Papers by Keyword: PVA

Abstract: Polyvinyl alcohol (PVA) is a non-toxic, thermoplastic polymer that is completely biodegradable. So it is based on many composite materials for biomedical applications. In this study, various specimens were prepared by solvent casting method and then tested by tensile, FTIR, contact angle, SEM, antibacterial and cytotoxicity test. The results obtained showed the tensile strength decreased with the addition of PEG and then tended to improve after the addition of collagen and nano-titanium oxide. The wettability test shows the prepared specimens changed from hydrophobic to hydrophilic properties. The biological properties explained that the prepared composite had a better antibacterial effect and none of the samples had a toxic effect.

Abstract: The optimization stage of the PDMS/PVA-PEG hydrophilic sponge has been prepared to increase water absorption, through the addition of wetting agents including bentonite, silicon oil, silica gel, and sodium hydrogen carbonate. The bentonite is purified by magnetic separation with a montmorillonite (MMT) content of approximately 33,17%. Silicon oil has hydrophilic properties due to the high surface energy of silicon dioxide, while silica gel is an adsorbent that will produce high silanol groups, and NaHCO₃ is used to expand pores when releasing CO₂. PDMS/PVA-PEG hydrophilic sponges were prepared with various ratios (w/w) PDMS: silicone oil: silica gel: NaHCO₃: ZnCl₂: PVA: PEG= 1:2:2:2,5:5:5:10 (V1 sponge); 1:2:2:1.25:5:5:10 (V2 sponge); 1:2:2:0:5:5:10 (V3 sponge). The sponge synthesis process is conducted by heating at a temperature of 110°C for 4 hours. The hydrophilic sponge composite incorporated bentonite in a ratio of 1:1 (w/w) to obtain VB1 sponge, VB2 sponge, and VB3 sponge have contact angle values 37.0°, 56.6°, and 58.8°, respectively. NaHCO₃ can increase the pore of the sponge, therefore the condition can increase the hydrophilicity. The contact angle of V1 sponge is 45.2°, while VB1 is 37°.0°, which indicates that bentonite can enhance hydrophilic properties. Excellent wetting properties will imply good dewatering properties for hydrocarbon fuel refining.

Abstract: Bone tissue engineering has been used in the biomedical field to treat bone defects by implanting scaffolds into bone tissue. However, the currently developed scaffold still needs to be developed to obtain scaffold building materials with good compatible properties and can regenerate damaged bone cells. This study combines PVA/Chitosan polymer with CHA of tuna bone using the porogen leaching method at a calcination temperature of 100°C for 12 hours. The purpose of this study was to determine the physicochemical properties by characterizing XRD, SEM-EDX, FTIR, and the porosity of the scaffold. The results obtained from the results of the PVA/Chitosan/CHA XRD patterns are the formation of the PVA/Chitosan phase at 2θ(°)=19.68, the IR spectrum of the 𝑃𝑂₄³⁻group band and 𝐶𝐻₂ stretching, the ratio mol Ca/P is 1.98, the pore diameter is 1.561 ± 0.07 μm and the porosity is 55.04%. These results indicate that the PVA/Chitosan/CHA scaffold is an amorphous calcium phosphate (ACP) that has the potential for bone tissue engineering.

Abstract: This study constructed poly (vinyl alcohol)/ biphasic-calcium phosphate (PVA/ BCP) composite scaffolds. The biphasic-calcium phosphate (BCP) was incorporated in 0, 5, 10, and 25 wt%; BP0, BP1, BP2, and BP3, respectively. The surface morphology was done with a scanning electron microscope (SEM) to observe the porosity and the pore size and distribution of fabricated samples. The Fourier Transform Infrared spectroscopy (FTIR), and some physical properties such as porosity, density, swelling ratio, flexural strength, impact strength, and compression strength were also investigated. The biodegradation and bioactivity were also tested. The SEM results showed that the pores increased and became more regular and interconnected to each other with the increasing addition of BCP. The density decreased with the addition of BCP, while the porosity and mechanical properties increased with additives. The sample of BP3 has a high porosity (67%) and high impact strength (11.9 MPa). The high porosity is favorable for bone implants, and the mechanical strength must also be considered. The bio tests show that the biodegradation became regular by adding the BCP powder, which leads to ease of controlling the gradual degradation and the samples are bioactive for bone tissue. Keywords: Bone Tissue Engineering, PVA, Biphasic-Calcium Phosphate, Porosity, Mechanical properties

Abstract: This research was conducted to determine the morphology, dimensions, and structure of carbon-nanofibers, using polyvinyl alcohol (PVA) as a source of polymer fibers fabricated by electrospinning technique, and given variations in carbonization temperature. Variations in temperature during the carbonization process are carried out to see changes in the structure and morphology of the carbon nanofibers formed. characterization by conducting XRD and SEM tests to determine the structure and morphology of the carbon nanofibers produced, it is seen that the amorphous carbon structure of the nanofibers produced is in the shape of random fibers and tends to be straight without beads. The results obtained from the XRD test, it appears that the structure is amorphous with two peaks that appear during the test, the two peaks are typical of amorphous carbon peaks, so that the fiber that has been formed, then with the carbonization process changes its structure to carbon nanofiber. Unique results were obtained when PVA nanofibers were characterized by SEM, namely the diameter of the fibers formed before and after the carbonization process had sizes in the range of 40 to 50 nanometers, these results were influenced by the process of initial formation of nanofibers using an electrospinning system.

Abstract: Due to the growing demand of the textile market, the production of synthetic fibers like polyester (PET), has been increasing compared to any other existing fiber group. However, this type of fiber has its own disadvantages, the main one being its hydrophobic nature. To improve its properties, it was sought to develop a chemical functionalization. This process consisted of three steps, the first one being the cleaning of the polyester with hydrochloric acid, followed by a subsequent hydrolysis of the textile substrate in an alkaline medium in the presence of sodium hydroxide. The last phase, that concerns the textile substrate functionalization with poly (vinyl alcohol), more commonly known as PVA, was made by a process of exhaustion at different pH values (3, 6, and 10), followed by a curing, which allowed the formation of bonds between the PVA and the polyester fibers and consequently improve polyester properties, namely the hydrophilicity, presenting a contact angle of 0º. This process of functionalization of the polyester with PVA at acidic pH, led to very promising results since a significant improvement of its properties was obtained. The functionalized and original polyester samples were further characterized through the application of several techniques, such as SEM, FTIR-ATR and differential scanning calorimetry DSC. These characterization techniques allowed to prove that the textile substrates were effectively modified. It can be concluded that, properties such as, contact angle, tensile strength, air permeability, coefficient of friction and water vapor permeability, were substantially improved by the functionalization of the polyester fabric with PVA.

Abstract: Polyvinyl alcohol (PVA) nanofibers were fabricated using the electrospinning method. The nanofibers were embedded with zinc oxide (ZnO) particles by mixing PVA liquid with the ZnO powders during the solution preparation stage. The FESEM images showed an increase in the amount of ZnO particles embedded in the PVA nanofibers as the powder content was increased. Other than that, there are no significant changes in other physical properties of the nanofibers caused by the increasing number of ZnO particle content. This means that ZnO nanopowders (with concentration in the range of 1.63 wt% - 8.14 wt%) can be effectively integrated and embedded into PVA nanofibers without negative consequences on the fibers formation and structure. This will facilitate the fabrication of ZnO embedded PVA nanofibers in some applications that may require it such as drug delivery, filtration, and biomedical application.

Abstract: Nanotechnology research has lacked to provide new studies on nanofibers using the electrospinning method, the reasons are attributed that all parameters have been covered by previous studies. Believing that science is in a state of constant renewal leads to the possibility to study a parameter that has not been studied before, which affects the morphology of nanofibers. One of the disadvantages of nanofibers manufacturing is the formation of beads, and controlling the parameter helps reduce these beads. Field emission scanning electron microscope (FESEM) images reveal the formation of nanofibers and surface topography observations by atom force microscopy (AFM) indicates that the roughness is improved by changing the distance between rods of the collector. The rods function as a collector for nanofibers, changing this parameter improves the morphology and diameter of the nanofibers.

Abstract: Zeolite filled polymer has recently emerged as a promising material with its immense applications. When taking water treatment into account, it is potentially an antibacterial film. In this study, poly vinyl alcohol (PVA)/chitosan/zeolite composite membranes were prepared with different proportions, including 5:1, 8:1 and 10:1 of PVA/chitosan ratios. Zeolite available in the film aimed to improve the morphology and the efficiency in water environment, with loading dosages of 10, 20 and 50 wt%, respectively. Characterization using scanning electron microscopy (SEM), SEM/EDX and X-ray diffraction (XRD) were also conducted to have a better view of the membranes. The results of antibacterial activity against aerobic bacteria using the 3M^TM Petrifilm^TM Aerobic Count (AC) Plate. The results indicated that pure chitosan film gave 75.7% of antibacterial activity and the composite film with 5:1 ratio of PVA/chitosan was the effective proportion, revealing the antibacterial rate around 53% to the applications of bacteria inhibition. The time test of antibacterial also reduced the level of bacteria in water environment to 2900 CFU of aerobic bacteria.

Abstract: Nanofiber membranes made of polymer materials are being extensively investigated and developed as air filter materials. This research aims to make and characterize the nanofiber membranes as filter materials capable of filtering gaseous pollutants from cigarette smoke. The electrospinning method manufactured the chitosan (CS)/PVA blend nanofiber membranes with CS/PVA ratios of (0/100, 20/80, 30/70, and 40/60 w/w) using low molecular weight (LMw) PVA and the ratios of (0/100, 10/90, 20/80, and 30/70 w/w) with high Mw (HMw) PVA. The CS concentration increased the CS-PVA solution‘s electrical conductivity and decreased the membrane‘s average fiber diameter and tensile properties. The filtration test on neat PVA and CS/LMw PVA (20/80) membranes set on the metallic substrate with a 0.08 mm hole size was conducted by varying membrane thickness (20, 35, and 45 µm). The filtration efficiency increased with the membrane thickness because membrane pores tend to be smaller, indicating that reducing the fiber diameter by adding CS increases pore size. The filtration test on CS/HMw PVA (20/80) membranes with 45 µm thickness on different substrate¢s hole sizes of (0.08, 1.19, and 1.41 mm) showed that the larger the hole size, the lower the filtration efficiency. By similar CS/PVA ratio, membrane thickness, and substrate size hole, the CS/HMw PVA's filtration efficiency (87.15%) is higher than CS/LMw PVA (85.79%). However, the CS/LMw PVA membrane showed higher tensile strength, low stiffness, and more economical air filtration material than CS/HMw PVA.