Water Vapor Permeability Properties Research Articles

Regenerated cellulose films combined with glycerol and polyvinyl alcohol: Effect of moisture content on the physical properties

Regenerated cellulose-based films combined with glycerol and polyvinyl alcohol (PVOH) show interesting UV-light barrier properties, with potential application in food packaging to prevent oxidative deterioration. However, these materials are sensitive to moisture, and their properties could be modified as a function of the relative humidity. Hence, the objective of the present work was to evaluate the changes in the main properties of regenerated cellulose-glycerol-PVOH films depending on the relative humidity. Using the GAB adsorption isotherms, the moisture content was related with the water activity of the films at several relative humidity conditions. According to the obtained results, water molecules manifested a plasticizing effect modifying the mechanical, water vapour permeability and optical properties of the developed films. Tensile strength and Young's modulus values ranged from 92.65 to 17.57 MPa and from 3639.09 to 227.89 MPa, respectively. Both of them decreased when the moisture content increased. The mechanical resistance to deformation of films enhanced at high moisture content, changing from 5.88 to 15.97% and from 0.59 to 2.97 mm in the tensile and puncture test, respectively. This effect was also observed for the burst strength. Water vapour permeability increased from 5.15·10−10 to 5.44·10−9 g/ms Pa when the moisture content increased, being more significative at higher values. No significant variations were observed in the UV-VIS transmittance at different moisture contents. The obtained results allow expanding the knowledge of the behavior of films based on regenerated cellulose.

INCORPORATION OF ESSENTIAL OILS FROM Piper aduncum INTO FILMS MADE FROM ARROWROOT STARCH: EFFECTS ON THEIR PHYSICOCHEMICAL PROPERTIES AND ANTIFUNGAL ACTIVITY

Starch is a promising source of biopolymers and the incorporation of essential oils (EOs) into it can improve some biological properties of films. This study aimed at developing and characterizing barrier, biodegradability and optical properties of biopolymeric films made from arrowroot starch and at incorporating EOs from Piper aduncum leaves and inflorescences in order to analyze their antifungal activity against Rhizopus microsporus and Colletotrichum gloeosporioides. The casting method was used for developing arrowroot starch films and incorporating EOs into them. Resulting films exhibited satisfactory barrier properties, low water vapor permeability (WVP), transparency and good barrier property against UV-vis light, besides being 100% biodegradable. In addition, films enriched with EOs at 0.75% and 1.0% revealed promising antifungal activity. Results showed, for the first time, that arrowroot starch enriched with EOs from P. aduncum can potentially be used as an active film due to its excellent physicochemical properties and antimicrobial activity.

The effect of sodium hydroxide concentration on yield and properties of Bacterial Cellulose membranes

Bacteria cellulose (BC) derived from Acetobacter xylinum strain possess several advantages such as elevated water holding capacity, high porosity and excellent mechanical strength. BC is useful to replace vegetal plant and applied into various industrial field such as papermaking, packaging and textile. In this study, BC membranes were produced from coconut water based consists of 8.0% sugar, 0.5% ammonium sulphate and 1.0% acetic acid at pH 4.5, followed with the addition of 10.0% inoculum before subjected to static incubation for 7 days. This study evaluated the changes of BC membrane properties using different concentration of sodium hydroxide (NaOH) under room temperature within 24 hours. The morphological, physical, chemical structure and water vapour permeability (WVP) of BC were analysed using FESEM, XRD, FTIR and WVP analysis, respectively. Results show that BC is mainly consist of cellulose I± with high crystallinity and smaller crystallite sizes. The differences in NaOH concentrations varied the fibrils diameter of cellulose, in accordance to FESEM images. The use of higher concentration of NaOH (≥ 2.0%) gave a smooth cellulose structure with less porosity, thus reducing the WVP properties of BC.

Preparation and characterization of whey protein isolate/polydextrose-based nanocomposite film incorporated with cellulose nanofiber and L. plantarum: A new probiotic active packaging system

There is growing interest in bioactive packaging systems due to their potential for extending the shelf life of food products. In this regard, the aim of this study was to prepare cellulose nanofiber (CNF) and polydextrose incorporated whey protein isolate (WPI) based probiotic nanocomposite film containing Lactobacillus plantarum. The prepared film samples were characterized by FT-IR, FE-SEM, DSC and XRD analyses. The results revealed good compatibility between WPI matrix, CNF and polydextrose, such that CNF and polydextrose had no adverse effect on the morphological and thermal properties and the crystallinity of WPI-based probiotic films. Furthermore, the CNF and polydextrose incorporated WPI-based films exhibited low water vapor permeability and good mechanical properties. The viability of probiotic bacteria was significantly (p < 0.05) enhanced following the incorporation of CNF and polydextrose during the storage time. Moreover, the probiotic film containing 5 g/100 g CNF and 20 g/100 g polydextrose exhibited inhibition zones against P. aeruginosa (14.6 ± 0.5 mm), S. aureus (14.0 ± 1.0 mm), and E. coli (12.6 ± 0.5 mm) bacteria. In conclusion, the CNF and polydextrose incorporated WPI-based probiotic nanocomposite film can be applied in bioactive food packaging system owing to its unique features.

Development and characterization of sodium alginate based active edible films incorporated with essential oils of some medicinal plants

The aim of this study was to develop sodium alginate based active films incorporated with essential oils (EO) of R. officinalis L, A. herba alba Asso, O. basilicum L and M. pulegium L. the films were characterized in terms of bioactive properties including thickness, moisture content, water vapor and oxygen permeability, release test, mechanical, molecular, biodegradability and thermal properties. The results showed that the active films had a strong antibacterial effect against the six pathogenic bacteria with the inhibition zone between18.5 and 38.67 mm. furthermore, the antioxidant capacity of the films ranged from 4.57% to 23.09%. According to results of release test, physical, molecular, mechanical, biodegradability, thermal and barrier properties, the EOs were uniformly dispersed in the polymer matrix and improved slightly thermal (Tm) and barrier properties, while decreased tensile strength and it was obtained that this film is biodegradable in the soil. In conclusion, it could be said that sodium alginate based edible films incorporated with EO have a potential to be used food packaging applications.

Chitosan and Starch Based Intelligent Films with Anthocyanins from Eggplant to Monitor pH Variations

The objective of this study was to develop and characterize a pH indicator based on chitosan (C) and starch (S) including anthocyanins from eggplant to indicate food quality changes through the detection of changes in the pH of packaged food products. Anthocyanins were extracted with solvents including ethanol and water (7:3, V:V) (EgP-E) and water (EgP-W) in acidic pH. The pH indicator films were obtained incorporating anthocyanin as 1.5 g extract/100 g film solution. The optical, mechanical and water vapor permeability properties were used to characterize the pH indicator films. The total monomeric anthocyanin content and phenolic content of extract solutions were also determined. Color variations of pH indicator films were measured by a colorimeter after immersion in different pH buffers (pH 2.0–10.0). Initially, dried C films and S based films were observed in a violet color and a magenta color, respectively. C and S films with anthocyanins showed color variations from pink (in acidic pH) to bluish-green (in neutral pH) and to violet (in basic pH) in different pH values. The water vapor permeability of films with anthocyanins was higher than films without anthocyanins. Additionally, C and S based films including anthocyanins extracted with water showed better permeability values. C:EgP-W and S:EgP-W films presented higher elasticity values when compared with films including ethanolic extracts (p

Dual responsive wool fabric by cellulose nanowhisker reinforced shape memory polyurethane

ABSTRACTShape memory wool fabrics having both temperature and moisture responsiveness were fabricated by a functional nanocomposite treatment comprising of shape memory polyurethane (SMPU) and cellulose nanowhisker (CNW). Water vapor permeability and sweat absorption properties were investigated under different temperature or relative humidity values to test smart comfort capabilities of the treated fabrics. Besides, felting shrinkage and weight loss of the fabrics after repeated washing cycles were investigated for end use performance. It was found out that the wool fabrics functionalized by nanocomposite treatments exhibited dynamic breathability and sweat absorption changing with temperature and relative humidity of body or environment. Moreover, nanocomposite application enhanced rigidity, tear strength, anti‐felting and weight loss performances of the wool fabric. 20 wt% CNW concentration can be suggested for thermal comfort, mechanical and end use performance enhancements to obtain smart garments having dynamic responsiveness to both body physiological and environmental changes. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 137, 48674.

Development of bionanocomposites of pectin and nanoemulsions of carnauba wax and neem oil pectin/carnauba wax/neem oil composites

AbstractThe search for biodegradable materials motivated the development of new materials for the food industry. Biomaterials (pectin, starch, and chitosan) are considered promising biodegradable polymers for developing or improving materials. This study aimed to develop biodegradable bionanocomposite films with neem oil and carnauba wax nanoemulsion using pectin (high methyl esterification) polymer matrix; and to evaluate the nanoemulsions effects on the water vapor permeability (WVP), mechanical, thermal, and biodegradability properties of the films. Nanoemulsions were characterized by the polydispersity index and mean particle diameter. These results showed an average diameter of 59 to 69 nm. The pectin and 30% of neem oil nanoemulsions showed a 27% reduction in WVP. In addition, the mechanical property was optimized. Young module showed a 66% to 75% reduction for pectin and 30% of carnauba wax film and pectin and 30% of neem oil film. In the biodegradability analysis was presented a very fast degradation in soil. In addition, there was no macroresidue formation in soil with neem oil films during the biodegradation process. This result showed a weight loss after 45 days of testing. Developed bionanocompositie materials have great potential for application in emerging packagings (edible films and coatings) for the food industry and agribusiness area (food and seeds).

Synthesis, characterization and properties of biomass and carbon dioxide derived polyurethane reactive hot-melt adhesives

AbstractPolyurethane reactive hot-melt adhesives (PURHs) are frequently employed in industries; however, there is still a need to develop more sustainable and versatile methodologies to expand the functions and fabrication of these important materials. Renewable feedstock can give PURHs with new functions, and reduce environmental impact. This study focuses on synthesizing PURHs using polyols derived from biomass (plants) and greenhouse gas (CO2) resources. These PURHs were characterized by multiple techniques, including solid-state 13C nuclear magnetic resonance (NMR), a dynamic mechanical analysis (DMA), single-lap adhesive joints strength of stainless steel, and hydrolytic ageing. The PURH film based on biomass poly(tetramethylene ether) glycol (bio-PTMEG) exhibited better water vapor permeability, tensile strength, and adhesive joints properties than PURHs based on cashew nutshell liquid (CNSL) polyester diol and poly(propylene carbonate)-poly(propylene glycol) (PPC-PPG) copolymer diol. The polyols blend of bio-PTMEG with biomass and CO2 based polycarbonate diols respectively provided PURHs films excellent hydrolysis resistance and adhesive strength on single-lap adhesively bonded stainless steel specimens. The work herein demonstrates that various renewable polyols can be employed in a sustainable fashion to optimize the structures and properties of PURHs for important applications.

Response surface methodology (RSM) of chicken skin gelatin based composite films with rice starch and curcumin incorporation

This study aims to optimize the formulation of composite films based on chicken skin gelatin with incorporation of rice starch (10–20%, w/w) and curcumin (0.03–0.10%, w/v). The effect of their interaction on film's tensile strength (TS), elongation at break (EAB), water vapor permeability (WVP) and antioxidant properties (DPPH%) were investigated using a response surface methodology-central composite design (RSM-CCD). The optimized film formulation was further validated to indicate the validity of the prediction model. The optimum conditions of the film were selected with incorporation of rice starch at 20% (w/w) and curcumin at 0.03% (w/v). The optimized film formulation has revealed better mechanical properties with low WVP value and good antioxidant activity. The results showed that optimized composite films formulation based on chicken skin gelatin with the incorporation of rice starch and curcumin has proving good validation of model prediction and can be effectively utilized in food packaging industry.

Preparation and Characterization of Chitosan–Alginate Polyelectrolyte Complexes Loaded with Antibacterial Thyme Oil Nanoemulsions

Biomedical industries are attempting to utilize natural materials, as they are bio-compatible, non-toxic, and show bioactive properties, like antimicrobial activity. In this study, natural polyelectrolyte complexed chitosan/alginate films (PECs) were prepared via a casting/solvent evaporation technique, and their characteristics and drug release properties were investigated. PEC films made with two different overall polymer contents, 0.4 and 1 w/v%, were loaded with thyme oil nanoemulsion as drug carrier. The structure of the films was studied by FTIR and optical and scanning electron microscopy. Prepared PEC films had good mechanical and water vapor permeability properties. Release of the thyme oil from the pH-sensitive PEC films (TM-PEC) was detected and followed by UV spectroscopy. The results indicated that the drug release rate of TM-PEC films was the fastest when the chitosan content was 1 %w/v, and various mathematical models were analyzed for investigating the drug release mechanism. Antibacterial tests were performed by counting the number of surviving gram-negative and gram-positive bacteria. The in vitro test indicated the limitation Escherichia coli (E. coli) and Staphylococcus aureus (S.aureus) growth in the presence of TM-PEC films. The MTT test showed more cell viability of the TM-PEC film in comparison with that of the PEC film without TM. Based on the measured physical and antibacterial properties, the chitosan–alginate PEC films loaded with antibacterial essential oils can be considered for biomedical applications, such as wound dressings or controlled release systems.

Production and characterization of chitosan-gelatin nanofibers by nozzle-less electrospinning and their application to enhance edible film’s properties

Abstract In this study nozzle-less electrospinning device has been introduced as a promising technology to produce food grade nanofibers with high production yield in comparison to nozzle based instrument. Electrospinning was set up with pure gelatin solutions and different volume ratios of chitosan to gelatin. SEM images showed that by increasing volume ratio of chitosan to gelatin a decrease in fiber diameter could be observed. The thinnest nanofibers had mean diameter of 96.26 ± 34.44 nm. DSC analysis indicated that thermal resistance of the nanofiber was higher than pure ingredients. ATR-FTIR analysis showed that the main peaks of ingredients can be detected in spectrum of produced nanofibers. The optimum nanofibers were used to enhance physical properties of edible gluten film. Nanofiber treated edible film had lower water vapor permeability and better mechanical properties in comparison to blank sample. The maximum force of the edible film containing 2 mg/cm2 nanofibers that could tolerate was 3.12 N and for blank edible film without nanofibers was 0.58 N. The results of this study indicated that nozzle-less electrospinning can be applied as a new method for production of nanofibers in large scale which can be further applied for enhancement of mechanical properties of edible films.

Preparation, characterization, and antibacterial properties of biofilms comprising chitosan and ε-polylysine

Of late, the demand for food-packaging materials, in particular, multifunction packaging materials that are biodegradable; antibacterial; have good mechanical and barrier properties; and are edible and transparent, has increased considerably. In this study, we prepared chitosan (CS)/ε-polylysine (PL) biofilms with different CS-to-PL ratios. We studied the preparation, mechanical properties, microstructures, thermal stability, transparency, water-vapor permeability, oil permeability, and antibacterial properties of the composite CS/PL biofilms. The results demonstrate that CS/PL biofilms are mechanically strong, have good thermal stability, high transparency, low water-vapor and oil permeability, and extensive antibacterial properties that act against Escherichia coli, Bacillus subtilis, and yeast. Therefore, we therefore conclude that CS/PL biofilms are promising food-packaging materials.

The effects of elastane and finishing properties on wicking, drying and water vapour permeability properties of denim fabrics

PurposeThe liquid water and water vapour transfer properties of fabrics play an important and decisive role in determining thermal comfort properties of clothing systems. The purpose of this paper is to analyse the effects of fabric composition (98 percent cotton–2 percent elastane and 100 percent cotton) and finishing treatments (rigid, resin, bleaching and softening) on the wicking, drying and water vapour permeability (WVP) properties of denim fabrics.Design/methodology/approachThe research design for this study consists of experimental study. Two fabric compositions (98 percent cotton–2 percent elastane and 100 percent cotton) and four finishing treatments (rigid, resin, bleaching and softening) were evaluated to see the effects of elastane and finishing treatments on wicking, drying and WVP properties of woven denim fabrics. Results were analysed statistically.FindingsExperimental results showed that the transfer wicking, drying and WVP values of denim fabrics were significantly influenced by fabric weight, fibre composition and finishing treatments.Practical implicationsThe wicking ability of sweat from the skin to the outer environment of a skin contact fabric layer is the primary requirement.Originality/valueAs a result of the literature review, it was seen that there are some studies in the literature about comfort properties of denim fabrics, but there is no study concerning the water vapour transmission, wicking and drying properties of denim fabrics.

Effects of Conjugation between Proteins and Polysaccharides on the Physical Properties of Emulsion‐Based Edible Films

AbstractThe effects of conjugation between protein (soybean or peanut protein isolates) and polysaccharides (dextran or gum acacia) with different glycation time (0–32 hours) on the physical properties of emulsion‐based edible films containing beeswax as dispersed phase were studied. Both the reaction time and type of polymers significantly (P &lt; 0.05) affected the emulsifying properties of conjugates. Pearson's correlation analysis showed that the emulsifying activity index (EAI), emulsifying stability index (ESI), and droplet size of emulsions were in strong correlation with the physical properties of films, such as whiteness index, transparency, water vapor permeability, surface hydrophobicity, thermal stability, and mechanical properties. Furthermore, even though glycation could significantly (P &lt; 0.05) affect intermolecular interactions between polymers in films, there was no strong correlation between the intermolecular interactions and the physical properties of films. Therefore, the emulsifying properties of conjugates are essential for preparing emulsion‐based edible films.

Development of biodegradable films based on seaweed polysaccharides and Gac pulp (Momordica cochinchinensis), the waste generated from Gac oil production

Gac (Momordica cochinchinensis) is a tropical fruit. It belongs to the Cucurbitaceae family. Gac pulp (or mesocarp) that accounts for 40–50% of fruit weight is commonly discarded during the processing of Gac fruit. However, this by-product is a rich source of nutrients and bioactive compounds, which are potential to produce edible films. This study aimed to determine the effect of sodium alginate, kappa-carrageenan, Gac pulp and glycerol on film properties and optimise the formula of this composite film for further applications using a response surface methodology (RSM).The results showed that sodium alginate, kappa-carrageenan, Gac pulp, and glycerol affected physical and barrier properties, colour parameters, and mechanical properties of the films. The optimal formulation to generate a composite film from Gac pulp include sodium alginate 1.03%, kappa-carrageenan 0.65%, Gac pulp 0.4%, and glycerol 0.85% (w/v), where this film produces high mechanical properties, low water vapour permeability and acceptable physical properties. This optimised film formulation demonstrates a potential for food application.

Influence of different concentrations of Zn-carbonate phase on physical-chemical properties of antimicrobial agar composite films

Abstract Agar-based composites with different Zn-carbonate mineral phase content were prepared by in situ mineralization and the solvent casting method. The mineral phase within the composite films was identified as hydrozincite, Zn5(CO3)2(OH)6. The presence of the mineral phase improved, both mechanical and water vapor permeability properties of the obtained composite films, in a concentration-dependent manner. The release of zinc ions from composite films is in accepted levels (up to 2.5%), and sufficient to provide complete inhibition growth of S. Aureus. The results of this study suggest that agar/Zn-carbonate composites could be potentially used as affordable, eco-friendly and functional materials with tunable properties for food packaging, agriculture or biomedical application. In situ procedure offers possibilities for tailoring the physical-chemical properties of composite films, by varying the Zn-mineral phase load.

Effect of polyvinyl alcohol on the physicochemical properties of biodegradable starch films

Biodegradable films based on starches have poor mechanical and barrier properties, limiting their applications as a food packaging material. The combination of two or more polymers allows obtaining new materials with better functional properties. Mixtures at different proportions (0–60%) of polyvinyl alcohol (PVOH) were studied and the effect on water adsorption, water vapor permeability (WVP), mechanical (percentage of elongation at break and tensile strength) and thermal (Tg) properties was evaluated. In all the formulations, both polymers showed a good compatibility during processing and in the resulting material. The addition of PVOH significantly favored the functional properties, improved the gas permeability and the mechanical properties of potato starch films. The formulation containing 60% PVOH (S4P6) showed the best barrier to water vapor, lower density and solubility as well as better mechanical performance. PVOH resulted in potato starch films with suitable properties for possible applications in food packaging and as a biodegradable alternative for the replacement of synthetic packaging materials.

Study on physical and mechanical properties of the biopolymer/silver based active nanocomposite films with antimicrobial activity

Silver nanoparticles (AgNPs) were prepared by reducing AgNO3 using biopolymer pullulan as both a reducing and stabilizing agent. The prepared AgNPs solution was blended with pectin to make active nanocomposite films. The formation of AgNPs in the solution was confirmed by characteristic surface plasmon resonance (SPR) peak of AgNPs at 400–500 nm, using UV–vis absorption spectroscopy. The prepared composite and nanocomposite films were characterized using UV, FE-SEM, and FT-IR. In addition, films color, optical, water contact angle, water vapor permeability, mechanical and antimicrobial properties were evaluated. FE-SEM analysis showed uniform distribution of AgNPs in the resulting nanocomposites films. The presence of AgNPs could affect the physical and mechanical properties of the prepared films. The color, moisture content, water vapor barrier properties, hydrophobicity, thickness, and elongation at break of the films were significantly increased after formation of composite with AgNPs, but tensile strength and elastic modulus of the films were decreased. FT-IR results indicated that AgNPs had good compatibility with biopolymers. In addition, nanocomposite films, especially pullulan/AgNPs and pullulan/pectin/AgNPs films exhibited better antimicrobial activity against food born pathogens, which suggests that prepared nanocomposite films can be used as active food packaging material to maintain food safety and to improve shelf life of the packaged food.

Moth bean starch (Vigna aconitifolia): isolation, characterization, and development of edible/biodegradable films.

In the current work, moth bean starch was separated from the moth bean seeds which were cultivated in the semi arid regions of Haryana and Rajasthan, India using alkali treatment technique and characterized. Isolated and purified moth bean starch comprised (12.89-20.37%) amylose, 0.8% protein, 0.4% ash, swelling index and solubility were 10.8-14.7% and 6.4-9.8% respectively. For wrapping application, starch was modified using citric acid as cross linking agent (1-7% w/w of total starch) and film was made using casting method, and investigated the influence of citric acid on the functional properties of the films such as moisture content, solubility, swelling index, water vapor permeability and mechanical property. Significant difference in the functional properties among native and modified moth bean starch films was noticed. Interactions among starch chains due to cross linking in the modified starch films were reported using FTIR spectra. Surface micrographs of both purfied starch granules and films were studied using scanning electron microscopy. From the outcomes, it was exhibited that obtained starch granules has range large to small size with distorted cylinder and oval shapes. While cross linked starch films showed compact, slightly rough and homogeneous surface. Tested modified moth bean starch films containing citric acid (CA) and sorbitol were utilized as wrapping films to improve the shelf life of fresh lemon. Outcomes showed that the film contains 5% CA could be most promising wrapping materials for lemon that enhanced the shelf life of lemon additionally up to 12days.