Ade Yeti Nuryantini

Preparation of Polyacrylonitrile Nanofibers with Controlled Morphology Using a Constant-Current Electrospinning System for Filter Applications

Polyacrylonitrile (PAN) fibers with average diameters in the range 100 nm with beaded morphology were prepared by a constant current electrospinning system. The fiber morphology could be easily varied by controlling the flow rate and electric current during the electrospinning process without changing the precursor solution. It was found that the use of lower flow rates resulted in more beaded fibers while the number of beads increases. The electric current could control the fiber morphology in which the beaded number (the number of beads or the beaded fibers) decreased as the electric current increased. It was also found that diameter and length of the beaded fibers increases as the electric current increases. Therefore, these results are able to be applied to find optimal conditions in obtaining high performance filter media.

A red emitting of manganese-doped boron carbon oxynitride (BCNO) phosphor materials: facile approach and photoluminescence properties

BCNO (boron carbon oxynitride) phosphors have attracted attention due to their non toxicity, simple synthesis process, and high quantum efficiency. However, the tunable emission, particularly a red emission, is still challenging to achieve. In the present study, a bright red emission (emission wavelength 620 nm under 365 nm UV excitation) of a manganese-doped BCNO (BCNO:Mn) phosphor synthesized by a solid state method is reported. Without Mn-doping, the BCNO phosphor exhibited a bright blue emission that can be ascribed to the closed-shell BO− and BO2− anions that act as luminescence center. Via Mn-doping, a red emission was exhibited that can be ascribed to the 4T1(4G) → 6A1(6S) transition from a new luminescence center of Mn2+ incorporated into the BCNO host lattice. The optimum red PL properties (λem: 611 nm, λex: 365 nm) were obtained with BCNO:Mn at a molar ratio of Mn/B at 0.71% mol/mol synthesized at 550 °C. We believe that the BCNO:Mn is a promising red-emitting phosphor for white light diodes.

Electrospun Polyvinylpyrrolidone as a Carrier for Leaves Extracts of Anredera cordifolia (Ten.) Steenis

Nanofibers produced by electrospinning method have high porosity, large surface area, long size, and their dimensions are ranging from nanometers to micrometers. The synthesis process was straightforward, uncomplicated and it can be processed from various type of materials and the nanofibers can be used as drug release. The polymer matrix acts as a carrier of other materials that will be spun. The purpose of this study was to to prepare electrospun fiber mats and to incorporate extracts from the leaves of Anredera cordifolia (Ten.) Steenis plant (Binahong). Polyvinylpyrrolidone (PVP) was used as a carrier matrix. Binahong leaf extract was added to a solution of PVP. The solution was then electrospun using a single nozzle and drum collector system under condition of voltage 12.5 kV, nozzle collector distance of 12 cm, and flow rate 10 μl /minute. In this study, the composite of Binahong extract and PVP solution was succesfully made into nanofiber.

Electrospinning of Poly(vinyl alcohol)/Chitosan via Multi-Nozzle Spinneret and Drum Collector

Poly (vinyl alcohol) (PVA)/chitosan nanofibers membranes were successfully prepared by electrospinning employing a multi-nozzle and a drum collector. The use of multi-nozzle and drum collector system is intended to produce stacked nanofibers to form a membrane as a matrix for burn wound healing application. The membranes thickness was controlled by varying applied voltage, flow rate, drum collector rotating speed, and nozzle-collector distance. The electrospinning process and nanofibers formation on the collector was observed using a digital camera. The scaling relationship between current-flow rate and current-voltage for PVA/chitosan fulfills power laws of I ~ Qα and I ~ Eβ, respectively.

Synthesis and Morphology Properties of Mn-doped Zinc Aluminate (ZnAl2-xO4: xMn4+, x=1%) Using Co-Precipitation Methods with Microwave Thermal Assisted

ZnAl2O4: Mn4+ particle were synthesize using co-precipitation using NaOH and PVA as precipitating agent and surfactants, followed by microwave-assisted thermal treatment. The morphology properties and absorption spectral of particles were investigate using SEM and UV-Vis spectrometer. The results showed that the ZnAl2O4 particles has a spinel structure with various particle size. Absorption spectral exhibits that particle has a potential photo catalytic properties at visible light spectra, especially for the pollutant degradation.

Mass Production of Stacked Styrofoam Nanofibers Using a Multinozzle and Drum Collector Electrospinning System

Electrospinning offers the unique ability to produce fibers with very small diameters down to a few tens of nanometers and an attractive mechanical appearance as well as the controllability of morphology, surface and pores structure. However, the main drawback of the conventional electrospinning technique is its low productivity. In order to produce high yield nanofibers, the production rate of nanofibers must be improved. The multinozzle and drum collector electrospinning system was then developed to overcome the problem. The multinozzle sub-system was used to increase the production rate of nanofibers while the drum collector was utilized to maintain the uniformity and thickness of stacked nanofibers. A solution prepared by dissolving waste styrofoam in the mixture of tetrahydrofuran (THF), citronella oil and cajuput oil was the precursor to produce the stacked styrofoam nanofibers.