PVA Blend Research Articles

Design and performance of sericin/poly(vinyl alcohol) hydrogel as a drug delivery carrier for potential wound dressing application

Developing a non-toxic, super-absorbent and antibacterial hydrogel as a skin wound dressing is of significant importance. Sericin hydrogel is an ideal dressing material as it has excellent biocompatibility, biodegradability, moisture retention, high affinity to biomolecules, self-healing and promoting cell proliferation activity. Here, we blended silk sericin (SS) with poly(vinyl alcohol) (PVA) to prepare a SS/PVA hydrogel through repetitive freeze-thawing. The photoluminescence of SS/PVA hydrogel indicated PVA was well blended with sericin. SS/PVA hydrogel showed excellent hydrophilicity and swelling behavior for its porous structure. PVA blending effectively improved the thermostability of sericin and enhanced the mechanical property of sericin, but did not affect the crystallinity of sericin and PVA. SS/PVA hydrogel exhibited the ability to load and release small molecule drugs and silver nanoparticles. Cytotoxicity and immuno-toxicity assays suggested the gentamicin loaded SS/PVA hydrogel had excellent cytocompatibility on mammalian cells. Bacterial inhibition assay and wound infection model demonstrated the gentamicin loaded SS/PVA hydrogel could effectively inhibit bacterial growth, thus maintain cells viability. This novel hydrogel with antimicrobial activity has shown great potential in wound dressing.

Effect of vinyl silane modification on thermal and mechanical properties of starch-polyvinyl alcohol blend

ABSTRACTThis study aims to observe the effect of addition of silane coupling agent on polyvinyl alcohol and starch-PVA blend. Starch and PVA blend with citric acid addition was prepared. Silane-modified polymer was obtained by treating polyvinyl alcohol and starch-PVA blend with Trimethoxyvinylsilane. The blend has been tested against the canarium wood substrate for tensile strength. A further property like viscosity has also been evaluated. Analytical tests such as DSC and DMA proved the phenomenon of cross-linking, having shown an increase in glass transition temperature and area under the curve of tan delta. The efficient and novel method for polymerization of vinyl groups present in the PVA and PVA-starch blends has contributed to better adhesion on the wood substrate and also better cohesion between the chains.

To study the effect of boric acid modification on starch–polyvinyl alcohol blend wood adhesive

Starch–polyvinyl alcohol blends with enhanced properties are achieved with cross-linking it with boric acid. These blends are characterized by FTIR and DSC. A film of starch and PVA blends were prepared by casting on glass plate. The effects of various factors such as increasing starch content, increasing amount of boric acid, on the performance properties like tensile strength, pencil hardness and thermal properties like glass transition temperature were studied. The results showed that the starch–polyvinyl alcohol films prepared by boric acid cross-linking had excellent mechanical, thermal properties and hardness of the film.

SiO2 particles effect on the mechanical properties of the starch/PVA blends

The present work studies the mechanical properties of SiO2 μPs, and NPs in St/PVA blends. The samples were prepared by casting method as PVA, St/PVA blends at different concentrations (30, 40, 50, and 60 %). DSC and TGA tests were carried out to the samples evolved. The result showed a single glass transition temperature (Tg) for all St /PVA blends that was attributed to the good miscibility of the blends involved. It was found that (Tg) decrease with starch ratio increase. It was seen that (PVA) of (Tg=105 oC); The glass transition temperature which was decrease with starch ratio that was attributed to glass transition relaxation process due to micro-Brownian motion of the main chain back bond. The endothermic peak at 200 oC was attributed to melting point of (PVA). Thermal properties of PVA; and St /PVA blends at different concentration (30, 40, 50, and 60 %) were evaluated by thermo gravimetric analysis (TGA). The analyses were carried out from 20 to 600 oC at 10 oC)/min heating rate in air oxygen atmosphere. The weight loss stages depended on polymer system. The starch addition causing shifting in the second degradation temperature to the higher temperature; which result in overlapping between the two main degradation steps, these result was attributed to the St/ PVA blend compatibility. The mechanical properties results showed a decrease in ultimate strength with starch ratio increase. The ultimate strength of (PVA) was (47 MPa), whereas the ultimate strength of 60 %St/PVA was (11 MPa) and for 30 %St/PVA was the highest ultimate strength of blends involved (26 MPa). SiO2μPs (753.7 nm), and NPs (263.1 nm) were added at different concentrations (1.5, 2, and 2.5 %). 1.5% SiO2μPs, and NPs of the best ultimate strength (69 MPa), (86 MPa) respectively then it was decreased by SiO2μPs, and NPs increase. Optical microscope of the samples involved was investigated. It was concluded the prepared samples were suggested to be used as packaging materials for agriculture application and its ultimate strength could be controlled by SiO2μPs, and NPs addition.

Silver hydroxyapatite reinforced poly(vinyl alcohol)—starch cryogel nanocomposites and study of biodegradation, compressive strength and antibacterial activity

In the present work polyvinyl alcohol‐starch/silver hydroxyapatite (PVA‐starch/AgHap) cryogel nanocomposites were prepared by successive freezing‐thawing of a blend of PVA and starch solutions to fabricate a cryogel followed by its reinforcement with silver hydroxyapatite (AgHap). The prepared macroporous cryogel nanocomposites were characterized by Infra‐red spectroscopy (FTIR), environmental scanning electron microscopy (ESEM), and particle size and charge analysis. The amylase induced enzymatic degradation of nanocomposites was studied gravimetrically in phosphate buffer saline (PBS) and effect of various parameters like chemical composition of the nanocomposite, number of freeze‐thaw cycles, and enzyme activity were assessed on the extent of degradation of the nanocomposite. The influence of chemical composition and experimental conditions like the number of freeze thaw cycles was studied on the elastic modulii of the cryogels. The in vitro cytotoxicity and antibacterial activity of nanocomposites was also evaluated against L‐529 fibroblast cells and gram positive and gram negative bacteria, respectively. POLYM. ENG. SCI., 59:254–263, 2019. © 2018 Society of Plastics Engineers

Elastin‐based polymer: synthesis, characterization and examination of its miscibility characteristics with poly(vinyl alcohol) and electrospinning of the miscible blends

AbstractMiscibility is an important factor for peptide‐based polymer blends for employment in the pharmaceutical, drug delivery and biomedical fields. The current study presents the synthesis of a repeating sequence of elastin, poly(GVGIP), characterized using1H NMR and13C NMR spectroscopy, and an investigation of its miscibility characteristics with poly(vinyl alcohol) (PVA) over a broad range of composition in solid and solution phase using various analytical techniques. The miscibility behaviour of the blend solutions was established quantitatively by the analysis of various parameters of simple viscometric measurements. The results confirmed the miscibility of the blends containing up to 50% of the polypeptide. Further, Fourier transform infrared spectroscopy indicated the existence of intermolecular hydrogen bonding between the two polymers in the blends. Scanning electron microscopy and X‐ray diffraction revealed the change in surface morphology and crystallinity for blend films. Differential scanning calorimetry demonstrated a single glass transition temperature of the blend films. Interestingly, long, thin nanofibre meshes were also successfully prepared through electrospinning of poly(GVGIP)/PVA blends from aqueous solutions at a very low concentration (5 wt%). © 2018 Society of Chemical Industry

Structural and morphological evaluation of CNC reinforced PVA/Starch biodegradable films

Nanocomposite films containing cellulose nanocrystals (CNC), as the reinforcing phase, and poly(vinyl alcohol) (PVA)/starch (S) blend, as the matrix, were prepared by solution casting technique. For the preparation, 5, 10, 15 wt% CNC suspension were incorporated in blends containing 90 wt% PVA/10 wt% S, 75 wt% PVA/25 wt% S and 50 wt% PVA/50 wt% S. Structural evaluation was done by Fourier transform infrared spectrometry and X-ray diffraction, and the morphological aspects by atomic force microscopy. Infrared spectroscopy evidenced the presence of H-bond interactions between the PVA and S and between PVA/S blend and CNC, and also variation in the conformational rearrangement, while the X-ray diffraction showed that the crystallite size and the degree of crystallinity were strongly affected by blending of PVA with S and also by the incorporation of CNC in the nanocomposite films. The surface roughness of studied samples increased with the increasing of S and filler content.

Morphology and Rheology of Nanofilled PP / PVA Blends

The influence of Ag/SiO2 as nanofiller and sodium oleate as compatibilizer and their mixtures on the patterns flow and structure formation processes in thermodynamically incompatible polypropylene/plasticized polyvinylalcohol (PP / PVA) systems were studied. It is found that the change in the sequence of mixing the ingredients of the composition allows adjusting the morphology phase type due to the predominant localization of nanoparticle additives in the melt amount of a component or on the border of phase separation. Injection of Ag/SiO2 to melt PP increases dispersion degree and homogeneity of its distribution in the matrix. Simultaneous use of nanoadditive and sodium oleate as compatibilizer improves the connections between the polymers and promotes thinner and more homogeneous dispersion of the particles of the dispersed phase. It is shown that the effective viscosity of melt nanofilled system is determined by components mixing method: viscosity of melt blend increases when the additive is localized predominantly in the PVA and decreases with the prior injection of PP. The nature of the flow for all researched compositions obeys a power law and almost does not depend on the method of mixing. The ability of the longitudinal deformation of ternary blends is deteriorating, but remains sufficient for their processing. Combining nanoadditive with compatibilizer promotes increased elasticity and the melt spinnability of modified blends.

A review on mechanical and water absorption properties of polyvinyl alcohol based composites/films

AbstractPolyvinyl alcohol (PVA) is a nontoxic and thermoplastic polymer which is completely biodegradable. PVA shows excellent mechanical and thermal properties due to better interfacial adhesion with reinforcing material such as fibers, particles or flakes because of which it can be used for fabrication of composite. PVA based fiber or particle reinforcing composites have gained interest in many applications in different fields. This paper reviews the mechanical and water absorption properties studied by different researcher and some of them were discussed here. The article also focused on the effect on the mechanical properties on PVA based composites with particle or fiber used as reinforcing material at nano/micro level and different polymers used to prepare PVA blend films. The major disadvantage of PVA based composites/films is higher water uptake or solubility in water. To over this negative aspect, many researchers studied crosslinking of PVA based composites/films, which are also discussed in the article. This review concludes that PVA has the potential for use in the synthesis of composites/films with their abundant applications.

Improving Properties of Arrowroot Starch (Maranta arundinacea)/PVA Blend Films by Using Citric Acid as Cross-linking Agent

This research studied the effect of PVA as organic polymer and citric acid as crosslinker agent in the arrowroot starch/PVA blend films. The properties of films were investigated by water uptake, water vapor permeability, mechanical properties, thermal stability, spectra of FTIR and XRD patterns. PVA used in this research influenced the film properties at the highest concentration. The cross-linkingsinter or intra molecules of arrowroot and PVA were developed as ester bonds which are formed from the reaction of hydroxyl groups consisting of starch and PVA with citric acid. The ester bond was confirmed by FTIR spectra. The increase of the amount of citric acid affected significantly on physical, chemical and mechanical properties, water uptake, WVP and crystallinity. Water barrier level was reduced by decreasing of water uptake and WVP succeeded significantly with increased crosslinking. Cross-linking impact the thermal stability of the films. The elasticity of the films also increases the production of citric acid as a plasticizer in the making of the films as a food packaging material.

Effect of PVA Blending on Structural and Ion Transport Properties of CS:AgNt-Based Polymer Electrolyte Membrane.

In this work, the role of poly(vinyl alcohol) (PVA) blending on structural and electrical properties of chitosan:silver nitrate systems is studied. The X-ray diffraction (XRD) results show that the crystalline phase of chitosan (CS) is greatly scarified by silver nitrate (AgNt) salt. The crystalline domain of CS:AgNt is more broadened at 10 wt % of PVA. The spike and semicircular arcs can be separated in impedance plots. At high temperatures, the spike regions remained. The direct current (DC) conductivity was calculated from the bulk resistance obtained from the impedance plots. The dielectric constant and DC conductivity versus PVA content exhibited similar behavior. The maximum DC conductivity at ambient temperature was 1.1 × 10−6 S/cm for 10 wt % of PVA. The DC ionic conductivity increased to 9.95 × 10−5 S/cm at 80 °C. Above 10 wt % of PVA, the drop in DC conductivity and dielectric constant were observed due to the increase in viscosity. Shifting of relaxation peaks towards the lower frequency revealed the increase of resistivity of the samples. The linear increase of DC conductivity versus 1000/T indicated that ion transport followed the Arrhenius model. The incomplete semicircular arc in Argand plots indicated the non-Debye type of relaxation process. The Argand plots were used to distinguish between conductivity relaxation and viscoelastic relaxation. Three regions were distinguished in the alternating current (AC) spectra of the blend electrolyte samples. The plateau region in AC spectra was used to estimate the DC conductivity. The estimated DC conductivity from the AC spectra was close to those calculated from the impedance plots.

Effect of deacetylation on property of electrospun chitosan/PVA nanofibrous membrane and removal of methyl orange, Fe(III) and Cr(VI) ions

In this study, effect of degree of deacetylation on property and adsorption capacity of chitosan/polyvinyl Alcohol electrospun membrane has been investigated. Resulting nanofibers were characterized by FESEM, FTIR, XRD, TGA, tensile testing, weight loss test and adsorption test. FESEM result shows, finer nanofiber was fabricated from 42h hydrolyzed chitosan and PVA blend solution. FTIR and XRD result showed a strong interaction between chitosan and polyvinyl alcohol. Higher tensile strength was observed for the nanofiber having 42h hydrolyzed chitosan. Blend solution of chitosan/PVA having low DD chitosan had higher viscosity. The nanofibrous membrane was stable in distilled water, acidic and basic medium. The isotherm study shows that the adsorption capacity (qm) of nanofiber containing higher DD chitosan was higher for Cr(VI). In contrary, the membrane containing chitosan with lower DD showed the higher adsorption capacity for Fe(III) and methyl orange. Moreover, the effect of DD on removal percentage of adsorbate was dependent on the initial concentration of the adsorbate.

Developing heat conduction pathways through short polymer chains in a hydrogen bonded polymer system

In the past couple of decades, high thermally conductive fillers are extensively used to develop thermally conductive polymer based composites. Such conventional methods suffer from wide variety of problems especially related to fabrication, high-cost, poor mechanical properties etc. Though covalent bonds in single polymer chain can lead to very high thermal conduction, it is irony that bulk polymers are thermal insulators due to significant phonon scattering. In this work, we have shown how by engineering intermolecular interaction within the polymer chain, one can create continuous thermal network which in turn drives thermal conduction in polymer without using any traditional fillers. Thermal conduction pathways were introduced in a blend film of long chain polymer Poly (vinyl alcohol) (PVA) and short chain Poly (ethylene glycol) (PEG). Thermal conductivity enhancement of around 1.6 times of neat polymer was achieved. The critical factor responsible for thermal conduction in these films was found to be homogeneous distribution of “thermal bridges” formed by hydrogen bonding between PVA and short PEG chain. Reduction in thermal conductivity was observed when PVA blend film with longer PEG chain, which is mainly due to poor thermal bridges distribution and chain agglomeration. This work presents a fascinating yet promising non-conventional method to make thermally conductive polymer based material without using traditional fillers for thermal management applications.

Chitosan/oxidized pectin/PVA blend film: mechanical and biological properties

This paper describes the preparation and characterization of flexible crosslinked chitosan (CH)/poly(vinyl alcohol) (PVA) films. These chitosan-based films are prepared using oxidized pectin as crosslinking agent, and PVA as plasticizer. The chemical structure of the obtained blend films were investigated using FTIR spectroscopy. Swelling behavior of hydrogels obtained was studied in various pH media. The blending of PVA with chitosan or chitosan/oxidized pectin (OP) was found to highly enhance the swelling of the prepared films compared to those obtained from pure chitosan. On the other hand, the use of lactic acid as solvent and the incorporation of PVA improve the flexibility of chitosan matrices. Examination of the hemolytic potential showed that the hydrogels were non hemolytic in nature. The hydrogels were non-toxic and blood-compatible. Reducing power was used to determine in vitro antioxidant activity and anti-inflammatory activity of chitosan films was investigated by protein denaturation method. The biological activity of CH/OP/PVA towards Pseudomonas aeruginosa, Staphylococus aureus, Bacillus subtilis and Escherichia coli has been examined in this study.

Topological and morphological analysis of gamma rays irradiated chitosan-poly (vinyl alcohol) blends using atomic force microscopy

In the present communication, binary blends of poly (vinyl alcohol) (PVA) and chitosan (CS) were prepared by solution cast method and the roughness parameters of PVA, native CS and CS-PVA blend films were determined using atomic force microscopy (AFM). Moreover, the changes in the morphology of the samples were also investigated after irradiation of gamma rays at absorbed dose of 1Mrad and 10Mrad for the scanning areas of 5×5µm2, 10×10µm2 and 20×20µm2. Amplitude, statistical and spatial parameters, including line, 3D and 2D image profiles of the experimental surfaces were examined and compared to un-irradiated samples. For gamma irradiated CS-PVA blends the larger waviness over the surface was found as compared to un-irradiated CS-PVA blends but the values of average roughness for both the films were found almost same. The coefficient of skewness was positive for gamma irradiated CS-PVA blends which revealed the presence of more peaks than valleys on the blend surfaces.

Papain wound dressings obtained from poly(vinyl alcohol)/calcium alginate blends as new pharmaceutical dosage form: Preparation and preliminary evaluation

Transparent, soft, flexible, mechanically resistant films, which are ideal for use as wound dressings were prepared in the presence of 2% papain, a proteolytic enzyme that can play a role in the chemical debridement of the skin and can accelerate the healing process. The films, based on poly(vinyl alcohol):calcium alginate blends with increasing concentrations of polysaccharide (10, 20, and 30% v/v), were obtained by casting method. FTIR and DSC analyses were performed to assess the composition and miscibility of blends. Mechanical properties such as tensile strength, elasticity modulus, and elongation at breakpoint were evaluated. The influence of different concentrations of calcium alginate on physical attributes of films like wettability, swelling capacity and mechanical properties was determined. The stability of papain in the films was assessed indirectly by hemolytic activity assay employing direct contact method and confirmed by technique based on blood agar diffusion. Preliminary cytotoxicity was evaluated with the XTT method. The results showed that at the polymer concentrations tested, the blends were miscible. The increase in the content of the calcium alginate increased the wettability and swelling capacity of the films, which is desirable in wound dressings. On the other hand, mechanical resistance decreased without causing breakage of the films during the swelling tests. The hemolytic activity of the films was maintained during the studied period, suggesting the stability of papain in the proposed formulations. Cellular viability indicated that the films were non-toxic. The analysis of the results showed that it is possible to prepare interactive and bioactive wound dressing containing papain from blends of PVA and calcium alginate polymers.

Rheological behavior of starch–poly(vinyl alcohol)–TiO2 nanofluids and their main and interactive effects

ABSTRACTIn this study, an investigation of the rheological behavior of starch/poly(vinyl alcohol) (PVA)/titanium oxide (TiO2) nanofluids was performed. It revealed that the rheological behavior of starch suspensions displays a particular change due to the presence of PVA and TiO2. All examined fluids demonstrated non‐Newtonian behavior and followed the Power law model. The main and interacting effects of starch, PVA, and TiO2 nanoparticles concentrations were studied using the analysis of variance. The results indicated that the flow behavior index (n), as well as the consistency index (K) of suspensions, is influenced by the PVA and TiO2 contents. The flow behavior index (n) decreased and consistency index (K) increased by an increase in PVA concentration. A reverse trend is observed by the addition of TiO2 nanoparticles to starch and PVA blend suspensions. The difference in rheological behaviors was ascribed to the presence of binary and triplet interactions between starch, PVA, and TiO2 nanoparticles. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44062.

Preparation of gelatin/poly(vinyl alcohol) film modified by methyl methacrylate and gamma irradiation

ABSTRACTThe properties of gelatin–polyvinyl alcohol (G–PVA) blend films were improved by methyl methacrylate (MMA) and γ irradiation for a practical viewpoint. The films were prepared by the casting method, modified by glycerol and MMA monomer, and their mechanical properties were also studied. The gelatin-based films were successfully prepared using γ irradiation (3.1 kGy) and gelatin: PVA = 97:3 (w/w) as optimized. Tensile properties of the films were studied and thermal properties of the films were characterized by thermogravimetric analysis and dynamic mechanical analysis pointed out that MMA treated both gelatin films, and G–PVA blend films showed less thermal degradation than untreated films. In addition, structural and morphological features of the gelatin-based films were examined by Fourier transform infrared and scanning electron microscopy, respectively. The ultimate results of the present study showed remarkable enhancement in tensile properties (> 40%) and a reduction in elongation at break of the films, thanks to the MMA addition and γ irradiation.

Chitosan:poly (vinyl) alcohol composite alkaline membrane incorporating organic ionomers and layered silicate materials into a PEM electrochemical reactor

Mixed matrix membranes (MMM) are prepared from equivalent blends of poly (vinyl alcohol) (PVA) and chitosan (CS) polymers doped with organic ionomers 4VP and AS4, or inorganic layered titanosilicate AM-4 and stannosilicate UZAR-S3, by solution casting to improve the mechanical and thermal properties, hydroxide conductivity and alcohol barrier effect to reduce the crossover. The structural properties, thermal stability, hydrolytic stability, transport and ionic properties of the prepared composite membranes were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), water uptake, water content, alcohol permeability, thickness, ion exchange capacity (IEC) and OH− conductivity measurements. The addition of both organic and inorganic fillers in a CS:PVA blend polymer enhances the thermal and ionic properties. All the membranes are homogenous, as revealed by the SEM and XRD studies, except when UZAR-S3 stannosilicate is used as filler, which leads to a dual layer structure, a top layer of UZAR-S3 lamellar particles bound together by the polymer matrix and a bottom layer composed mostly of polymer blend. The loss of crystallinity was especially remarkable in 4VP/CS:PVA membrane. Thus, the 4VP/CS:PVA membrane exhibits the best ionic conductivity, whereas the UZAR-S3/CS:PVA membrane the best reduced alcohol crossover. Finally, the performance of the CS:PVA-based membranes were tested in a Polymer Electrolyte Membrane Electrochemical Reactor (PEMER) for the feasibility use of alkaline anionic exchange membranes in electrosynthesis under alkaline conditions, showing the 4VP/CS:PVA and UZAR-S3/CS:PVA membranes the best performances in PEMER.

In-situ crosslinked nanofiber mats of chitosan/poly(vinyl alcohol) blend: Fabrication, characterization and MTT assay with cancerous bone cells

Biocompatible crosslinked nanofiber mats of chitosan (CS)/poly(vinyl alcohol) (PVA) were fabricated using electrospinning technique. CS and PVA blends (7, 9 and 11 weight %) of prepared keeping ratios of CS: PVA to 1:4 and was crosslinked with tetraethoxysilane (TEOS). Fourier transform infrared (FTIR) analysis confirmed the existence of inter- and intramolecular hydrogen bonding between polymer chains and the development of siloxane linkage within the nanofibers. X-ray diffractometry (XRD) analysis showed an increase in the crystallinity of electrospun nanofibers after crosslinking as compared to the uncrosslinked nanofibers and with an increase in CS/PVA content. Scanning electron microscopy (SEM) micrographs exhibited the formation bead-free fibers at higher polymer concentration. The average size of the nanofibers was found in the range of 40 to 100 nm. The concentration and crosslinker content affected the mechanical and thermal properties of the nanofibers. The crosslinker has increased the tensile strength (TS) values upto 120 % and Young’s modulus by 71 % as compared to the uncrosslinked nanofibers while elongation at break was decreased in all nanofibers. The cell viability of the nanofibers was investigated by employing human cancerous bone cells (MG63). The obtained results showed that cancerous bone cells were not proliferated in the presence of nanofibers and the growth of the cells was inhibited confirming the worth of CS/PVA nanofibers against cancerous bone cells. This inherent behaviour can be exploited as base material for anticancer biomedical applications.