The release of cefazolin from chitosan/polyvinyl alcohol/sepiolite nanocomposite hydrogel films

Films of chitosan/polyvinyl alcohol (PVA)/sepiolite nanocomposite were prepared by a simple and “green” route through solution mixing; followed by freezing–thawing cycles. The structures of nanocomposites were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetric analysis, X-ray diffractometry, and Fourier transform infrared spectroscopy. The SEM and TEM micrographs confirmed a needle-type dispersion of sepiolite nanoclay in the hydrogel nanocomposites. The effects of sepiolite and chitosan/PVA weight ratio on the swelling of nanocomposites were investigated. The water absorbency of nanocomposites was decreased by introducing sepiolite nanoclay. The nanocomposites with high content of chitosan showed high swelling capacity. The nanocomposite films showed pH-dependent swelling behavior with a maximum water absorbency under acidic pH. The cefazolin with a broad-spectrum activity toward gram-positive and gram-negative bacteria was loaded in hydrogels. The release of cefazolin from nanocomposites was evaluated at pH 7.4. The content of released drug was affected by both sepiolite amount and chitosan/PVA weight ratio. The nanocomposites films released more cefazolin than the neat hydrogel film. Cefazolin-loaded nanocomposites showed the antibacterial activity with a large zone of inhibition against gram-positive Bacillus cereus bacterium.     

Effects of halloysite nanotubes and kaolin loading on the tensile,swelling, and oxidative degradation properties of poly(vinyl alcohol)/chitosan blends

[Halloysite nanotubes (HNT)]‐filled and kaolin filled composite films based on poly(vinyl alcohol) (PVA)/chitosan (CS) blend were prepared via solution casting method. Tensile properties, fracture morphology, FTIR spectra, thermal stability, swelling properties, moisture absorption, and oxidative degradation of the composite films were investigated. Addition of 0.5 wt% of filler led to the optimum tensile properties of the films. Increased roughness and tearing in the fracture surface morphology supported the tensile results. The FTIR results indicated there were physical interactions present in the composite films. Thermal stability of the composite films differed slightly where PVA/CS/HNT composite films showed better thermal stability than PVA/CS/kaolin composite films. Moreover, the presence of HNT and kaolin fillers in the blend reduced the swelling and moisture absorption properties of the films. Finally, the composite films were degraded by using Fenton's reagent. Degradation percentage of the composite films decreased with increasing filler loading. J. VINYL ADDIT. TECHNOL., 19:55–64, 2013. © 2013 Society of Plastics Engineers     

Tensile,Swelling, and Oxidative Degradation Properties of Crosslinked Polyvinyl Alcohol/Chitosan/Halloysite Nanotube Composites

Glutaraldehyde (GA) crosslinked polyvinyl alcohol (PVA)/chitosan (CS)/halloysite nanotube (HNT) composite films were prepared using a wet casting method. The tensile, morphology, thermal degradation, swelling, moisture, and oxidative degradation properties of crosslinked composite films were carried out. The presences of crosslinking in the composite films were confirmed by FTIR result. The tensile strength of the crosslinked composite films increased up to 0.5 wt% of HNTs loading. Increasing HNTs reduced the thermal degradation, swelling, and moisture properties of crosslinked composite films reduced with the increase of HNTs content. Results also indicated that the crosslinked composite films were degraded using Fenton reagent.     

Comparative delivery of Diltiazem hydrochloride through synthesized polymer: Hydrogel and hydrogel microspheres

In this study, interpenetrating polymer network (IPN) hydrogel based on polyvinyl alcohol (PVA) networking with polyacrylic acid (PAA) were prepared by a non‐conventional emulsion method without any added crosslinker, using benzoyl peroxide as initiator and sodium chloride (NaCl) as additive. The IPN hydrogel was characterized by using Fourier transformed infrared (FTIR) spectrophotometry, Thermo gravimetric analysis (TGA), and Scanning electron microscopy (SEM). (PVA‐co‐PAA)/NaCl normal IPN hydrogel (H) were fabricated into hydrogel microspheres (HM) by modified emulsion crosslinking method using glutaraldehyde‐saturated toluene as crosslinker and were loaded with Diltiazem hydrochloride (DL). The IPN hydrogel showed more swelling in simulated intestinal fluid (SIF). (PVA‐co‐PAA)/NaCl HM formulation A1 showed comparatively higher DL entrapment (79%) and better control over DL release up to 24 h. By comparing antihypertensive activity of DL loaded two formulations in normotensive rats, HM formulation A1 found more effective in reducing blood pressure to 40.1%. The experimental results demonstrated that (PVA‐co‐PAA)/NaCl HM had the greater potential than normal hydrogel to be used as a drug carrier. A single use of the prepared hydrogel microsphere system of DL can effectively control hypertension in rats. The system holds promise for clinical studies. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Radiation synthesis and characterization of poly(vinyl alcohol)/poly(N-vinyl-2-pyrrolidone) based hydrogels containing silver nanoparticles

A series of PVA/PVP based hydrogels at different compositions were prepared by gamma irradiation. The gel fraction degree of swelling were investigated. Highly stable and uniformly distributed silver nanoparticles have been obtained onto hydrogel networks. The morphology and structure of (PVA/PVP) hydrogel and dispersion of the silver nanoparticles in the polymeric matrix were examined by scanning electron microscopy (SEM) and infrared spectroscopy (FT-IR), respectively. The formation of silver nanoparticles has been confirmed by ultraviolet visible (UV–vis) spectroscopy. A strong characteristic absorption peak was found to be around 420 nm for the silver nanoparticles in the hydrogel nanocomposite. The X-ray diffraction pattern confirmed the formation of silver nanoparticles with average particle size of 12 nm. The diameter distribution of silver nanoparticles was determined by dynamic light scattering DLS. Transmission electron microscope (TEM) showed almost spherical and uniform distribution of silver nanoparticles through the hydrogel network and the mean size of silver nanoparticles ranging is 23 nm. The good swelling properties and antibacterial of PVA/PVP-Ag hydrogel suggest that it can be a good candidate as wound dressing.     

Biodegradability, antimicrobial activity and properties of PVA/PVP hydrogels prepared by γ-irradiation

Polyvinyl alcohol/polyvinyl pyrrolidone (PVA/PVP) hydrogel has been prepared by using γ-irradiation technique. In the present study the conclusion on miscibility of PVA/PVP blends, confirmed qualitatively and quantitatively by using Fourier transform infrared spectroscopy and differential scanning calorimetry, respectively. PVA and PVP are found to form a thermodynamically miscible pair. The physical properties such as gel fraction and water absorption performance of the prepared hydrogels were measured, it was found that the gel fraction increases with increasing irradiation dose while the swelling of PVA/PVP blended hydrogels nearly tends to increase with increasing PVP content and reduced with enhanced irradiation doses. The hydrogel pore structure of various PVA/PVP compositions were tested with SEM. Ability of PVA/PVP hydrogels to absorb and release antimicrobial compounds was tested using amoxicillin as an antibacterial and ketoconazole as an antifungal. Antimicrobial activity of PVA/PVP hydrogels was examined using four bacteria, and four fungi. No antibacterial or antifungal activities of non-loaded PVA/PVP of various compositions were detected while the loading ones found to have antimicrobial activity. Results showed resistance of Pseudomonas aeruginosa and Candida albicans to PVA/PVP, while Bacillus subtilis was very sensitive. Biodegradation of PVA/PVP hydrogels was investigated by burial method in two types of local soils (clay and sandy soils). The highest degradation rate was found to be achieved using clay soil. Also, effect of irradiation dose on its biodegradability was tested. The results showed that the radiation prepared PVA/PVP hydrogels can be use as biomaterials.     

多孔n-HA/PVA/CS复合水凝胶的制备与抑菌性能研究

以纳米羟基磷灰石、聚乙烯醇、壳聚糖为原料,采用物理交联法制备复合水凝胶(n-HA/PVA/CS),并测定其含水率、力学强度及微观结构。采用比浊法和平板计数法测定n-HA/PVA/CS复合水凝胶在酸性条件下的最低抑菌浓度和抑菌率,同时对比研究其对革兰氏阴性菌大肠杆菌(E.coli)和革兰氏阳性菌金黄色葡萄球菌(S.aureus)的抑菌性。结果表明,n-HA/PVA/CS复合水凝胶具有均匀分散的三维多孔结构,含水率75%,拉伸强度0.26 MPa。经过2%(质量分数)的醋酸溶液处理的n-HA/PVA/CS复合水凝胶材料对S.aureus和E.coli的最低抑菌质量浓度均为0.5 g/L;在该复合水凝胶质量浓度为2.0 g/L时,对S.aureus的抑菌率为84%,对E.coli的抑菌率达到99%,当其样品质量浓度为2.5 g/L时,对E.coli抑菌率接近100%。n-HA/PVA/CS复合水凝胶可望成为性能优良的人工角膜支架材料。     

Surface modification of polypropylene film by grafting with vinyl monomers for the attachment of chitosan

Polypropylene (PP) film activated by corona discharge treatment was grafted with methyl methacrylate (MMA) and acrylic acid (AA). The grafted PP was characterized by spectral, thermal analysis and swelling behavior which confirmed the occurrence of the grafting. The water vapor and oxygen permeability (OTR and WVTR) as well as the mechanical properties have been enhanced by grafting with both AA and MMA. The grafted PP was further immobilized with chitosan (CS) using ceric ammonium nitrate (CAN) as an initiator under ultraviolet radiation. The chitosan immobilized grafted film was characterized by FTIR, mechanical properties, thermal properties and swelling measurements. Scanning electron microscope (SEM) confirmed that the CS is bonded to the grafted PP film. The CS modified PP film has acquired enhanced antibacterial and antifungal properties.     

Synthesis,characterization, and enzymatic degradation of chitosan/PEG hydrogel films

Poly(ethyleneglycol) (PEG)/tartaric acid (TA)‐crosslinked chitosan hydrogel (CPT) films were prepared, and the formation of the PEG/TA‐crosslinked structure was confirmed by Fourier transformed infrared (FTIR), nuclear magnetic resonance (NMR), and scanning electron microscope (SEM) measurements. The thermal properties of the crosslinked films were also determined with thermogravimetric analysis (TGA) and differential scanning calorimeter (DSC) analysis. The swelling properties of the films were investigated at different temperature and pH values. It was found that the swelling ratio increased with the decrease of pH value of the surrounding buffer solutions, amount of PEG, and with the increase of temperature. Swelling behavior of the PEG/TA‐crosslinked chitosan hydrogel films depended on pH and reversible with the temperature. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

壳聚糖/聚乙烯醇共混膜的氢键和相容性

采用溶液共混法制备了不同配比的壳聚糖/聚乙烯醇共混膜,通过变温FTIR、TG、DTA、DSC及XRD等对共混膜的结构、氢键相互作用、热行为和结晶性等进行研究。实验结果表明,共混膜中壳聚糖与聚乙烯醇间存在强烈的氢键相互作用。氢键的存在使壳聚糖的热稳定性提高,聚乙烯醇结晶性下降,促进壳聚糖与聚乙烯醇相容。当壳聚糖/聚乙烯醇共混膜的质量比分别为10/0、7/3、5/5、3/7和0/10时,共混膜的初始分解温度分别为244 ℃、257 ℃、260 ℃、262 ℃和285 ℃。聚乙烯醇熔融温度从193 ℃下降到173 ℃,玻璃化转变温度从74.2 ℃上升至80 ℃,结晶度Xc从3.57%下降到1.97%。     

Synthesis and characterization of polyvinyl alcohol/dextran/Zataria wound dressing with superior antibacterial and antioxidant properties

The aim of the present research was to synthesize and characterize polyvinyl alcohol/dextran/Zataria essential oil hydrogel wound dressings. For this purpose, dressings were made with different concentrations of polymers (PVA and Dex) and ZMO by solvent casting method. By dissolving PVA and Dextran in de-ionized water, PVA-Dex gel was made. The polymeric solution was mixed with glycerol. The pH of PVA-DEX-Glycerol solution was adjusted to 3 and glutaraldehyde was used as a cross-linker. ZMO, as the antibacterial and antioxidant agent, was added to the samples in different percentages (2,5,10%). It was found that both Dex and ZMO significantly influenced the hydrophilicity, gel fraction, and water uptake capacity of hydrogel films. The results showed that by the addition of Dex to PVA, the contact angle decreased from 48.54° ± 0.95 to 45.90 ± 0.73°, whereas by the addition of ZMO, the contact angle increased to 71.1 ± 2.43. SEM investigations revealed that the fabricated films had a uniform structure and the surface roughness increased with the addition of ZMO. The results indicated an increased elongation of 11.5% with the incorporation of ZMO into the films. The antimicrobial evaluation of the produced films showed that the loading of 10% v/v ZMO could broaden the microbicidal activity of PVA/Dex/ZMO film. The investigations on the interactions between synthesized wound dressings and fibroblast cells showed that the addition of ZMO into hydrogel films improved cell viability. The findings showed that PVA/Dex/ZMO films could have considerable use as wound dressing.     

Properties of chitosan/poly(vinyl alcohol) films for drug‐controlled release

With bovine serum albumin (BSA) as a model drug, drug‐loaded films of chitosan (CS) and poly(vinyl alcohol) (PVA) were obtained by a casting/solvent evaporation method and crosslinked by tripolyphosphate (TPP). The films were characterized by FTIR, XRD, and SEM. The influential factors of drug‐loaded films on drug‐controlled release were studied. These factors included, primarily, the component ratio of CS and PVA, the loaded amount of BSA, the pH and ionic strength of the release solution, and the crosslinking time with TPP. The results showed that within 25 h, when the weight ratios of CS to PVA in the drug‐loaded films were 90 : 10, 70 : 30, 50 : 50, and 30 : 50, the cumulative release rates of BSA were 63.3, 72.9, 81.8, and 91.8%, respectively; when the amounts of model drug were 0.1, 0.2, and 0.3 g, the release rates were 100, 81.8, and 59.6%, respectively; when the pH values of the drug release medium were 1.0, 3.8, 5.4, and 7.4, the release rates reached 100, 100, 37.9, and 7.8%, respectively; the cumulative release rates of BSA were 78.4, 82.3, 84.3, and 91.7% when the ionic strengths of the release solution were, respectively, 0.1, 0.2, 0.3, and 0.4M; when the crosslinking times of these drug films in the TPP solution were 0, 5, 15, 30, and 60 min, the release rates attained 100, 100, 81.8, 65, and 43.3%, respectively. All the results indicated that the CS/PVA film was useful in drug delivery systems. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 808–813, 2005     

Comparison the properties of PVA/Na+‐MMT nanocomposite hydrogels prepared by physical and physicochemical crosslinking

A novel physicochemical crosslinked nanocomposite hydrogel based on polyvinyl alcohol (PVA) and natural Na‐montmorillonite (Na⁺‐MMT) was synthesized by chemical crosslinking of nanocomposite hydrogel followed by a freezing‐thawing process. The effects of physical crosslinking, as well as physicochemical crosslinking, on the structure, morphology, and properties (thermal, mechanical, swelling, and deswelling) of nanocomposite hydrogels were investigated and compared with each other. The structure and morphology of nanocomposites were studied by Fourier transform infrared, X‐ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy techniques. The thermal and mechanical properties of nanocomposites that were affected by physical and physicochemical crosslinking were evaluated by thermogravimetric analysis, differential scanning calorimeter, dynamic mechanical analysis, hardness test, and Water vapor transmission rate (WVTR) experiments. The results showed that the physicochemical crosslinking of a PVA nanocomposite leads to a reduction in crystallinity and melting temperature, as well as an increase in the Hardness and WVTR compared to a physically crosslinked PVA nanocomposite hydrogel. The swelling and deswelling experiments were performed using a gravimetric method, and it was shown that controlled crosslinking of PVA nanocomposite hydrogel with glutaraldehyde causes the swelling ratio to increase and the cumulative amount of water loss to decrease. The swelling (sorption) and deswelling (desorption) kinetics data for physically and physicochemical crosslinking of nanocomposite hydrogels were fitted with a fickian model. It is concluded that through control crosslinking of PVA nanocomposite can lead to a hydrogel with higher swelling capacity than that is in conventional PVA nanocomposite hydrogel. POLYM. COMPOS., 37:897–906, 2016. © 2014 Society of Plastics Engineers     

Synthesis and characterization of hybrid polymeric networks (HPN) based on polyvinyl alcohol/chitosan

The aims of this study are the preparation of hybrid polymer network (HPN) hydrogels with slight differences in their hydrophilic balance and evaluate the influence of the chemical composition on the HPN for application as solid polymeric electrolytes (SPEs). A hydrogels series of polyvinyl alcohol (PVA)/chitosan (CHI) were prepared using glutaraldehyde as crosslinking agent. The hydrogels were characterized by Fourier transformed infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), swelling ratio (SR) and electrochemical impedance spectroscopy (EIS). For sample with higher chitosan in the HPN the PVA crystallization was decreased and HPN with higher PVA content presented an increased swelling ratio. The electrochemical impedance studies demonstrated that the ionic conductivity of PVA/CHI HPN films depend on their composition and it is higher as the PVA content in hydrogel was diminished.     

3D gel printing of magnetic hydrogel scaffolds assisted by in-situ gelation in a water level-controlled crosslinker bath

Polyvinylalcohol/chitosan (PVA/CS) is an excellent dual-network hydrogel material, but some significant challenges remain in fabricating composites with specific structures. In this study, 3D gel printing (3DGP) combined with a water-level controlled crosslinker bath was proposed for the rapid in-situ prototyping of PVA/CS/Fe₃O₄ magnetic hydrogel scaffolds. Specifically, the PVA/CS/Fe₃O₄ hydrogels were extruded into the crosslinker water to achieve rapid in-situ gelation, improving the printability of hydrogel scaffolds. The effect of the PVA/CS ratio on the rheological and mechanical properties of dual-network magnetic hydrogels was evaluated. The printing parameters were systematically optimized to facilitate the coordination between the crosslinking water bath and printer. The different crosslinking water baths were investigated to improve the printability of PVA/CS/Fe₃O₄ hydrogels. The results showed that the printability of the sodium hydroxide (NaOH) crosslinker was significantly better than that of sodium tripolyphosphate (TPP). The magnetic hydrogels (PVA: CS= 1: 1) crosslinked by NaOH had better compressive strength, swelling rate, and saturation magnetization of 1.17 MPa, 92.43%, and 22.19 emu/g, respectively. The MC3T3-E1 cell culture results showed that the PVA/CS/Fe₃O₄ scaffolds promoted cell adhesion and proliferation, and the scaffolds crosslinked by NaOH had superior cytocompatibility. 3DGP combined with a water-level controlled crosslinker bath offers a promising approach to preparing magnetic hydrogel materials.     

The Preparation and Characterization of Esterified Banana Trunk Fibers/Poly(vinyl alcohol) Blend Film

Polymer composite using natural fiber as reinforcement material is getting attention due to easy availability and its low cost. In this work, poly(vinyl alcohol) (PVA)/fatty acid esterified banana trunk fibers (FAGBTF) of various compositions were produced by a solution casting method. The characteristic properties of PVA/ FAGBTF composite films were examined by Fourier Transform Infra-Red (FTIR), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and tensile tests. On the whole, the increase in the amount of BTF in the composite systems improved the thermal properties and decreased percentage degree of swelling as compared to pure PVA.     

Hydrogels of starch/carboxymethyl cellulose crosslinked with sodium trimetaphosphate via reactive extrusion

Hydrogels are materials with advantages in specific applications, such as, retention of food active compounds. This work aims to develop starch (S)/carboxymethyl cellulose (CMC) hydrogels with porous structure, using reactive extrusion to promote crosslinking with sodium trimetaphosphate (STMP). The expansion, porosity, degree of substitution, gel fraction, swelling properties, and FTIR are studied, comparing S, S/CMC, S/STMP, and S/CMC/STMP formulations. Samples containing STMP present the same degree of substitution (0.050 ± 0.001). Higher porosity and percentage of open pores are observed in the mixed hydrogel (S/CMC/STMP). Crosslinking increase the swelling capacity at pH 7, and this property, just like the gel fraction, are sensitive to pH variations. The hydrogel S/CMC present the highest swelling rate compared with the other samples, suggesting strong interaction between components. The reactive extrusion process is efficient to produce starch and starch/CMC hydrogels crosslinked with STMP and the overall results demonstrate the advantages of the mixed hydrogel.     

The effect of antimicrobial peptide HX-12C on the properties of chitosan/polyacrylic acid hydrogel

Antimicrobial peptide (AMP) hydrogel is a novel biomaterial widely used in wound healing. However, there have been limited studies investigating the effect of AMP on hydrogel properties so far. Therefore, this study aimed to examine the influence of the AMP HX-12C on the chitosan/polyacrylic acid (CS/PAA) double-network (DN) hydrogel. The results showed that the mechanical properties of CS/PAA/HX-12C hydrogel are significantly improved compared with those of CS/PAA hydrogel. The maximum tensile stress increased from 41.0 to 258.5 KPa, and the compression stress required for 80% hydrogel deformation increased from 3.7 to 6.7 MPa. Furthermore, the thermal stability of CS/PAA/HX-12C showed a noticeable enhancement when compared with CS/PAA hydrogel. In addition, the CS/PAA/HX-12C hydrogel exhibited improved porosity and swelling performance. The addition of HX-12C significantly enhanced the antibacterial activity of the hydrogel against Escherichia coli and methicillin-resistant Staphylococcus aureus. Cytotoxicity test showed that the viability of L929 cell remained above 90% after treatment with CS/PAA/HX-12C hydrogel extract, indicating the good biocompatibility. In conclusion, AMP assuredly enhances the mechanical property, swelling performance and antimicrobial activity of hydrogel. The CS/PAA/HX-12C hydrogel shows potential for use as anti-infective medical material.     

Fabrication and characterization of alginate/chitosan hydrogel combined with honey and aloe vera for wound dressing applications

Hydrogels can be one of the best polymeric wound dressings due to the desirable properties of wound healing. In this study, emphasizing the use of natural biomaterials such as Aloe vera and honey in the structure of cross-linked polymers, a novel hydrogel was produced that might be applied to healing wounds. In the beginning, four hydrogel groups were made from a combination of Sodium Alginate and Chitosan with Aloe vera extract and honey in optimum concentrations. Then the structure of those was evaluated by SEM and FTIR. After confirming hydrogels' structural properties, their physical properties, including swelling, porosity, density, mass loss, stability, and WVTR, were examined. Besides, the hydrogel biocompatibility was assessed by analyzing the cell viability and hemolytic activity. Adhesion of the cells to the hydrogel was also observed by SEM imaging. The results showed that the designed hydrogel has a porous structure with interconnected cavities, which their size can provide suitable conditions for cell adhesion, migration, and proliferation. Also, their physical and structural properties can be a strong suit to wound healing. Although honey's application can weaken the hydrogel structure, honey has beneficial properties due to its complex biomolecules. In contrast, Aloe vera in hydrogel generally improved the hydrogel's specificity for wound healing. According to the results of this study, taking advantage of hydrogels containing honey and Aloe vera based on alginate and chitosan polymers led to the formation of an acceptable structure and biocompatibility that can be used in future researches to repair tissues, especially wounds.     

Improvement of polyvinyl alcohol/casein blend film properties by adding cellulose nanocrystals

This study aims to prepare and examine the properties of poly(vinyl alcohol)/casein (PVA/CAS) based films reinforced with cellulose nanocrystals (NC), which can be presented as an alternative to petroleum-based polymer packaging materials. PVA/CAS and 0.5–1–3–5 wt% NC containing PVA/CAS biocomposite films were prepared by solution casting method. Afterward, the 1NC film, which exhibited the best mechanical properties, was crosslinked with various amounts of glyoxal. Structural, morphological (polarized optical microscope), mechanical (tensile), thermal (differential scanning calorimetry, thermogravimetric analysis), contact angle, and water vapor transmission rate (WVTR) properties of the samples were investigated. The 1NC film exhibited the highest tensile strength (TS) and elongation values in PVA/CAS/NC films, and its mechanical properties decreased due to agglomeration with increasing NC amount. As expected, crosslinking improved the TS. The thermal stability of the PVA/CAS film was generally improved with the addition of NC and crosslinking. The high WVTR value of the PVA/CAS film decreased with the addition of NC and the 1NC film presented the lowest value. Thanks to the complex structure formed as a result of crosslinking and the reduced free volume, the WVTR of the 1NC film has reduced. The results showed that PVA/CAS-based films with good mechanical properties and water vapor barrier are promising as packaging materials.