And 3-aminopropyltriethoxysilane Research Articles

Ti3C2Tx MXene-assisted solar-driven CO2 adsorption and photothermal regeneration over mesoporous SiO2

Due to the high energy consumption associated with regenerating adsorbents with high carbon dioxide adsorption capacity, utilizing renewable solar energy as an alternative to traditional thermal energy for photothermally regenerating adsorbents is a feasible approach. In this research, a solar-induced regeneration technique has been formulated, employing fumed silica as the framework, MXene as the photothermal conversion component, and (3-aminopropyl)triethoxysilane (APTES) as the site for carbon dioxide adsorption. The findings suggest that incorporating MXene can substantially enhance the photoresponsive and photothermal conversion properties of aminosilica. Beneath an brightening concentrated of 1 kW·m−2, aminosilica@MXene(7 wt%) reaches a maximum temperature of 76.8 °C, compared to only 53.4 °C when using aminosilica alone. Notably, aminosilica@MXene (7 wt%) achieves complete desorption at an illumination intensity of 2 kW·m−2. Through multiple cycling tests, aminosilica@MXene (7 wt%) demonstrates outstanding recyclability. As a result, using solar energy to power the adsorbent photothermal regeneration turns into a useful strategy for lowering the energy required for regeneration.

Generalized Multifunctional Coating Strategies Based on Polyphenol-Amine-Inspired Chemistry and Layer-by-Layer Deposition for Blood Contact Catheters.

Blood-contacting catheters play a pivotal role in contemporary medical treatments, particularly in the management of cardiovascular diseases. However, these catheters exhibit inappropriate wettability and lack antimicrobial characteristics, which often lead to catheter-related infections and thrombosis. Therefore, there is an urgent need for blood contact catheters with antimicrobial and anticoagulant properties. In this study, we employed tannic acid (TA) and 3-aminopropyltriethoxysilane (APTES) to create a stable hydrophilic coating under mild conditions. Heparin (Hep) and poly(lysine) (PL) were then modified on the TA-APTES coating surface using the layer-by-layer (LBL) technique to create a superhydrophilic TA/APTES/(LBL)4 coating on silicone rubber (SR) catheters. Leveraging the superhydrophilic nature of this coating, it can be effectively applied to blood-contacting catheters to impart antibacterial, antiprotein adsorption, and anticoagulant properties. Due to Hep's anticoagulant attributes, the activated partial thromboplastin time and thrombin time tests conducted on SR/TA-APTES/(LBL)4 catheters revealed remarkable extensions of 276 and 103%, respectively, when compared to uncoated commercial SR catheters. Furthermore, the synergistic interaction between PL and TA serves to enhance the resistance of SR/TA-APTES/(LBL)4 catheters against bacterial adherence, reducing it by up to 99.9% compared to uncoated commercial SR catheters. Remarkably, the SR/TA-APTES/(LBL)4 catheter exhibits good biocompatibility with human umbilical vein endothelial cells in culture, positioning it as a promising solution to address the current challenges associated with blood-contact catheters.

Ag Doping and rGO Coupling of TiO<sub>2</sub> within Polysiloxane Matrix for the Ecofriendly Development of High-Performance Cotton Fabric

In this work, TiO2 was applied to cotton fabric by a sol–gel-hydrothermal process. A combination of 3-(trihydroxysilyl) propyl methylphosphonate monosodium salt solution (TPMP) and (3-aminopropyl)triethoxysilane (APTES) was used as a matrix to enhance the interfacial interaction between TiO2 and surface of the cotton fibres. During the hydrothermal treatment, silver nitrate (AgNO3) or reduced graphene oxide (rGO) were added to produce Ag-doped TiO2- or rGO-coupled TiO2-coated textiles. The successful application of all investigated components on cotton fabric was confirmed by the analysis of SEM and EDS. The results of UPF determination and self-cleaning activity showed excellent performance of both studied nanocomposite coatings, whereas the use of rGO proved to be better than Ag.

XPS and ARXPS for Characterizing Multilayers of Silanes on Gold Surfaces

X-ray photoelectron spectroscopy (XPS) and angle-resolved XPS (ARXPS) characterization of surface layers resulting from the functionalization of polymers such as polyvinylchloride (PVC) modified with 3(mercaptopropyl)-trimethoxysilane (MPTMS) and (3-aminopropyl) triethoxysilane (APTES) is challenging due to the overlap in signals, deriving both from the substrate and the functionalized layers. In this work, a freshly cleaved, ideally flat gold surface was used as carbon-free model substrate functionalized with MPTMS and subsequently grafted with APTES. Avoiding the overlap of signals from carbon atoms present in the substrate, the signals in the C1s, O1s, Si2p, S2p and N1s high-resolution spectra could be assigned to the MPTMS/APTES functionalized layer only and the curve-fitting parameters could be determined. Quantitative analysis was in very good agreement with the expected stoichiometry of the functionalized layer, confirming the adopted curve-fitting procedure. In addition, it was found that one molecule of APTES grafted two MPTMS via silane groups. ARXPS allowed for determining the thickness of the functionalized layers: MPTMS thickness was found to be 0.5 (0.2) nm, whereas MPTMS + APTES thickness 1.0 (0.2) nm was in good agreement with Avogadro model calculations. This approach can be considered a powerful tool for characterizing functionalized surfaces of more complex systems by XPS.

Mussel-inspired superhydrophilic and antibacterial membranes for effective gravity-driven separation of oil-in-water emulsions

Substantial discharge of industrial oily wastewater calls for an efficient and sustainable treatment for resource recovery. Superwetting membranes offer a feasible approach to fractionate oil species and water from oily wastewater for addressing this technical challenge. In this study, we proposed a useful strategy for constructing a superhydrophilic membrane with superior antibacterial properties through rapid co-deposition of dopamine and 3-aminopropyltriethoxysilane (APTS) initiated by ammonium persulfate on the Cu nanoparticles-loaded porous PVDF substrate. The resultant superhydrophilic membrane yielded an underwater oil contact angle of 163.5°, enabling a fast and robust gravity-driven filtration for various oil-in-water emulsions with a separation efficiency of >99.9 %. Additionally, incorporating of Cu nanoparticles and polydopamine endowed the superhydrophilic membrane with superior antibacterial activity (100 % inhibition efficiency against Escherichia coli), and thereby remarkably enhancing the anti-biofouling performance. This study provides a viable approach to design high-performance membranes for separation of oil-in-water emulsions, with promising applications in the industrial and environmental sectors.

Enhanced mechanical properties and environmental stability of polymer-bonded magnets using three-step surface wet chemical modifications of Nd–Fe–B magnetic powder

This research focuses on the surface modification of Nd–Fe–B magnetic powder to enhance its thermal and oxidation resistance without compromising magnetic properties and to improve adhesion to the polymer binder for enhanced mechanical properties. A three-step surface modification process involving phosphatization treatment, tetraethyl orthosilicate (TEOS) application, and 3-aminopropyltriethoxysilane (APTES) grafting, was applied to the powder, which was then compounded with polyamide 12 and injection-moulded into cylinders and dog-bone-shaped tubes. The resulting magnets exhibited remanence (Br) of 487.6 mT, coercivity (Hci) of 727.7 kA/m, and energy product (BHmax) of 39.3 kJ/m3. The modified magnets demonstrated exceptional corrosion resistance and thermal stability, with less than 5% irreversible flux loss after exposure to hot water, temperature shock, and pressurised steam. Furthermore, the modified magnets displayed significantly higher tensile strength, elongation at break, and elastic modulus with improvements of 62%, 16.7%, and 19.9%, respectively, compared to the non-modified batch. Additionally, the modified batch showed a notable 52% increase in flexural stress during flexural testing. These findings underscore the potential of silane surface modifications in producing injection-moulded permanent magnets based on Nd–Fe–B alloy, extending their shelf life and enhancing their overall performance.

Bubble Wrap-like Carbon-Coated Rattle-Type silica@silicon Nanoparticles as Hybrid Anode Materials for Lithium-Ion Batteries via Surface-Protected Etching

Severe volumetric expansion (~400%) limits practical application of silicon nanoparticles as anode materials for next-generation lithium-ion batteries (LIBs). Here, we describe the fabrication and characterization of a conformal polydopamine carbon shell encapsulating rattle-type silica@silicon nanoparticles (PDA–PEI@PVP–SiO2@Si) with a tunable void structure using a dual template strategy with TEOS and (3-aminopropyl)triethoxysilane (APTES) pretreated with polyvinylpyrrolidone (PVP K30) as SiO2 sacrificial template via a modified Stöber process. Polyethylene imine (PEI) crosslinking facilitated the construction of an interconnected three-dimensional bubble wrap-like carbon matrix structure through hydrothermal treatment, pyrolysis, and subsequent surface-protected etching. The composite anode material delivered satisfactory capacities of 539 mAh g−1 after 100 cycles at 0.1 A g−1, 512.76 mAh g−1 after 200 cycles at 1 A g−1, and 453 mAh g−1 rate performance at 5 A g−1, respectively. The electrochemical performance of PDA–PEI@PVP–SiO2@Si was attributed to the rattle-type structure providing void space for Si volume expansion, PVP K30-pretreated APTES/TEOS SiO2 seeds via catalyst-free, hydrothermal-assisted Stöber protecting Si/C spheres upon etching, carbon coating strategy increasing Si conductivity while stabilizing the solid electrolyte interface (SEI), and PEI carbon crosslinks providing continuous conductive pathways across the electrode structure. The present work describes a promising strategy to synthesize tunable yolk shell C@void@Si composite anode materials for high power/energy-density LIBs applications.

Enhanced Photoelectric Properties of CsPbBr3 by SiO2 and TiO2 Bilayer Heterostructures.

CsPbBr3/SiO2 heterostructures were synthesized by the hydrolysis reaction of a mixture of CsPbBr3 nanocrystals (NCs) and (3-aminopropyl)triethoxysilane (APTS) in air. Compared with CsPbBr3 NCs, the CsPbBr3/SiO2 heterostructures exhibit stronger photoluminescence (PL) intensity, longer lifetime of PL (∼40.5 ns), and higher PL-quantum yield (PLQY, ∼86%). The carrier dynamics of CsPbBr3/SiO2 was detected by the transient absorption (TA) spectrum. The experimental results show that SiO2 passivates the surface traps of CsPbBr3 NCs and enhances the PL intensity. However, photoelectrochemical impedance spectra (PEIS) demonstrate that the impedance of CsPbBr3/SiO2 is higher than that of CsPbBr3 NCs, which reduces carrier transport and extraction. Because the application of CsPbBr3/SiO2 in optoelectronics is limited, CsPbBr3/SiO2/TiO2 heterostructures were synthesized by the further reaction of tetrabutyl titanate (TBT). The TiO2 coating can reduce the impedance of the CsPbBr3/SiO2. Importantly, ∼68% of the PL intensity of CsPbBr3/SiO2 is retained. Compared with CsPbBr3/SiO2 and CsPbBr3 NCs, the CsPbBr3/SiO2/TiO2 demonstrates faster carrier transport (κct = 2.4 × 109 s-1) and higher photocurrent density (J = 76 nA cm-2). In addition, CsPbBr3/SiO2/TiO2 shows good stability under (ultraviolet) UV irradiation, along with water stability and thermal stability. Therefore, the double protection approach can enhance the stability of CsPbBr3 NCs and tune the optoelectronic properties of CsPbBr3 NCs.

Annealing Ti3C2Tz MXenes to Control Surface Chemistry and Friction.

Although surface terminations (such as ═O, -Cl, -F, and -OH) on MXene nanosheets strongly influence their functional properties, synthesis of MXenes with desired types and distribution of those terminations is still challenging. Here, it is demonstrated that thermal annealing helps in removing much of the terminal groups of molten salt-etched multilayered (ML) Ti3C2Tz. In this study, the chloride terminations of molten salt-etched ML-Ti3C2Tz were removed via thermal annealing at increased temperatures under an inert (argon) atmosphere. This thermal annealing created some bare sites available for further functionalization of Ti3C2Tz. XRD, EDS, and XPS measurements confirm the removal of much of the terminal groups of ML-Ti3C2Tz. Here, the annealed ML-Ti3C2Tz was refunctionalized by -OH groups and 3-aminopropyl triethoxysilane (APTES), which was confirmed by FTIR. The -OH and APTES surface-modified ML-Ti3C2Tz are evaluated as a solid lubricant, exhibiting ∼70.1 and 66.7% reduction in friction compared to a steel substrate, respectively. This enhanced performance is attributed to the improved interaction or adhesion of functionalized ML-Ti3C2Tz with the substrate material. This approach allows for the effective surface modification of MXenes and control of their functional properties.

Ambipolarity Sensitivity Investigation using a Charge-Plasma TFET with Graphene Channel for Biomolecule Detection

This research proposes a label-free detection of neutral and charged biomolecules using a graphene channel-based charge-plasma tunnel field effect transistor (GC-CPTFET). The presence of a graphene channel provides a greater tunneling barrier at the channel/drain interface, significantly reducing ambipolarity and increasing the current gradient in the ambipolar condition. A nanocavity is created underneath the drain metal to investigate the sensitivity. Here, the various analog sensitivity parameters of the suggested biosensor are evaluated for a few neutral biomolecules in the ambipolar condition, including gelatin, biotin, and 3-aminopropyl-triethoxysilane (APTES). The sensor’s electrostatic performance, including its IDS-VGS characteristics, energy band, and tunneling distance, has been estimated in the ambipolar state. The sensitivity analysis is carried out in terms of ambipolar sensitivity (SAMB), transconductance (Sgm), cut-off frequency sensitivity (Sft), and maximum frequency sensitivity (Sfm). Further research has been done to study the effects of Deoxyribonucleic Acid (DNA), a charged biomolecule (k = 6) with varied positive and negative charge densities, on various sensitivity parameters. The detailed simulation work for the designed biosensor is achieved using the 2D Silvaco ATLAS device simulation tool.

Eco-friendly phosphorus-free flame-retardant coating for microfiber synthetic leather via alginate-based layer-by-layer technology

The excellent comprehensive properties of microfiber synthetic leathers have led to their wide application in various aspects of our lives. However, the issue of flammability remains a significant challenge that needs to be addressed. Nowadays, the bio-based chemicals used in the flame-retardant materials have extremely grabbed our eyes. Herein, we developed an ecologically friendly flame-retardant microfiber synthetic leather using phosphorus-free layer-by-layer assembly technology (LBL) based on natural polysaccharide alginate (SA) coupled with polyethyleneimine (PEI) and 3-aminopropyltriethoxysilane (APTES). The effect of different LBL coating systems on the flame retardancy of microfiber synthetic leather was investigated. The results demonstrated that the introduction of APTES can completely inhibit the melt-dripping by enhancing char formation through silica elements. Furthermore, the trinary coating system consisting of SA/APTES/PEI exhibited excellent flame retardancy by combining gas-phase action from PEI and condensed-phase function from APTES. This modified microfiber synthetic leather showed a significantly higher limiting oxygen index (LOI) value of 33.0 % with no molten droplet. Additionally, the SA-based coating slightly suppressed the heat release, resulting in a 20 % reduction in total heat release during the combustion test. Overall, this work presents a facile and environmentally-friendly approach for achieving flame-retardant and anti-dripping microfiber synthetic leather.

Multi-functionalized MCNs effectively improve the interfacial compatibility of mixed matrix membranes and enhance CO2 separation performance

Traditional two-dimensional (2D) membrane fillers are prone to interfacial defects such as agglomeration and phase separation in the membrane, limiting the separation performance of membrane. In this paper, microporous carbon nanoplates (MCNs) with controllable microporous structures were functionalized with two different amine carriers of low molecular weight polyethyleneimine (PEI) and 3-aminopropyl triethoxysilane (APTES) to prepare multi-functionalized microporous carbon nanoplates (MfMCNs). It is worth noting that with the success of composite functionalization, the filling content of mixed matrix membranes is also high to a certain extent. To a certain extent, it has been demonstrated that interfacial compatibility between the polymer and the fillers has been improved. It was confirmed by characterization technology that the morphology of the fillers had not been changed, but the pore size of MfMCNs was declined to 0.53–0.55 nm because part of the amino carrier was immersed in the pore structure of MfMCNs. The gas permeability tests under dry gas and wet gas conditions show that the improvement of phase interface by MfMCNs is significant. Under the condition of a dry gas test, the CO2/N2 selectivity of MfMCNs/Pebax-1.0 wt% MMMs is 76.3, which is 27 % higher than that of MCNs/Pebax-1.0 wt% MMMs. Under the moisture condition, the permeability and selectivity of MfMCNs/Pebax-1.0 wt% MMMs CO2 are 287.72 Barrer and 79.1 separately. Compared with Pebax membrane, the permeability of CO2 (176.6 Barrer) was rose by 62.9 %, and the selectivity of CO2 (59.1) was rose by 33.84 %. Significantly, the best MMMs separation performance exceeds upper limit of Robeson. This provides a powerful strategy to strengthen the compatibility between inorganic materials and polymers and strengthen the performance of MMMs in CO2 gas capture.

Intermolecular Interactions in 3-Aminopropyltrimethoxysilane, N-Methyl-3-aminopropyltrimethoxysilane and 3-Aminopropyltriethoxysilane: Insights from Computational Spectroscopy

In this work, a computational spectroscopy approach was used to provide a complete assignment of the inelastic neutron scattering spectra of three title alkoxysilane derivatives—3-aminopropyltrimethoxysilane (APTS), N-methyl-3-aminopropyltrimethoxysilane (MAPTS), and 3-aminopropyltriethoxysilane (APTES). The simulated spectra obtained from density functional theory (DFT) calculations exhibit a remarkable match with the experimental spectra. The description of the experimental band profiles improves as the number of molecules considered in the theoretical model increases, from monomers to trimers. This highlights the significance of incorporating non-covalent interactions, encompassing classical NH···N, N–H···O, as well as C–H···N and C–H···O hydrogen bond contacts, to achieve a comprehensive understanding of the system. A distinct scenario emerges when considering optical vibrational techniques, infrared and Raman spectroscopy. In these instances, the monomer model provides a reasonable description of the experimental spectra, and no substantial alterations are observed in the simulated spectra when employing dimer and trimer models. This observation underscores the distinctive ability of neutron spectroscopy in combination with DFT calculations in assessing the structure and dynamics of molecular materials.

Synergistic Passivation Inducing Long‐Term Stability for Fluorescent CsPbI3 Perovskite Nanocrystals

AbstractCesium lead halide perovskite nanocrystals (PNCs) are promising candidates for photoelectric applications due to their remarkable optoelectronic properties. However, the poor stability of PNCs, especially oleic acid (OA)/oleylamine (OAm)‐capped CsPbI3, is the main obstacle to their commercialization. In this study, CsPbI3 PNCs with long‐term stability are prepared through synergistic passivation of n‐octylphosphonic acid (OPA) and (3‐aminopropyl) triethoxysilane (APS). OPA provides a stronger binding affinity to passivate surface defects, while the SiO2 layer formed by APS can further reduce ligand detachment and block the access of external factors to the PNCs. The stability of OPA/APS‐capped CsPbI3 PNCs can be synergistically enhanced in comparison with that of OA/OAm‐capped PNCs, the fluorescence of which can be also increased significantly. Employing the high‐performance OPA/APS‐capped CsPbI3 PNCs as color‐converting materials, a white light‐emitting diode with a color coordinate of (0.33 and 0.32) and a wide color gamut of 126% National Television Standard Committee color space is fabricated.

One-step, low-cost and environmentally friendly method to prepare superhydrophilic polyester fabric for oil-water separation

Polyester (PET) fabric is currently the world's most produced and widely used synthetic fiber due to its excellent mechanical properties, thermal stability and corrosion resistance. However, the poor hydrophilicity and hygroscopicity of PET fabric limit its application. In this paper, based on tannic acid (TA) and 3-aminopropyltriethoxysilane (APTES), a simple and efficient one-step method was used to construct TA-APTES nanoparticle coating on the surface of PET fabric to obtain superhydrophilicity. The surface morphology, microstructure and coating durability of the modified PET fabric were investigated. The results showed that under the optimal reaction conditions, the water contact angle (CA) of the modified fabric surface was 0°, which remained superhydrophilic after 800 times of rubbing or 20 times of washing. The modified PET fabric exhibited exceptional breathability, dyeing properties, and ultraviolet (UV) resistance, suggesting its high potential in the apparel industry. It could separate the oil-water mixture with high separation efficiency (98.98 %) and water flux (6705.53 L·m−2·h−1). The separation efficiency (97.64 %) and water flux (5968.45 L·m−2·h−1) for separating oil-in-water emulsions were satisfactory. Moreover, the modified PET fabric exhibited excellent chemical stability and can perform efficiently in harsh environment.

Amino-Functionalized Silica@Resorcinol-Formaldehyde Nanocomposites for the Removal of Cr(VI) from Aqueous Solutions.

Amino-functionalized silica@resorcinol-formaldehyde nanocomposites (NH2-SiO2@RF) were synthesized for the removal of Cr(VI) from aqueous solutions using the sol-gel technique with two simple preparation steps, including the one-pot synthesis of SiO2@RF using the Stöber method and (3-aminopropyl)triethoxysilane (APTES) modification. The morphology, particle size, functional group, and thermal stability of the obtained nanocomposites were systematically characterized, with the results indicating a uniform sphericity with a particle size of 200 nm and high thermal stability. The adsorption results demonstrated that the preferred pH value was 2, and the data were well fitted with the Langmuir and Temkin isotherm models and quasi-second-order kinetic equation, indicating a high adsorption capacity. The maximum Cr(VI) adsorption capacity from the nonlinear form of the Langmuir model was 272.6 mg·g-1. The intra-particle diffusion model accurately described the adsorption of Cr(VI) onto NH2-SiO2@RF. The changes in Gibb's free energy, enthalpy, and entropy revealed that Cr(VI) adsorption onto NH2-SiO2@RF was a spontaneous and endothermic process. Furthermore, high selectivity was demonstrated in the material for the removal of Cr(VI) from commonly coexisting ions. The obtained nanocomposites had good regeneration properties and maintained a removal rate above 85% in the fifth adsorption-desorption experiments. Moreover, under the optimized adsorption conditions, the obtained nanocomposites were preliminarily applied to tannery wastewater, demonstrating an excellent removal effect, which indicates their potential application value.

Efficient removal of fluoride ion by the composite forward osmosis membrane with modified cellulose nanocrystal interlayer

In this paper, the performance of three-layer film composite (TFC) forward osmosis (FO) membrane for the retention of fluoride ions was investigated. A cellulose nanocrystal (CNC) interlayer was introduced on the porous substrate by coating method to enhance the hydrophilicity and retention capacity of the FO membrane. In order to improve the dispersibility of CNC, boric acid (BA) and (3-aminopropyl)triethoxysilane (APTES) were used for chemical modification, respectively. The characterization results demonstrated the successful introduction of CNC, BA/CNC and APTES/CNC–CNC interlayers. The introduction of the interlayer enhanced the hydrophilicity of the membrane and increased the negative surface charge, which facilitated the transport of water molecules and the retention of fluoride ions. The FO tests indicated that the water flux of TFC/CNC membrane was increased by 46.4% compared to the original TFC membrane, and the water flux of TFC/APTES-CNC and TFC/BA-CNC membranes were higher than that of TFC/CNC membranes by 5.9% and 13.0%, respectively. 97.0% and 97.6% of the fluoride ions of TFC/BA-CNC and TFC/APTES-CNC could be retained. Based on the molecular simulation of adsorption, it was demonstrated that BA-CNC interlayer was more favorable for the adsorption of water molecules than CNC and APTES-CNC interlayer. This study contributes to the development of high-performance TFC-FO membrane for the treatment of wastewater containing fluoride.

A new SERS quantitative analysis method for trace malathion with recognition and catalytic amplification difunctional MOFTb@Au@MIP nanoprobe

New multifunctional nanomaterial preparation and its application to trace pollutant analysis are interesting to peoples. Using terbium metal-organic framework loaded gold nanoparticles (MOFTb@Au) as the nanosubstrate and 3-aminopropyltriethoxysilane (APTES) as the functional monomer, a new bifunctional nanosurface molecularly imprinted polymer nanoprobe of MOFTb@Au@MIP with strongly recognition and catalytic amplification functions was prepared by the microwave sol-gel procedure. It was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier infrared spectroscopy (FTIR) and other techniques. The nanoprobe was found to specifically recognize malathion (MAL) and catalyze the L-cysteine (Cys)-HAuCl4 nanogold indicator reaction to amplify the molecular spectral signal. The gold nanoparticles (AuNPs) generated in the system show a strong surface-enhanced Raman scattering (SERS) effect, resonant Rayleigh scattering (RRS) peak and UV absorption (Abs) peak at 1615 cm−1, 370 nm and 520 nm, respectively. Based on this, a new SERS/RRS/Abs trimode method for the detection of MAL can be established. It has been applied to the analysis of cereal samples with satisfactory recoveries of 95.2–107.4% and precision of 3.76–9.06%.

Nanocomposites of poly(butylene adipate‐co‐terephthalate) containing sepiolite modified with 3‐aminopropyltriethoxysilane and octadecyl isocyanate

AbstractThe properties of nanocomposites are directly affected by the filler–matrix interaction and therefore surface filler modification is often necessary to improve the mechanical properties of nanocomposites. Our study evaluated surface modification of sepiolite (SEP) on properties of poly(butylene adipate‐co‐terephthalate) (PBAT)‐based nanocomposites. The nanofillers were modified using two organic modifiers, octadecyl isocyanate (OI), and 3‐aminopropyltriethoxysilane (APTES). OI showed higher treatment efficiency than APTES and better results in alkyl groups on the surface of the nanofiller, with crystalline profile, which remained in the nanocomposites. The effect of organo‐sepiolites on the properties of PBAT nanocomposites was investigated by DSC, XRD, TGA, FTIR, scanning electron microscopy (SEM), and mechanical tensile tests. TGA analysis showed that the addition of O‐SEP on PBAT decreases its thermal stability. SEM analysis showed cavities and fiber tips in the matrix associated with clay agglomerates and some untreated clay faces, which impair filler‐matrix interfacial adhesion. Both treatments increased the elastic modulus and preserved the elongation and tensile strength of PBAT and the treatment with OI results in a higher modulus. Although some studies to improve the clay dispersion are necessary, the promising results reveal the potential of using OI and APTES as SEP modifiers to reinforce PBAT or other polyesters.

Synthesis and modification of MIL-101-NH2-based metal organic frameworks for preparation of SPME fibers using sol-gel methodology

Implementation of metal-organic frameworks (MOFs) in the separation science is attractive for many researchers, nowadays. In this study, three MOFs were synthesized and employed as extractive coating fibers. The MIL-101-NH2-based coatings were implemented in immersed solid phase microextraction (ISPME) of organophosphorus pesticides (OPPs) from real-life samples. The three different kinds of fiber coatings included MIL-101-NH2 and its acyl and ethyl modified structures as particles and 3-aminopropyl triethoxysilane (APTES) sol-gel precursor as binder. Each single MOF was coated on a stainless steel substrate via sol-gel technique. The uniform and tunable pore structure, high surface area, and capability to functionalization of MIL-101-NH2, make it susceptible for isolation of a wide range of analytes from small to large molecules. Extraction performance of the synthesized fiber coatings with different functionalities was examined on some model OPPs, followed by gas chromatography-mass spectrometry (GC–MS). The highest extraction efficiency was achieved by the acyl-modified (MIL-101-NHCOCH3) fiber coating. The effects of various parameters affecting the extraction and desorption efficiency such as desorption time, desorption temperature, ionic strength, stirring rate, extraction time and temperature for the selected fiber were investigated and optimized. All the synthesized fiber coatings showed sufficient affinity while the acyl modified extractive phase was found to be very sensitive for determination of OPPs with reliable figures of merit such as acceptable linear dynamic ranges (1–1000 & 5–1000 ng.kg−1, here two linear dynamic ranges (LDR) are reported due to the variation of LDR ranges from one analyte to another), low limits of detection (0.2–1 ng.kg−1), suitable intra–day (RSD% <13%) and inter–day relative standard deviation (RSD% <15%).