelluloses (QH), bentonite, and polyethyleneimine (PEI). The QH/PEI/bentonite composite films were prepared by vacuum filtration, and the properties of the composite film were investigated. The results showed that the QH was inserted into bentonite nanosheets through hydrogen bonding and electrostatic interactions. PEI was cross-linked with hemicellulose by hydroxyl groups, electrostatically attracted by the bentonite flake layers. The mechanical properties of the composite films were significantly increased by the incorporation of PEI. When the PEI content was 20%, the tensile stress of the composite film was increased by 155.18%, and the maximum tensile stress was reached 80.52 MPa. The composite films had strong UV absorption ability with the transmittance was almost 0 in the UV region from 200 to 300 nm. The thermal property of composite film was also improved, and the residual mass increased by three times compared to QH. These results provide a theoretical basis for the use of hemicellulose-based composite films in packaging applications.

PLA-Based Materials Containing Bio-Plasticizers and Chitosan Modified with Rosehip Seed Oil for Ecological Packaging.

Several recipes based on PLA, bio-plasticizers, and active agents such as vitamin E and cold-pressed rosehip seed oil encapsulated into chitosan by the emulsion method named here as chitosan modified (CS-M) were elaborated by melt compounding for food packaging applications. Resulted biocomposites have been investigated from the point of view of physical-mechanical, thermal, barrier, antimicrobial, and antioxidant properties to select the formulations with the optimum features to produce food trays and films for packaging applications. The obtained results showed that the elaborated formulations exhibit tensile strength and flexibility dependent on their composition being either rigid or flexible, as well as antimicrobial and antioxidant activity, which will potentially lead to prolonged use for food packaging. The recipe with PLA matrix and 40:60 Lapol®108 as masterbarch/polyethylene glycol (MB/PEG) bio-plasticizers ratio was distinguished by an improvement of over 100 times in terms of flexibility compared with neat PLA, while the highest antioxidant activity (36.27%) was recorded for the sample containing a CS-M and MB/PEG ratio of 60:40. An enhancement of ~50% for the water vapor barrier was recorded for PLA/CS-M_100:0 material. By modulating the MB and PEG bio-plasticizers ratio, the design of new eco-friendly food packaging materials with antimicrobial/antioxidant characteristics by using the existing technologies for processing synthetic polymers (melt mixing, compounding, pressing, thermoforming) has been successfully realized.

Influence of esterification and ultrasound treatment on formation and properties of starch nanoparticles and their impact as a filler on chitosan based films characteristics

Starch nanoparticles were prepared by citrate esterification and ultrasound treatment. With the increase of ultrasonic treatment time, the mean size and PDI of the particles decreased gradually, when the ultrasonic treatment time was 5 min, the prepared starch nanoparticles had a mean size and PDI of 352.8 nm and 0.292, respectively. X-ray diffraction (XRD) showed that the starch nanoparticles prepared by ultrasonic treatment for 5 min had an A-type crystalline structure and a crystallinity of 41.42%. The chitosan composite films were reinforced by esterified starch with different ultrasound treatment times, the results indicated that the addition of starch nanoparticles resulted in a significant increase in the mechanical properties of films.This study indicates that esterification and ultrasound treatment can be used to prepare starch nanoparticles with a higher crystallinity and higher efficiency, which will further promote the application of nanocomposite films in packaging applications.

Characterization of Ecofriendly Poly (Vinyl Alcohol) and Green Banana Peel Filler (GBPF) Reinforced Bio-Films

With an intention to replace the synthetic non-biodegradable films in packaging applications, the polyvinyl alcohol (PVA) blended with green banana peel filler (GBPF), the biodegradable films were prepared by solution casting method with varying the concentrations of GBPF (5–25 wt%) in PVA matrix. The bio films were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermo gravimetric analysis, transmissibility, FESEM, tensile test, film solubility and water absorption, water vapour transmission (WVT), soil burial test. Based on results obtained, the changes evidenced in the FTIR spectrum of this PVA/GBPF biofilms suggest that strong hydrogen bonding is taking place due to interfacial exchanges of GBPF in PVA matrix. The XRD results showed that crystallinity of bio films are greater than PVA. Thermo gravimetric analyses predicted that PVA/GBPF bio films are thermally stable up to 300 °C. The light is 45% for transmittance in the visible light region for the PVA/GBPF (25 wt%) bio film. The FESEM micrographs of biofilms palpable that formation of good physical interaction and compatibility between polymer matrix and GBPF up to 20 wt% of GBPF in PVA Matrix. FESEM results also confirmed that higher loading of GBPF (25 wt%) in PVA matrix, observed voids and agglomerations in film surface. The PVA/GBPF bio films with 20% of GBPF gave the highest tensile strength and young’s modulus 44.5 MPa and 66.7 GPA respectively compared to other samples. The elongation at break decreases with increases the GBPF in PVA Matrix up to 20 wt%.The slight decrease in mechanical properties perceived due to higher loading of GBPF (25 wt%) with PVA matrix. The solubility, water absorption and WVT of the PVA/GBPF bio films increased upon increasing the GBPF content. The biodegradation test results discovered that he highest weight loss at 42.3% (25 wt% of GBPF) probably due to the hydrophilic nature of GBPF in PVA matrix. On the whole, the present investigation confirmed that the PVA/GBPF bio films potential for possible utilization in active packaging applications attributable to its better mechanical, thermal, optical, water absorption and biodegradation properties.

Facile strategy for improvement properties of whey protein isolate/walnut oil bio-packaging films: Using modified cellulose nanofibers

This work aims to explore the addition impact of surface modified cellulose nanofibers (CNF) with poly (methyl methacrylate) (PMMA), CNF-g-PMMA, on the required properties of whey protein isolate (WPI)/walnut oil (WNO) films for packaging applications. WPI/WNO films containing 15 wt% WNO were selected for CNF incorporation. The addition effects of different quantities of unmodified and modified CNF (CNF and MCNF) on mechanical strength, fracture surface morphology, hydrophobicity, water vapor permeability (WVP), water uptake, and transparency of bionanocomposite films were studied. Fracture surface was observed by Scanning electron microscopy (SEM). The maximum ultimate tensile strength (UTS) was obtained to be 9 ± 0.11 and 10.38 ± 0.16 MPa, respectively, at 7.5 wt% of both CNF and MCNF. Compared with WPI/WNO unfilled films, while CNF increased the hydrophilicity of the films, MCNF resulted in more hydrophobic films. In addition, 51% and 64% improvement in water vapor barrier features of CNF and MCNF-loaded films was observed, respectively. The similar trend was occurred for the water uptake behavior. In the case of film transparency, MCNF-loaded films were opaque with 18.12% light transmittance (600 nm wavelength). Generally, WPI films including 15 wt% of WNO and 7.5 wt% MCNF shows promising potential as bio-packaging films.

Preparation and Investigation of Ag Nanoparticles/TOPAS Nanocomposite Films for Packaging Applications

Preparation and Investigation of Ag Nanoparticles/TOPAS Nanocomposite Films for Packaging Applications

Preparation and Assessment of Heat-Treated α-Chitin Nanowhiskers Reinforced Poly(viny alcohol) Film for Packaging Application.

In this study, poly(vinyl alcohol) (PVA) composite films enhanced by α-chitin nanowhiskers (ChWs) were prepared through heat treatment. The obtained membranes were assessed by means of FTIR spectroscopy, X-ray diffraction, thermogravimetric analysis, regular light transmittance, mechanical tests, permeability and water absorption. The influence of the nano-component and heat treatment on the mechanical, thermal and water-resistant properties of the composite membrane were analyzed. From the results of the work, the produced films with excellent barrier properties and inexpensive raw processed materials have great prospects in packaging applications.

Preparation of acylated microcrystalline cellulose using olive oil and its reinforcing effect on poly(lactic acid) films for packaging application

A novel poly(lactic acid) (PLA) based composite, reinforced by microcrystalline cellulose (MCC) was prepared. MCC was modified by esterification reaction using olive oil for improving the compatibility with PLA matrix. The acylated microcrystalline cellulose (AMCC) exhibited reduced polarity in comparison to unmodified MCC. AMCC/ PLA composite films were prepared using solvent casting technique. The effects of the MCC surface modification on morphological, mechanical, physical, thermal, biodegradability and barrier properties of the PLA based MCC composites were studied. FTIR analysis confirmed acylation reaction of MCC. Scanning electron microscopy analysis exhibited a uniform distribution of AMCC in PLA matrix. Barrier properties of AMCC based composites were improved as compared to MCC based composites. The tensile strength and tensile modulus of composite films (at 2 wt.% AMCC) were improved about 13% and 35% as much as those of the pure PLA films, respectively. These biodegradable composite films can be a sustainable utilization of olive oil and microcrystalline cellulose in the food packaging application.

Preparation and characterization of PVA/nanocellulose/Ag nanocomposite films for antimicrobial food packaging

Antimicrobial packaging is an area of emerging interest and is rapidly expanding with application of nanotechnology. The present work investigates the effect of nanocellulose (NC) and Ag NPs on the physical, mechanical and thermal properties of PVA nanocomposite films. The tensile strength of PVA was improved from 5.52 ± 0.27 MPa to 12.32 ± 0.61 MPa when filled with 8 wt% of NC. Nanocomposite films exhibited strong antibacterial activity against both Staphylococcus aureus (MRSA) and Escherichia coli (DH5-alpha). The maximum inhibition zone at 0.5 g Ag NPs with 12 wt% NC against DH5-alpha was 14 ± 0.70 mm. While, the maximum inhibition zone at 0.3 g Ag NPs for 16 wt% NC was 13.6 ± 0.68 mm against MRSA. Moreover, nanocomposites films have no cytotoxicity effect on HepG2 and cell viability was more than 90%. Based on mechanical properties and antibacterial potential of the developed nanocomposite films, it can be envisaged to use these films for packaging applications.

Formation and characterization of BC and BC-paper pulp films for packaging application

It was found beneficial to manufacture bacterial cellulose (BC) obtained from waste food sources to create value-added packaging products by firstly performing purification and disintegration processing of the BC and then reinforcing it with paper pulp. The purification treatment involved using sodium hydroxide (2% w/v at 100°C for 1 h) on BC pulp to remove the bacterial protein and the resulting cultured medium film was characterized with respect to its physical properties. An acid treatment on the purified BC pulp was applied to disintegrate cellulose network before forming a film. The results showed that the sodium hydroxide treatment increased the film burst index and brightness. Heating the BC pulp to 70–100°C in 1.25–5.00% v/v sulfuric acid treatment for 30 min degraded the film’s mechanical properties. Also, a study of the addition and mixing of paper pulps or modified cationic starch to the BC was found to improve the film properties with respect to packaging properties. Inclusion of short fiber paper pulp by 30 wt.% created a good synergistic effect by improving the mechanical properties of film especially for tear strength. Moreover, cationic-modified cassava starch (2% w/w) improved the tensile and burst index as well as resistance to oxygen permeation of the BC film. The results indicate that the BC pulp could be used to improve mechanical properties and resistance to water vapor and oxygen permeation of the short fiber paper pulp film which is ideal for packaging materials.

Flexible and Tough Poly(lactic acid) Films for Packaging Applications: Property and Processability Improvement by Effective Reactive Blending

This study demonstrates a practical means to overcome inherent brittleness problem of poly(lactic acid) (PLA) and make PLA feasible as packaging material. PLA with suitable processability is utterly required for package manufacturers, where flexible, tough PLA film is essential for packers and end users. Highly flexible PLA films with 60-fold increase in elongation at break (Eb) over that of the neat PLA were successfully produced by integrating effective reactive blending and economical film blowing process. The ‘two-step’ blending was used to prepare PLA compound; poly(butylene adipate-co-terephthalate) (PBAT – another biodegradable polymer) was first blended with 0.5–1% chain extender (epoxy-functionalized styrene acrylic copolymer) (ESA), followed by subsequent blending with PLA in twin-screw extruder. Blown films of reactive blend of PLA/PBAT/ESA (80/20/1) showed impressively high Eb of 250% versus a very low Eb of 4% for the neat PLA. Resulting blown films still possessed high modulus of 2 GPa, yield stress of 50–60 MPa and good toughness of ~100 MPa. Significant enhancement in the film's ductility was attributed to homogeneous blend with developed fine strand-like structure as a result of effective in situ compatibilization and good interfacial adhesion between the PLA and PBAT. PLA/PBAT/ESA blend also offered improved processability. Resulting films had acceptable haze of ~10% for common packaging, and clearer film close to PLA (≤2%) could be obtained by designing PLA skin layers in multilayer structure. Films of PLA/PBAT/1%ESA exhibit potential as packaging material; their mechanical and optical properties are comparable with or even exceed some existing films used in the market. Copyright © 2015 John Wiley & Sons, Ltd.

Nanostructured biocomposite films of high toughness based on native chitin nanofibers and chitosan.

Chitosan is widely used in films for packaging applications. Chitosan reinforcement by stiff particles or fibers is usually obtained at the expense of lowered ductility and toughness. Here, chitosan film reinforcement by a new type of native chitin nanofibers is reported. Films are prepared by casting from colloidal suspensions of chitin in dissolved chitosan. The nanocomposite films are chitin nanofiber networks in chitosan matrix. Characterization is carried out by dynamic light scattering, quartz crystal microbalance, field emission scanning electron microscopy, tensile tests and dynamic mechanical analysis. The polymer matrix nanocomposites were produced in volume fractions of 8, 22, and 56% chitin nanofibers. Favorable chitin-chitosan synergy for colloidal dispersion is demonstrated. Also, lowered moisture sorption is observed for the composites, probably due to the favorable chitin-chitosan interface. The highest toughness (area under stress-strain curve) was observed at 8 vol% chitin content. The toughening mechanisms and the need for well-dispersed chitin nanofibers is discussed. Finally, desired structural characteristics of ductile chitin biocomposites are discussed.

Preparation and properties of hydrophobic layered silicate-reinforced UV-curable poly(urethane acrylate) nanocomposite films for packaging applications

Abstract A series of poly(urethane acrylate)/Cloisite 15A (PUA/C15A) nanocomposite films were successfully prepared via a UV-curing system, and their physical and barrier properties were investigated as a function of clay content. The physical properties were strongly dependent upon the chemical and morphological structures originating from differences in Cloisite 15A content. With high clay content, the PUA/C15A nanocomposite films displayed an intercalation/exfoliation combined structure. However, no strong interfacial interactions occurred between the PUA and clay, possibly leading to poor dispersion with relatively high clay content. The thermal stability displayed some enhancement with the introduction of clay into PUA, while the gas and moisture barrier properties showed significant enhancement. The oxygen transmission rate (OTR) and water vapor transmission rate (WVTR) decreased with increasing contents of Cloisite 15A, and varied within the range of 714.0–71.1 cm3/m2 day and 29.9–13.9 g/m2 day, respectively. Thus the enhanced gas and moisture barrier properties of PUA/C15A nanocomposite films make them promising candidates for food and pharmaceutical packaging applications. However, further studies will be performed to increase the compatibility and dispersion of clay particles in the PUA polymer matrix.