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Tensile, Thermal, And Moisture Absorption Properties of Polyvinyl Alcohol (PVA) / Bengkuang (Pachyrhizuserosus) Starch Blend Films

Tensile, Thermal, And Moisture Absorption Properties of Polyvinyl Alcohol (PVA) / Bengkuang (Pachyrhizuserosus) Starch Blend Films

Mixing PVA and starch become special concern for researchers in the field of food packaging. This way was effective to reduce the cost of PVA film production. Besides that, the presence of starch made it no longer time for degradable in environment. Therefore, this study investigated the mixture of PVA and bengkuang starch blend films. According to the best our knowledge, there is no publication about the mixing of these two materials. The film was characterized by tensile test, thermogravimetric analysis, and moisture absorption rate.

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Gold nanoparticles embedded on the surface of polyvinyl alcohol layer

Gold nanoparticles embedded on the surface of polyvinyl alcohol layer

The FESEM observation of the PVA film, PVA-MPTMS film and PVA-Gold film are shown in Figure 7 (a), (b) and (c) respectively. Obvious contrast can be seen between all three PVA samples. The surface of the PVA is homogeneous and the silica phase did not form. However, silica particles can be found in the surface of PVA- MPTMS due to the polycondensation of MPTMS leading to conglomeration in the polymer matrix.

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Thermostable Polarizing Film on the Basis of Poly (vinyl alcohol) and New Dichroic Synthesized Azo Dye for Optical Applications: Theoretical and Experimental Investigations

Thermostable Polarizing Film on the Basis of Poly (vinyl alcohol) and New Dichroic Synthesized Azo Dye for Optical Applications: Theoretical and Experimental Investigations

The occurrence of anisotropy of thermal conductivity is connected that at orientation of PVA occurs orientation of the amorphous part of polymer and also formation of additional number of intermolecular connections. Thermal conductivity of PVA films changes after the injection of dye and along an axis of orientation and in perpendicular axis decreases (Table 5).

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Synthesis and Characterization of CdS Nanoparticles Grown in a Polymer Solution using in-situ Chemical Reduction Technique

Synthesis and Characterization of CdS Nanoparticles Grown in a Polymer Solution using in-situ Chemical Reduction Technique

Cadmium sulfide (CdS) nanoparticles embedded in poly(vinyl alcohol) (PVA) in the form of films with different CdS content have been prepared successfully using in-situ chemical reduction technique and casting of aqueous solutions. The nano-CdS characterised using UV-Vis spectroscopy which shows an absorption shoulder around 500 nm confirming the formation of CdS nanoparticles. Moreover, the linear increase in absorbance with increasing CdS concentration revealed that the CdS nanoparticles are homogeneously distributed in the host PVA polymer matrix. To detect structural changes, XRD and FTIR spectra of pure and CdS doped PVA films have been analysed. FTIR analysis evidently shows the interaction between CdS nanoparticles with the hydroxyl groups of PVA. It is also found that the ac conductivity of doped PVA samples increases with the increase of CdS content as well as frequency. The calculated values of frequency exponent (s) suggest that the electrical conduction is followed by the correlated barrier hopping (CBH) model. The temperature dependence of ac conductivity also indicated that the minimum activation energy associated with the maximum conductivity composition. The experimental results reveal that the optical and electrical behaviour of PVA can be improved significantly by the addition of a small amount of CdS nanoparticles. This enhanced properties of PVA/CdS nanocomposite proposed to be used in optoelectronic devices.
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Spectroscopic (Polarization, ExcitedState, FT-IR, UV/Vis and 1H NMR) and Thermophysical Investigations of New Synthesized Azo Dye and Its Application in Polarizing Film

Spectroscopic (Polarization, ExcitedState, FT-IR, UV/Vis and 1H NMR) and Thermophysical Investigations of New Synthesized Azo Dye and Its Application in Polarizing Film

films are generally used in combination with other dyes, having absorption in a particular wavelength range to provide the polarizing films with a neutral color and wide range spectra [5, 6]. PVA-films are easily exposed to uniaxial orientation, then it becomes optically anisotropic and partially polarize passing light beams. These properties of PVA have defined theoretical and practical interest in it from the point of view of their use for the manufacturing of film polarizers. The majority of films with dichroic dyes finding practical application polarize light in a visible area (400-700 nm) electromagnetic spectrum where the basic strips of absorption of molecules with stretched chains of the interfaced double bond conjugation are located. Theoretical quantum chemistry methods based on HF and DFT are used for the calculation of optimized geometry, absorption spectrum, FT-IR and 1 H NMR spectra of the organic molecules [5-17]. In this work on the basis of PVA and new synthesized dichroic azobenzene dye A thermostable polarizing film absorbing invisible spectral range of spectrum (λ max = 550 nm) for application in Display Technologies and
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Preparation of PANI PVA Composite Film with High Conductivity

Preparation of PANI PVA Composite Film with High Conductivity

The PANI-PVA composite films adopting PVA as the base material and doped with hydrochloride, DBSA, amino sulfonic acid aqueous solution were prepared and their conductivity was compared. Among these PANI-PVA composite films, the conductivity of HCl-PANI-PVA film is the highest. At the same time, the influences of mass ratio between PANI and PVA, acid content, oxidant content, reaction time and drying temperature of film on the conductivity of HCl-PANI-PVA film were stu- died. The result shows that the conductivity of HCl-PANI-PVA film is the highest when the mass percentage of PVA is 40%; the C(HC1) = 0.5 mol/L; the n(APS/An) = 1.0; the reaction time is 6 hours and the drying temperature of the film is 80˚C, and that the maximum conductivity of HCl-PANI- PVA film is 16.0 S∙cm −1 .
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Ribosomal Protein P0 Promotes Potato Virus A Infection and Functions in Viral Translation Together with VPg and eIF(iso)4E

Ribosomal Protein P0 Promotes Potato Virus A Infection and Functions in Viral Translation Together with VPg and eIF(iso)4E

Exogenous VPg increases viral translation together with eIF(iso)4E and P0 but reduces the spread of infection. We showed previously that exogenously expressed VPg is unable to enhance viral translation when both eIF4E and eIF(iso)4E are si- lenced (40). To extend this finding, we cosilenced eIF4E and eIF(iso)4E and analyzed RLUC activities and RNA levels of RLUC-tagged wt PVA at 9 DAI (Fig. 10A). Both RLUC activity and viral RNA levels were reduced during eIF4E/eIF(iso)4E silencing and during P0 silencing (Fig. 10A). As both P0 and eIF4E/eIF(iso)4E are required for normal PVA infection and for a VPg-mediated boost in translation, the effects of different combi- nations of eIF(iso)4E, VPg, and P0 on wt PVA RLUC activity were determined at 3 DAI (Fig. 10B). To our surprise, RLUC activity was not increased by VPg or eIF(iso)4E and was increased only slightly by the combination of VPg, P0, and eIF(iso)4E but was markedly increased by VPg plus eIF(iso)4E. We therefore ana- lyzed the effects of VPg, P0, and eIF(iso)4E expression on the development of infection foci by GFP-tagged wt PVA by deter- mining the average area of infection foci at 3 DAI (Fig. 10C), at which time cell-to-cell movement had already occurred (see also Fig. 3F and 4D). Exogenous VPg expression reduced the intercel- lular spread of infection (Fig. 10C), an effect even more pro- nounced when the proportion of infected to noninfected tissue was determined at 4 DAI (Fig. 10D andF). Interestingly, coexpres- sion of P0 with VPg reduced cell-to-cell infection spread even more than VPg alone (Fig. 10D), despite an increase when P0 was expressed alone (Fig. 3F). Also, the positive effect of VPg and eIF(iso)4E coexpression on PVA RLUC activity was overpowered when P0 was coexpressed. Importantly, the total number of infec- tion foci remained similar under these conditions, showing that altering the PVA infection initiation rate was not responsible for the observed effects (Fig. 10E).
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Silver nanoparticle/chitosan oligosaccharide/poly(vinyl alcohol) nanofibers as wound dressings: a preclinical study

Silver nanoparticle/chitosan oligosaccharide/poly(vinyl alcohol) nanofibers as wound dressings: a preclinical study

According to the histological examination shown in Figure 14, the PVA/COS-AgNP nanofiber demonstrated superior wound healing compared with gauze and the PVA/COS/AgNO 3 nanofiber. Seven days after grafting, the wounds in the PVA/COS/AgNO 3 nanofiber and gauze groups displayed ulcerated surfaces, formation of granulation tis- sue, and infiltration of inflammatory cells. In contrast, the granulated tissue in the PVA/COS-AgNP group disappeared without capillary hyperplasia. Late-stage healing processes in the control group were similar to those in the AgNP- containing nanofiber groups. On day 14, newly synthesized fibrous tissue and sparse inflammatory cells in the dermis and subcutis were covered by completely re-epithelialized epidermis in each group. These data further confirm that the PVA/COS-AgNP nanofibrous membrane could provide a suitable scaffold for wound healing.
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Esterification of fatty acids from waste cooking oil to biodiesel over a sulfonated resin/PVA composite

Esterification of fatty acids from waste cooking oil to biodiesel over a sulfonated resin/PVA composite

Poly (vinyl alcohol) (PVA), a water-absorbing polymer, is commonly used as a polymeric material to prepare membrane since it displays good mechanical strength, high thermal stability and good chemical resistance. 19-24 Because of its superior hydrophilicity, citric acid (CA) cross-linked PVA membrane has been used as a pervaporation membrane to separate water during esterification but not as a catalyst support. 22 In addition, PVA was used as a main membrane matrix to prepare poly (styrene sulfonic acid) (PSSA)/PVA membrane for catalyzing esterification although its role as a water absorber was not recognized. 19 Based on these results, we hypothesize that incorporating commercial s-CER in the matrix of PVA can provide a way to continuously remove the produced water from sulfonate sites of s-CER to PVA during esterification and therefore not only enhance the catalytic activity of s-CER but also reduce water separation steps in biodiesel production.
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Characterization of Bacterial Cellulose (Nata De Coco)/Pva Composite for Drug Delivery Application

Characterization of Bacterial Cellulose (Nata De Coco)/Pva Composite for Drug Delivery Application

Nevertheless, sample S6, as expected, exhibited exceptional mechanical strength since it had the highest amount of PVA absorbed. Based on Figure 3 the ultimate stress point is way beyond that of pure bacterial cellulose. The results of sample S8 and S10, however came out different with what was expected, considering the fact these two samples were impregnated with PVA. One possible explanation for this was that the amount of water present in these two samples may be greater than the amount of water present in sample SP. Another factor could be the anisotropic property of natural polymer composites. Contrary to isotropic, anisotropy that pertained to the property of material that varies with orientation, such as ultimate strength [12,13]. This also explains the large standard deviation shown by samples SP and S10. This means that the mechanical property of the samples varies, as it was stretched in a particular orientation. This suggested that, if the material was tested in another orientation, the results could have been different.
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Polydopamine Formation In Poly (Vinyl Alcohol) + Montmorillonite Blends Allows To Produce Flexible And Robust Materials.

Polydopamine Formation In Poly (Vinyl Alcohol) + Montmorillonite Blends Allows To Produce Flexible And Robust Materials.

It is shown that stable sheets of PDA@PVA-MMT materials can be easily obtained by allowing for the oxygen triggered oxidation of dopamine (in alkaline conditions) in PVA-MMT blended solutions. However when PVA-MMT blends of identical composition are dried in a Petri dish mold, a brittle crack-full material which decomposes in water is obtained. This finding is attributed to the adhesive properties of PDA creating some non covalent bonds between PVA and the clay platelets. It has to be noted that the XRD data suggest that PDA has a different structure in the presence of PVA than in its absence. Of the highest interest is also the finding that the detachment of the PDA@PVA-MMTcompositeis easy, contrarily to the detachment of the highly adhesive PDA@PVA composite, and that the detachment process produces some anisotropy in the optical appearance as well as in the wettability of the obtained sheets of composite. These preliminary findings will be completed by other investigations aimed to characterize the distribution of PDA in the composite and its influence on the mechanical properties. The applications of these inexpensive and easy to prepare PDA@PVA- MMT materials will be investigated in terms of water purification.
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Dielectric Spectroscopy of Polyvinyl Alcohol Hydrogels and Nanocomposites

Dielectric Spectroscopy of Polyvinyl Alcohol Hydrogels and Nanocomposites

In a PVA solution, the polymer chains are relatively free to move. During the cooling stage of the first freeze-thaw cycle, the formation of ice concentrates the polymer in certain regions. Small PVA crystallites can form in these PVA-rich regions. The crystallites act as physical crosslinks between chains. In the heating portion of the cycle, the melting ice results in PVA poor regions surrounded by crosslinked PVA rich regions. Further freeze-thaw cycles form secondary crystallites in the amorphous PVA lying between the crosslinks made in the first cycle [31]. The crosslinking restricts dipole movement on the PVA chains even after one freeze-thaw cycle. Further restrictions that result from additional freeze-thaw cycles apparently do not cause a noticeable additional change in the permittivity. These results suggested that we should explore the changes in dielectric properties that take place during the freeze-thaw cycles to better understand the e ff ects of physical crosslinking on the permittivity.
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Thermal Degradation Behavior of Polyvinyl Alcohol/Starch/Carboxymethyl Cellulose/ Clay Nanocomposites

Thermal Degradation Behavior of Polyvinyl Alcohol/Starch/Carboxymethyl Cellulose/ Clay Nanocomposites

That is the incorporation of clay fillers into the polymer matrices results to the improvement of their thermal stability. The effect of clay layers has been more explained as superior insulation and mass transport barrier against the volatile compounds generated during the decomposition of polymer under thermal conditions [21]. Also it has been reported that clays assist in the formation of layered carbonaceous char during degradation of polymer/clay nanocomposite [1]. Clay minerals are inorganic materials and are almost stable in the temperature ranges that organic polymers are degraded in to volatile compounds. Therefore in TGA experiments the clay content of nanocomposites is remain as residue after heating program [22]. Blumstein first reported the improved thermal stability of PMMA/MMT nanocomposite. TGA showed that PMMA intercalated into the Na-MMT has 40-50 °C higher decomposition temperature [23]. Vyazovkin et al. [24] reported the thermal stability of polystyrene/clay nano-composite compared to pure PS. They have showed that PS/clay nanocomposites have 30-40 °C higher degradation temperature compared to pure PS under nitrogen and air heating degradation conditions. Other studies have been showed that the nature of the clay modifier can affect on the thermal stability of modified clay and related nanocomposites [25]. The understanding of their thermal stability and degradation has importance in processing and recycling. Thermal degradation of PVA [26, 27] and PVA/S was recently studied [28, 29]. The main goal of this paper is to evaluate the effect MMT on the PVA/S/CMC blends
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Thermal and morphological characteristics of cellulose nanocrystals filled PVA/starch nanocomposites

Thermal and morphological characteristics of cellulose nanocrystals filled PVA/starch nanocomposites

starch as the starch is available in abundance at low price. Particularly, plant materials derived from renewable crops by-product or their industrially processed wastes offer a good source of fiber for applications [6]. Starch possesses similar function as PVA which is biocompatible and consumable by micro organism. When PVA and starch are blended together, the presence of hydroxyl groups (-OH) tend to form strong hydrogen bonding among the molecules and subsequently lead to synergistic stability and better system integrity. Both PVA and starch disperse homogeneously in solution cast film under the scanning electron microscopy [8].
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Structural, Optical and Thermal Characterization of PVA/2HEC Polyblend Films

Structural, Optical and Thermal Characterization of PVA/2HEC Polyblend Films

XRD patterns (b and c) of blend samples with concentrations 70 and 50 wt% PVA exhibited the characteristics of pure PVA, but with less intensity for the reflection peak. Thus, one can say that the semi-crystalline structure of PVA is decreased upon mixing with relatively lower content of 2HEC. However, XRD pattern (d) of 30 wt% PVA shows an intense broad halo amorphous covering the positions of those found in homopolymers, for the semi-crystalline/amorphous blends, the non- crystallizing component could strongly modify the crystallization behavior of crystallizing component [16]. For such blends, compatibility between the amorphous components of both homopolymers is possible. Thus, it can be suggested that the crystal forms in PVA do not prevent the compatibility between amorphous regions of the two polymers in the blend system.
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Synthesis and Characterization of PVA-Ether Starch Film from Alkoxylation of Fatty Acid Methyl Ester Epoxide of Candlenut Oils with Cassava Starch

Synthesis and Characterization of PVA-Ether Starch Film from Alkoxylation of Fatty Acid Methyl Ester Epoxide of Candlenut Oils with Cassava Starch

Analysis of the mechanical properties of the film was carried out for the purpose of bioplastic applications, where the analysis was performed by tensile test. The result of test of mechanical properties in table 3.3 showed that tensile strength for starch ether was higher than cassava starch. This result was consistent with previous research [20] which suggested that fatty acids might affected the mechanical properties of the polymer matrix. In the presence of saturated fatty acids would produce a higher tensile strength than the original starch due to the formation of amylose-fatty acids complexes during the process of film formation.
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SACU tariff policies: Where should they go from here?

SACU tariff policies: Where should they go from here?

APPENDIX Table A: Measures of distortion 2006 values ERP Pva Final Input final ERP Export Pva Final Pva Input Export tariff tariff goods inputs tax Agriculture Coal mining Gold & Plat Ot[r]

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Preparation Characterization and Evaluation of Solid Dispersions of Aceclofenac - an Attempt to Develop Fast Release Formulations of Selected Solid Dispersion of Aceclofenac Tablets

Preparation Characterization and Evaluation of Solid Dispersions of Aceclofenac - an Attempt to Develop Fast Release Formulations of Selected Solid Dispersion of Aceclofenac Tablets

Studies were under taken on the preparation and evaluation of solid dispersions of aceclofenac with view to develop fast release formulation of aceclofenac. Four carriers viz PVP10, PVP40, PVP 360 and PVA 8136 were used to prepare the solid dispersions of aceclofenac by solvent evaporation and kneading method at various drug: carrier ratios namely (1:1, 1:3 and 1:9). The solid dispersions prepared were found to be fine and free flowing powders. X-ray diffraction studies revealed that crystalline nature of aceclofenac in pure form was reduced to amorphous form in the dispersions The thermal behavior of aceclofenac-PVP 40 solid dispersion was studied using DSC indicating that aceclofenac has complexed with PVP 40. This phenomenon is indicative of stronger interaction between aceclofenac and PVP 40 in the solid state. Interaction studies like TLC, FTIR indicated no interaction between drug and polymer used.
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Cells Attachment Property of PVA Hydrogel Nanofibers Incorporating Hyaluronic Acid for Tissue Engineering

Cells Attachment Property of PVA Hydrogel Nanofibers Incorporating Hyaluronic Acid for Tissue Engineering

IRPrestige-21 (Shimadzu Co., Japan). In order to deter- mine the amount of HA presenting in the cross-linked PVA/HA nanofibers, thermogravimetric analysis (TGA) (TG/DTA6200, Seiko Instruments Inc. Japan) was car- ried out by heating from room temperature to 600˚C un- der a continuous nitrogen purge of 20 mL/min. The mor- phologies of electrospun PVA/HA hydrogel nanofibers were characterized using scanning electron microscopy (SEM, S-3000N HITACHI, Japan) on samples sputtered with Pd-Pt. The fiber diameter and its distribution were determined by using image J (ImageJ v1.41, Wayne Rasband National institutes of Health, USA) software. 2.5. Swelling Behavior
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Preparation and in vitro evaluation of buclizine oral thin film strips

Preparation and in vitro evaluation of buclizine oral thin film strips

The stabilizing and thickening agents are employed to improve the viscosity and consistency of dispersion or solution of the strip preparation solution or suspension before casting. Drug content uniformity is a requirement for all dosage forms, particularly those containing low dose highly potent drugs. To uniquely meet this requirement, thin film formulations contain uniform dispersions of drug throughout the whole manufacturing process 9 .

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