A Novel Fabrication of Heterogeneous Saponified Poly(Vinyl Alcohol)/Pullulan Blend Film for Improved Wound Healing Application.

In this study, a novel film of poly(vinyl alcohol) (PVA)/pullulan (PULL) with improved surface characteristics was prepared from poly(vinyl acetate) (PVAc)/PULL blend films with various mass ratios after the saponification treatment in a heterogeneous medium. According to proton nuclear magnetic resonance (1H-NMR), Fourier transform infrared, and X-ray diffraction results, it was established that the successful fabrication of saponified PVA/PULL (100/0, 90/10, and 80/20) films could be obtained from PVAc/PULL (100/0, 90/10, and 80/20) films, respectively, after 72 h saponification at 50 °C. The degree of saponification calculated from 1H-NMR analysis results showed that fully saponified PVA was obtained from all studied films. Improved hydrophilic characteristics of the saponified films were revealed by a water contact angle test. Moreover, the saponified films showed improved mechanical behavior, and the micrographs of saponified films showed higher surface roughness than the unsaponified films. This kind of saponified film can be widely used for biomedical applications. Moreover, the reported saponified film dressing extended the lifespan of dressing as determined by its self-healing capacity and considerably advanced in vivo wound-healing development, which was attributed to its multifunctional characteristics, meaning that saponified film dressings are promising candidates for full-thickness skin wound healing.

Preparation and Characterization of Thermal-Insulating Microporous Breathable Al/LLDPE/CaCO3 Composite Films.

Breathable films were prepared based on linear low-density polyethylene (LLDPE), calcium carbonate (CaCO3), and aluminum (Al; 0, 2, 4, and 8 wt.%) using extrusion molding at a pilot scale. These films must generally be able to transmit moist vapor through pores (breathability) while maintaining a barrier to liquids; this was accomplished using properly formulated composites containing spherical CaCO3 fillers. The presence of LLDPE and CaCO3 was confirmed by X-ray diffraction characterization. Fourier-transform infrared spectroscopy results revealed the formation of Al/LLDPE/CaCO3 composite films. The melting and crystallization behaviors of the Al/LLDPE/CaCO3 composite films were investigated using differential scanning calorimetry. Thermogravimetric analysis results show that the prepared composites exhibited high thermal stability up to 350 °C. Moreover, the results demonstrate that surface morphology and breathability were both influenced by the presence of various Al contents, and their mechanical properties improved with increasing Al concentration. In addition, the results show that the thermal insulation capacity of the films increased after the addition of Al. The composite with 8 wt.% Al showed the highest thermal insulation capacity (34.6%), indicating a new approach to transform composite films into novel advanced materials for use in the fields of wooden house wrapping, electronics, and packaging.

Manufacture and Vibration-Damping Effect of Composites for Archery Carbon Fiber-Reinforced Polymer Limb with Glass Fiber-Reinforced Polymer Stabilizer.

Typically, archers prepare two sets of bows for competitions in case of bow breakage, but if the limbs of the bow break during a match, archers can become psychologically disadvantaged, leading to potentially fatal consequences. Archers are very sensitive to the durability and vibration of their bows. While the vibration-damping properties of Bakelite® stabilizer are excellent, its low density and somewhat lower strength and durability are disadvantages. As a solution, we used carbon fiber-reinforced plastic (CFRP) and glass fiber-reinforced plastic (GFRP) for the archery limb with stabilizer, commonly used for the limbs of the bow, to manufacture the limb. The stabilizer was reverse-engineered from the Bakelite® product and manufactured using glass fiber-reinforced plastic in the same shape as the existing product. Analyzing the vibration-damping effect and researching ways to reduce the vibration that occurs during shooting through 3D modeling and simulation, it was possible to evaluate the characteristics and the effect of reducing the limb's vibration by manufacturing archery bows and limbs using carbon fiber- and glass fiber-reinforced composites. The objective of this study was to manufacture archery bows using CFRP and GFRP, and to assess their characteristics as well as their effectiveness at reducing limb vibration. Through testing, the limb and stabilizer that were produced were determined to not fall behind the abilities of the bows currently used by athletes, and they also exhibited a noticeable reduction in vibrations.

Alkaline Treatment Variables to Characterize Poly(Vinyl Alcohol)/Poly(Vinyl Butyral/Vinyl Alcohol) Blend Films.

Novel poly(vinyl alcohol) (PVA)/poly(vinyl butyral-vinyl alcohol) (P(VB-VA)) films with improved hydrophobicity were prepared from poly(vinyl acetate) (PVAc)/poly(vinyl butyral) (PVB) blend films with various mass ratios by saponification in a heterogeneous medium. The successful conversion of PVAc to PVA and PVAc/PVB to PVA/P(VB-VA) films was confirmed by Fourier transform infrared spectrometry, X-ray diffraction, and proton nuclear magnetic resonance analysis. This study also shows that the degree of saponification (DS) depends on the saponification time. The maximum DS of 99.99% was obtained at 96 h of saponification for all films, and the presence of PVB did not affect the DS at saponification times of 48-96 h. The effects of the PVAc/PVB blend ratio before and after saponification were determined by contact angle measurement, and the hydrophobicity was found to increase in both cases with increasing PVB content. Additionally, all the films exhibited improved mechanical properties after saponification, and the treated films possessed an unusual porous and uneven surface, in contrast with the untreated films. The prepared films with improved hydrophobicity can be used for various applications, such as biomaterials, filters, and medical devices.

Blown Composite Films of Low-Density/Linear-Low-Density Polyethylene and Silica Aerogel for Transparent Heat Retention Films and Influence of Silica Aerogel on Biaxial Properties.

Blown films based on low-density polyethylene (LDPE)/linear low-density polyethylene (LLDPE) and silica aerogel (SA; 0, 0.5, 1, and 1.5 wt.%) were obtained at the pilot scale. Good particle dispersion and distribution were achieved without thermo oxidative degradation. The effects of different SA contents (0.5-1.5 wt.%) were studied to prepare transparent-heat-retention LDPE/LLDPE films with improved material properties, while maintaining the optical performance. The optical characteristics of the composite films were analyzed using methods such as ultraviolet-visible spectroscopy and electron microscopy. Their mechanical characteristics were examined along the machine and transverse directions (MD and TD, respectively). The MD film performance was better, and the 0.5% composition exhibited the highest stress at break. The crystallization kinetics of the LDPE/LLDPE blends and their composites containing different SA loadings were investigated using differential scanning calorimetry, which revealed that the crystallinity of LDPE/LLDPE was increased by 0.5 wt.% of well-dispersed SA acting as a nucleating agent and decreased by agglomerated SA (1-1.5 wt.%). The LDPE/LLDPE/SA (0.5-1.5 wt.%) films exhibited improved infrared retention without compromising the visible light transmission, proving the potential of this method for producing next-generation heat retention films. Moreover, these films were biaxially drawn at 13.72 MPa, and the introduction of SA resulted in lower draw ratios in both the MD and TD. Most of the results were explained in terms of changes in the biaxial crystallization caused by the process or the influence of particles on the process after a systematic experimental investigation. The issues were strongly related to the development of blown nanocomposites films as materials for the packaging industry.

Preparation of the Heterogeneous Saponified Poly(Vinyl Alcohol)/Poly(Methyl Methacrylate-Methallyl Alcohol) Blend Film.

For the first time, poly(vinyl alcohol) (PVA)/poly(methyl methacrylate-methallyl alcohol) (P(MMA-MAA)) (9:1, 7:3, 5:5) blend films were made simultaneously using the saponification method in a heterogeneous medium from poly(vinyl acetate) (PVAc)/poly(methyl methacrylate) (PMMA) (9:1, 7:3, 5:5) blend films, respectively. The surface morphology and characteristics of the films were investigated using optical microscopy (OM), atomic force microscopy (AFM), X-ray diffractometer (XRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Moreover, the effect of the PVAc content on the degree of saponification (DS) of the PVAc/PMMA films were evaluated and revealed that the obtained DS value increased with the increase in PVAc content in the PVAc/PMMA blend films. According to the OM results, the saponified films demonstrated increased surface roughness compared with the unsaponified films. The AFM images revealed morphological variation among the saponified PVAc/PMMA blend films with different mass ratios of 9:1, 7:3, and 5:5. According to the DSC and TGA results, all blend film types exhibited higher thermal property after the saponification treatment. The XRD and FTIR results confirmed the conversion of the PVAc/PMMA into PVA/P(MMA-MAA) films. Thus, our present work may give a new idea for making blend film as promising medical material with significant surface properties based on hydrophilic/hydrophobic strategy.

Ethylene Acts as a Negative Regulator of the Stem-Bending Mechanism of Different Cut Snapdragon Cultivars.

This study investigated whether ethylene is involved in the stem-bending mechanism of three different snapdragon cultivars 'Asrit Red', 'Asrit Yellow', and 'Merryred Pink', by treating their cut stems with an ethylene-releasing compound (ethephon), an ethylene-action inhibitor [silver thiosulfate (STS)], and distilled water (as the control). Ethephon completely prevented stem bending in all cultivars, whereas STS exhibited a higher bending rate compared with the control. The bending rates were influenced by several factors, such as the degree of stem curvature, relative shoot elongation, ethylene production, and lignin content, indicating their involvement in the stem-bending mechanism of the cultivars. The analysis of the expression of genes involved in the ethylene and lignin biosynthetic pathways also supported the importance of lignin and ethylene in the stem-bending mechanism. Taken together, as ethephon completely prevented stem bending of the three snapdragon cultivars, this study suggested that ethylene acts as a negative regulator of the stem-bending mechanism of snapdragon cultivars, and the information will be valuable for the prevention of stem bending in other commercially important ornamental flowers.

Electrically Conducting Pullulan-Based Nanobiocomposites Using Carbon Nanotubes and TEMPO Cellulose Nanofibril.

Hybrid nanobiocomposite films are prepared using a solution casting by incorporating TEMPO cellulose nanofibrils (TOCNs) and carbon nanotubes (CNTs) into an aqueous solution of pullulan (PULL). The presence of CNT is confirmed by XRD characterization, and the prepared film shows an increased degree of crystallinity after the addition of TOCNs and CNT. The maximum degree of crystallinity value is obtained for CNT 0.5 % (59.64%). According to the Fourier-transform infrared spectroscopy, the shifts of the characteristic -OH peak of PULL occurred after the addition of TOCNs and aqueous CNT (3306.39 to 3246.90 cm-1), confirming interaction between the TOCNs, CNTs, and PULL matrix. The prepared films show enhanced material properties including higher tensile strength (65.41 MPa at low CNT content (0.5%)), water barrier properties, and reduced moisture susceptibility (5 wt.% CNT shows the lowest value (11.28%)) compared with the neat PULL film. Additionally, the prepared films are almost biodegradable within 64 days and show excellent electrical conductivity (0.001 to 0.015 S/mm for 0.5-5% CNT), which suggests a new approach to transform natural polymers into novel advanced materials for use in the fields of biosensing and electronics.

Fabrication and characterization of pullulan-based nanocomposites reinforced with montmorillonite and tempo cellulose nanofibril.

Nanocomposite film of pullulan (PULL), tempo cellulose nanofibrils (TOCNs) and, montmorillonite clay (MMT) were prepared using a solution casting method with aqueous solutions. X-ray diffraction data revealed that exfoliated MMT nanoplatelets are distributed within the PULL/TOCNs/MMT film structure. Fourier-transform infrared results revealed that there might be interactions among the TOCNs, MMT and PULL matrix led to improved tensile strength, thermal stability, water barrier properties, and decrease moisture susceptibility while maintained reasonable transparency and biodegradability of the ternary PULL nanocomposites. These excellent properties of the nanocomposites clearly indicate towards a new strategy for developing high-performance PULL-based nanocomposites by using two different types of fillers with various geometric shapes and aspect ratio. This kind of ternary nanocomposite film can be broadly used in food packaging and protection as a green and biodegradable film.

Electrospinning Fabrication of Poly(vinyl alcohol)/Coptis chinensis Extract Nanofibers for Antimicrobial Exploits.

Coptis chinensis (CC) is used in conventional Chinese medicine. The main active components of CC are isoquinoline alkaloids, including berberine, coptisine, palmatine, and magnoflorine; all these are known to have several pharmacological properties. Poly(vinyl alcohol) (PVA) is a well-known synthetic biocompatible polymer suitable for a range of pharmaceutical uses; it can be used as a matrix for the incorporation of functional materials and has a wide range of applications in the cosmetics, food, pharmaceutical, and packaging industries. In this study, PVA-based electrospun nanofibers containing CC extract were successfully fabricated. Furthermore, the effects of different CC extract contents on the morphologies, and antimicrobial and antifungal properties of PVA/CC extract nanofibers were investigated. Morphological changes were observed using different molecular weights of PVA. For characterization, field-emission scanning electron microscopy, thermogravimetric analysis, and Fourier transform infrared analysis were performed. The effectiveness of these nanofibers has been demonstrated by evaluating the thermal stability against Staphylococcus aureus, antimicrobial activity against Staphylococcus aureus and Staphylococcus epidermidis, and the antifungal activity against the fungi Aureobasidium pullulans and Penicillium pinophilum. The PVA/CC extract nanofibers were found to have excellent antibacterial and antifungal activity and thermal stability; hence, their use in medicinal sectors is highly recommended.

Surface Properties of a Novel Poly(vinyl alcohol) Film Prepared by Heterogeneous Saponification of Poly(vinyl acetate) Film.

Almost general poly(vinyl alcohol) (PVA) films were prepared by the processing of a PVA solution. For the first time, a novel poly(vinyl alcohol) (PVA) film was prepared by the saponification of a poly(vinyl acetate) (PVAc) film in a heterogenous medium. Under the same saponification conditions, the influence of saponification time on the degree of saponification (DS) was studied for the preparation of the saponified PVA film, and it was found that the DS varied with time. Optical microscopy was used to confirm the characteristics and surface morphology of the saponified PVA film, revealing unusual black globules in the film structure. The contact angle of the films was measured to study the surface properties, and the results showed that the saponified PVA film had a higher contact angle than the general PVA film. To confirm the transformation of the PVAc film to the PVA film, ¹H nuclear magnetic resonance spectroscopy, X-ray diffraction measurements, differential scanning calorimetry, and Fourier-transform infrared spectroscopy were employed.

Characterization of Pullulan/Chitosan Oligosaccharide/Montmorillonite Nanofibers Prepared by Electrospinning Technique.

Pullulan/Chitosan oligosaccharide (COS)/Montmorillonite (MMT) hybrid nanofibers were electrospun from their aqueous solution using different Pullulan/COS mass ratios and variable amounts of MMT. The effects of Pullulan/COS mass ratios and MMT contents on the morphologies and properties of PulluIan/COS/MMT hybrid nanofibers were investigated. The obtained nanofibers were characterized with field emission-scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermo gravimetric analysis (TGA), and tensile strength measurement. The Pullulan/COS mass ratio and MMT contents significantly influence the morphologies and properties of the Pullulan/COS/MMT hybrid nanofibers. Higher Pullulan contents than COS contents forms uniform and bead free nanofibers. The addition of COS to Pullulan improves the thermal stability of Pullulan/COS blend nanofibers. The incorporation of MMT to the Pullulan/COS/MMT hybrid nanofibers increase their fiber diameter, improves their thermal stability and tensile strength. These morphological changes and property enhancement depend on the amount of MMT added. The XRD and TEM results suggest the coexistence of Pullulan, COS and MMT within polymer matrix through intercalation of polymer chain between silicate layers forming well-ordered multiplayer morphology with alternating polymeric and silicate layers.

Effect of Saponification Condition on the Morphology and Diameter of the Electrospun Poly(vinyl acetate) Nanofibers for the Fabrication of Poly(vinyl alcohol) Nanofiber Mats.

Novel poly(vinyl alcohol) (PVA) nanofiber mats were prepared for the first time through heterogeneous saponification of electrospun poly(vinyl acetate) (PVAc) nanofibers. The effect of varying the saponification conditions, including temperature, time, and concentration of the alkaline solution, on the morphology of the saponified PVA fibers were evaluated by field-emission scanning electron microscopy. At 25 °C, the saponified PVA fibers exhibited a broad diameter distribution. The average fiber diameter, however, was found to decrease with increasing saponification temperature. When the saponification time was increased from 6 to 30 h, the average fiber diameter decreased gradually from 1540 to 1060 nm. In addition, the fiber diameter and morphology were also affected by the concentration of the alkaline saponification solution. The most optimal conditions for fabrication of thin, uniform, and smooth PVA nanofibers corresponded to an alkaline solution containing 10 g each of NaOH, Na2SO4, and methanol per 100 g of water, a temperature of 25 °C, and a saponification time of 24 h.

Optimum Conditions for the Fabrication of Zein/Ag Composite Nanoparticles from Ethanol/H2O Co-Solvents Using Electrospinning.

The optimum conditions for the fabrication of zein/Ag composite nanoparticles from ethanol/H2O cosolvents using electrospinning and the properties of the composite were investigated. The zein/Ag nanoparticles were characterized using field-emission scanning electron microscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), and thermogravimetric analysis. The antibacterial activity of the zein/Ag composite nanoparticles was also investigated. The XRD patterns and TEM images indicate the coexistence of a zein matrix and well-distributed Ag nanoparticles.

Electrospun novel super-absorbent based on polysaccharide-polyvinyl alcohol-montmorillonite clay nanocomposites.

A novel super-absorbent material was fabricated by electrospinning the natural polysaccharide pullulan (PULL) with polyvinyl alcohol (PVA) and montmorillonite (MMT) clay to form nonwoven webs, which were then heat treated. Transmission electron microscopy (TEM) micrographs, X-ray diffraction (XRD) patterns, and Fourier transform infrared (FTIR) analysis of the novel super-absorbent nanofibers suggest the coexistence of PULL, PVA, and MMT through the exfoliation of MMT layers in the super-absorbent nanofiber composite. The heat-treated PULL/PVA/MMT webs loaded with 5 wt% MMT electrospun nanofibers exhibited a water absorbency of 143.42 g g(-1) in distilled water and a water absorbency of 39.75 g g(-1) in a 0.9 wt% NaCl solution. Under extremely dry conditions, the PULL/PVA/MMT webs exhibited the ability to retain 43% distilled water and 38% saline water after being exposed to the atmosphere for one week. The heat treatment improved the crystallinity of the electrospun PULL/PVA/MMT super-absorbent webs and thus made the webs highly stable in aqueous environments. Overall, the addition of MMT resulted in improved thermal stability and mechanical properties and increased the water absorbency of the PULL/PVA/MMT composite.

Polyethyleneimine-mediated synthesis of superparamagnetic iron oxide nanoparticles with enhanced sensitivity in T2 magnetic resonance imaging.

The development of iron oxide nanoparticles (IONPs) with enhanced r2 relaxivity is important for achieving greater sensitivity in in vivo magnetic resonance (MR) imaging. In this study, it was considered that polyethyleneimine (PEI) could play a role in varying the particle and cluster sizes in IONP synthesis, leading to different r2 relaxivities. To demonstrate this, superparamagnetic IONPs were synthesised in the presence of NH4OH and PEI using a co-precipitation method. PEI acted as an active stabiliser during IONP synthesis, and therefore the particle size, hydrodynamic cluster size, coating layer thickness, saturation magnetisation, and r2 relaxivity were all strongly influenced by the PEI concentration. Monodispersed IONPs with a mean hydrodynamic cluster size of 14.4nm were synthesised at a PEI concentration of 0.05wt% and in this case, the r2 relaxivity was increased up to 227.6mM(-1)s(-1). This confirmed the viability of PEI-mediated synthesis as a means of controlling the particle/cluster size and enhancing the r2 relaxivity. The PEI-IONPs exhibited no significant cytotoxicity up to 132ppm. Rapid and strong uptake of PEI-IONPs was detected in rat liver by in vivo MR imaging. The superparamagnetic PEI-IONPs prepared in this study are considered to be sufficiently sensitive for use as MR imaging contrast agents, which can be used as parent particles for further functional modification.

Polymeric vehicles for topical delivery and related analytical methods.

Recently a variety of polymeric vehicles, such as micelles, nanoparticles, and polymersomes, have been explored and some of them are clinically used to deliver therapeutic drugs through skin. In topical delivery, the polymeric vehicles as drug carrier should guarantee non-toxicity, long-term stability, and permeation efficacy for drugs, etc. For the development of the successful topical delivery system, it is of importance to develop the polymeric vehicles of well-defined intrinsic properties, such as molecular weights, HLB, chemical composition, topology, specific ligand conjugation and to investigate the effects of the properties on drug permeation behavior. In addition, the role of polymeric vehicles must be elucidated in in vitro and in vivo analyses. This article describes some important features of polymeric vehicles and corresponding analytical methods in topical delivery even though the application span of polymers has been truly broad in the pharmaceutical fields.

Characterization of carbon nanotube-cdse hybrid nanomaterials.

MWNT-CdSe hybrid nanomaterials were prepared with carboxylic acid-treated CdSe nanoparticles and amino-functionalized MWNTs. The hybridization of MWNT-CdSe nanomaterials was performed by the formation of covalent bond between MWNT and CdSe. Their covalent bond lengths were varied with changing the linking spacers. Amino-functionalized MWNTs were reacted with CdSe nanoparticles which were functionalized with carboxylic acid groups. Their detailed structures were characterized by FT-IR, XPS, and small angle X-ray scattering. Through small angle X-ray scattering experiments, it was found that the structures of CdSe nanoparticles were not regular, and their sizes were broadly distributed in solution. The longer amino-functionalized MWNTs were thermally decomposed at lower temperature. The photoluminescence (PL) of chemically-linked MWNT-CdSe hybrid nanomaterials were weaker than that of CdSe nanoparticles. In addition, their PL intensities more weakened on the MWNT-CdSe with the longer spacers.

Effect of pullulan/poly(vinyl alcohol) blend system on the montmorillonite structure with property characterization of electrospun pullulan/poly(vinyl alcohol)/montmorillonite nanofibers.

Nanofibers of the composite of pullulan (PULL), poly(vinyl alcohol) (PVA), and montmorillonite clay (MMT) were prepared using electrospinning method in aqueous solutions. Pullulan is an interesting natural polymer for many of its merits and good properties. Because of biocompatibility and non-toxicity of PVA, it could be used in numerous fields. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), X-ray diffraction (XRD), and thermal gravimetric analysis (TGA) were done to characterize the PULL/PVA/MMT nanofibers morphology and properties. XRD patterns and FTIR data demonstrated that there were good interactions between PULL and PVA caused by possibly hydrogen bonds. Moreover, XRD data and TEM images indicated that intercalated and exfoliated MMT nanoplatelets can be obtained within the PULL/PVA/MMT nanofibers depending on the PULL/PVA blend ratios. Furthermore, the thermal stability and mechanical property (tensile strength) of PULL/PVA/MMT nanofibers could be enhanced more by exfoliated MMT nanoplatelets than intercalated structures of that nanoplatelets.

Synthesis of poly(vinyl acetate-methyl methacrylate) copolymer microspheres using suspension polymerization.

Poly(vinyl acetate-methyl methacrylate) (VAc-MMA) copolymer microspheres were prepared using suspension polymerization at low temperature initiated with 2,2'-azobis(2,4-dimethyl valeronitrile) (ADMVN). The poly(VAc-MMA) copolymer microspheres can be used over a large area where homopolymers, polyvinyl acetate (PVAc) and methyl methacrylate (PMMA) microspheres are capable of being put to use. The prepared microspheres were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Obtained copolymer microspheres which have 200 µm average diameter and higher thermal stability than those of homopolymer.