Improving barrier and antibacterial properties of chitosan composite films by incorporating lignin nanoparticles and acylated soy protein isolate nanogel

Antimicrobial and UV Blocking Properties of Composite Chitosan Films with Curcumin Grafted Cellulose Nanofiber

Development of chitosan-based antibacterial and antioxidant bioactive film incorporated with carvacrol-loaded modified halloysite nanotube

Poly(lactic acid) (PLA) and poly(propylene carbonate) (PPC) blends with different levels of chain extender were prepared and cast into films. The effect of chain extender on the mechanical, thermal and barrier properties of the films were investigated. With the inclusion of the chain extender, the compatibility and interfacial adhesion between the two polymer phases were significantly improved by a mean of forming a PLA–chain extender–PPC copolymer. Reactions between the chain extender, PLA and PPC were observed through FTIR study. SEM study also confirmed the improved compatibility and interfacial adhesion. The elongation at break of the compatibilized film with optimal amount of chain extender showed dramatic increase by up to 1940 %. DSC studies revealed that chain extender hindered the crystallization of the film which explained the decrease in both water and oxygen barrier when adding chain extender. PLA was found to be able to enhance both oxygen and water barrier of the blend as compared to neat PPC, while in the case of the blend with chain extender, oxygen and water barrier properties exhibited reduction at the beginning. However, when increasing chain extender concentration, these two barrier performance exhibited an upward trend. It was found that PLA/PPC blend showed much better oxygen barrier property than both parent polymers, which can be ascribed to the acceleration effect of PPC on the crystallization of PLA.

Lignin nanoparticles were obtained by a simple acid precipitation method from lignin KOH alkali solution and used as a reinforcing agent to prepare chitosan based lignin nanoparticles nanocomposite films. The effect of lignin nanoparticles concentrations (3, 5, 10, 15 and 30% v/v chitosan solution) on structural, mechanical, water vapor, ultra-violet light barrier, thermal and antioxidant properties of chitosan nanocomposite films was investigated. Particle size analysis reveals that the lignin nanoparticles are formed with an average size of 55 nm. The tensile strength and modulus were increased by 86 and 93%, respectively, in the presence of 15% of lignin nanoparticles compared to the values of chitosan film. The water vapor transmission rate of chitosan-lignin nanoparticles nanocomposite film reduced (32% for 15% LNPs) up to 15% concentrations. The ultraviolet barrier properties of the chitosan films were increased with an increase in the concentration of lignin nanoparticles. Lignin nanoparticles reinforced chitosan films were also significantly enhanced with antioxidant activity in comparison with neat chitosan film.

Fabrication of flexible composite film based on xylan from pulping process for packaging application

Preparation of sulfur nanoparticle-incorporated antimicrobial chitosan films

Flexible hydroxypropyl guar/TEMPO-oxidized cellulose nanofibrils (HPG/TOCNs) composite films were prepared using a conventional solvent-casting technique. Their properties were investigated with a variety of techniques including tensile test, Fourier-transform infrared spectroscopy, scanning electron microscopy, oxygen permeability test, water vapor permeability test, thermogravimetric analysis and water contact angle measurement. The results indicate that HPG and TOCNs have an excellent miscibility and their blending mass ratio can significantly affect the physical, thermal, oxygen barrier and water vapor barrier properties of the composite films. Compared with pure HPG film, the composite films exhibit higher tensile strength and oxygen barrier properties. The water vapor resistance and thermal stability of the composite films are slightly lower than those of HPG film. However, the excellent flexibility, transparency and gas-barrier properties of the environmentally friendly HPG/TOCNs composite film make it a promising packaging material for food and pharmaceutical industries.

Rice husk and nanoclay (montmorillonite)-filled low-density polyethylene composite films were prepared by extrusion blown film. Maleic anhydride-modified polyethylene was used as compatibiliser in various concentrations ranging from 0 to 8 parts per hundred. X-ray difractograms showed an increase in interlayer spacing of montmorillonite from the use of compatibiliser when compared to the uncompatibilised composites; an increase of 20, 33, 36 and 38% for 2, 4, 6 and 8 parts per hundred, respectively, of maleic anhydride-modified polyethylene. With the incorporation of maleic anhydride-modified polyethylene, a better dispersion of the fillers was also achieved, as confirmed by scanning electron microscopy. The compatibilised composite films showed improved tensile and barrier properties. The addition of 4 parts per hundred of the compatibiliser resulted in an improvement by 22% in tensile strength. Furthermore, oxygen barrier property of the composite films improved more than twofold by adding 4 parts per hundred of maleic anhydride-modified polyethylene. This improvement in tensile and barrier properties is due to an increase in the interfacial adhesion between the fibre and matrix and better dispersion of impermeable nanoparticles.

Poly (lactic acid)/Poly (butylene adipate-co-terephthalate) films with simultaneous high oxygen barrier and fast degradation properties

Poor mechanical and barrier properties of biopolymer-based packaging materials limit their widespread applications. The combination of biopolymers with different nature is considered an effective strategy to obtain complementary properties, but this method is always restricted by the incompatibility between matrices. To combine polyamide 4 (PA4) and poly(lactic acid) (PLA), which present excellent oxygen barrier and water barrier properties, respectively, this study puts forward the use of polyvinyl alcohol (PVA) as a bonding layer to connect them and form the PA4/PVA/PLA multilayer films by the layer-by-layer solution casting method. PA4 and PLA are successfully linked through hydrogen bonding and electrostatic interactions with PVA. The cross-section morphology and peel test results proved the good interlayer adhesion between layers. After combination with PA4, the tensile strength, elongation at break, and oxygen barrier properties of PLA were greatly improved. The oxygen barrier of the PA4/PVA/PLA multilayer film was more than 260 times higher than that of the PLA monolayer. PA4/PVA/PLA films presented better thermal stability, transparency, and water barrier properties compared to the PA4 monolayer. Besides, PA4/PVA/PLA multilayer films presented a one-way water barrier characteristic, which made them effective in avoiding the condensation phenomenon when used as fruit or vegetable packaging. The study improved the poor interfacial compatibility between PA4 and PLA and provided a simple strategy for developing sustainable packaging with excellent performance.

Preparation, physicochemical and biological evaluation of chitosan Pleurotus ostreatus polysaccharides active films for food packaging

This work investigates the construction of biodegradable packaging film based on polylactic acid (PLA) reinforced with a novel antibacterial hybrid nanofiller to improve barrier and mechanical properties. The study focuses on incorporating silver‐ingrained silica particles (Ag–In–Si) into PLA matrix to prepare the packaging film (Ag–In–SiPLA) that has superior antibacterial, and barrier property with negligible oxygen and water vapour penetration. The Ag was synthesized using natural neem leaf extract as a reducing agent. To ingrain silver over rice husk silica (Si) an in situ technique was adopted. Hence called Ag‐In‐Si bio‐filler. The Ag–In–SiPLA films were fabricated using melt blending and sheet extrusion methods by means of a micro‐compounder. The addition of rice husk silica served the purpose of cost‐effectiveness of the packaging film along with the enhancement of the oxygen and water barrier properties of the films. The optimized sample (PLA loaded with 3% Ag–In–Si), exhibited optimum transparency, moisture resistance, and barrier properties compared with control PLA film. The experiments on Muntingia calabura (Jamaica cherry) preservation have verified the remarkable effectiveness of Ag–In–SiPLA films in preserving their quality for an extended period. These biodegradable packaging films, composed of food‐grade materials and sustainable ingredients, have the potential to provide a compostable and environmentally friendly solution for various packaging applications. This research shed light on the antibacterial Ag–In–SiPLA film as a long‐term, high‐performance fruit packaging solution.Highlights Novel antibacterial PLA composite with enhanced barrier and mechanical properties. Silver‐ingrained silica particles improve antibacterial and barrier properties. Green synthesis of silver using neem leaf extract Melt blending and sheet extrusion used to create cost‐effective packaging films. Ag–In–SiPLA films extend Muntingia calabura preservation, proving effective.

As a result of environmental concern, there is an increasing interest in the development of biodegradable polymers for packaging with suitable properties, as an alternative to the synthetic petroleum-based polymers. However, such biodegradable polymers are prevented for use in wide industrial and commercial packaging because of their limited gas and vapor barrier properties. This obstacle urges innovative strategies to achieve enhanced gas barrier properties using “bio-layering” technologies. Whey protein isolate (WPI), a by-product of the cheese industry, has quite promising properties for packaging purposes. It possesses good oxygen, aroma, and oil barrier properties; however, its permeability to water vapor is high. In this study, several WPI coatings were obtained, adding polyvinyl alcohol and pectin to improve the coated film properties; in addition, nanoclays were used to improve water vapor barrier properties. Comparison of neat poly (lactic acid) film versus poly (lactic acid) coated with WPI presented advantage of the later: improvement of about 90% in the oxygen barrier properties and about 27% in the water vapor barrier properties. Copyright © 2016 John Wiley & Sons, Ltd.

Hemicellulose has potential advantages in food packaging because of its abundant reserves, degradability and regeneration. However, compared with fossil-derived plastic films, hemicellulose-based films show inferior hydrophobicity and barrier properties because of their low degree of polymerization and strong hydrophilicity. Focusing on such issues, this work covers the modification of a xylan/polyvinyl alcohol (PVOH) film using 1,2,3,4-butane tetracarboxylic acid (BTCA) as esterifying agent. The thus prepared composite film was more compact owing to the esterification reaction with xylan and PVOH forming a crosslinked network structure and reducing the distance between molecular chains. The results showed that BTCA had a positive effect on the oxygen barrier, hydrophobicity and mechanical properties of the composite film. The tensile strength of the xylan/PVOH composite film with 10% BTCA content increased from 11.19 MPa to 13.99 MPa. A 20% BTCA loading resulted in an increase in the contact angle of the composite film from 87.1° to 108.2°, and a decrease in the oxygen permeability from 2.11 to 0.43 (cm3·µm)/(m2·d·kPa), corresponding to increase in the contact angle by 24% and a decrease in oxygen permeability by 80%. The overall performance enhancement indicates the potential application of such composites as food packaging.

Potential of polysaccharides for food packaging applications. Part 2/2: An experimental review of the effect of aging conditions on the functional properties of polysaccharide films