Addition Of PVA Research Articles

Enhancing thermal stability and mechanical resilience in gelatin/starch composites through polyvinyl alcohol integration

In practical scenarios, destabilizing the physical attributes of natural polymers such as gelatin and starch occurs readily when exposed to specific moisture levels and heat. In this context, this work was carried out to assess the impact of PVA addition (up to 13 wt%) on the structure and physical properties of a 6:4 (w/w) gelatin/starch blend. The inclusion of PVA unfolded the molecular chains of gelatin and starch, thereby disrupting gelatin α-helices and impeding biopolymer crystallization. This facilitated hydrogen-bonding interaction between PVA and the two biopolymers, enhancing the stability of the molecular network structure. Rheological results indicate that composites (added with 4 % or 7 % PVA) with good compatibility exhibited excellent mechanical properties and deformation resistance. The addition of PVA elevated the gelling temperature (Tgel) of the composites from 41.31 °C to 80.33 °C; the tensile strength and elongation at break were increased from 2.89 MPa to 3.40 MPa and 341.62 % to 367.56 %, respectively; and the thermal stability was also apparently improved, signifying the effective enhancement of the physical properties of gelatin/starch-based composites and the broadening of their application scope. This work could provide insights into the development of biodegradable natural/synthetic polymer composites with application-beneficial characteristics.

Development of crosslinked gelatin films through Maillard reaction and reinforced with poly(vinyl alcohol) for active food packaging

In order to improve the functionality of natural gelatin films for active food packaging applications, a combined strategy of crosslinking via Maillard reaction and blending enhancement incorporated with poly(vinyl alcohol) (PVA) was explored. In this study, when the mass ratio of gelatin to glucose was 10:1, Maillard reaction of crosslinked gelatin films was the highest, UV absorption and browning index reached the maximum. Infrared analysis showed that PVA could form strong interfacial interactions with gelatin matrix. The presence of PVA could significantly improve the toughness, water absorption, transparency, and oxygen barrier properties of crosslinked gelatin films. When the amount of PVA reached 5 %, elongation at break and oxygen barrier properties of crosslinked gelatin films were improved by 76.7 % and 47.9 % compared with pure crosslinked gelatin film. Even when the amount of PVA reached 10 %, UV absorption (at 315 nm) of crosslinked gelatin films still exceeded 98.7 %. The addition of PVA could accelerate the dissolution and swelling of crosslinked gelatin films, promoting the migration and release of active substances (Maillard reaction products (MRPs)). The two antioxidant activities tests (DPPH and ABTS method) achieved the highest radical scavenging rates of 71.6 % and 91.2 %, respectively, with corresponding PVA addition of 5 % and 7.5 %. After continuing to add PVA, antioxidant activities began to significantly decrease, which was directly related to the decrease in the generation of MRPs. Therefore, crosslinked gelatin films reinforced with appropriate amount of PVA can be considerable potential as active films for renewable food packaging applications.

Peningkatan Ikatan Adhesi terhadap Pengurangan Retak Lapisan PVA pada Ti-6Al-4V ELI untuk Aplikasi Biomedis

The lack of adhesion bonding of the hydroxyapatite (HA) coating layer on the surface of implant material can cause the coating layer to peel off during implantation and will increase the risk of metallic ion release to human body and may also to increase inflammatory effect and slow down the osseointegration process. In order to increase the adhesion of HA coated Ti-6Al-4V ELI by adding Zirconium Oxide (ZrO2) into the coating layer.The coating process of the HA suspension with addition ZrO2 into Ti-6Al-4V ELI sample surfaces was conducted by using dip-coating method. The samples were then heated at 800, 900, and 950 °C. The improvement of adhesion coating was correlated by calculating the removed area. The low value of removed coating area indicated the adhesion coating is good. The test specimen with the addition of ZrO2, has a removed area fewer than the test specimen without the addition of PVA- ZrO2 has. This shows that the test specimen with the addition of ZrO2 has good coating adhesion.The addition of PVA- ZrO2 to the HA suspension increases adhesion bonding of the coating layer, as indicated by the low removed area as compared to that of without PVA- ZrO2 coating.

A film composed of PEDOT:PSS/PVA as a sensitive medium for pH sensor in optical fiber

In this work, a pH sensitive transducer element attached to a multimode optical fiber section is proposed. The sensitive element is a PEDOT:PSS/PVA composite film that exhibited sensitivity at low pH values in the range of 1–7 pH. The addition of PVA was important for the adhesion process to the optical fiber surface. The morphology of the PEDOT:PSS polymers allowed characterization at pH stimuli that were based on the optical power transmission generated from the interaction of the light propagating in the optical fiber core and the optical fiber section coated with the sensitive film. A sensitivity of −0.05 dB/pH and a linear fit R2 of 0.93 was obtained, the response time was 3 s, while the sensor recovery time was 50 s maintaining stability higher than 10 min.

Comparative Study on Structural, Dielectric Behavior and AC Conductivity of PPY-PVA Incorporated with TiO2 Fine and Nano Particles

Abstract An in-situ oxidative chemical polymerization technique to prepare thin films of PPY, PVA, and PPY-PVA blend doped with variable concentrations of TiO2 fine- and nano-particles was further investigated by X-ray diffractometer (XRD) and impedance spectrometer to study structural, dielectric, and AC conducting behavior. XRD spectra established that sharp and high intense peaks of PPY-PVA- fine TiO2 films indicated more crystallinity, which might be due to higher compactness and modification in interplanar spacing. Dielectric plots revealed that PPY-PVA-nano TiO2 films exhibited higher dielectric constants and lower dielectric loss compared to films of PPY-PVA- fine TiO2 in shorter frequency region, suggesting that these films are more suitable for charge storage devices. Conductivity plots revealed that AC conductivity of pure PPY was low (4.8 x10-3 S/cm at 313 0K) and was increased to 5.3 x10-3 S/cm by addition of PVA. AC conductivities of PPY-PVA-nano TiO2 thin films are relatively higher (7.43x10-3 S/cm to 1.14x10-2 S/cm) than PPY-PVA-fine TiO2 films (6.35x10-3 to 9.78x10-3 S/cm) with increasing frequency and temperature, which could be due to large surface area to volume ratio of nano-size dopant. This suggests that PPY-PVA-nano TiO2 thin films may be used for sensing various gasses.

Effects of addition of PVA, Mg and Zn to HAp on biocompatibility for hard tissue implants

Hydroxyapatite (HAp) is a well-known biomaterial due to its bioactivity, osteoconductivity and biocompatibility. The present research aims to study the effects of addition of a polymer and two different ions in the HAp matrix to make it a better participant to function as an orthopaedic implant. The polymer taken for the study is polyvinyl alcohol and ions taken was magnesium (Mg2+) and zinc (Zn2+) ions. The synthesis of Pure HAp and composite fabricated HAp was performed using ethanol-based Sol-gel method. The X-Ray diffractions studies showed that composite fabricated showed slight increase in the crystallite size than Pure HAp with a value of 39.7363 nm. Moreover, both the lattice parameters ‘a’ and ‘c’ showed an increase with values of 9.41 (Å) and 6.92 (Å) respectively. The corrosion rate as calculated from the Tafel plot was found to be lower for composite sample in comparison to pure HAp with a value of 3.95 mmpy. Lower pore size and lower pore volume was exhibited by the composite sample as calculated from BET studies. The composite samples exhibited good antimicrobial activity against both E. coli and S. aureus bacteria.The composite fabricated samples could be a potential participant to function as a future hard tissue implant.

The Mechanical Performance and Reaction Mechanism of Slag-Based Organic-Inorganic Composite Geopolymers.

A series of organic-inorganic composite geopolymer paste samples were prepared with slag-based geopolymer and three types of hydrophilic organic polymers, i.e., PVA, PAA, and CPAM, by ordinary molding and pressure-mixing processes. The reaction mechanism between slag-based geopolymer and organic polymers was studied by FT-IR, NMR, and SEM techniques. The experimental results showed that the slag-based geopolymer with the addition of 3% PVA presented the highest 28-day flexural strength of 19.0 MPa by means of a pressure-mixing process and drying curing conditions (80 °C, 24 h) compared with the geopolymers incorporating PAA and CPAM. A more homogeneous dispersion morphology was also observed by BSE and SEM for the 3% PVA-incorporated slag-based geopolymer. The FT-IR testing results confirmed the formation of a C-O-Si (Al) bond between PVA and the slag-based geopolymer. The deconvolution of the Q3 and Q2(1Al) species obtained by 29Si NMR testing manifested the addition of PVA and increased the length of the silicon backbone chain in the geopolymer. These findings confirmed that a composite geopolymer with high toughness can be produced based on the interpenetrating network structure formed between organic polymers and inorganic geopolymer.

Optimalisasi Temperatur Sintering Pada Sintered Body Hidroksiapatit Dengan Penambahan Silika Sebagai Material Penguat

Sintered body hydroxyapatite (HA) in the form of pellets has been made by adding silica as a reinforcing material (ratio 60:40 wt.%) by varying the sintering temperature. HA and silica were subjected to a dry mixing process for 2 h, then a wet mixing process was carried out for 2 h with the addition of PVA and alcohol as a binder. The mixing process uses a rotary drum with the addition of zirconia balls with the aim of making the mixture more homogeneous. After the mixing process, the samples were dried for 48 h to remove the alcohol contained. The green body was made using the uniaxial pressing method at a pressure of 100 MPa and held for 3 minutes. The sintering process is carried out variously at temperatures of 800°C, 900°C, 1000°C, 1100°C, 1200°C, 1300°C, and 1400°C. with a heating rate of 5ºC/minute and holding time of 4 h. Next, the temperature was lowered to 300ºC with a cooling rate of 5ºC/minute. The results showed that linear shrinkage increased significantly (weight shrinkage increased 12.83% - 25.08% and diameter shrinkage increased 3.26% - 23.21%). The results of the relative density calculation show that there is a significant increase with each variation in sintering temperature, where the increase occurs from 44.4% - 85.6%. The compressive strength value also shows an increase with increasing sintering temperature, namely from 21.2 MPa at 800 oC to 65.9 MPa at 1300 oC. Meanwhile, at a sintering temperature of 1400°C, compressive strength values decreased and oxidation occurred as evidenced by color changes. It can be concluded that the optimization of the sintering process occurs at a temperature of 1300 oC which is proven by the highest compressive strength value and no oxidation occurs.

Development of a Temperature-Responsive Hydrogel Incorporating PVA into NIPAAm for Controllable Drug Release in Skin Regeneration.

Melanoma, a highly malignant and aggressive form of skin cancer, poses a significant global health threat, with limited treatment options and potential side effects. In this study, we developed a temperature-responsive hydrogel for skin regeneration with a controllable drug release. The hydrogel was fabricated using an interpenetrating polymer network (IPN) of N-isopropylacrylamide (NIPAAm) and poly(vinyl alcohol) (PVA). PVA was chosen for its adhesive properties, biocompatibility, and ability to address hydrophobicity issues associated with NIPAAm. The hydrogel was loaded with doxorubicin (DOX), an anticancer drug, for the treatment of melanoma. The NIPAAm-PVA (N-P) hydrogel demonstrated temperature-responsive behavior with a lower critical solution temperature (LCST) around 34 °C. The addition of PVA led to increased porosity and faster drug release. In vitro biocompatibility tests showed nontoxicity and supported cell proliferation. The N-P hydrogel exhibited effective anticancer effects on melanoma cells due to its rapid drug release behavior. This N-P hydrogel system shows great promise for controlled drug delivery and potential applications in skin regeneration and cancer treatment. Further research, including in vivo studies, will be essential to advance this hydrogel system toward clinical translation and impactful advancements in regenerative medicine and cancer therapeutics.

Synthesis and Characterization of PES/PEG/PVA/SiO2 Nanocomposite Ultrafiltration Membrane

This study aims to synthesis and characterize PES/PEG/PVA/SiO2 composite membranes. The composite membranes were synthesized by phase inversion method with composition (% w/w) Polyethersulfone/ PES (17.25), Polyvinylalcohol/ PVA (3.58; 0.85; 1.43; 2.57; 3.57, Polyethylene glycol/ PEG (3.72), Silica/SiO2 (0.35; 0.85; 1.43; 2.57; 3.57), and Dimethyl acetamide/DMAc solvent. Composite membranes were characterized using FTIR spectroscopy, X-ray diffraction, Scanning Electron Microscopy (SEM), and water contact angle. The results showed that the interaction between PES, PVA, and SiO2 was indicated by a shift in the typical absorption spectrum of the FTIR. SEM cross-sectional photos showed that the addition of PVA and SiO2 caused significant changes in the morphology and pore structure of the PES membrane. The results of the X-ray diffractogram (X-Ray) showed a shift in the typical diffraction peaks of PES, PEG, PVA and the presence of new diffraction peaks of SiO2. The crystallinity of the membrane increased from 34.99% to 57.25% which indicated that the composite membrane was successfully synthesized. The addition of PEG/PVA/SiO2 also increased the hydrophilicity of the composite membrane. Based on these findings, it can be concluded that the PES/PEG/PVA/SiO2 composite membrane has been synthesized through the phase inversion method with the optimum composition of PES: PEG: PVA: SiO2 was 17.25%: 3.72%: 0.85%: 0.35%, respectively. The addition of PEG/PVA/SiO2 increased the hydrophilicity and modified the morphological structure of the PES membrane.

Synthesis of Silver Nanoparticles using Gandaria Seeds Bioreductor

The silver nanoparticles (NPP) are synthesized with the chemical reduction method by using a water extract bioreductor of gandaria seed (Bouea macrophylla G.) which acts as a reducing precursor, in this case, AgNO3 Ag+ is reduced to AgO. The concentration of AgNO3 is made between 0.5 mm and 1 mm. The characteristic of NPP is unstable, so a modification is needed with and without the addition of PVA 1 %. The process of NPP shaping is monitored by observing the uptaken of UV - Vis when the color changes occur. The high NPP concentration of AgNO3 has higher absorbance and is wider if compared to the lower AgNO3 concentration. The result of this research based on the absorbance value and the wavelength showed the NPP synthesized without the addition of PVA 1 % (b/v) is wider. The addition of PVA 1 % (b/v) provides better stability and maintains the absorbance of spectrum changes from day to day. The maximum uptaken of UV-Vis from NPP AgNO3 0.5 mm by using green synthesis and 1 mm without adding PVA are 0.946 and 0.980, respectively. However, NPP with the addition of PVA has 0.968 and 0.978 absorbance. The best concentration of NPP produced was 1 mm AgNO3.

Lithium trivanadate thin films by polymer-assisted spin coating method for supercapacitor applications

Lithium trivanadate (LiV3O8) thin films were prepared by polymer assisted spin coating method. Here, the effect on addition of the polymers PVA, PVP, PEG and their combination on the preparation step were explored. The structural and morphological changes were analyzed by varying the substrate temperature, and its effect on the electrical and electrochemical performances were also studied. The thin films exhibited mixed micro and nanorod morphology. The XPS spectrum shows the stable 5+ oxidation state for vanadium. The electrochemical performance of the LiV3O8 thin film made using PVA:PVP and PVA:PEG in the 1:1 ratio outperformed the material made using PVA alone. The aqueous LiNO3 solution served as the electrolyte in three-electrode system. A specific capacitance of 359 F g−1 for a current density of 0.5 A g−1 as well as an areal capacitance of 143.8 F cm−2 at 0.2 mA cm−2 current density was obtained for the material made with PVA:PVP (1:1).

Enhanced mechanical and water resistance properties of cassava starch-PVA composites with TiO2 nanofillers for triboelectric nanogenerators films

The utilization of biopolymers for energy applications continues to attract researchers, due to the unique properties of biopolymers that are easily modified, such as cassava starch (CS) biopolymer that has hydroxyl molecular chains. However, the brittle, and non-waterproof nature of starch films is an obstacle to their use in triboelectric nanogenerator (TENG) solid-solid films. This study aims to improve the physicochemical properties of cassava starch films by modifying them into nanocomposite films. The nanocomposite film was made from 70:30 CS/polyvinyl alcohol (PVA) composite and variation of TiO2 nanoparticles addition using solvent casting method. The results showed that the mechanical properties of cassava starch film increased with the addition of PVA. Meanwhile, the addition of TiO2 above 1 wt % of the mechanical properties of the film tends to decrease. The film has low wettability properties with a contact angle of 83.6°. The performance of the nanocomposite film as a Rotary disc freestanding film (RDF-TENG) produces 4.4-fold the output voltage and 2.8-fold the current compared to the film without TiO2. This is a new finding that the CS/PVA-TiO2 nanocomposite film has the potential for TENG films in high-humidity environmental conditions

The synthesis, characterization, and mechanism of a dense plate-like C-S-H based on cation exchange membrane-templating

An ordered structure and high mechanical property of calcium silicate hydrate (C-S-H) gel has been always pursued in the field of cementitious materials. In this paper, compacted and layer-by-layer stacking C-S-H plates were fabricated based on Layer-by-Layer (LBL) method and H-cell penetration (HCP) method through cation exchange membrane templating. This new way changed the randomly packing structure of traditional C-S-H, and synthesized a high-orderly C-S-H platelets with denser structure. Based on molecular dynamics simulations, it can be attributed to the strong adsorption and nucleation sites contributed by sulfonic acid groups on the cation exchange membrane. Besides, AFM indentation experiments indicate this C-S-H owns significantly higher elastic modulus than traditional C-S-H, while the mechanical properties can be further increased by the addition of PVA and the regulation of reaction time. This new type C-S-H may pave the way to the preparation of high-performance concrete in the future.

Preparation and Characterization of Geopolymers Based on Metakaolin with the Addition of Organic Phase PVA

Geopolymers have excellent physical and mechanical properties, so they can be used as a substitute for ordinary polymers. Geopolymers are ceramic materials, which exhibit the property of brittleness, which can be a limitation in some structural applications. To overcome this shortcoming, a new group of materials (organic geopolymers) was developed. The aim of this work is the synthesis of organic (hybrid) geopolymers. A geopolymer based on metakaolin was synthesized as a reference sample, while polyvinyl alcohol was added as an organic phase for synthesizing a hybrid geopolymer. It was concluded that the systems follow the rule of behavior in liquid systems. The chemical composition of the samples was determined by X-ray fluorescence analysis (XRF). Structural and phase characterization of hybrid and reference materials were analyzed using X-ray diffraction (XRD)and Fourier-transform infrared spectroscopy (FTIR), which revealed new phases in the PVA-added samples. The results show that the content of added PVA in the reaction mixture affects the phase composition of the synthesized materials. To examine the possibility of adsorption of the samples, Ultraviolet-visible spectroscopy (UV/VIS) was used. The morphology was analyzed using a scanning electron microscope with energy dispersive spectroscopy (SEM/EDS), where efflorescence was observed and identified. After characterizing the geopolymer with the addition of PVA, we obtained a material that was far more porous than the basic sample, and we can conclude that we have synthesized a material that shows good mechanical properties.

Multi-scale analysis of mechanical properties of KH-560 coupling agent modified PVA fiber-rubber concrete

ABSTRACT Amphiphilic Silane coupling agent (SCA) improves the weak bond between the two phases of rubber and hydration products, fills the interfacial gaps and effectively repairs the interfacial defects between rubber and hydration products. The addition of PVA fibers mainly improves the cracking performance and durability of concrete. However, most of the studies addressing this issue have been limited to phenomenology, ignoring the mechanism of action at the atomic structure level. Therefore, this study investigates the strengthening mechanism of the interfacial properties of KH-560 coupling agent-reinforced PVA fiber-rubber concrete from the multi-scale analysis of macro-mechanical properties, micro and fine structure, chemical composition and nano-optical level. Based on the results of macro-mechanical tests, it was found that the KH-560 coupling agent could improve the compressive, flexural and shear strength of PVA-rubber concrete, so that the damage morphology also changed from brittle damage to plastic damage, and the compressive strength of concrete was slightly reduced due to the addition of PVA, but the durability and cracking resistance were enhanced. XRD (X-ray diffraction), FT-IR (Fourier transform infrared spectroscopy) and SEM (scanning electron microscopy) tests observed the presence of some gels and polymers that filled the interfacial slits and effectively repaired the interfacial defects. The two-phase interface was simulated by molecular dynamics at the nano level, and it was found that KH560 molecules could be closely connected with C-S-H gel collectively through Si-O-Si chemical bonding, and KH560 molecular bonds were unevenly distributed between the C-S-H and rubber interfaces, while the addition of modifier KH560 and PVA fibers caused more hydrogen and ionic bonds at the interface, which enhanced the interfacial interaction energy. Systematic experiments were conducted on PVA fiber-rubber soil materials before and after SCA modification under macroscopic, microscopic, fine and nano-level multi-scale analyses, which ultimately lead to the design and performance improvement of SCA modification of PVA-rubber cement-based materials in a multi-scale framework. The graphic summary is shown in Figure 1.

Preparation of Sm2Zr2O7 Slurry for Thermal Spraying

The orthogonal experiment with three factors and three levels was designed to control the process conditions in the thermal spraying process. The solid content, pH value and PVA addition on the stability and fluidity of sm2zr2o7 slurry at different levels were studied. The stability of sm2zr2o7 slurry was characterized by sedimentation experiment, and the fluidity of sm2zr2o7 slurry was detected by rheometer. It was determined that the solid content had the greatest influence on the properties of sm2zr2o7 slurry. The addition of PVA had the least effect. The optimized sm2zr2o7 slurry is as follows: solid content 50%, pH value 7 and PVA addition 4%.

Ti3C2Tx-based composite coating on AZ31B Mg alloy surface for improved anti-corrosion/wear-reducing properties

The poor wear resistance and corrosion resistance of AZ31B magnesium alloy are the main factors limiting its application. Herein, a simple spin-coating method was used to prepare MXene/polyvinyl alcohol (Ti3C2Tx/PVA) composite coating on the magnesium alloy surface. The results of corrosion resistance tests of the composite coating in a solution of 3.5% sodium chloride showed that the corrosion rate of the composite coating was about five orders of magnitude less than that of the substrate of the magnesium alloy. On the one hand, the layered structure of Ti3C2Tx could extend the corrosive media's diffusion path. On the other hand, PVA entering into the non-oxidized area of Ti3C2Tx could reduce the inherent defects of Ti3C2Tx and help to form a complete and continuous layer, resulting in a good barrier effect and improving the corrosion resistance of the substrate. In addition, the Ti3C2Tx/PVA coating has the best tribological properties with the lowest coefficient of friction (COF) and wear rate, with a wear rate approximately two orders of magnitude lower than that of the magnesium alloy substrate, approximately 4 × 10−5·mm3·N−1·m−1. Due to the excellent wear resistance of the layered Ti3C2Tx and the addition of PVA, the coating exhibits good bonding strength and presents an ordered brickwork structure through the hydrogen bonding network. Therefore, the suitable surface coating design combing Ti3C2Tx with PVA could endow the AZ31B Mg alloys with excellent corrosion/wear resistance.

Facile synthesis of nafion based self-healable proton exchange membranes for direct methanol fuel cells

Growing interest has been paid to the importance of the capability of a material to self-heal, since it can extend the service period and reduce the replacement cost of the product. Thus, proton exchange membrane (PEM) was designed to self-heal in this study. Freezing-thawing method was used to impart physical crosslinking without the incorporation of crosslinkers in the preparation of a self-healable PEM with Nafion and PVA. Nafion-PVA membrane was found to be able to repair the damage and restore its original properties. The results also showed that the addition of PVA in Nafion reduced the methanol permeability by 40.33% as compared to recast Nafion membrane. A good methanol blocker with self-healing capability, Nafion-PVA membrane is a promising PEM for use in direct methanol fuel cells (DMFCs).

Pengaruh Penambahan Serat Kulit Kopi dan PVA terhadap Karakteristik Biodegradable Foam dari Pati Kulit Singkong

Polystyrene plastic or stryrofoam is very popular to be used as a food packaging container even though Styrofoam has a bad impact on health. In addition, Styrofoam also cannot be biodegraded naturally in the environment so that the use of Styrofoam is also a problem for the environment. One alternative to styrofoam is biodegradable foam (biofoam) made from starch and cellulose. It is safe for health and can be broken down naturally.Cassava peel is rich in starch (carbohydrates) but has low cellulose content. Meanwhile coffee peel is rich in cellulose and minimal in carbohydrates. Both types of waste have the potential to become biodegradable foam raw materials. The addition of synthetic PVA polymer is expected to improve the mechanical quality of biodegradable foam. This study aims to obtain the best formulation for the manufacture of biodegradable foam from cassava starch with the addition of coffee peel cellulose and PVA. The quality of biofoam evaluated includes tensile strength, water absorption, and biodegradability. The best biofoam characteristics were obtained at the addition of 15% fiber and 15% PVA, resulted in water absorption of 28.87%, tensile strength of 2.70 N / mm2 and biodegradability of 93.66% for 30 days.