The use of acoustic panels is one of the most important methods for sound insulation in buildings. Moreover, it has become increasingly important to use green/natural origin materials in this area to reduce environmental impact. This study focuses on the investigation of acoustic, mechanical and thermal properties of natural fiber waste reinforced green epoxy composites. Three different types of fiber wastes were used, e.g., cotton, coconut and sugarcane with epoxy as the resin. Different fiber volume fractions, i.e., 10%, 15% and 20% for each fiber were used with a composite thickness of 3 mm. The sound absorption coefficient, impact strength, flexural strength, thermal conductivity, diffusivity, coefficient of thermal expansion and thermogravimetric properties of all samples were investigated. It has been found that by increasing the fiber content, the sound absorption coefficient also increases. The coconut fiber-based composites show a higher sound absorption coefficient than in the other fiber-reinforced composites. The impact and flexural strength of the cotton fiber-reinforced composite samples are higher than in other samples. The coefficient of thermal expansion of the cotton fiber-based composite is also higher than the other composites. Thermogravimetric analysis revealed that all the natural fiber-reinforced composites can sustain till 300 °C with a minor weight loss. The natural fiber-based composites can be used in building interiors, automotive body parts and household furniture. Such composite development is an ecofriendly approach to the acoustic world.

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Core-shell nanofibers with the ability to carry multiple drugs are attracting the attention to develop appropriate drug delivery systems for wounds dressing applications. In this study, biocompatible core-shell nanofibers have been designed as a promising dual-drug carrier with the capability of delivering both water-soluble and organic solvent-soluble drugs simultaneously. With the aim of fabricating the core-shell nanofibers, the dipping method has been employed. For this propose, core nanofibers made from polyvinyl alcohol (PVA) were immersed in various concentrations of polyacrylonitrile (PAN) and cross-linked by dipping into ethanol. Diclofenac sodium salt (DSs) and gentamicin sulfate (GENs) have been loaded into the core and shell nanofibers as models of the drug, respectively. The morphology study of core-shell nanofibers showed that the concentrations between 1% w/w up to 2% w/w PAN/GENs, with deep penetration into the internal layers of PAV/DSs nanofibers could lead to the core-shell structure. The cytotoxicity results showed the competency of designed core-shell nanofibers for wound dressing application. Also, the release profile exhibits the controllable behavior of drug release.

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In this report, we designed and synthesized polyacrylonitrile/silver (PAN/AgNPs) nanofibers via an in-situ method to obtain a washable with high-dispersed silver nanoparticles membrane to form the hierarchically organized antibacterial mask to prevent the two-way effect of bacteria from person to environment and environment to person. For this objective, the electrospun PAN nanofibers were stabilized via the heating method. Different amounts of AgNPs were loaded into the PAN nanofibers by using silver nitrate and sodium hydroxide solutions. The basic results showed that AgNPs was homogenously loaded in PAN nanofiber matrixes. Furthermore, the release profile based on two-stage release theory showed that when the negligible amount of AgNPs was loaded into the nanofibers, the release significantly decreased, whereas antibacterial activity increased. The greatest potential antibacterial activity of the lowest amount of AgNPs showed controllable AgNPs release from PAN nanofibers that has a direct relationship with the washability and could promote the application of the produced product.

Background: Silver, incorporation with natural or synthetic polymers, has been used as an effective antibacterial agent since decades. Silver has potential applications in healthcare especially in nanoparticles form but silver sulfadiazine (AgSD) is the most efficient antibacterial agent especially for burn wound dressings. Method: In this report, mechanical, structural, and antibacterial properties of PAN nanofibers incorporation with silver sulfadiazine are mainly focused. AgSD was loaded for the first time on electrospinning as well as self-synthesized AgSD on PAN nanofibers by solution immersion method and then compared the results of both. Results: Occurrence of chemical reaction among the functional groups of AgSD and PAN were analyzed using FTIR, for both types of specimen. Morphological and surface properties of prepared nanofiber mats were characterized by scanning electron microscope, and it resulted in uniform nanofibers without bead formation. Diameter of nanofibers was slightly increased with addition of AgSD by in situ and immersion methods respectively. Nanoparticles distribution was analyzed by transmission electron microscopy. Thermal properties were analyzed by thermogravimetric analyzer and it was observed that AgSD decreased thermal stability of PAN which is better from biomedical perspective. X-ray diffraction declared crystalline structure of nanofiber mats. Presence of Ag and S contents in nanofiber mats was analyzed by X-ray photo spectroscopy. Antibacterial properties of nanofiber mats were investigated by disc diffusion method was carried out. E. coli and Bacillus bacteria strain were used as gram-negative and gram-positive respectively. Zone inhibition of the bacteria was used as a tool to determine effectiveness of AgSD released from PAN nanofiber mats. The antibacterial properties of PAN nanofibers impregnated with AgSD were determined with both types of bacteria strains to compare with control one. Conclusion: On the basis of characterization results it is concluded that PAN/AgSD (immersion) nanofiber mats have better structural and antibacterial properties than that of PAN/AgSD (in situ) nanofiber mats. So, from our point of view, self-synthesized AgSD is recommended for further production of nanofiber mats for antibacterial applications.

In this report a novel antibacterial wound dressing was prepared and then characterized for required testing. We loaded silver sulfadiazine (AgSD) for the first time by electrospinning.