Permeability Of Films Research Articles

Preparation and Characterization of Chitosan‐Tremella fuciformis Polysaccharide Edible Films for Meat Preservation

ABSTRACTThe objective of this research was to develop and analyse a chitosan‐Tremella fuciformis polysaccharide (CS‐TFP) edible film using chitosan (CS) and Tremella fuciformis polysaccharide (TFP) as the primary raw materials. The findings revealed significant improvements in the thickness, solubility, opacity, mechanical properties and barrier properties (water vapour and oxygen permeability) of the chitosan film upon the addition of TFP, but water content and hydrophobicity were reduced. Moreover, TFP addition markedly enhanced the antibacterial and antioxidant activities of the chitosan films. Structural analysis of the CS films and CS‐TFP edible films indicated that the formation of hydrogen bonds and high compatibility between CS and TFP. Specifically, TFP increased crystallinity, reduced roughness and improved the compactness of the edible film. This increase in compactness was directly linked to enhanced physical properties, whereas increased crystallinity contributed to better thermal stability. Furthermore, the application of CS‐TFP‐3 edible films in chicken preservation proved that they could significantly delay the deterioration of chicken. Findings in this study suggested that CS‐TFP edible film as a bioactive packaging material showed great potential to preserve chicken meat and extend the shelf life.

Starch-based films with incorporated apple peel and chokeberry polyphenols

The aim was to prepare biodegradable starch-based films with active substances, and to examine the influence of temperature (80, 90, 99 °C), plasticizer (glycerol 1, 2, 4 %), and incorporation of phenolic compounds form apple peel and chokeberry on the properties of the films. The hygroscopic nature of glycerol affected the film properties. With the increase in glycerol content the water content, water solubility, and water vapor permeability of films significantly increased, while the swelling degree and hardness significantly decreased (p<0.05). Temperature did not have a significant influence on film properties. Phenolic compounds from apple peel and chokeberry increased the water solubility of films, and the loss of weight in water, in some cases significantly (p<0.05). The increase in hydrophilicity of films after the addition of phenolic compounds could be suggested, which affected the higher solubility and weight loss in the water. However, phenolic compounds decreased the swelling degree of films, in some cases significantly (p<0.05). The denser structure of films with the addition of phenolic compounds can be suggested, which caused the swelling degree to decrease. All films were biodegradable in water (the weight loss 18-38 %). The properties of starch-based films need to be studied and adjusted further for packing foods.

Improvement of the properties of essential oil-starch film with whey protein isolated fibril and sodium caseinate

Essential oil-starch films are important bioactive films, but their properties are not good enough and need improved. In this work, sodium caseinate (CAS) was utilized to improve the distribution and release of Cinnamon essential oils (CEO), and whey protein isolate fibril (WPIF) of different loadings (0 %, 4 %, 8 % and 12 %, w/w) in starch basis was added to enhance the mechanical properties of starch films. Physical, mechanical, thermal, structural, antibacterial properties, and essential oil release in the films were investigated. CAS-CEO nanoemulsion (190.7±9.4 nm) promoted the compatibility between starch and WPIF. The addition of CAS-CEO nanoemulsion and WPIF synergistically enhanced the tensile strength, stiffness, crystallinity and antibacterial effects, reduced the water vapor permeability of films, and especially delayed the release of essential oil from the films. The starch film composited with CAS-CEO nanoemulsion and appropriate loading of WPIF (8 %) significantly improved the film properties, but the addition of 12 % WPIF disrupted the properties, which might be attributed to the excessive aggregation of WPIF. The work provided useful information for improving the properties of CEO films via adding the emulsifier of CAS and the texture booster of WPIF, which could help to improve the film properties containing oil-soluble bioactive agents.

Permeable Film Enabled Evaporation Control of Liquid‐Assisted Assembly for Printing High‐Uniformity Functional Patterns

Permeable Film Enabled Evaporation Control of Liquid‐Assisted Assembly for Printing High‐Uniformity Functional Patterns

Molecular flow model of gas transmission rate test device with auxiliary chamber for high barrier film

The oxygen barrier test of plastic film is an important step in the sealing and preservation process of food and drugs, and the system leakage is pivotal factor of the test device that affecting the efficiency and accuracy. In order to reduce the impact of system leakage on the oxygen barrier detection of plastic film, a test device with an auxiliary seal on the outer layer is designed by using series dual sealing structure technology. Based on the molecular flow states hypothesis, according to the conservation of gas throughput and the invariance of flow resistance, a mathematical model and simulation platform for permeability test of flexible packaging materials with high barrier with outer auxiliary sealing chamber and forward leakage are established. By using Laplace transform method, the analytical solutions and corresponding characteristics of the pressure and leakage rate changes in the inner and outer sealing chamber are discussed, and the equivalent test time expression of the forward leakage test device is derived. The simulation and measured results show that the equivalent test time of the test device with the outer auxiliary sealing chamber is much longer than 24 h, and the test results of the pressure change of the inner sealing chamber are the same as the ideal leak-free system. Compared with the single sealing structure test device, the test error of the same high barrier film permeability test is negligible. By using the test device with an auxiliary sealing chamber, the oxygen barrier property can be accurately measured without any leak measurement and correction.

Cellulose nanofibrils-based packaging films synergistically reinforced by lignin and tea polyphenols for strawberry preservation

Developing biomass-based food packaging materials could alleviate resource scarcity and environmental pollution. This study successfully fabricated cellulose nanofibrils-based packaging films synergistically reinforced by lignin and tea polyphenols for fruit preservation. Thanks to the abundant carboxyl and hydroxyl groups in modified lignin and tea polyphenol, the composite film delivered the highest tensile strength and Young’s modulus of 230.7 MPa and 11.9 GPa, respectively. The water vapor permeability (WVP) and oxygen permeability (OP) of composite film were as low as 2.53 × 10−11 g m−1 s−1 Pa−1 and 1.69 × 10−16 cm m−2 s−1 Pa−1, respectively, demonstrating excellent barrier performance. Furthermore, the composite film possessed remarkable antibacterial (100 % antibacterial activity against two types of bacteria), antioxidant (DPPH free radical scavenging activity of 90 %), and UV shielding properties (impressive UV shielding rate of 99.0 %). Strawberry preservation experiments showed that these composite films could significantly extend shelf life, owing to the excellent barrier and antimicrobial properties. Our research indicated that these composite films could be promising food packaging material compared with traditional plastic and showed great application potential in fruit preservation.

High moisture permeable cellulose diacetate films by reactive polyethylene glycol plasticizers

High moisture permeable cellulose diacetate films by reactive polyethylene glycol plasticizers

Surface modification of talc powder by silane functionalized polycarboxylates and its effect on the performance of polyvinyl chloride composite

AbstractIn this work, modified polycarboxylates were prepared by copolymerizing γ‐Methacryloxy propyl trimethoxyl silane (KH‐570) with acrylic acid and allyl polyoxyethylene ether. Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR) indicate that silane copolymerized polycarboxylates have been successfully synthesized. The talc powder (TP) modified with synthesized polycarboxylate and modified polycarboxylates was blended with polyvinyl chloride (PVC) to prepare composite films. FTIR and x‐ray photoelectron spectroscopy (XPS) were used to determine changes in the surface properties of unmodified and modified TP. The effects of TP and polycarboxylate‐modified TP on the tensile properties, light transmission and moisture transmission of the PVC composite films were investigated. Compared with untreated TP filled PVC film, the PVC composite films filled with organosilicon polycarboxylate‐modified TP exhibit enhanced tensile strength, light transmittance, barrier, and other properties. Especially, the tensile strength of PVC composite film filled with 7 wt% Si0.5‐PCE modified TP is increased by 19.5% and the elongation at break is increased by 21.6%. In addition, the moisture permeability of the composite film is reduced by a maximum of 80.6% compared with the pure PVC film.

Preparation and characterization of gelatin/Kappa-carrageenan halochromic films containing curcumin for active and smart food packaging

Gelatin (GE) and Kappa carrageenan (KC) are prominent examples of natural, biodegradable polymers for food packaging. In this study, edible films were fabricated using various GE:KC ratios (25:75, 50:50, 75:25), and distinct concentrations of curcumin (Cur; 1%, 2%, and 4%). Then, spectroscopic assessments were conducted, including Fourier transform infrared (FTIR), morphological characterization via scanning electron microscopy (SEM), and sensitivity to pH variations. Furthermore, the efficacy of these halochromic films in preserving food quality and inhibiting spoilage was assessed. It was shown that the incorporation of Cur to GE-KC hybrid films produces an active and smart biodegradable film with a suitable color identifier. Adding Cur to GE-KC polymer significantly decreased the solubility and permeability of the optimal films compared to the control samples (without Cur) (p < 0.05). Also, Cur increased the tensile strength and stiffness of films in comparison to the control films. FTIR results indicated the creation of appropriate interactions between Cur and other components of the films. In addition, the films including Cur had more antioxidant power than the film without Cur. It can be concluded that the halochromic film prepared from GE-KC containing 2% Cur can be used as a suitable coating for food products and monitoring their freshness.

Characterization of polyethylene films drawn by machine direction orientation and consequences on their photooxidation

The effect of uniaxial drawing by Machine Direction Orientation (MDO) on polyethylene films was first studied by complementary analytical methods. XRD and polarized FTIR spectroscopy revealed the transformation of the initial spherulitic structure of PE into microfibrils composed of small crystalline blocks connected by amorphous chains oriented along the drawing direction. No stress-induced crystallization was observed upon MDO processing, but the permeability to oxygen was reduced by 30 % owing to this morphology change. In a second time, the effect of photooxidation on undrawn and MDO-drawn films was studied. There was no difference in the photooxidation kinetics and stoichiometry between them. A slight reorganization of the polymer structure due to physical ageing was observed before any photooxidation, but no change in orientation occurred upon photochemical ageing. Finally, the oxygen permeability of undrawn and MDO-drawn films decreased owing to the changes brought by photooxidation, especially the formation of polar functions within the initially apolar polyethylene and the occurrence of chemicrystallization.

Fabrication of bamboo nanocellulose fibril-based food packaging with dual-antimicrobial property

The development of cellulose-based packaging films with excellent antimicrobial properties and biocompatibility has garnered significant attention. In this work, nanocellulose fibrils (NCFs) derived from from bamboo parenchyma cells were utilized to fabricate nanocomposite film with antimicrobial properties. This system exhibited distinct release behaviors for two antimicrobial agents, with the slow release of Ag nanoparticle (AgNP) in the initial stage contributed to delaying food spoilage, while the subsequent pH change in the microenvironment facilitated the release of essential oil of sour orange blossoms (SEO) for secondary antimicrobial activity. Additionally, the composite film demonstrated improved thermal stability and UV blocking capacity. Moreover, AgNP has been proven to enhance the mechanical properties, with the tensile strength of the novel composite film increasing by 34.85 % compared to control group. The water vapor permeability and oxygen permeability of the novel composite film were reduced, which could potentially reduce weight loss and slow down the rate of after-ripening. Following the acidification treatment, the films containing EO@MPN (essential oil encapsulated with metal-polyphenol network) component performed different antimicrobial patterns, indicating their pH-responsive antimicrobial capabilities, and they are effective against both Gram-positive and Gram-negative bacteria. After a 24-h exposure to a food simulant, the release amount of Ag was measured at 67.6 μg/dm2, within the acceptable limit, and the release profile of Ag was characterized. Cytotoxicity and Live/Dead staining tests confirmed that the novel composite film film had no significant toxicity, thus making it safe for application in food preservation. Furthermore, in a 15-day preservation experiment with mangoes, the novel composite film demonstrated the best performance, underscoring its potential as a sustainable antimicrobial packaging material.

Evaluation of the permeability of ultrathin parylene AF4 films to determine minimum closed thickness for nanoscale packaging

This study investigated the permeability of parylene AF4 films of varying thickness to determine the minimum closed thickness for nanoscale packaging coatings. In particular, films with thicknesses of 15, 20, and 25 nm were deposited using 1 g of dimer and by adjusting the coating machine’s chamber height. Closeness analysis and electrochemical impedance spectroscopy (EIS) were employed to determine the minimum closed thickness. The closeness analysis results revealed a resistance of 1.35 MΩ (below the 20 MΩ threshold) for the 15 nm film, indicating a nonclosed film; conversely, the 20 and 25 nm films exhibited resistance values of 66.1 and 111.7 MΩ (above the threshold), respectively, indicating closed films. The EIS results indicated that the failure soaking times of the 15, 20, and 25 nm films were approximately &amp;lt;10, 20, and 50 min, respectively. These results indicate that the 20 nm film exhibited the lowest minimum closed thickness and was effective for waterproofing. These findings contribute valuable data toward developing nanoscale waterproof coatings for packaging applications.

Effect of CO2 Concentration on the Performance of Polymer-Enhanced Foam at the Steam Front.

This study examines the impact of CO2 concentration on the stability and plugging performance of polymer-enhanced foam (PEF) under high-temperature and high-pressure conditions representative of the steam front in heavy oil reservoirs. Bulk foam experiments were conducted to analyze the foam performance, interfacial properties, and rheological behavior of CHSB surfactant and Z364 polymer in different CO2 and N2 gas environments. Additionally, core flooding experiments were performed to investigate the plugging performance of PEF in porous media and the factors influencing it. The results indicate that a reduction in CO2 concentration in the foam, due to the lower solubility of N2 in water and the reduced permeability of the liquid film, enhances foam stability and flow resistance in porous media. The addition of polymers was found to significantly improve the stability of the liquid film and the flow viscosity of the foam, particularly under high-temperature conditions, effectively mitigating the foam strength degradation caused by CO2 dissolution. However, at 200 °C, a notable decrease in foam stability and a sharp reduction in the resistance factor were observed. Overall, the study elucidates the effects of gas type, temperature, and polymer concentration on the flow and plugging performance of PEF in porous media, providing reference for fluid mobility control at the steam front in heavy oil recovery.

Analysis of Relationship between Microwave Magnetic Properties and Magnetic Structure of Permalloy Films

Changes in the microwave permeability of permalloy films with an increase in the film thickness are studied. Measurement data on the evolution of microwave permeability with film thickness are analyzed in the framework of a model for the film with a regular stripe domain structure and out-of-plane magnetic anisotropy. A correlation between the microwave magnetic properties and magnetic structure of permalloy films is established. It is demonstrated that the observed decrease in the ferromagnetic resonance frequency and the static permeability with a growth in the film thickness can ascribed to the appearance of perpendicular anisotropy and the formation of a stripe domain structure. The calculated dependences of the ferromagnetic resonance frequency and static permeability on the film thickness are in reasonable agreement with the measurement results. Based on the analysis of these dependences, the domain width in the permalloy films is estimated. It is found that for thick permalloy films, the domain width is of the order of the film thickness. The results obtained may be useful for high-frequency applications of soft magnetic films.

Cross-Linked Metathesis Polynorbornenes Based on Nadimides Bearing Hydrocarbon Substituents: Synthesis and Physicochemical Properties.

Metathesis homo- and copolymerization of bifunctional monomers bearing two norbornene moieties was studied. The monomers were synthesized from cis-5-norbornene-exo-2,3-dicarboxylic anhydride and various diamines (hexamethylenediamine, decamethylenediamine, 1R,3S-isophoronediamine). The metathesis homopolymerization of these bis(nadimides) in the presence of the second-generation Grubbs catalyst afforded glassy cross-linked polymers in more than 90% yields. The metathesis copolymerization of the bis(nadimides) and a monofunctional norbornene derivative containing the β-pinene fragment also resulted in insoluble cross-linked polymers in nearly quantitative yields. The structures and purity of the synthesized polymers were confirmed via IR spectroscopy and CP/MAS NMR spectroscopy. Conditions for the fabrication of mechanically strong solution-cast thin films based on copolymers synthesized from the comonomers mentioned above were determined by varying the content of the cross-linking agent. It was shown that the films made in this way are stable in a range of organic solvents and could be useful as semipermeable or membrane materials for use in liquid organic media. The permeability of the polymer films in question to 1-phenylethanol and mandelic acid was studied. The results obtained are discussed along with the data from the DSC, TGA, and powder X-ray diffraction studies of the properties of the synthesized metathesis homo- and copolymers.

Deciphering the role of plasticizers and solvent systems in hydrophobic polymer coating on hydrophilic core

The type of plasticizer and the choice of solvent or co-solvents used for coating of a hydrophilic core can greatly impact the permeability, porosity, and mechanical strength of the polymer film. Although, Ethylcellulose (EC) is an old polymer, it is a polymer of choice for modifying the drug release due to its inherent properties. The ability of polymers like EC alone to form a diffusion-controlling membrane with good mechanical properties is limited. To modulate the drug release as per the desired profile and modify the film properties, ethylcellulose is often used with hydrophilic hypromellose (HPMC) along with plasticizers. The main focus of the current study was the identification of an appropriate solvent system and plasticizer for the ethylcellulose-hypromellose polymer combination. The study evaluated the coating solution properties, the feasibility and efficiency of the process, the physical attributes of the tablet, the surface properties of the polymer film, the in-vitro drug release and behavior, and the impact of curing time on surface properties and drug release, among other factors.The isopropyl alcohol-water mixture (9:1) produced a homogeneous film in comparison to films produced by other solvents. Although both hydrophilic and hydrophobic plasticizers produce homogeneous films, hydrophilic plasticizers have a higher rate of drug diffusion than hydrophobic plasticizers. During the tablet curing and stability study, the drug release from the polymeric film coating with triethyl citrate decreased moderately and with polyethylene glycol decreased significantly. The presence of hydrophobic plasticizers, viz., dibutyl sebacate and acetyl tributyl citrate, in the polymeric film coating does not impact drug release. For the combination of ethylcellulose and hypromellose, it was found that a mixture of isopropyl alcohol and water (9:1) worked better as a solvent for coating solutions, and hydrophobic plasticizers lower the risk associated with coating ethylcellulose and hypromellose together.

Characterizations of the pullulan/sodium alginate coatings incorporated with sodium silicate and EDTA-2Na and the antifungal effect on citrus green mold

Citrus has suffered great losses from postharvest fungal diseases. The strategy of polysaccharide-based coating combined with antimicrobial salts was introduced to preserve citrus and control green mold. Sodium silicate and ethylene diamine tetraacetic acid-2Na (EDTA-2Na) (SE) were incorporated with pullulan (PUL)/sodium alginate (SA) solutions to fabricate PSA-SE systems. The results indicated that the PSA-SE films had good biocompatibility based on hydrogen bonds and showed uniform and dense. The molecular of PUL and SA were assembled through entanglement to form a network structure and the surface roughness of the PSA-SE films increased with the addition of SA. The P3SA2-SE film indicated appropriate tensile strength and elongation at break, as well as the lowest water vapor permeability. The carbon dioxide and oxygen permeability and dissolution of P3SA2-SE film were at low values. The P3SA2-SE film had the highest water contact angle (66°). With the addition of SA, the absorbance of the PSA-SE films increased, which was conducive to light blocking. The antifungal experiments revealed that the P3SA2-SE coating showed a significant effect on controlling citrus green mold, especially in Citrus sinensis Osbeck ‘Lane Late’ almost completely inhibited Penicillium digitatum (P44). This study will promote the development of citrus postharvest disease control.

Amphiphilic colloidal particles/Ca2+ reinforced edible agar nanocomposite film by multiple cross-linking/microphase separation strategies

The agar (AG) film exhibited poor mechanical and water-resistant properties which limited its application for food packaging. The structural modification of AG nanocomposite film greatly impacts their macroscopic properties. In this paper, edible AG nanocomposite films were achieved by incorporating colloidal particles based on conjugates of whey protein isolate (WPI) and alginate oligosaccharides (AOS) as the nanofiller to obtain the micro-phase separation structure and the multiple cross-linking network with the synergistic interactions of the Ca2+ crosslinking. Firstly, WPI-AOS colloidal particles were synthesized through the Wet-heating Maillard reaction. Good compatibility between WPI-AOS colloidal particles and AG was exhibited, resulting in improved mechanical and water-resistant properties of AG composite films. Compared to pure AG film, the tensile strength (TS) of the agar composite film with 10% WPI-AOS colloidal particles increased significantly to 81.87 MPa from 24.02 MPa, and the elongation at break (EAB) also improved to 46.25% from 18.65%. The moisture content (MC), water solubility (WS), and water vapor permeability (WVP) of the AG composite film decreased by 33.1%, 18.0%, and 22.4% respectively. In addition, the multiple cross-linking network hindered the relative sliding between the AG molecular chain, which resulted in improved thermal stability of the composite film. Using soft colloidal particles as nanofillers to fabricate edible films for improving their properties is an effective and promising strategy.

Magnetic shielding properties of an iron-based nanocrystalline alloy for induction heating systems

A nanocrystalline alloy, with an iron-based composition (Fe58.5Si16.7B6.5Nb5.1Cu13.2) and a Curie temperature of 570 °C, was investigated for its effectiveness as magnetic shielding films in an induction heating system. The primary focus of the research was to evaluate the shielding performance of the 3-turned (9-layered) shielding films with dimensions of 135 mm × 17 mm × 0.15 mm. Upon winding, these films formed a cylindrical structure that enveloped the coil, with a diameter of 13.9 mm and a height of 17 mm. The results showed that increasing the degree of fragmentation within the nanocrystalline shielding films significantly reduced the magnetic permeability by decreasing the real component from 11,500 to 400 and the imaginary part from 2800 to 20. However, a lower degree of fragmentation led to a 10 % increase in the resistance (Rs) of the heating module, although this effect was less pronounced as the relative permeability continued to increase. Furthermore, observations on preheating time to a set temperature of 400 °C and total energy consumption over a duration of 250s revealed an initial downward trend, followed by a rapid increase that even exceeded the initial values as the magnetic permeability of the nanocrystalline shielding films augmented. Notably, the study emphasized that nanocrystalline shielding films with a relative permeability value of 1000 demonstrated exceptional magnetic shielding performance, resulting in a 12.5 % reduction in preheat time and 7 % less energy consumption during preheating. In addition to empirical findings, the study developed a theoretical model elucidating the shielding mechanism inherent in induction heating systems. This model serves as a robust framework for the application of nanocrystalline shielding materials in such systems, laying the groundwork for enhanced magnetic shielding capabilities in future applications.

Vapour permeation characteristics of aliphatic alcohols through PVA/PVC thin films

Nonsolvent induced phase separation (NIPS) method using NMP/water system was adopted to prepare PVA/PVC thin films and were characterized by FTIR &amp; FE-SEM analysis. Mechanical strength measurements indicated that an optimum composition of PVA/PVC has maximum tensile strength and might be due to the intercalation of viscous PVA into the stiff PVC matrix. Degree of swelling (DS) and water contact angle (WCA) measurements showed greater wettability of the films with increasing PVA content as is revealed from the higher film porosity and diminished contact angle. Pure water flux (PWF) and mean pore size were studied to determine the water permeation capacity of the film. Vapour permeability of various films was evaluated by using three different aliphatic alcohols viz. Methanol, ethanol and propanol. Barrier property and selectivity in permeation were studied for a particular PVA/PVC composition with moderate number and size of the pores which exhibited minimum permeation capacity.