Fourier Transform Infrared Spectroscopy Results Research Articles

Depth of Cure, Mechanical Properties and Morphology of Dual-Cure Bulk-Fill Composites

This study evaluated selected structural and physical properties, such as degree of conversion (DC), Vickers hardness (VHN), and compression strength (CS), of three new dual-cure bulk-fill resin-based composites (RBCs; ACTIVA, HyperFIL, and Fill-Up) and compared them to those of a conventional RBC (Filtek Z250) at three clinically relevant depths. Samples (n=180) were prepared in three depths (2,4, and 6mm). Fourier-transform infrared spectroscopy (FTIR) analysis and VHN and CS tests were performed. The DC value was calculated by considering the relative change in the aliphatic C=C peaks. The fractured surfaces of representative samples were characterized using scanning electron microscopy (SEM). Data were statistically evaluated using two-way analysis of variance and post hoc Bonferroni tests (p<0.05). According to the VHN results, Filtek Z250 showed the highest bottom/top hardness ratio (97.94±1.01) at 2mm thickness and ACTIVA showed the lowest bottom/top hardness ratio (43.48±5.64) at 6mm thickness (p<0.001). According to the FTIR results, the DC decreased with increasing thickness in all materials (p<0.05). Filtek Z250 showed the highest (301±12.4 MPa) and ACTIVA exhibited the lowest (232±17.2 MPa) CS values at 2mm thickness (p<0.05). The lowest CS values were obtained for ACTIVA, and the highest values were obtained for Filtek Z250 for samples with thicknesses of 4 and 6mm, respectively (p<0.05). The structural features of restorative composites, such as the resin chemistry and filler type and content, and the operational parameters (i.e., material thickness and curing conditions) strongly affect crosslinking reactions and thus the DC, VHN, and CS values.

Physical Properties of Fast-Growing Wood-Polymer Nano Composite Synthesized through TiO2 Nanoparticle Impregnation.

Mangium (Acacia mangium Willd.) is a fast-growing wood that is widely grown in Indonesia. The impregnation method is needed to improve the qualities of the wood. In this study, TiO2 nanoparticle (79.17 nm) was produced using the hydrothermal method. The purpose of this study was to analyze the effect of TiO2 nanoparticle impregnation on the density and dimensional stability of mangium and the effectiveness of the presence of TiO2 nanoparticle in wood in degrading pollutants. The mangium samples (2 cm × 2 cm × 2 cm) were placed inside impregnation tube. The impregnation solutions included water (untreated), 1% TiO2 nanoparticle, and 5% TiO2 nanoparticles. The samples were analyzed for density, weight percent gain (WPG) dan bulking effect (BE). Samples were also analyzed by X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). TiO2 nanoparticle resulted in an increase in density, WPG, and BE-treated mangium. Based on XRD and FTIR results, TiO2 nanoparticle was successfully impregnated into mangium wood. Scanning electron microscopy–energy-dispersive X-ray spectroscopy analysis indicated that TiO2 nanoparticle covered the surface of the wood cells. The TiO2-impregnated mangium wood has a higher photocatalyst activity than untreated, indicating better protection from UV radiation and pollutants.

Succeeded high-temperature acid hydrolysis of granular maize starch by introducing heat-moisture pre-treatment

Acid hydrolysis is a crucial method for modifying granular starch, but it is often conducted at low temperatures (below 55 °C) for an extended period of time to prevent crystallinity loss. The high-temperature acid hydrolysis (HTAH) behavior of heat-moisture treated (HMT) starch at 69 °C was investigated for the first time. The crystalline structure of starch was enhanced by HMT, confirmed by its rheological, thermal, and infrared Fourier transform spectroscopy results. The amorphous structure of HMT starch was preferentially hydrolyzed with high reactivity, related to a fast hydrolysis stage (4.17 × 10−2 min−1). And the crystalline flakes were separated from starch granules, accompanied by strengthened molecular interactions. HMT starch was transformed from 16.98 μm granules to 158 nm thick and 2.57 μm broad flakes with a 6.40 % increase in crystallinity after 40 min of hydrolysis. For native starch, the HTAH destroyed the crystalline structure due to gelatinization, resulting mainly gelatinous aggregates. These evidenced that the hydrolysis of granular starch was successfully performed at a relatively high temperature by introducing heat-moisture pre-treatment. This study could provide a novel perspective on the combination of increasing temperature and pre-treatment for granular starch hydrolysis intensification design, as well as a strategy for efficiently preparing small-sized crystalline starch, which has promising applications in Pickering emulsion and material filler.

Activation of zirconia nanophosphors with Eu3+ to demonstrate multifunctional optical applications

Pristine ZrO2 and Eu3+ activated ZrO2 nanophosphors were synthesized by urea assisted solution combustion method. The synthesized nanophosphors were characterized by Powder X-ray diffraction (PXRD), Field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and photoluminescent (PL) spectroscopy for their structural, morphological, surface, vibrational and luminescent studies. The crystal structure and phase transformation were studied by PXRD which was supported well by XPS and FTIR results. FESEM studies reveal the porous morphology due to the combustion synthesis. XPS results reveal that activator Eu was predominantly present in the +3 oxidation state in the nanpohosphor. PL emission spectra of Eu3+ activated zirconia show characteristic reddish emission corresponding to 5D0→7FJ (J = 0, 1, 2, 3, and 4) transitions of Eu3+ ion. Photometric parameters were calculated to check the possible application of the nanophosphors for solid-state lighting. The high color purity ∼94% of the synthesized phosphors indicates their application in phosphor-converted white light-emitting diodes (pc-wLEDs). The fluorescence intensity ratio (FIR) of non-thermally coupled levels 5D0→7F2 and 5D0→7F3 were used to calculate the temperature. At 623 K, a maximum relative and absolute sensitivity of 0.11% K−1, and 0.76% K−1 was observed. The possible anti-counterfeiting application of ZrO2:Eu3+ has been tested using a standard screen-printing procedure. The high contrast fingerprints of the synthesized phosphor taken under near-ultraviolet (n-UV) light indicate that the synthesized phosphor can be used for latent fingerprinting applications. All these results indicate that Eu3+ activated zirconia has the potential to be used as multifunctional material.

Amine‐modified graphene enhanced mechanical properties and catalytic effect on imidization of polyimide composite films

AbstractThe degree of the imidization reaction determines the properties of polyimide (PI) obtained by the thermal curing process. In this paper, amine‐modified graphene (N‐GO) was designed by integrating pyridine structure with graphene and acting as a catalyst to promote the imidization reaction of PI. Fourier‐transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) were then used to confirm the morphology and structure of N‐GO. The catalytic effect of N‐GO in imidization reaction was obtained by FTIR and subsequently characterized by differential scanning calorimetry (DSC) and water contact angle (WCA). Surprising results suggest that the agglomeration of N‐GO can also contribute to solid‐phase reactions in imidization reactions. Lastly, the results of mechanical property tests, thermogravimetric analysis (TGA), and FTIR demonstrated that the composite films showed excellent tensile strength (176.2 MPa) and thermal stability (513.0 °C); at the same content, only 0.5% of N‐GO addition reduced the imidization temperature by 20°C, exhibiting remarkable enhancement effects. This research is a valuable solution to the problem in performance caused by low‐temperature curing agent residues in films, and it is expected to be used in the microelectronics field.

"One-pot" preparation of aminated carbon nanotube-modified magnetic nanoparticles and their application to the quantification of phenoxyacetic acid herbicides in cereal and vegetable samples

有效萃取是分析复杂样品中苯氧羧酸类除草剂(PAs)残留的关键步骤。为此,该文利用“一锅法”水热技术快速、简便地制备了氨基碳纳米管功能化磁性纳米粒子(NH2-CNTs@M)并作为磁固相萃取(MSPE)的萃取介质,用于萃取谷物和蔬菜样品中痕量PAs。研究利用多种手段对NH2-CNTs@M的形貌、尺寸、磁性性质等进行了表征,结果表明Fe3O4的粒径、氨基化碳纳米管的直径以及NH2-CNTs@M的磁饱和值分别为30 nm、40 nm和44.2 emu/g。详细考察了制备条件和萃取参数对NH2-CNTs@M/MSPE萃取性能的影响,结果表明,NH2-CNTs@M/MSPE可通过π-π、疏水和氢键作用有效富集目标化合物,最佳萃取条件如下:吸附剂用量为30 mg,解吸溶剂为含2.0%(v/v)甲酸的乙腈溶液,吸附时间和解吸时间分别为8.0 min和3.0 min,基底pH值为6.0,不调节基底的离子强度。将NH2-CNTs@M/MSPE与高效液相色谱-二极管阵列检测技术(HPLC-DAD)联用,建立了谷物和蔬菜中PAs的灵敏检测方法。谷物和蔬菜基质中苯氧羧酸类除草剂的检出限(LOD, S/N=3)分别为0.32~1.6 μg/kg和0.53~1.6 μg/kg,定量限(LOQ, S/N=10)分别为0.94~4.8 μg/kg和1.6~4.8 μg/kg。在两种实际样品中不同浓度下的加标回收率分别为73.1%~112%和72.3%~113%。与现有方法相比,所建方法具有萃取速度快、灵敏度高和环境友好等特点。

Martian and lunar sulfur concrete mechanical and chemical properties considering regolith ingredients and sublimation

• Sulfur sublimation rate at vacuum is 8000 times lower at −60 °C than at 20 °C. • Sulfur concrete permeability decreases strongly with higher sulfur content. • Sulfur concrete porosity does not change much with varying sulfur content. • The presence of alumina in sulphur concrete results in higher porosity. • Alumina and iron oxide together in sulphur concrete leads to lower porosity. Space constructions require unique materials suitable for the harsh conditions in space. Sulfur concrete (SC) is one of the most promising materials for such applications. However, the behavior of sulfur concrete in a vacuum, microgravity, and different temperature conditions and its chemical changes has not been well established yet. This study investigated the effect of vacuum, sulfur content, and compaction (trowel effect) on mechanical and hydro-mechanical properties. Moreover, this study assesses the impact of chemical reactions of aluminum and iron oxides with molten sulfur on the sulfur concrete’s mechanical properties via X-ray diffraction analysis (XRD), scanning electron microscopy (SEM-EDS), and Fourier-transform infrared spectroscopy (FTIR). The predictions from this research show that the sublimation rate under vacuum conditions at very low temperature (−60 °C) can be reduced nearly 8000 times compared with that at 20 °C according to the vapor pressure-sublimation rate relationship. In addition, mechanical experimental tests show that a slight increase in sulfur content dramatically reduces the permeability of sulfur concrete. On the other hand, the porosity is not much affected by the sulfur content. Moreover, sample compaction leads to a significant reduction and increment of the hydro-mechanical and mechanical strength, respectively, indicating the trowel's positive effect. Chemically, sulfur dioxide reacts with alumina and iron oxide via chemical adsorption, and then reaction with molecular oxygen produces S O 4 2 - confirmed by SEM-EDS, XRD, and FTIR results. The presence of alumina increases the sample porosity, although, together with iron oxide, another mineral, namely A l 2 F e 2 S O 4 6 ( H 2 O ) 12 . 6 H 2 O (Aluminocoquimbite), is formed resulting in a lower porosity. To conclude, we have shed light on sulfur concrete properties and preparation processes in unconventional environments and we have shown how different unknown parameters affect the mechanical and chemical properties of the sulfur binder.

Synthesis and characterization of silver-indium and antimony selenide: role in photocatalytic degradation of dyes

These days, water contamination poses a severe threat to the ecosystem and demands immediate care. This study examined the need to reduce water pollution using clean, renewable energy (solar light irradiations) for the degradation of Congo red by Silver-indium and antimony selenide with chemical composition AgInSbSe3. The sample was fabricated through a hydrothermal technique. The synthesized sample was characterized through X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and Ultraviolet-Visible spectroscopy. The X-ray diffraction confirms crystalline structure of the synthesized sample. The SEM analysis reveals irregular grains and exhibits a very small inter-particle distance. SEM provides the morphology of the synthesized sample, the grain size of the synthesized sample was 0.58 μm. FTIR results revealed specific absorption bands in the range of 400–4000 cm−1; optical properties are studied through UV-Vis-spectroscopy. The synthesized sample has 1.97 eV bandgap which is suitable for degradation of organic pollutants. The photocatalytic activity of the material is checked by degrading the Congo red dye under direct sunlight irradiation and for the 75 min illumination 77.8% degradation efficiency is attained.

Characterization of the mural blue paintings in ornamental motif of Ali Qapu palace in Isfahan, Iran, using spectroscopic and microscopic methods (a case study)

This study aimed to investigate the painting technique and identify the blue pigments used in the ornamental motif of mural paintings of Ali Qapu palace as the seat of rule of Shah Abbas I Safavid and part of Naghsh-e Jahan square world heritage site in Isfahan. For this investigation, five samples collected from the murals located at different sections of the palace were studied by polarized light microscopy (PLM), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, and energy-dispersive X-ray spectroscopy (EDS). Also, the Fourier self-deconvolution was applied to the FTIR spectra of chloroform extract of the paint layer to identify the type of binder used in the painting. The results showed that the blue pigment used in all five samples is natural ultramarine (lapis lazuli). In four of the five samples, huntite has been used as the filler in the priming layer. However, the results suggest that huntite has also been combined with ultramarine to create lighter tonalities. The findings indicate the use of three different priming methods in creating the ornamental motif murals: creating a priming layer with iron-rich soil, creating a priming layer with huntite as the filler, and placing an organic layer underneath the huntite priming layer. This shows the variety of priming techniques used in creating the ornamental motif murals of Ali Qapu. Furthermore, FTIR results indicate the possible use of the tempera and oil technique in the murals.

The Role of Zeolite Structure in Its β-cyclodextrin Modification and Tetracycline Adsorption from Aqueous Solution: Characteristics and Sorption Mechanism.

Modification of zeolites with organic compounds is of increasing interest due to their significant potential in removing emerging pollutants from water. In this work, zeolites from fly ash with three different structure types, NaX (faujasite), NaA (Linde A) and NaP1 (gismondine), were modified with β-cyclodextrin (β-CD), and their adsorption efficacy towards tetracycline (TC) antibiotic in aqueous solutions have been studied. To assess the effect of modification on the zeolites, they were subjected to chemical, mineralogical and surface analyses using X-ray diffraction (XRD), thermogravimetry (TG), scanning electron microscope (SEM), N2 adsorption/desorption isotherm, Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The maximum adsorption capacity for NaX-CD, NaA-CD and NaP1-CD was around 48, 60, and 38 mg/g, respectively. The fastest adsorption rate was observed for NaP1-CD, which achieved adsorption equilibria after 200 min, while for NaX-CD and NaA-CD it was established after around 24 h. The kinetic data were best described by the Elovich model, followed by pseudo-second order, while the Sips and Redlich–Peterson models were the most suitable to describe the adsorption isotherms. Based on the adsorption data as well as FTIR and XPS results, TC adsorption efficacy is strongly related to the amount of CD attached to the mineral, and hydrogen bonding formation probably plays the major role between CDs and adsorbate.

Cold-Pressed Pomegranate Seed Oil: Study of Punicic Acid Properties by Coupling of GC/FID and FTIR.

Over the last decades, we have witnessed an increasing interest in food-related products containing vegetable oils. These oils can be obtained either by extraction or by mechanical pressing of different parts of plants (e.g., seeds, fruit, and drupels). Producers of nutraceuticals have ceaselessly searched for unique and effective natural ingredients. The enormous success of argan oil has been followed by discoveries of other interesting vegetable oils (e.g., pomegranate oil) containing several bioactives. This work describes the pomegranate fruit extract and seed oil as a rich source of conjugated linolenic acid as a metabolite of punicic acid (PA), deriving from the omega-5 family (ω-5). Through the chemical characterization of PA, its nutritional and therapeutic properties are highlighted together with the physiological properties that encourage its use in human nutrition. We analyzed the composition of all fatty acids with beneficial properties occurring in pomegranate seed oil using gas chromatography (GC) with flame-ionization detection (FID) analysis combined with Fourier transform infrared spectroscopy (FTIR). Pomegranate seed oil mainly consists of 9,11,13-octadic-trienoic acid (18:3), corresponding to 73 wt % of the total fatty acids. Nine components were identified by GC in PSO, varying between 0.58 and 73.19 wt %. Using midinfrared (MIR) spectroscopy, we compared the composition of pomegranate seed oil with that of meadowfoam seed oil (MSO), which is also becoming increasingly popular in the food industry due to its high content of long chain fatty acids (C20-22), providing increased oil stability. From the results of FTIR and MIR spectroscopy, we found that punicic acid is unique in PSO (73.19 wt %) but not in MSO.

Synthesis of Green and Red-Emitting Polymethyl Methacrylate Composites Grafted from ZnAl2O4:Mn-Bonded GO via Surface-Initiated Atom Transfer Radical Polymerization.

A novel dual green and red-emitting photoluminescent polymer composite ZnAl2O4:Mn-bonded GO/polymethyl methacrylate (PMMA) was synthesized in a single-step reaction by surface-initiated atom transfer radical polymerization (SI-ATRP). The polymer chain was surface-initiated from the ZnAl2O4:Mn/GO, and the final products have a homogenous photoluminescent property from ZnAl2O4:Mn and better mechanical properties strengthened by graphene oxide (GO). The morphologies of ZnAl2O4:Mn/GO and the polymer composites were verified by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). X-ray diffraction analysis (XRD) revealed the two valence states of Mn (Mn2+, Mn4+) existing in the ZnAl2O4 host lattice, while Fourier-transform infrared spectroscopy (FTIR) spectra proved the transference of the active group, C-Br, from the initiator to the monomer during the polymerization. Gel permeation chromatography (GPC) shows the narrow dispersity of polymer composites fabricated through SI-ATRP. The SEM and FTIR results show the successful ‘graft’ of the polymer chains from the surface of ZnAl2O4:Mn/GO. The dual green and red-emitting polymer composites were synthesized, confirmed by the photoluminescence (PL) and photoluminescence excitation (PLE) results.

Preparation and characterization of slow dissolving linezolid salts for direct pulmonary delivery

Linezolid is a second line antituberculosis which is currently available in the form of oral and parenteral dosage form. Compared to oral and parenteral dosage forms, the direct delivery of antituberculosis drugs to the lungs has proven to be better in maintaining the desire drug concentration. The present investigation was aimed to prepare the slow dissolving salts of linezolid using with long chained fatty acids – lauric acid(LA), palmitic acid (PA) and stearic acid (SA) as counterions for direct pulmonary delivery. The rotary vacuum evaporator and lyophilizer were used sequentially to evaporate the solvent in which the drug and counterions were dissolved. The results of DSC (differential scanning calorimetry) study, microscopic analysis and PXRD (powder X-ray diffraction) study proved the formation of novel crystalline material due to reaction between drug and counterions. The results of FTIR (Fourier transform infrared spectroscopy) and 1H NMR (Nuclear magnetic resonance) confirmed the transfer of hydrogen ion from the carboxylic acid group (–COOH–) of the counterions to the amide (–CONH–) group of the drug and thus the salt formation. The in-vitro dissolution study performed in the simulated lung fluid (SLG), the prepared salts exhibited significantly slower dissolution compared to pure drug and physical mixture. MMAD (Median mass aerodynamic diameter) for all the prepared salt was found to be less than 5 μm which proved ability of the prepared salt particles to reach deep affected area. MIC (Minimum inhibitory concetration) study indicated no significant difference in the MIC value of the pure drug and the prepared salts.

Evaluation of CNTs and SiC Whiskers Effect on the Rheology and Mechanical Performance of Metakaolin-Based Geopolymers

Despite geopolymers having emerged as a more sustainable alternative to Portland cement, their rheological properties still need to be thoroughly investigated, aiming at the material’s applicability. Additionally, studies that evaluated the fresh state of geopolymer composites with nanomaterials are scarce. Thus, two metakaolin-based geopolymer systems were reinforced with nanomaterials with a similar geometry: carbon nanotubes (CNT) and silicon carbide whiskers (SCW). The nanomaterials incorporation was assessed by rotational rheometry (conducted up to 110 min), isothermal calorimetry, compressive strength after 7 and 28 days, and the microstructure was investigated using X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). CNT and SCW incorporation (0.20 wt.%) did not significantly affect the yield stress and viscosity of the R2-group (based on metakaolin type 2), while increasing the rheological parameters up to 56.0% for the R1-group (based on metakaolin type 1). Both additions modified the reaction kinetics. Increments of up to 40.7% were observed in the compressive strength of geopolymer pastes with the incorporation of a SCW content of 0.2 wt.%. XRD and FTIR results suggest similar structural modifications between precursors. Nevertheless, R2 showed substantial transformations while the R1 group exhibited anhydrous material that can react over time. Overall, incorporating CNT and SCW contributed to higher mechanical increments on systems with average mechanical strength (R1) compared to systems with higher potential mechanical performance (R2).

Exploration for UV Aging Characteristics of Asphalt Binders based on Response Surface Methodology: Insights from the UV Aging Influencing Factors and Their Interactions

• Provide a new insight for exploring the UV aging mechanism of asphalt binders. • Explore the effects of some potential influencing factors and their interactions on the UV aging characteristics of asphalt binders with RSM method. • Characterize the micro properties of asphalt binders irradiated by UV light with different wavelengths through some microscopic experiments. To explore the UV aging characteristics of asphalt, effects of potential influencing factors as well as their interactions on asphalt’s properties were investigated with the aid of Response Surface Methodology (RSM). Four influencing factors, including ultraviolet irritation wavelength, irritation intensity, asphalt film thickness, and aging temperature, were selected as the response variables of RSM. And complex shear modulus aging index G*AI , DSR function aging index DAI and fatigue factor aging index FAI were selected as the responses’ values. Then, the Central Composite Design (CCD) model of RSM was adopted to establish the statistical models to analyze the effects of different variables on asphalt’s UV aging behaviors. On this basis, aging degree of asphalt under ultraviolet irradiation with different wavelengths was analyzed emphatically with Fourier Transform Infrared Spectroscopy (FTIR) and Atomic Force Microscope (AFM) tests. Meanwhile, method for speeding up the efficiency of asphalt UV aging test by reducing the asphalt film was also proposed. Test results show that UV aging rate of asphalt increases gradually with the decreasing of asphalt film and the increasing of radiation intensity and aging temperature; among them, the effect of asphalt film thickness is the greatest, while that of aging temperature is the smallest. In addition, radiations with different wavelength have different effects on UV aging behaviors of asphalt, and asphalt irradiated by UV-340 to UV-360 has the highest aging degree, which can be further proved by FTIR and AFM test results. Interactions between different factors will also affect the UV aging characteristics of asphalt, and the results are related to the types of asphalt. However, interaction between UV radiation wavelength and asphalt film thickness all have the significant effects on the UV aging behaviors of base asphalt and SBS modified asphalt. Decreasing the asphalt film thickness can effectively increase the UV aging rate of asphalt. Thus, the aging time can be appropriately reduced on the basis of thinner asphalt film, so as to improve the test efficiency. And finally, it can be found that two processes may exist during the UV aging process of asphalt, namely molecular excitation process and chemical bond breaking process. Under the two actions, unstable chemical bonds in asphalt will reach the excited state or break, and combine easily with the oxygen atom and then generate some polar oxygen-containing functional groups, thus causing the decline of asphalt’s properties.

Efficient separation of magnesite and quartz using eco-friendly Dimethylaminopropyl lauramide experimental and mechanistic studies

To achieve efficient separation of magnesite from quartz, a novel cationic collector—Dimethylaminopropyl lauramide (DPLA), was introduced into the quartz-magnesite reverse flotation system. The flotation performance and adsorption mechanism of DPLA on the minerals surfaces were investigated by micro-flotation tests, contact angle measurements, zeta-potential measurements, Fourier transform infrared spectroscopy (FTIR) analysis, Atomic force microscope (AFM), and Density functional theory (DFT) calculation. The single mineral micro-flotation results showed that when DPLA concentration was 25 mg/L, 94.6% of quartz was removed and 97.14% of magnesite was recovered under natural pulp pH. Further, the artificial mixed mineral flotation results demonstrated that DPLA had a superior selectivity for quartz and the concentrate with 44.36% MgO grade and 98.69% MgO recovery was obtained at 25 mg/L DPLA, and the separation efficiency was 89.52%. Contact angle measurement results suggested that the hydrophobicity of quartz surface increased significantly after treatment with DPLA and indicated the interaction between DPLA and quartz was stronger than that with magnesite. The results of zeta-potential measurements, FTIR, AFM, and DFT calculation revealed that the adsorption of DPLA on the quartz surface was mainly by the electrostatic force and hydrogen bonding interactions. In addition, the advantages of DPLA as the collector were analyzed in terms of environmental aspects and economics. DPLA has great potential for industrial application to effectively separate magnesite from quartz.

Production of pumice-containing nanofibers by electrospinning technique

Abstract The scope of the study involves identifying the optimal means to effectively use the electrospinning technique to obtain pumice-containing nanofibers. Nanofiber containing pumice in a solution was electrospun to obtain smooth, cylindrical, bead-free, and ultrafine nanomaterials. The study also analyzed the molecular [Fourier transform infrared spectroscopy (FTIR)], thermal [differential scanning calorimetry (DSC)], zeta potential, size, polydispersity index [dynamic light scattering (DLS)], and surface [scanning electron microscope (SEM)] parameters of the pumice-containing nanofibers having JP6 (applied voltage: 6 kV) and JP12 (12 kV) properties. While the distance (10 cm), flow rate (0.8 mL/h), and other parameters of the electrospinning process were fixed, two different voltages were applied to obtain the pumice-containing nanofiber. The average diameter of the nanoencapsulated pumice produced at 6 kV was defined as 98.6 nm in gelatin nanomats with 31.8 nm. The average diameter of the nanocapsule pumice produced under a 12 kV voltage was found to be 85.8 nm, and the average diameter of the nanomats (non–nanoencapsulated) was 35.2 nm. The average zeta potential values of the pumice-containing nanofiber were also determined in the nanosize range. The JP6 and JP12 PDI values were determined as 0.165 and 0.566, respectively. Peaks characteristic of pumices as defined in the literature were observed in the FTIR results, while DSC analysis results revealed strong endo- and exothermic peaks. As a result of this study, it has been proved that pumice can be reduced to nanosize with the electrospinning technique and it is nanoencapsulated in nanofiber. When the obtained pumice-containing nanofiber was examined, it was determined that the surface area of the nanofiber was large and resistant to thermal heat.

Study on properties and biocompatibility of poly (butylene succinate) and sodium alginate biodegradable composites for biomedical applications

Providing better biodegradable materials for medical applications has always been an important premise for improving the therapeutic effect of clinical diseases. The Poly (butylene succinate) (PBS) and Sodium alginate (SA) composites were prepared using melt blending technique. Fourier transform infrared spectroscopy (FTIR), scanning electron microscope-energy dispersion spectrum (SEM-EDS), mechanical properties, water contact angle, thermal properties, and in vitro degradation and cytotoxicity tests were determined to evaluate the properties of the composites with a varied SA proportion of 5%, 10%, 15%, and 20%. The FTIR and SEM-EDS results confirmed the successful preparation and microphase distribution of the composites. With the increasing in SA loading, the distribution of the filler became unevenly gradually from evenly, the Young’s modulus increased first and then decreased, the tensile strength and elongation at break decreased gradually, the hydrophilicity, in vitro biodegradability increased, thermostability decreased, and the Tm, Tg, and crystallinity of the composites did not change significantly. The composite with 10% SA loading has uniform dispersion of the filler, the highest Young’s modulus (1091.21 MPa), mild hydrophilicity (θ = 88.40°), an adequate thermal processing temperature range (110 °C–200 °C), and has good biodegradability and biocompatibility with no significant deleterious impact on the cell membrane, lysosomal membrane, cell proliferation, cell apoptosis, cytoskeleton, or intracellular reactive oxygen species levels. It can be used as a biodegradable material for medical applications such as suture anchors.

The effects of additives on anti-wear properties of lubricating grease formulated from waste engine oil

The goal of this study was to study the anti-wear properties of grease formulated from waste engine oil (WEO) when additives are added. There were two types of grease formulated namely sodium and fumed silica (FS) greases. The greases were formulated using a weight percentage ratio with and without the addition of additives before the attributes of consistency, FTIR (Fourier transform infrared spectroscopy), and anti-wear analysis were conducted. Results showed that the addition of additives did not affect the properties of the formulated grease except for that of sodium grease as demonstrated by the FTIR result. Sodium grease produced a spectrum with a peak in the region < 600 cm−1 when analyzed using FTIR. The corrosiveness of the grease toward the copper strip was also low, as determined by class 1 corrosiveness. The addition of additives resulted in no improvement in the anti-wear properties of the grease as the coefficient of friction (COF) was low for the grease without additives than for the grease with additives. However, the addition of additives can reduce the wear scar diameter of the greases. Based on the findings of this investigation, it was found that the addition of additives did not alter the properties of the greases or improve the anti-wear properties of the greases except for the wear scar diameter.

Apatitic calcium phosphate/montmorillonite nano-biocomposite: in-situ synthesis, characterization and dissolution properties

Recently, calcium phosphate/montmorillonite composites have received attention as a synthetic bone substitutes. In this study, apatitic calcium phosphate/Montmorillonite nano-biocomposites were in-situ synthesized at 22 °C by reaction between calcium hydroxide and orthophosphoric acid in the presence of different contents of montmorillonite (MNa). Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Brunauer–Emmett–Teller (BET) surface areas were used to characterize the prepared powders. The XRD results show that the composites prepared with 2 and 5 wt% MNa and sintered at 900 °C, show the formation of hydroxyapatite (HAP) structure, whereas that prepared with 10 wt% MNa leads to the formation of β-tricalcium phosphate (β-TCP) structure. The HAP structure decomposes at 1000 °C and leads to the formation of biocomposite containing HAP, β and α-TCP. However, β-TCP composites show thermal stability. FTIR and structural refinement results show the incorporation of clay ions into the apatitic structure causing changes in the crystal structure of the formed calcium phosphate phases. The changes in the composition and structure lead to an increase in the dissolution rate of HAP and a decrease in that of β-TCP.