Surface Micromorphologies Research Articles

ANALYSIS OF THE MIXED ELASTOHYDRODYNAMIC LUBRICATION CHARACTERISTICS OF DOUBLE CIRCULAR ARC GEARS CONSIDERING MICRO-MORPHOLOGY

Different machining methods result in diverse morphologies on the surface of gears. Under mixed lubrication, the friction and contact behavior of the real morphology interface becomes more complex. This study aims to analyze the influence of different process tooth surface micro-morphologies on the lubrication performance of the meshing area of double circular arc gears. Focusing on elastohydrodynamic lubrication (EHL) characteristics of the double circular arc gears as the research object, the study involved measuring the three-dimensional morphology of the meshing position of the double circular arc gears. Non-Gaussian simulation technology was then used to characterize the micromorphology of the tooth surface resulting from different processes (i.e. hobbing process and skiving process). The tooth surface suction speed was determined based on the meshing characteristics of double circular arc gears. Based on the theory of point contact EHL, Reynolds equation and film thickness equation considering micromorphology were derived, and numerical solutions were obtained using the multi-grid method. A point contact EHL model for double circular arc gears was established considering the micromorphology of tooth surfaces in different processes. Results show that, the oil film pressure is positively correlated with rotational speed and torque. The oil film thickness is positively correlated with rotational speed, and negatively correlated with input torque. The negative of micro-morphology on the tooth surface on the lubrication performance could lead to an increase in pressure fluctuations and the absence of the second pressure peak. The uneven distribution of oil film and the lager roughness value could result in obvious fluctuations. The lubrication performance of the contact area in the gear hobbing process is superior to that in the gear skiving process. This study lays the foundation for further exploring the coupling characteristics between the double circular arc gear transmission system and elastic fluid dynamic lubrication. Keywords: Double circular arc gears, Point contact, Mixed EHL, Lubrication characteristics, Micro- morphology.

Corrosion protection of steel bar enabled by monofluorophosphate-bearing composites with sustained-release capability

This paper selected the polyethylene (PE) and polystyrene (PS) as polymer carriers of the sodium monofluorophosphate (MFP) to prepare PE/MFP and PS/MFP composites using melt-extrusion technique with a sustained-release capacity for smart corrosion protection. The releasing behavior of two MFP-containing composites in the simulated concrete pore solution was evaluated in terms of residual content, releasing rate and the side/fractured surface micro-morphologies. Besides, related releasing mechanisms of MFP-bearing polymer composites are explained, which are different from the mechanisms of most microcapsules and tablets. The experimental analyses showed that two composites all displayed a uniform elemental distribution on their side surface and intrinsic hydrophobicity. The PE/MFP composites obtained higher initial encapsulation efficiency and a lower but relatively controllable releasing rate compared to the PS/MFP composites due probably to the higher hydrophobicity and crystallinity of the PE carrier. In addition, the physical appearance of the corroded carbon steel bar after immersion in sodium chloride-contaminated simulated concrete pore solutions and corresponding electrochemical outcomes revealed that PE/MFP composites generally led to better corrosion protection performance than the PS/MFP counterpart, which could be due to their better sustained-release capacity. The obtained composites provide another promising option as concrete inhibitors, making inroads into improving the long-term durability of concrete structures.

Stability of plasma improved adhesive property of polytetrafluoroethylene surface

In this study, the authors investigated the wettability change of atmospheric-pressure-cold-plasma (APCP)-treated polytetrafluoroethylene (PTFE) surfaces with time under different storage temperatures and pressures, and the results indicate that low temperature can hinder wettability recovery. After storage for 5 days, the water contact angle (WCA) of PTFE stored at room temperature (25°C) recovered from 19 ± 2 to 54 ± 2°, while the WCA of PTFE stored at low temperature (−10°C) increased to just 42 ± 3°. Then, the mechanism contributing to the slower wettability recovery was investigated by analyzing surface chemical compositions through X-ray photoelectron spectroscopy and observing surface morphologies using atomic force microscopy. After 15-day storage, the oxygen (O) and nitrogen (N) contents decreased obviously, while the fluorine (F) content increased. The fluorine content of the sample stored at low temperature was 20% less than that of the sample stored at room temperature. In contrast, surface micromorphologies were unchanged during storage, and the surface roughness R a of each sample was around 7 nm. Finally, peel strength tests were conducted on APCP-treated PTFE surfaces stored at different temperatures, and the surfaces stored at low temperature maintained better adhesive properties. After 15 days of storage, the adhesive strength could still reach 400 N/m, which was 376% higher than that of the untreated surface. The research results are expected to facilitate practical applications of APCP modification and PTFE surfaces significantly.

Ni-Fe Alloy Coatings Prepared via Jet Electrodeposition for the Optimization of the Electrochemical Detection Performance of Laser-Induced Graphene for Pb(II)

Heavy metal pollution in water, particularly Pb ion pollution, has seriously threatened human life and health. Therefore, the manufacture of efficient and sensitive heavy metal ion detection materials is essential. The objective of this study was to improve the electrochemical detection performance of laser-induced graphene (LIG) for Pb(II). Considering the excellent ion affinity and high activity of transition metals, Ni-Fe alloy coatings were prepared on the surface of LIG through jet electrodeposition. The prepared LIG and Ni-Fe/LIG were qualitatively analyzed through Raman spectrometry, X-ray diffraction analysis, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The surface micromorphologies, charge transfer capabilities, and electrochemically active surface areas of LIG and Ni-Fe/LIG were characterized. The detection range and limit of detection (LOD) of Pb(II) for LIG and Ni-Fe /LIG as electrochemical sensors were analyzed. Results showed that compared with LIG, Ni-Fe/LIG had more surface active sites, a higher charge transfer capability, and a larger electrochemically active surface area that reached 0.828 cm2. Ni-Fe/LIG had a detection range of 20–1200 µg/L and an LOD of as low as 0.771 µg/L. Ni-Fe/LIG demonstrated a better electrochemical detection performance for Pb(II) than LIG when used as an electrochemical sensor.

Influence of (Zn0.5Ti0.5)3+ substitution on structural evolution, bond characteristics, and microwave dielectric properties of spinel Li(Zn0.5Ti0.5)xGa5-xO8 solid solutions

In this study, the evolution of phase and bond characteristics, as well as the consequent effects on the microwave dielectric properties of Li(Zn0.5Ti0.5)xGa5-xO8 ceramics were investigated. XRD and Rietveld refinement patterns revealed that the sample underwent a transformation from a low-symmetry inverse cubic spinel phase, characterized by the P4332 space group, to a high-symmetry cubic spinel phase associated with the Fd-3m space group. All samples displayed compact grain structures in their surface micro-morphologies, and they achieved high relative densities exceeding 97% when sintered at their respective optimal temperatures. With increasing x value, the dielectric constant increases due to the growth in ionicity and αtheo/Vm. Concurrently, the τf value shifts from −69.29 ppm/°C to −48.73 ppm/°C, a trend that aligns with the bond valence changes at the octahedral position as a function of x. In the range of 0 ≤ x ≤ 3, the Q × f value initially increased due to the change in symmetry, growth in lattice energy, and reduction of Ti3+ content. However, it subsequently decreased as a result of further disruption in ordering and diminishing lattice energy. The optimal microwave dielectric properties were obtained for the x = 3 sample (LiZn1.5Ti1.5Ga2O8) sintered at 1220 °C, displaying characteristics of εr = 16.46, Q × f = 79,268 GHz and τf = −53.36 ppm/°C.

Carbon fiber to improve the resistance of high strength PVA-ECC to elevated temperatures

Engineered cementitious composite (ECC) with polyvinyl alcohol (PVA) fiber shows great potential in buildings and infrastructure constructions due to its characteristics of strain-hardening and multiple-cracking. However, its fire resistance shall be paid with great attention since the fibers would melt and components are prone to spall under elevated temperatures, especially for cement-based materials with high strength. Present study focuses on the fire resistance improvement of high strength ECC (HSECC) by adopting carbon fiber with higher thermal performance. Behaviors were qualitatively compared in the aspects of visual observation, surface cracking and spalling in HSECC with and without carbon fiber. Mass loss, residual strength and brittleness of all groups are quantitatively analyzed. Results show that carbon fiber enhances high temperature-exposed residual strength of HSECC and shows hysteresis effect on the decomposition of calcium hydroxide (CH) and calcium carbonate. The bridging and take-over effect of carbon fiber contributes to microcrack inhibition at elevated temperatures observed from surface cracking and micro-morphologies. HSECC with higher carbon fiber content shows greater resistance to high temperatures.

Study on thermal shock resistance of Sc2O3 and Y2O3 co-stabilized ZrO2 thermal barrier coatings

In order to reveal the effect of Sc2O3 and Y2O3 co-doping system on the thermal shock resistance of ZrO2 thermal barrier coatings, Y2O3 stabilized ZrO2 thermal barrier coatings (YSZ TBCs) and Sc2O3–Y2O3 co-stabilized ZrO2 thermal barrier coatings (ScYSZ TBCs) were prepared by atmospheric plasma spraying technology. The surface and cross-section micromorphologies of YSZ ceramic coating and ScYSZ ceramic coatings were compared, and their phase composition before and after heat treatment at 1200 °C was analyzed. Whereupon, the thermal shock experiment of the two TBCs at 1100 °C was carried out. The results show that the micromorphologies of YSZ ceramic coating and ScYSZ ceramic coating were not much different, but the porosity of the latter was slightly higher. Before heat treatment, the phase composition of both YSZ ceramic coating and ScYSZ ceramic coating was a single T′ phase. After heat treatment, the phase composition of YSZ ceramic coating was a mixture of M phase, T phase, and C phase, while that of ScYSZ ceramic coating was still a single T′ phase, indicating ScYSZ ceramic coating had better T′ phase stability, which could be attributed to the co-doping system of Sc2O3 and Y2O3 facilitated the formation of defect clusters. In the thermal shock experiment, the thermal shock life of YSZ TBCs was 310 times, while that of ScYSZ TBCs was 370 times, indicating the latter had better thermal shock resistance. The difference in thermal shock resistance could be attributed to the different sintering resistance of ceramic coatings and the different growth rates of thermally grown oxide in the two TBCs. Furthermore, the thermal shock failure modes of YSZ TBCs and ScYSZ TBCs were different, the former was delamination, while the latter was delamination and shallow spallation.

Early taphonomic processes in a microbial-based sedimentary system from a temperate salt-pan site (Cervia salterns, Italy)

AbstractIn the only salt evaporation pond retaining its natural setting of the historic Salina di Cervia (Italy), the northernmost salterns of the Mediterranean area, a number of potentially preservable textures derive from the interactions between photosynthetic mat producers and the sedimentary substrate. These morphologies occur at the beginning of the taphonomic processes when repeated emerged-submerged conditions take place. In these conditions the cohesive nature of the diatom- and cyanobacterial-derived mucilage favours the stabilization of otherwise ephemeral structures. Surface micromorphologies for which diatoms and cyanobacteria have played some active role when still living in the soft microlayer and down to the sediment-water interface, such as during the gliding motility, can overcome the surface layer of most intense mixing (i.e., the taphonomically active zone) and keep traces of them in the fossil record either as body fossils or as texture contributors. Tiny microbial-derived remnants, such as filaments and biofilm strands of halotolerant microorganisms, while fragile upon their formation, can therefore stabilize as biosignatures when combined with salt precipitation. Halophilic and halotolerant ecosystems are models for life in extreme environments (analogue sites) with similarity to those strongly suspected to occur and/or have occurred on Mars and on other planetary bodies. The study of hypersaline systems such as Salina di Cervia which harbour diverse and abundant microbial life, can be relevant for astrobiology since it allows the investigation of potential biosignatures and their preservation, and of further understand the range of conditions and the planetary processes sustaining potentially habitable systems.

Changes in physicochemical and leachate characteristics of microplastics during hydrothermal treatment of sewage sludge

Sewage sludge is an important source for microplastics (MPs) entering into environment. Hydrothermal treatment has been considered a promising method for reducing MPs in sewage sludge. However, MPs degradation characteristics and mechanism during sludge hydrothermal treatment are not fully understood. In the study, three common MPs, i.e. polyethylene (PE), polystyrene (PS) and polyethylene terephthalate (PET) were used to explore the effect of hydrothermal treatment on the properties of MPs in sewage sludge. The hydrothermally-treated (HT) MPs in sludge feature more broken and rougher surfaces with higher O-containing functional groups in the sludge than those in water. The dissolved leachates from the HT MPs in the sludge show higher concentrations than the counterparts, implying that certain components in sludge serve to promote the MP degradation and leaching during hydrothermal treatment. Three model components in the sludge, including protein, carbohydrate, and SiO2, were further investigated for their individual effects on the hydrothermal degradation of MPs. Compared with those in water, the HT MPs in the protein and carbohydrate solutions show greater changes in the surface micro-morphologies and carbonyl index, and generate more leachates. However, the SiO2 solution results in similar difference in the MPs changes with the water solution, indicating that organic components of sludge play a more critical role in the enhanced MPs hydrothermal degradation than inorganic components. The HT PET leads to more pronounced changes in the physicochemical and leaching characteristics than the HT PE and PS, possibly due to more susceptible hydrolysis of the PET. Hydrothermal degradation of the MPs is found to be mainly driven by depolymerization of the polymer and leaching of the plastics additives. The findings imply that the sludge organic components significantly promote the MPs aging and degradation during hydrothermal treatment, and potential changes in the environmental risk of the treated MPs upon their subsequent land applications.

The role of titanium surface micromorphology in MG-63 cell motility during osteogenesis

Different surface micromorphologies influence osteoblast movements and impact the osteogenesis around implants. In this study, a biomimetic chip that simulates the microenvironment of the implant and bone in vitro was developed (tissue-on-chip of group T and group C) to study the correlation of cell movement velocity (CMV), direction (CMD), acceleration (CMA), and cell attachment number (CA) with the surface micromorphology of the Titanium material. Computational fluid dynamics (CFD) was used for flow analysis. Changes in intraosseous pressure (IOP), local blood perfusion index (LBPI), new bone microstructure, microvessel density (MVD), and bone-implant contact (BIC) in beagle dogs were detected as implant surface alterations. Surface skewness (Ssk) and surface arithmetic mean height (Sa) were the most important negative factors for high CMV, accounting for 51% and 32%, respectively, of all the influencing factors. Higher Ssk (SskT > 0, SskC < 0) and Sa (SaT > SaC) resulted in lower CMV (CMVT:CMVC = 0.41:1), greater CA (CAT:CAC = 1.44:1), and higher BIC (BICT:BICC = 3.06:1) (P < 0.05). The surface micromorphology influenced the CMD of MG-63 cells within 20 μm from the material surface. However, it could not regulate the IOP, LBPI, MVD, new bone microstructure, or CMD (P > 0.05).

Eco-friendly, cost-effective electroless Ag plating based on a novel Ni–P activation process on magnesium titanate ceramic

An eco-friendly, cost-effective route for fabrication of silver (Ag) coatings on the surface of magnesium titanate ceramic by electroless plating (EP) based on a novel Ni–P activation process was developed successfully. Coarsened ceramic surface was implanted in situ abundant nano-scale Ni–P spherical active particles via facilely soaking in aqueous solution containing nickel sulphate as Ni source, sodium hypophosphite as major reducing agent and introducing a trace of sodium borohydride to induce initial deposition. The validity of the novel activation process was confirmed by the subsequent experimental fact that Ag EP coatings could deposit smoothly. The surface and cross-section micro-morphologies of typical samples and their element constituent as well as distribution were characterized by SEM and EDS. The deposition rate of Ag coatings and their comprehensive performances including appearance, electric conductivity, adhesion and microhardness were evaluated. The results indicates that the novel Ni–P process could provide the best activating effect to ensure the deposition of high-quality Ag coatings by comparison with traditional Ni–B activation and classical stannous activation.

The effect of oil heat treatment on biological, mechanical and physical properties of bamboo

Bamboo is now widely used in construction, papermaking, textile, furniture and other fields because of its renewable, fast-growing, high-strength, high-yield and easy processing. However, compared with wood, bamboo and bamboo products are more vulnerable to damage by fungi and pests. An effective and eco-friendly method is urgently needed to improve their physical and chemical properties, decay resistance and anti-mildew properties, and hydrophobic properties. Here, bamboo was heated with methyl silicone oil. The effect of different temperatures (140 °C–200 °C) and different times (2 h–6 h) on the properties of bamboo was studied systematically, including chemical composition, physical and mechanical properties, surface wettability, decay resistance and anti-mildew property. No starch granules were observed inside the parenchymal cell lumen of bamboo specimen heat treated at 200 °C for 6 h. And with the increase of heat treatment temperature and time, the content of cellulose and hemicellulose decreases gradually while relative content of lignin increases due to its better thermal stability. Accordingly, the surface wettability decreases due to the changes of the surface functional groups and micro-morphologies. Under the condition of oil heat treatment at 160 °C for 2 h, the compressive strength parallel to grain of bamboo samples reach the maximum of 109.52 MPa. With further increase of heating temperature, the corresponding compressive strength decreases. The resulted bending strength and MOE both display similar changing trend. However, the optimal parameter is at 180 °C for 2 h, with the highest bending strength and MOE values of 142.42 MPa and 12,373.00 MPa, respectively. Finally, the decay resistance and anti-mildew property are dramatically enhanced with increased heat treatment temperature and time. All the corresponding changing mechanisms are investigated in depth and in detail. Our results provide comprehensive process parameters and micro-mechanism for the performance of oil heat treatment of bamboo, which can be used to guide the actual production.

Characterization and electrochemical analysis of silver electrodeposition in ChCl–urea deep eutectic solvents

Electrochemical reduction behaviours of silver ions in ChCl–urea deep eutectic solvents (DESs) were investigated by cyclic voltammetry. The results showed that equilibrium potential Eeq of the electrode system in ChCl–urea DESs was −0.112 V. The Tafel curve was used to obtain the exchange current density j0 = 2.92 ± 0.2 cm−2 and the transfer coefficient α = 0.16 ± 0.2. The nucleation and growth mechanism of silver were studied by cyclic current method. The results showed that electrodeposition consisted of two processes, 3D nucleation with diffusion-controlled growth j3D-dc(t) and a small amount of water in the reduction jWR(t). By calculating the percentage of different charge densities of j3D-dc and jWR, the contribution rate of different processes to the total current was analysed. With the increase in potential, the charge in water reduction process decreased, while the charge in silver 3D nucleation process increased. Scanning electron microscope and energy spectrum scanning were used to characterize the surface and section micro-morphologies of silver coating. The results showed that silver grew dendritically at −0.97 V, and the thickness was 22.98 μm. The results of X-ray photoelectron spectroscopy showed that silver coating was composed of Ag2O and Ag.

Experimental study on short electric arc machining of Ti6Al4V in terms of power output characteristics

As a new development direction for electrical discharge machining, short electric arc machining (SEAM) has emerged as an efficient machining technology for difficult-to-machine conductive materials, as this method is not limited by the strength, hardness, toughness, and other mechanical properties of metal materials. In this paper, the pulse voltage, DC voltage, and DC superimposed pulse (comb) voltage were used as energy inputs to study the SEAM of Ti6Al4V. Experiments were carried out with a graphite tube material as the tool and Ti6Al4V as the workpiece. The current waveform of the experimental process was analyzed; the material removal rate (MRR) and tool wear ratio (TWR) were calculated; and the surface and cross-sectional micro-morphologies and micro-hardness were studied. The experimental results showed that the comb voltage input mode yields the highest machining efficiency, with an MRR of 19,620 mm3/min and a maximum current of 1475 A, which was 35 times higher than that in the conventional pulse voltage input mode. Moreover, the processing was more stable; however, the surface quality was poor. The study results are expected to help select an appropriate processing method depending on the process requirements.

Investigation of micro-surface potential of coals with different metamorphism by AFM

Micro-surface potential of different coals (Reflectance range; Ro = 0.90% ~ 2.47%) was measured by atomic force microscopy (AFM) at five scanning scales, attempting to gain clearer insights into the electrical characteristics of coal micro-surface. Results show that coal micro-surface potential is affected by metamorphism and has significant scale effect. Generally, the distribution of coal micro-surface potential is heterogeneous (showing Gaussian distribution) and the potential is mostly positive, which can reach more than 800 mV. The potential difference of various points measured in certain scanning area can exceed 100 mV. The mean potential is more likely to decrease with increasing scanning scale, while the variance increases obviously. Analysis indicates that the scale effect is mainly due to the heterogeneity of coal and the metamorphism can affect surface potential by changing functional groups, distribution of surface microstructures, micro-morphologies and internal connectivity. Moreover, the contribution of coal micro-surface potential to electromagnetic radiation (EMR) produced by coal fracture has been discussed, revealing that the existence of coal micro-surface potential especially its scale effect provides a physical basis for the generation of EMR.

Effects of Different Microstructured Surfaces on the Osseointegration of CAD/CAM Zirconia Dental Implants: An Experimental Study in Rabbits.

To assess different microstructured surfaces created by sandblasting and acid etching in an effort to optimize the osseointegration performance of dental zirconia implants with an optimized surface. Sixty CAD/CAM zirconia implants were divided into four groups. The control group had no surface treatment after sintering. The other groups had three different types of surface modifications: sandblasting; sandblasting and etching with hydrofluoric acid; and sandblasting and etching with an experimental hot etching solution composed of methanol, 37% hydrochloric acid, and ferric chloride, heated to 100°C and applied for 60 minutes. Commercially available titanium implants with sandblasted and etched surfaces and identical dimensions were employed as a positive control. Surface micromorphologies of implants from the five groups were evaluated. The osseointegration performance of all the implants was assessed in adult New Zealand rabbits based on microcomputed tomography (micro-CT) and histologic analysis. Sandblasting and acid etching with hot etching solution or hydrofluoric acid exhibited moderately rough surfaces with microstructures in both microscale and nanoscale. The sandblasting and etching with hydrofluoric acid group showed the highest surface roughness. Micro-CT revealed a significantly lower mean bone volume/total volume for the control group compared with the other four groups (P < .05). Among the groups, the sandblasting and hydrofluoric acid etching group was the highest, significantly higher than the titanium implant and sandblasting groups (P < .05). The sandblasting and etching with hot etching solution (P = .006) group also showed a significantly higher bone volume/total volume value than the titanium implant group. Histologic analysis revealed significantly higher boneto- implant contact for implants with modified surfaces compared with a sintered surface (P < .05), and no significant difference was found with respect to the sandblasted and etched titanium implants. The microstructured surfaces created by sandblasting and acid etching show osseointegration comparable to that of commonly used titanium implants.

Nickel-free sealing technology for anodic oxidation film of aluminum alloy at room temperature

Different additives were added into the potassium fluorozirconate solution to prepare different nickel-free sealing reagents, with which the anodic oxidation film of aluminum alloy was sealed at room temperature. The phosphor chromic acid weight loss method was used to evaluate the sealing effects. Using electron scanning microscopy (SEM), the surface and cross-sectional micro-morphologies of the anodic oxidation films sealed by different fluorozirconate sealants were observed. The position and state of zirconium element distribution in the film hole were investigated by the further quantitative and distribution analysis of Zr element. This study provides an experimental evidence for the theoretical studies of fluorozirconate-sealed anodic oxidation films. It is shown that the fluorozirconate has good sealing effects and has a wide prospect for sealing the aluminum alloy samples. Its products were highly corrosion resistant, and were filled in the openings of the micropores in the oxide film.

Properties of Ce0.85Sm0.15O2-δ-CuO electrolytes for intermediate-temperature solid oxide fuel cells

To improve the ionic conductivity of the common electrolyte Sm-doped CeO2 (SDC) for intermediate-temperature solid oxide fuel cells (IT-SOFCs) and to facilitate its production, we synthesized electrolyte materials SDC(Ce0.85Sm0.15O2-δ)-x mol %CuO (x = 0, 0.5, 1, 2) (named SDC, SDC + 0.5CuO, SDC + 1CuO, and SDC + 2CuO). The structural properties, surface micro-morphologies, and electrical properties of these four electrolyte materials were studied, as well as the performances of corresponding SOFCs. The results showed that all the materials had highly-crystalline CeO2 cubic fluorite structures and highly-dense ceramic electrolyte sheets. Adding an appropriate amount of CuO significantly reduced the grain-boundary resistance of SDC and improved its ionic conductivity. The SDC + 0.5CuO electrolyte showed the best ionic conductivity (σt = 0.088 Scm−1 at 800 °C), and the SOFC based on SDC + 0.5CuO had the highest output power, reaching a maximum power density of 380 mWcm−2 at 800 °C. In addition, the SOFC based on SDC + 0.5CuO exhibited good stability. The above results show that the optimal CuO amount was 0.5 mol% in our case, and SDC-CuO materials are promising candidates for use as electrolytes in IT-SOFCs.

Bio-based, nontoxic and flame-retardant cotton/alginate blended fibres as filling materials: Thermal degradation properties, flammability and flame-retardant mechanism

The effect of the blending amount of alginate fibres to cotton fibres on thermal stabilities, surface micromorphologies, flame-retardant and combustion properties of prepared cotton/alginate blended fibres were explored. The alginate fibres improved the thermal degradation properties at a higher temperature zone, showing in the increase of the residual chars. The alginate fibres enhanced flame-retardant properties and fire behaviors of prepared cotton/alginate blended fibres. The alginate fibres obviously decreased total heat release, peak heat release rate, total smoke production, CO2 production, and the released amount of inflammable volatiles. And the flame-retardant properties of cotton/alginate blended fibres can meet the requirements of filling materials for indoor furniture.

Novel aniline and haloaniline binary copolymer films for electro-emissive devices

In this study, sulfuric acid (H2SO4)-doped novel binary copolymer films using aniline and haloanilines as monomers, including aniline/o-fluoro-aniline (PFANI), aniline/o-chloro-aniline (PCANI), and aniline/o-bromo-aniline (PBANI), have been constructed for electro-emissive devices (EEDs). Significantly different electropolymerization behaviors, surface micromorphologies and infrared (IR) emissivity regulation ability are observed by these copolymer films. The results show that PFANI film exhibits the highest IR emissivity modulation capability. The nucleation process and surface morphology of copolymer films are explained by the theory of atomic electronegativity. High emissivity changes (△ε) of 0.113, 0.417 and 0.343 in the wavelength ranges of 3–5 μm, 8–14 μm, and 2.5–25 μm, respectively, are obtained by PFANI film. The EEDs based on PFANI films show promising applications in IR thermal control, and dynamic visible light and IR camouflage.