Papers by Keyword: Poly(vinyl alcohol)

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Authors: Sai Zhang, Guo Jun Jiang
Abstract: In this paper, we presented a novel system of electrospinning to directly prepare fibrous meshes with micro/nanoparticles. Acetate cellulose (CA) as the material of micro/nanoparticles was dissolved in the mixture of acetone and dichloromethane as well as polyvinyl alcohol (PVA) was dissolved into deionized water, respectively. We successfully fabricated CA microspheres by an oil-in-water (O/W) emulsion/solvent evaporation technique, instilling CA solution into the stirring PVA aqueous solution. Then the hybrid solution was fabricated into a fibrous mat through electrospinning. CA micro/nanoparticles were wrapped in PVA fibers which indicated that the hybrid system of electrospinning had great potential in biomedicine when combing biodegradable microspheres with drugs.
Authors: Yu Liang An, Qing Yi Hou, Xia Yuan, Gang Zhang
Abstract: A novel and practical route for preparing carbon coating metal nanomaterials using polyvinyl alcohol as the starting materials was presented. Carbon coating iron nanoparticles can be effectively synthesized by carbonizing polyvinyl alcohol using Fe as catalyst in hydrogen flow. The carbohydrate was carbonized in a controllable way that leads to a large amount of carbon coating iron nanoparticles. Transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) and thermogravimetric analysis (TG) were employed to characterizing nanomaterials. The growth mechanism of carbon coating iron nanoparticles is briefly discussed in term of composition and structure of precursor.
Authors: Zenji Kato, Satoshi Tanaka, Nozomu Uchida, Keizo Uematsu
Authors: T. Siritientong, Pornanong Aramwit
Abstract: Silk sericin, a gumming protein from silk cocoons, has been a considerable natural protein-based biopolymer for fabrication of desired constructs for potential tissue engineering applications. This study investigated the formulation of a novel biopolymeric silk sericin/poly (vinyl alcohol) film with genipin as crosslinking agent and its physical properties. Silk sericin itself forms a fragile material, adding other polymers such as poly (vinyl alcohol) and glycerin, a plasticizer, resulting in a strong and flexible matrix. The results indicated that at higher concentration of genipin (0.1% w/v), the percentages of crosslinking in sericin/poly (vinyl alcohol) films was significantly higher. The matrices also exhibited higher tensile modulus value and higher elasticity at higher genipin concentration which can be inferred to higher integrity of the structure compared to matrices with genipin at low concentration (0.01% w/v). On the other hand, the reverse patterns were found in percentages of light transmission and the releasing profile of sericin from the composite films. Adding genipin into the matrices resulted in a lower percentage of light transmission indicated the increase in opacity. The releasing profile of sericin from the films showed that high genipin concentrations reduced the peak of protein released and trended to provide the sustain-released profile of protein. These findings indicated that silk sericin film can be formed and the concentrations of crosslinking agents really affect its physical properties.
Authors: Si Jia Liu, Ran Xu
Abstract: Chitosan/Poly (vinyl alcohol) (CS/PVA) composite nanofibrous membranes with diameter between 150-350 nm have been fabricated by electrospinning. The effect of contact time, temperature, pH and concentration of triclosan on the adsorption capacity of the membranes were investigated. The equilibrium adsorption capacity of triclosan on CS/PVA nanofibrous membranes was 61.61 mg/g. The favorable pH for triclosan adsorption was pH 6. After five regeneration cycles, the removal rate of triclosan maintained above 67%. The adsorption of triclosan on the membranes fitted both Freundlich and Langmuir isotherm model. Its adsorption kinetics followed a pseudo-second-order model.
Authors: Xiao Chun Li, Ji Liang Cao
Abstract: The soybean/casein/polyvinyl alcohol blend fiber was treated in sodium carbonate solutions to evaluate its alkali resistance which was very important for wet processing. The weight loss and whiteness of the treated fibers were examined. UV spectra of the alkaline treatment solutions were analyzed. The study showed that the fiber exhibited poor alkali resistance. Treating temperature, time and alkali concentration affected the weight loss of the treated fibers. A high weight loss was found even at low alkali concentration. The weight loss was primarily due to the hydrolysis of casein.
Authors: Jun Hua Cheng, Di Jiang Wen
Abstract: An aqueous photocrosslinkable binder system for tapecasting ceramic substrates was investigated based on chitosan (CS) and polyvinyl alcohol (PVA) by adding UV photoinitiator 2-hydroxy-1- [4-(hydroxyethoxy)phenyl]-2-methyl-1-propanone (Darocur 2959). Alumina green sheets were prepared by using the binder and exposed to UV irradiation. SEM, FT-IR, XRD and DSC verified that these CS/PVA polymeric films or green sheets obtained using the binder were homogeneous, which indicated that CS was compatible with PVA in the binder, polymeric films and green sheets. Blending CS and PVA may created a semi-interpenetratin structure with good mechanical properties enough for handling and machining, and the process may not have oxygen retarding effect in arcylamide system.
Authors: Hui Min Huang, Z.Y. Li, C. Wang
Abstract: Polyaniline doped with camphorsulfonic acid (PANI.HCSA) nanofibers have been successfully prepared using “nanofibers template” via electrospinning. The PVA nanofibers were used as a template to get the PANI/PVA composite fibers. After removing the template by heat treatment, the PANI fibers were obtained. Scanning electron microscope (SEM) with the Energy Dispersive X-Ray Spectrometer software (EDX) and FT-IR spectra were used to characterize the composite fibers and the PANI.HCSA nanofibers. The average diameters of the composite fibers obtained and PANI fibers were 920 nm and 530 nm, respectively.
Authors: Jin Hui Wu, Run Ze Wang, Li Mei Hao, Ying Yi, Ming Zhao, Zheng Wang, Song Lin
Abstract: In our previous work, silver nanoparticles (AgNPs) with ultrasmall sizes (4.3 ± 0.7 nm) can be in-situ obtained within the poly (vinyl alcohol) (PVA) fibers by mediating the electro-spun conditions. The obtained AgNPs “trapped” within the electro-spun PVA nanofibers were believed to be stable in the dry state, as the abundant PVA molecules could protect the dispersed AgNPs from agglomerating with each other. In this study, based on former study, aging tests about the nanohybrid mats were performed. Through ATR-FTIR spectra analysis, the formation mechanism of AgNPs within the PVA nanofiber by one-step electro-spun was confirmed. Atomic Absorption Spectroscopy analysis of the as-prepared PVA-Ag samples was performed in 14 h and the release of Ag+ was believed to be the main cause of its bactericidal effects. Scanning electron microscopy and transmission electron microscopy were used to characterize the nanofibers with AgNPs. After 4-month storage, the size of AgNPs doped in the PVA nanofiber became twice larger and the content of AgNPs was almost doubled.
Authors: Caihong You, Toshiki Miyazaki, Eiichi Ishida, Masahiro Ashizuka, Chikara Ohtsuki, Masao Tanihara
Abstract: Organic polymers with ability of apatite formation in body environment are expected as novel bone substitutes having not only bone-bonding ability, i.e. bioactivity, but also mechanical performance analogous to natural bone. Several metal oxides have been found to be effective for the apatite deposition in body environment. In addition, release of calcium ions from the materials significantly enhances it. In this study, we attempted to synthesize bioactive organic-inorganic hybrids from Poly(vinyl alcohol) (PVA) by incorporation of various metal oxides and calcium salt. Silica and molybdenum oxides were selected as metal oxides. Ability of apatite formation on the hybrids was examined in vitro using simulated body fluid (SBF, Kokubo solution). Apatite deposition were observed to occur on the surfaces of PVA/silica and PVA/molybdenum oxide hybrids in SBF, when their compositions were appropriately controlled.
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