Water Vapor Permeability Values Research Articles

Cellulose‐Reinforced Starch Biocomposite: Optimization of the Effects of Filler and Various Plasticizers using Design–Expert Method

AbstractIn this study, the effect of cellulose as a reinforcement agent and different ratio of glycerol/sorbitol as plasticizers to improve properties in starch biocomposite are optimized with Design–Expert method for the first time. Thermoplastic starch granule is produced with plasticized and cellulose‐reinforced starch by a twin extruder. After conditioning, the starch granule, is molded into sheet using a hot press with thick plates. Dynamic mechanical thermal analysis show that cellulose increases the glass transition temperature to 120 °C. Optimum point of the starch composite obtained by Design–Expert software 7.1.5, is run with 5 wt% cellulose, 17.5 wt% glycerol and 17.5wt% sorbitol that has water vapor permeability value equally of 7.81E‐10g s−1 m−1 Pa−1, tensile strength of 0.85 MPa, Young´s modulus equally of 377.65 MPa, and elongation at break of 7.08%. Field emission scanning electron microscopy of the optimized biocomposite shows uniform distribution of cellulose in the matrix. Hydroxyl stretching vibrations at 3286 cm−1 is a result of new hydrogen bonding between cellulose and starch molecules and peaks at 3366 and 1702 cm−1 are attributed to glycerol and sorbitol, respectively in the Fourier transform infrared spectra.

Hydrolyzed collagen on PVA‐based electrospun membranes: Synthesis and characterization

AbstractPhysicochemical, structural, and thermal properties of electrospun membranes depend on process conditions and the type and concentration of the raw materials used to produce them. In this work, the electrospinning technique (ES) is used to synthesize membranes with hydrolyzed collagen (HC) and polyvinyl alcohol (PVA) at two different distances. The characterization of these membranes is then carried out by X‐Ray diffraction, Raman spectroscopy, differential scanning calorimetry, water vapor permeability (WVP), microscopy techniques, and porosity measurements. Results show that the morphology of the ES membranes depends mainly on the polymer/solvent system's physicochemical properties and the distance to the collector. Thicker samples (68–86 μm) are formed when using the furthest distance (10 cm), having fiber diameters smaller than 1 μm, porosity percentages up to 90%, and WVP values close to or in the recommended range for wound dressing commercial products. Moreover, the presence of HC results in samples with a less crystalline structure. To the best of our knowledge, this is the first report in which PVA and HC membranes are successfully synthesized by electrospinning and physicochemically characterized.

Physicochemical and Rheological Properties of Cross‐Linked Litchi Kernel Starch and Its Application in Development of Bio‐Films

AbstractIn this study, starch from a non‐conventional source, that is, litchi is extracted and cross‐linked (CL) with varying concentrations (1%, 3%, and 5%) of sodium trimetaphosphate (STMP). The starches are characterized for their physicochemical, pasting, rheological, and thermal properties. Bio‐films are also prepared from these starches and analyzed for selected barrier and mechanical properties. The results indicate that an increase in cross linking agent concentration resulted in a significant decrease in amylose content, swelling power (SP), and solubility of starches. Peak viscosity (PV) and breakdown viscosity (BV) of CL starches are lower in comparison to native starch. Steady shear properties reveal that magnitudes of yield stress (σo) and consistency index (K) decrease upon increase in the concentration of cross linking reagent. CL starches exhibit significantly (p < 0.05) higher transition temperatures than native starch. Native starch film shows water solubility of 43.66% while for films from CL starches, the values ranged between 35.12 and 41.53%. Significant (p < 0.05) reduction in water vapor permeability (WVP) values of CL starch films (1.24–1.52 g m Pa−1 s−1 m−2) is observed in comparison to native (2.32 g m Pa−1 s−1 m−2) starch films. Cross linking significantly improves tensile strength (TS) of films, however, films elongation is lower (14.71–17.97%) than native starch film (19.88%).

A study on comfort properties of oak Tasar silk waste and acrylic blended fabrics

Oak Tasar is wild silk with natural golden brown colour and unique texture available in Himalayan region of India. A lot of fibre waste is generated during hand spinning of oak Tasar silk yarn which can be utilized by blending it with compatible fibre to incorporate the properties of both fibres in the yarn. The present study aimed to develop Oak Tasar silk waste and acrylic blended fabrics and study their comfort properties. The oak Tasar silk and acrylic blended plain weave and twill weave fabrics were prepared with five different blend ratios viz. 100:0, 60:40, 50:50, 40:60 and 0:100. The prepared fabrics were studied for comfort properties like thermal insulation (clo, TIV %), Q-max (warm/cool feeling), air permeability, water vapour transport rate and were statistically analysed. Results revealed that thermal insulation and clo value were found to be increased with increasing acrylic content in the fabric whereas Q- max, air permeability, water vapour permeability values were reduced with the addition of oak Tasar silk fiber in the blend. The 50:50 blended plain weave fabric among the blended fabrics had the highest clo value, i.e. 0.52 and 50:50 blended twill weave fabric had highest Q max value i.e. 0.109W/cm2. It was found from the study that the developed fabrics are comfortable and can be used for light winters.

Organophosphorus Polyurethane Ionomers as Water Vapor Permeable and Pervaporation Membranes.

Organophosphorus polyurethane ionomers (AEPA-PU) based on aminoethers of ortho-phosphoric acid (AEPA) were obtained and studied as pervaporation membrane materials for separating isopropanol/water mixtures. The regularities of the change in the water vapor permeability of AEPA-PU were also investigated. It has been established that an increase of solute content in the composition of the urethane-forming system and the content of ionogenic groups in AEPA leads to a noticeable increase in the vapor permeability of the resulting film materials. An increase in water vapor permeability values is accompanied by a significant increase in the pervaporation characteristics of AEPU-PU. It was shown that the conditions promoting clustering of phosphate anions cause an increase in the values of the vapor permeability coefficient of AEPA-PU obtained using polyoxypropylene glycol. However, the hydrophobicity of the polypropylene glycol surrounding the clusters makes it difficult for water to move through the polymer matrix. Due to the hydrophilicity of polyoxyethylene glycol, the highest values of water vapor permeability and pervaporation characteristics are achieved for AEPA-PU synthesized using PEG.

Preparation and characterization of chitosan-based edible active films incorporated with Sargassum pallidum polysaccharides by ultrasound treatment

In this study, Sargassum pallidum polysaccharides (SPPs) were incorporated into chitosan (CH) to develop a novel edible active film (CH/SPPs-US) via ultrasonication. The mechanical, water vapor permeability, surface morphology, crystallinity, antioxidant, and fruit preservation properties of CH/SPPs-US films prepared under sequences of matrix ratios and ultrasound treatment were investigated. The results revealed that the addition of SPPs combined with ultrasonic treatment could significantly enhance the transparency, elongation and tensile strength of the films whereas the water vapor permeability was decreased. Tensile strength and elongation at break of the C2/SP1.2-US film were 12.07 N and 54.18%, respectively, which were significantly higher than those for CH film. Meanwhile, the water vapor permeability value of C2/SP1.2-US was reduced by as high as 40.2% compared with that of chitosan film. In addition, antioxidant effect evaluation showed that the CH-based films added with SPPs exhibited better antioxidant activity than CH film, and ultrasonic treatment could further strengthen the antioxidant activity of the film. The CH/SPPs-US films could effectively extend the shelf life and inhibit the deterioration of the strawberry at room temperature (25 ± 1 °C) and 70% ± 5% relative humidity for 7 days. These results indicated that the CH/SPPs edible films via ultrasonication could be developed as edible packaging films for the preservation of fresh fruits.

Reduction of Water Vapor Permeability in Food Multilayer Biopackaging by Epitaxial Crystallization of Beeswax

In this paper, multilayer pectin-beeswax/colophony-pectin (P-BC-P) films including different proportions of beeswax/colophony mixtures were prepared in order to reduce the water vapor permeability. FTIR, XRD, DSC, polarized light microscopy (PLM), and water vapor permeation assays were performed. Characterization techniques showed (i) polar interactions between beeswax and colophony at the amorphous phase, (ii) changes in beeswax crystalline phase from sponge-like to needle-like structure, and (iii) formation of a eutectic mixture at BC3 70/30 ratio which guides the epitaxial crystallization of beeswax. Pure pectin films showed low resistance to the water vapor permeation (361 × 10−13 g m m−2 s−1 Pa−1), while multilayer films showed major control over the transport process. P-BC3-P showed one of the lowest water vapor permeability (WVP) values (56 × 10−13 g m m−2 s−1 Pa−1) and the closest WVP value to that of polyethylene films (LDPE 5.8 × 10−13 g m m−2 s−1 Pa−1). This result was attributed to the ordered crystalline structure reached by the epitaxial crystallization of beeswax within the hydrophobic phase.

Optimization of the water vapor permeability of starch/alginate edible system reinforced with microcrystalline cellulose for the shelf-life extension of green capsicums

Water vapor permeability (WVP) is an important parameter for systems used in edible coatings of food. WVP should be optimized to a minimum value to control the passage of fluids between food and its environment. In this work, Box-Behnken design was applied to optimize the edible coating based on alginate, soluble starch and microcrystalline cellulose (MCC) to its minimum. The optimized theoretical value of WVP was 9.94 g mm/m2 day kPa which was in a greement with the experimental obtained value. The molecular structure of the prepared edible coating films was verified using FTIR. MCC addition significantly improved the thermal and mechanical properties of the edible coating. Shelf-life studies on green capsicums coated with the optimized edible system showed great resistance to mass loss and spoilage. The prepared edible coating, based on the excellent obtained data, could be used potentially to extend the shelf-life of food.

Flavor, antimicrobial activity and physical properties of gelatin film incorporated with of ginger essential oil.

Adding essential oil into the gelatin-based film can enhance the antibacterial activity of the film, but excessive amounts of addition will bring the film an unpleasant flavor and reduce its mechanical performance. Hence, we prepared functional gelatin-based films by incorporating low content of ginger essential oil (GEO). The flavor of GEO was not detected from the films containing less than 1% GEO. The antimicrobial activity of films was found to be proportional to GEO content. As GEO content increased from 0 to 1%, the value of water vapor permeability (WVP) and elongation at break (EAB) increased, whereas the value of tensile strength (TS) of film decreased. The Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy analysis revealed the vibration of gelatin film was affected by adding low content of essential oil. Surface morphologies demonstrated oil droplets and a discontinuous structure, and cross-section morphologies proved the formation of a loose structure as GEO was incorporated in the film through SEM. Sensory evaluation revealed that composite films incorporated with 0.5% GEO exhibited the best performance. The resulting films can be used as antimicrobial packaging materials with good physical properties and sensory performance.

Restoration of ancient gypsum-based plasters: Design of compatible materials

In this paper, the process of design and evaluation of compatible materials to partially or completely substitute damaged interior walls and ceilings coatings made of gypsum-based plasters is presented and the results obtained are discussed.The methodology used comprised the definition of quantitative requirements to be accomplished by the new materials, based on previous works of the authors with characterization of an extensive set of samples of historic buildings. It was concluded that there is need to develop three different restoration materials, one for each family of plaster elements: thin-layer finishing plasters (L), elements moulded on site (M) and precast decorative elements (P).The physical and mechanical properties of seven mixes based on gypsum and lime, with addition of other components, were determined and allowed concluding that the binder proportions (gypsum: lime) is the most influential factor. Higher gypsum content leads to stiffer materials, less shrinkage and higher absorption coefficients than in lime-based mixes. The formation of micro cracks was pointed out as a possible cause for the decrease of flexural strength and water vapour permeability values of the M mixes.The comparison of the results obtained with the compatibility requirements allowed finding well-suited restoration materials for thin-layer coatings and precast elements. The mixes for moulded on site elements revealed to be the less balanced, and some adjustments are advised.

Chitosan Films Obtained from Brachystola magna (Girard) and Its Evaluation on Quality Attributes in Sausages during Storage.

High molecular weight chitosan (≈322 kDa) was obtained from chitin isolated from Brachystola magna (Girard) to produced biodegradable films. Their physicochemical, mechanical and water vapor permeability (WVP) properties were compared against commercial chitosan films with different molecular weights. Brachystola magna chitosan films (CFBM) exhibited similar physicochemical and mechanical characteristics to those of commercial chitosans. The CFBM films presented lower WVP values (10.01 × 10−11 g/m s Pa) than commercial chitosans films (from 16.06 × 10−11 to 64.30 × 10−11 g/m s Pa). Frankfurt-type sausages were covered with chitosan films and stored in refrigerated conditions (4 °C). Their quality attributes (color, weight loss, pH, moisture, texture and lipid oxidation) were evaluated at 0, 5, 10, 15 and 20 days. Sausages covered with CFMB films presented the lowest weight loss (from 1.24% to 2.38%). A higher increase in hardness (from 22.32 N to 30.63 N) was observed in sausages covered with CFMB films. Compared with other films and the control (uncovered sausages), CFMB films delay pH reduction. Moreover, this film presents the lower lipid oxidation level (0.10 malonaldehyde mg/sample kg). Thus, chitosan of B. magna could be a good alternative as packaging material for meat products with high-fat content.

A visual bi-layer indicator based on roselle anthocyanins with high hydrophobic property for monitoring griskin freshness

This study designed a new type indicator with hydrophobic Polyvinylidene Fluoride (PVDF) film as a moisture prevent-layer. And the sensor layer was provided based on polyvinyl alcohol/Sodium alginate (PS) and Roselle anthocyanins (RAs). Physical properties, microstructure, and color stability of the bi-layer indicator have been investigated. The Water contact angle (WCA) of PS/RAs/ PVDF film (PSRF) was 108.85°, which can be considered as an excellent hydrophobic surface. The lowest Water Vapor Permeability (WVP) value of PSRF exhibited a good barrier property for moisture. Therefore, PSRF film was used to monitor the griskin freshness. The Total volatile basic nitrogen (TVB-N) level was increased to 18.02 mg/100 g at 72 h, and the color of the indicator presented visible color changes. The acquired results revealed a good correlation between TVB-N, pH and color change of the indicator. The research indicated that PSRF indicator has increasing potential application on food intelligent packaging.

Use of Chia by-Products Obtained from the Extraction of Seeds Oil for the Development of New Biodegradable Films for the Agri-Food Industry.

Chia oil production and consumption have increased in recent years, producing a large number of by-products that had low utility or economic value for the industry. In this study, a biodegradable film was successfully prepared from mucilage extracted from defatted chia flour. The physical-chemical, optical, water vapor permeability (WVP), and mechanical properties of films made with two different types of chia matrixes (defatted flour and whole seeds) were determined. In general, defatted chia flour films exhibited a slightly reddish and yellowish color but still transparent in appearance, were good visible light barriers, and had better mechanical properties than films made with whole seeds. They also have greater WVP values than synthetic films such as low-density polyethylene. The results of the present study demonstrated that defatted chia flour can be used in producing edible films with improved quality characteristics.

Development of novel collagen hydrolysate bio-nanocomposite films extracted from hide trimming wastes reinforced with chitosan nanoparticles

The wide availability of pollutant by-products from the leather industries has been a key factor in driving the research into converting these low-cost by-products into high value-added collagen-based products. In this study, collagen hydrolysate (CH) was extracted from hide trimming waste from the tanneries and used to prepare biodegradable films with chitosan nanoparticles (CNPs) with different concentrations to develop an alternative product to non-biodegradable plastics. The effects of CNPs concentration on the thickness, mechanical, water barrier, thermal, light transmittance, color properties, and opacity of CH-based films were investigated. The results clearly show that the tensile strength and elastic modulus values of CH/CNPs films increase significantly as the concentration of CNPs increases, while the elongation at break, water solubility, and water vapor permeability values decrease. In addition, scanning electron microscopy (SEM) showed uniform distributions of CNPs in the CH-based films. Based on the results obtained, the extraction of CH from hide trimming wastes and reuse in the production of biodegradable films will both prevent these valuable wastes from being dispose into the landfills and will be an alternative to fossil-derived plastics in the future.

Development of Chitosan and Polycaprolactone Based Trilayer Biocomposite Films for Food Packaging Applications

Chitosan (CH) films were obtained by casting method and sandwiched between 2 layers of polycaprolactone (PCL), which were formed by compression molding, to form trilayers. CH films were also incorporated with grape seed extract (G) (15%, w/w) and/or nanocellulose (N) (1-5%, w/w). The tensile properties, transmittance, opacity, water vapor permeability (WVP), antimicrobial activity, and release behavior of trilayers were determined. The elastic modulus (EM) of trilayer films were not significantly affected by the N content, while higher N concentrations resulted in higher tensile strength (TS) values. The incorporation of G led to higher elongation values and resulted in lower EM and TS values. Film samples, including N, presented lower WVP values, whereas higher WVP and water solubility values were obtained with G inclusion (p<0.05). L* and transmittance values increased with the increasing N content while the opacity values decreased (p<0.05). Furthermore, films added G showed significantly higher a* and b* values. The addition of N caused slower release of G from CH films through the selected food simulants. The obtained trilayer films also inhibited selected main pathogenic bacteria. The fabrication of PCL and CH films in the trilayer form enhanced the properties of CH and made these films more appropriate for food packaging.

Effect of ultrahigh-pressure treatment on the functional properties of poly(lactic acid)/ZnO nanocomposite food packaging film.

Our living environment is being increasingly polluted by petroleum-based plastics and there is an increasing demand for biodegradable food packaging. In this study, the effect of various ultrahigh-pressure (UHP) treatments (0, 200 and 400 MPa) on the microstructure and thermal, barrier and mechanical properties of poly(lactic acid) (PLA)/ZnO nanocomposite films was studied. The film-forming solution was processed using UHP technology. The crystallinity, strength and stiffness of the composite film after UHP treatment increased. In addition, barrier property analysis showed that the UHP treatment significantly (P< 0.05) reduced the oxygen permeability and water vapor permeability (WVP) coefficient of the PLA/ZnO nanocomposite film. Furthermore, the WVP value of the film treated at 400 MPa (50 g kg-1 nano-ZnO content) was the lowest and reduced by 47.3% compared with that of pure PLA film. The improvement in these properties might be due to the interaction between nano-ZnO and PLA matrix promoted by UHP treatment. Therefore, the application of UHP technology on the film-forming solution could improve the crystallinity and functional properties of the nanocomposite film, and has great potential in the production of food packaging films with ideal functions. © 2021 Society of Chemical Industry.

Effect of orange (Citrus sinensis L.) peel essential oil on characteristics of blend films based on chitosan and fish skin gelatin

A novel composite packaging film based on fish (Cynoglossus semilaevis) skin gelatin (FSG) and water soluble chitosan (CH) incorporated with the concentrations(0.25,0.5,1.0%, v/v) of orange peel essential oils (OPEO) were prepared and characterized. OPEO incorporation dose-dependently lowered the values of tensile strength, elastic modulus, water solubility, moisture content and water vapor permeability. Nevertheless, OPEO raised elongation at break, contact angle. Fourier transform infrared spectroscopy analyses spectra pattern suggested the structural interaction between OPEO and FSG/CH molecules in the films. The noticeable decline in values of L* and a* with coincidental enhancement in values of b*, △E and Opacity were observed when OEPO concentrations increased. Films containing OPEO showed slightly lower degradation temperature and weight loss compared with the control film. Moreover, inclusion of OPEO promoted the inhibitory activity of the bio-composite films against free radicals (DPPH and ABTS) and the tested microorganisms (Staphylococcus aureus and Escherichia coli). Overall, it can be suggested that FSG/CH based active blend films incorporated with OPEO could offer potential packaging material to maintain food quality.

Biodegradable and Edible Film Based on Persimmon (Diospyros kaki L.) Used as a Lid for Minimally Processed Vegetables Packaging

Biodegradable films based on persimmon (Diospyros kaki L.) with glycerol and pectin were developed, characterized, and applied as a lid for bowls with minimally processed vegetables (MPV) (cucumber, carrot, and beetroot), with PVC as a positive control. Microbiological and physical parameters of MPV were investigated during refrigerated storage. The films presented high values of water vapor permeability (WVP) (5.77–6.63 × 10−6 g h−1 m−1 Pa−1) and water solubility (WS) (68.80–80.86 %) and 0.75–1.35 MPa, 17.71–20.55%, and 3.82–10.06 MPa of tensile strength (TS), elongation at break (EB), and Young’s modulus (YM), respectively. The addition of glycerol and pectin decreased TS and increased YM, EB, and WS of films. Thermogravimetric analysis showed two important steps of degradation related to glycerol, polymer backbone, pectin, and monosaccharide ring: 205 and 335 °C. Scanning electron microscopy revealed a homogenous microstructure of the films. The film with lower WVP and thickness, higher TS, good flexibility, and a more vivid color was selected as a lid for MPV bowls. Vegetables covered with film or PVC presented similar results regarding thermotolerant coliform evolution (< 3 to 160 MPN g−1); psychrophiles and fungi count (< 2 to 8.72 log CFU g−1); pH value (5.95 to 6.18 for cucumber; 5.96 to 6.10 for carrot; 6.02 to 5.75 for beetroot); and optical properties. Persimmon film reduced the dehydration process of MPV, though to a lower extent than PVC. This study indicates the potential of persimmon-based film as an alternative to synthetic lids for vegetable packaging.

Active Biodegradable Polyvinyl Alcohol–Hemicellulose/Tea Polyphenol Films with Excellent Moisture Resistance Prepared via Ultrasound Assistance for Food Packaging

Poor water-vapor barriers and mechanical properties are common problems of biobased films. To maintain food quality, the barrier and its strength performance need to be improved. Tea polyphenols (TP) are a natural active substance, and their benzene ring structure provides a barrier for them as a film material. Films that incorporate TP also have enriched functionalities, e.g., as antioxidants. Here, active poly (vinyl alcohol) (PVA)-hemicellulose (HC)/TP films with good moisture resistance and antioxidant capacity were prepared via ultrasound assistance. The effects of TP incorporation and ultrasonication on the physical, antioxidant, and micromorphological properties of the films were investigated. Results showed that the addition of TP improved the thermal stability and water-vapor permeability (WVP) of the composite films. When a PVA-HC/TP composite film with a PVA-HC to TP mass ratio of 100:10 was treated with ultrasonication for 45 min, tensile strength was 25.61 Mpa, which was increased by 54% from the film without any treatment, and water-vapor permeability (WVP) value declined from 49% to 4.29 × 10−12 g·cm/cm2·s·Pa. More importantly, the films’ DPPH scavenging activity increased to the maximal levels of 85.45%. In short, these observations create a feasible strategy for preparing high-performance biodegradable active-packaging films.

Effect of DMDHEU treatment on properties of bacterial cellulose material

The aim of this study was to estimate the influence of purification and treatment with textile finishing agent procedures on structural, mechanical, and water barrier properties of bacterial cellulose (BC) in order to predict the end-use properties. Kombucha fungus generated by Komagataeibacter xylinus species, formerly known as Gluconacetobacter xylinus, was used to produce the BC material. The BC was purified with 0.5% sodium hydroxide (NaOH) solution and treated with 5%, 10%, and 20% concentration of N, N-dimethylol 4,5-dihydroxy-ethylene urea (DMDHEU). By Fourier transform spectroscopy (FTIR) and X-ray diffractometer (XRD) was estimated, that the purification with a weak alkali solution was effective to remove amorphous matter of the BC material. Scanning electron microscope (SEM) images demonstrated the BC structure, similar to a non-woven textile fabric with clearly visible three-dimensional networks of fine cellulose fibers. After the purification process, the BC material tensile strength increased by 52%; however, the strain decreased by 93%. BC material after treatment with 20% DMDHEU regained deformability and tensile properties analogous to untreated samples. Water vapor permeability (WVP) values increased and water absorption capacity (WAC) decreased in BC material with increasing DMDHEU concentration. According to the FTIR results, the crosslinking reaction of DMDHEU and adjacent BC molecules was proved. The treatment with DMDHEU restores the amorphous properties of BC material, and therefore blocks water absorption, and the decrease in the water absorption parameter might be determined.