Soaking Test Research Articles

Potassium methyl siliconate‐treated pulp fibers and their effects on wood plastic composites: Water sorption and dimensional stability

AbstractPotassium methyl siliconate (PMS) was investigated as a new nano modifier of wood fiber and wood flour to improve the compatibility between the fiber/flour and the plastic matrix in fiber reinforced plastic composites. Before injection molding, bleached and brown pulp fibers and mixed species wood flour were pretreated in PMS solutions. The morphology of the treated and untreated fiber and flour, the compatibility of PMS‐treated fiber and flour with polyethylene (PE), and the water sorption and volumetric swell of PMS‐treated fiber/flour plastic composites in a long‐term soaking test were evaluated. Fiber and flour treated with PMS increased the compatibility between the fiber/flour and the PE matrix. The increased compatibility of PMS‐treated fiber and flour with the matrix contributed to the reduction of water sorption and, thus, increased dimensional stability. For all composites, water sorption and volumetric swell of fiber/four plastic composites decreased as the ratio of fiber to flour increased. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

In vitro and in vivo biological characterizations of a new poly(amino acids)/calcium sulfate composite material for bone regeneration

A new poly(amino acids)/calcium sulfate (PAA/CS) composite was synthesized by melt polycondensation from a biodegradable PAA copolymer based on 6-aminocaproic acid and the bioactive CS. Its degradability, biocompatibility, bioactivity, and osteoconductivity were evaluated in vitro and in vivo, using phosphate buffer solution soaking test, MG63 adhesion test, and bone defect model repair test, respectively. The PAA/CS composite exhibited a much lower degradation rate than the CS, as 21.6 % of weight loss after immersing in phosphate buffer solution for 5 weeks. Moreover, the pH value of local environment restored to neutrality condition after a sharp drop in the first week. The MG63 cells adhered well on the surfaces of PAA and PAA/CS plates with their filopodium and lamellipodium, and displayed great osteogenic differentiation competence. The bone defect model repair test revealed that the composite could be intimately incorporated with the surrounding bone without causing any deleterious reaction. Radiological and histological evaluation indicated the PAA/CS granules were capable of guiding new bone formation and had a much slower degradation rate than the CS. In conclusion, the PAA/CS composite is expected to be a new bone graft material for its favorable bioactivity and biocompatibility and reasonable degradability.

Thin-film composite nanofiltration membranes with improved acid stability prepared from naphthalene-1,3,6-trisulfonylchloride (NTSC) and trimesoyl chloride (TMC)

Thin-film composite (TFC) nanofiltration (NF) membranes with improved acid stability were fabricated through the interfacial polymerization of trimesoyl chloride (TMC) naphthalene-1,3,6-trisulfonylchloride (NTSC), and piperazine (PIP) on a porous polysulfone support membrane by varying the NTSC content in TMC-organic solution. The physico-chemical characteristics of the membranes were analyzed by ATR-FTIR, streaming potential measurement and surface contact angle measurement, the permeation properties were evaluated through cross-flow permeation tests, and the acid stability was investigated through both static acid soaking tests and long-term permeation tests under acidic condition. It was found that, as the NTSC content in TMC-organic solution increased, the membrane surface became more hydrophilic and negatively charged, the pure water permeability and molecular weight cut-off of the formed NF membrane increased from 5.5 to 10.6l/m2hbar and about 360 to 660Da, respectively, while the rejection rate to Na2SO4 firstly increased from 98.2 to 98.7% and then declined to a lower value of 97.8%. After soaking in 8w/v% H2SO4 for 30days or filtration with 4.9w/v% H2SO4 for 60days, the TFC membranes prepared from TMC and NTSC showed little performance change, while serious performance deterioration occurred with the TFC membrane prepared from TMC.

Mechanical and electrical stability of parylene-based platinum-black coated wire microelectrode for implantable applications

In this paper, a parylene-based platinum-black coated wire microelectrode with multi-electrode sites for neuromuscular stimulation was fabricated. The electrodes with tunable electrode site position, quantity, and width will achieve multi-stimulation during functional electrical stimulation. The platinum-black coating was electroplated on electrode sites by applying a current pulse train in chloroplatinic acid solution (H2PtCl6) under ultrasonic bath, which contributed to achieve excellent mechanical and electrical stability of the microelectrode. After electroplating, the 90 % of impedance reduction and 13 times of cathodic charge storage capacity increase were achieved. Finally, the mechanical and electrochemical stability test, the passive soaking test, and the bending test were performed. The results showed that the platinum-black coated wire microelectrode had good stability after 5 min of ultrasonic vibration and 122 h of current pulses stimulation. After soaking in 0.9 % saline solution at 87 °C for 8 months, the average impedance at 1 kHz just increased by 1.6 kΩ. The bending test (with maximum bending angle of 90°) also showed that there was a little change in the electrochemical characteristics of the electrode. This parylene-based platinum-black coated wire microelectrode will be promising for facial prosthesis applications.

Improvement on solvent resistance of photonic crystals by surface modification

In this study polystyrene (PS) spheres were synthesized by emulsifier-free emulsion copolymerization of styrene with methacrylic acid for the fabrication of photonic crystals. A facile method to significantly improve the solvent resistance of photonic crystals was developed through surface modification of PS spheres by poly(vinyl pyrrolidone) (PVP). We used an ethanol soaking test to evaluate the solvent resistance of photonic crystals prepared by pristine, thermal-treatment, and PVP-modification methods. The crystal structure and the absorption band of the photonic crystals before and after the soaking test were investigated. Experimental results revealed that the photonic crystals prepared from the unmodified PS spheres have a very weak resistance to ethanol, resulting in impossibility of carrying out inverse opal photonic crystals. The improvement on solvent resistance by the thermal-treatment method was limited due to the weak bonding or the mergence of PS spheres. We found the photonic crystal prepared from the PVP-modification PS spheres maintains its integrity very well in the ethanol solution after 5-h soaking. Moreover, the photonic crystal and the corresponding inverse opal photonic crystal revealed excellent structure and optical properties.

Effect of boiling, roasting and frying on disintegration of peanuts in simulated gastric environment

The objective of this study was to investigate the influence of boiling, roasting and frying on the digestion of peanuts in simulated gastric environment. Raw and processed peanuts were tested for disintegration in a model stomach system. The differences in disintegration rate were explained with respect to the changes in moisture absorption and texture. The absorption of moisture and the swelling of peanuts during gastric digestion were studied using Magnetic Resonance Imaging (MRI). The results show that processing improved the gastric disintegration of peanuts, and the disintegration rate was in an order of fried > roasted > boiled > raw peanuts. The changes in total weight, moisture and the dry solid loss in the samples were described by Linear–exponential equation, Peleg's equation and the Weibull equation, respectively. Absorption of gastric juice played a critical role in softening the texture contributing to the breakdown of peanuts. Static soaking test indicated that the disintegration rate, as indicated by half time, has a good exponential relationship with the textural parameters of soaked samples. MRI shows potential as being used to analyze the mass transfer phenomenon in solid foods under digestion.

Influence of heat treatment on Ti6Al4V for biomimetic biolayer

This study presents preliminary results on a coating method based on biomimetic techniques which are designed to form a calcium-phosphate layer very similar to the process corresponding to the formation of natural bone. The proposed deposition route has several advantages of controlled conditions, application to complex shapes, without adverse effect of heating besides being cost effective. Samples were alkali etched and subsequently heat treated. Afterwards, the biomimetic deposition process of a calcium-phosphate coating on the chemically pretreated substrates, were investigated using the SBF immersion route for 4 and 6 days subsequently and discussed. The formed layers were studied using FESEM, confocal microscopy and FT-IR before and after SBF soaking tests. Biochemical analyses of calcium and phosphorous contents in SBF—solutions after samples withdrawal—were performed for the biomimetic assessment of the formed layer along with pH measurements. The data suggests that this method can be successfully applied to obtain deposition of calcium-phosphate and calcium carbonate layers on titanium substrates.

Structure and properties of TiC/Ti coatings fabricated on NiTi by plasma immersion ion implantation and deposition

A titanium carbide (TiC) nanostructured coating and Ti intermediate layer are fabricated on NiTi by plasma immersion ion implantation and deposition (PIII&D) to improve the surface properties. The chemical composition and structure are determined by X-ray diffraction, Auger electron spectroscopy, scanning electron microscopy, and atomic force microscopy. Nano-indentation is used to evaluate the mechanical properties of the thin film and the biological characteristics are assessed by electrochemical measurement and soaking tests in simulated body fluids. Based on the potentiodynamic polarization and Ni release data after the polarization test, the Ti/TiC nanostructure coating has better corrosion resistance compared to the NiTi substrate and there is significantly less Ni ion release from the NiTi substrate into the simulated body fluids than the uncoated NiTi alloy.

Acid stable thin-film composite membrane for nanofiltration prepared from naphthalene-1,3,6-trisulfonylchloride (NTSC) and piperazine (PIP)

Abstract Acid stable thin-film composite membrane for nanofiltration was fabricated by interfacial polymerization of naphthalene-1,3,6-trisulfonylchloride (NTSC) and piperazine (PIP) on porous polysulfone support membrane. The performance of the membrane was optimized by studying the preparation parameters including monomer content, reaction temperature and additive in organic phase. The separation performance of the resultant membrane was evaluated through permeation experiments, the membrane property was characterized by ATR-FTIR, XPS AFM, SEM and streaming potential measurements, and the acid stability was investigated through both static acid soaking tests and long-term permeation tests under acidic condition. After exposure to 20%(w/v) H2SO4 for 2 months or running with 4.9%(w/v) H2SO4 for 60 day, the PIP-NTSC composite membrane showed minor change in separation performance and no evident chemical change in the active skin layer, indicating that the developed membrane possessed good acid stability. The desired membrane exhibited a pure water permeability of about 5.8 l/m2 h bar, a MWCO of as high as 5000 Da, and an attractive solute rejection of higher than 86.5% for a feed containing 500 mg/l Na2SO4 at 0.5 MPa. Furthermore, the PIP-NTSC composite membrane could be used to treat acidic effluents from metal industries with good perm-selectivity and long-term stability.

Experimental investigation of influence of acid rain on leaching and hydraulic characteristics of cement-based solidified/stabilized lead contaminated clay

Remediation of contaminated lands in China urban areas is of great concern. Degradation of construction facilities caused by acid rain is a serious environmental pollution issue in China. This paper presents an investigation of the effects of acid rain on leaching and hydraulic properties of cement-based solidified/stabilized lead contaminated soil. Laboratory tests including infiltration test and soaking test are conducted. It is found that the soil hydraulic conductivity decreases with increase in the pore volume of flow of permeant liquids (acid rain and distilled water). The decreasing rate in the case of the acid rain is lower than that in the case of the distilled water. The soaking test results show that pH and the presence of sulfate ions of acid rain have considerable influence on the leached concentrations and leaching rate of calcium.

Experimental Studies on Disintegration Features of Carbon Mudstone

Carbon Mudstone will have a complicated change in the aspect of physics, chemistry and mechanics behavior when wet. Thus, it is difficult to describe the process in a quantitative standard. In order to find out the effect of testing conditions and water content, there are two different conditions in test drying and original state samples, one is outdoor test and the other is indoor soaking test. What’s more, Fractal Theory is used in the research of Carbon Mudstone. The result shows: A short-lived process of water absorption and weight increment appears in the initial disintegration; Different conditions will result in different destructional forms of samples; The key reason of disintegration is that wetting and drying cycle results in the change of water content; The difference of water content partly affects the process before disintegration, but less affects fractal dimension after disintegration.

Structure, corrosion resistance and apatite-forming ability of NiTi alloy treated by micro-arc oxidation in concentrated H2SO4

Titanium oxide coatings were prepared on NiTi alloys by MAO treatment in concentrated H2SO4 electrolyte using DC power supply. The surface of the coating exhibited a typical MAO porous and rough structure. XPS analysis indicated that the coatings were mainly consisted of O, Ti, and a trace amount of Ni, and the concentration of Ni was greatly reduced compared to that of the NiTi substrate. The curves of potentiodynamic polarization indicated that the corrosion resistance of NiTi alloy was significantly improved by micro-arc oxidation. The coatings were tightly adhesive to the substrates with the bonding strength higher than 45MPa. The SBF soaking test result showed that a kind of bone-like apatite was observed on the MAO coating after soaking for 28days, suggesting that MAO treatment in concentrated sulfuric acid electrolyte was an effective way to improve the bioactivity of NiTi alloys.

Synthesis and in vitro evaluation of hydroxyapatite with controlled morphology

Hydroxyapatite (HA) ceramics have been used as bone-repairing materials. Particles in HA ceramics show different properties depending on their compositions and morphologies. It is expected that the control of the composition and morphology contributes to improvement of biological properties of HA ceramics. In order to reveal the effect of the composition and morphology, the HA ceramics composed of rod-shaped or plate-shaped particles with calcium-deficient composition were prepared by the hydrothermal process. The in vitro evaluation, simulated body fluid (SBF) soaking test, was then conducted for these samples. The calcium-deficient HA ceramics composed of rod-shaped or plate-shaped particles were reacted with SBF and incorporated calcium and phosphate ions from SBF. This implies that these HA ceramics show high affinity to bone in the body.

Effect of Disinfectants on Glucose Monitors

Monitoring blood glucose levels is an integral part of routine diabetes management. To minimize the risk of transmission of bloodborne pathogens during monitoring, the Centers for Disease Control and Prevention (CDC) recommends that glucose meters be disinfected after each use whenever they are used to test multiple patients. The objective of this study is to assess the compatibility of some common disinfectants with certain blood glucose meter systems. We tested six disinfectants for adverse impact on meter performance or the exterior meter surfaces. The disinfectants tested were 0.525% sodium hypochlorite, 20% 2-propanol and 10% ethanol, 17.2% isopropanol, 55% isopropanol, 70% isopropanol, and hydrogen peroxide. To assess meter performance, we tested OneTouch® Ultra® blood glucose monitoring systems with control solution before and after application of either water or disinfectant. To assess the effect on exterior meter surfaces, we performed a soaking test to simulate long-term exposure to disinfectant. Paired t-test results showed that the control solution data associated with disinfectant and with water application were not significantly different for each meter type. However, most of the meter types were adversely affected by hydrogen peroxide and/or by the higher concentrations of alcohol-based disinfectants. Although none of the six disinfectants affected meter performance, hydrogen peroxide and isopropanol >20% adversely affected the exterior surfaces of the tested meters. When complying with CDC instructions for meter disinfection, users should use caution and choose disinfectants that have been validated by the meter manufacturer.

Protective graphite coating on metallic bipolar plates for PEMFC applications

A new design of metallic bipolar plates with pure graphite coating on metal substrates has been developed. The top layer was a continuous graphite sheet made by the expanded graphite flakes. The pure and layered graphite surface provides high electrical conduction and high chemical inertness in PEMFC environments. Between the graphite sheet and the metal substrate was a binder layer, which mainly consisted of ester resin and conductive fillers. It functions as a binder for the graphite layer and as the second protection layer from acid solution as well. The results from the potentiodynamics tests showed rather low corrosion current densities for our proposed materials, even after soaking tests for over 2000 h. The graphite-coated 316L revealed negative (cathodic) current densities either in the PEMFC cathodic or in the anodic environment for the whole polarization period in the potentiostatic experiments. Thus, the graphite-coated SS316L could potentially be used as a bipolar plate material in the PEM fuel cell applications.

Cathodic electrodeposition of highly porous cobalt sulfide counter electrodes for dye-sensitized solar cells

In this study, cobalt sulfide (CoS) counter electrodes (CEs) fabricated by potentiodynamic deposition in a near-neutral solution (pH 6) were incorporated into Pt-free dye-sensitized solar cells (DSSCs). It was found that the potentiodynamic deposition mode can facilitate the formation of CoS within the deposit compared to the conventional chronoamperometric deposition. Different sweep cycle (charge capacity) had great impact on the morphology and electrocatalytic activity of CoS films. The CoS film fabricated by five-sweep-cycle potentiodynamic deposition was observed with highly porous morphology and multilayer structure, thus resulting in a lower charge-transfer resistance of ∼1.03 Ω cm 2 in comparison with a sputtered-Pt CE. The DSSC assembled with this kind of CoS CE showed a higher photovoltaic conversion efficiency of 6.33 ± 0.15% compared to 6.06 ± 0.17% for DSSC with the sputtered-Pt CE under full sunlight illumination (100 mW cm −2, AM 1.5G). In addition, consecutive cyclic voltammetric and long-term light soaking tests demonstrated that such DSSC had excellent stability. Therefore, the highly porous CoS film can be considered as a promising alternative CE for use in DSSC due to its high electrocatalytic performance and electrochemical stability.

ChemInform Abstract: Efficient and Stable Panchromatic Squaraine Dyes for Dye‐Sensitized Solar Cells.

A new series of stable, unsymmetrical squaraine near-IR sensitizers (JK-216 and JK-217), which are assembled using both thiophenyl pyrrolyl and indolium groups, exhibit a panchromatic light harvesting up to 780 nm. The JK-216 based cell exhibited a record efficiency of 6.29% for near-IR DSSCs. In addition, the JK-217 device showed an excellent stability under a light soaking test at 60 °C for 1000 h.

Long-term in-vivo Investigation of Parylene-C as Encapsulation Material for Neural Interfaces

In this paper, we present in-vitro soak testing results used to measure the long term encapsulation and insulation properties of parylene-C based on interdigitated electrodes (IDEs) (Fig. 1). The parylene-C layer has been deposited by chemical vapor deposition using the Gorman process [1]. Our primary investigations showed that parylene-C is a great encapsulation material based on its extremely low leakage current (20 pA for quartz substrate) and high insulation impedance (2 Masterisk at 1kHz for quartz substrate) after 180-day of soaking test. Substrate materials with high resistivity were recommended in order to actually measure the insulation performance of encapsulation materials rather than that of the substrates.

Efficient and stable panchromatic squaraine dyes for dye-sensitized solar cells

A new series of stable, unsymmetrical squaraine near-IR sensitizers (JK-216 and JK-217), which are assembled using both thiophenyl pyrrolyl and indolium groups, exhibit a panchromatic light harvesting up to 780 nm. The JK-216 based cell exhibited a record efficiency of 6.29% for near-IR DSSCs. In addition, the JK-217 device showed an excellent stability under a light soaking test at 60 °C for 1000 h.

Stabilization of metal counter electrodes for dye solar cells

The purpose of this study was to identify stable metal based counter electrodes (CE) for dye solar cells (DSC). Previous studies have shown that stainless steel (StS 304) suffers from corrosion when used as a counter electrode. Therefore metals which have inherently higher corrosion resistance, such as stainless steel types 321, 316 and 316L, Inconel 600 and titanium, were investigated here. When using thermal platinization for the preparation of the catalyst layer on CE, only the titanium foil based metal based DSC remained consistently stable in the 1000h light soaking test. The counter electrodes were also prepared with sputtering ∼20nm thick layer of Pt which provides a highly uniform layer on the CE which acts also as a protective coating on the metal. With sputtered Pt, DSC on all studied metals expect for Inconel remained at 80–95% of the initial efficiency after light soaking test for 1000h.