Methyltrimethoxysilane Research Articles

Conductive and superhydrophobic lignin/carbon nanotube coating with nest-like structure for deicing, oil absorption and wearable piezoresistive sensor

The development of multifunctional coatings is a trend. Here, a conductive and superhydrophobic coating with nest-like structure was prepared on the wood or polyurethane (PU) sponge by spraying or soaking methods. The coating contains lignin and carboxylated multi-wall carbon nanotubes (MWCNT) as the main materials, both methyl trimethoxysilane (MTMS) and polydimethylsiloxane (PDMS) as the modifiers. And benefiting from the protective effect of the nest-like structure, the coating exhibits excellent abrasion resistance (withstanding 43 abrasion cycles), stability, and UV resistance (little change in water contact angle after 240 h of ultraviolet (UV) irradiation) by optimizing the proportions. Additionally, the coating provides eminent deicing (complete removal after 142.7 s) and self-cleaning on the wood, as well as the superior sensing performance and oil absorption (15.0–49.6 g/g for various oils) on the PU sponge. When assembled into compressible piezoresistive sensor, it could clearly sense the signals of rapid, short, circulation, different speed and deformation, possessing a prosperous wearable device prospect. It is envisaged that the coating supplies a new platform for superhydrophobicity, wearable electronics and oil absorption.

Controlling the Size of Hydrotalcite Particles and Its Impact on the Thermal Insulation Capabilities of Coatings.

This study focuses on the development of high-performance insulation materials to address the critical issue of reducing building energy consumption. Magnesium-aluminum layered double hydroxides (LDHs), known for their distinctive layered structure featuring positively charged brucite-like layers and an interlayer space, have been identified as promising candidates for insulation applications. Building upon previous research, which demonstrated the enhanced thermal insulation properties of methyl trimethoxysilane (MTS) functionalized LDHs synthesized through a one-step in situ hydrothermal method, this work delves into the systematic exploration of particle size regulation and its consequential effects on the thermal insulation performance of coatings. Our findings indicate a direct correlation between the dosage of MTS and the particle size of LDHs, with an optimal dosage of 4 wt% MTS yielding LDHs that exhibit a tightly interconnected hydrotalcite lamellar structure. This specific modification resulted in the most significant improvement in thermal insulation, achieving a temperature difference of approximately 25.5 °C. Furthermore, to gain a deeper understanding of the thermal insulation mechanism of MTS-modified LDHs, we conducted a thorough characterization of their UV-visible diffuse reflectance and thermal conductivity. This research contributes to the advancement of LDH-based materials for use in thermal insulation applications, offering a sustainable solution to energy conservation in the built environment.

Harnessing the Flexibility of Lightweight Cellulose Nanofiber Composite Aerogels for Superior Thermal Insulation and Fire Protection.

Thermally insulating materials from renewable and readily available resources are in high demand for ecologically beneficial applications. Cellulose aerogels made from lignocellulosic waste have various advantages. However, they are fragile and breakable when bent or compressed. In addition, cellulose aerogels are flammable and weather-sensitive. Hence, to overcome these problems, this work included the preparation of polyurethane (PU)-based cellulose nanofiber (CNF) aerogels that had flexibility, flame retardancy, and thermal insulation. Methyl trimethoxysilane (MTMS) and water-soluble ammonium polyphosphate (APP) were added to improve the cross-linking, hydrophobicity, and flame-retardant properties of aerogels. The flexibility of chemically cross-linked CNF aerogels is enhanced through the incorporation of polyurethane via the wet coagulating process. The aerogels obtained during this study have exhibited low weight (density: 35.3-91.96 kg/m3) together with enhanced hydrophobic properties, flame retardancy, and decreased thermal conductivity (26.7-36.7 mW/m K at 25 °C). Additionally, the flame-retardant properties were comprehensively examined and the underlying mechanism was deduced. The aerogels prepared in this study are considered unique in the nanocellulose aerogel category due to their integrated structural and performance benefits. The invention is considered to substantially contribute to the large-scale manufacture and use of insulation in construction, automobiles, and aerospace.

Anion-Induced Uniform and Robust Cathode-Electrolyte Interphase for Layered Metal Oxide Cathodes of Sodium Ion Batteries.

Layer metal oxides demonstrate great commercial application potential in sodium-ion batteries, while their commercialization is extremely hampered by the unsatisfactory cycling performance caused by the irreversible phase transition and interfacial side reaction. Herein, trimethoxymethylsilane (TMSI) is introduced into electrolytes to construct an advanced cathode/electrolyte interphase by tuning the solvation structure of anions. It is found that due to the stronger interaction between ClO4- and TMSI than that of ClO4- and PC/FEC, the ClO4--TMSI complexes tend to accumulate on the surface of the cathode during the charging process, leading to the formation of a stable cathode/electrolyte interface (CEI). In addition, the Si species with excellent electronic insulation ability are distributed in the TMSI-derived CEI film, which is conducive to inhibiting the continuous side reaction of solvents and the growth of the CEI film. As a result, under a current density of 250 mA g-1, the capacity retention of the NaNi1/3Fe1/3Mn1/3O2 (NFM) cathode after 200 cycles in the TMSI-modified electrolyte is 74.4% in comparison to 51.5% of the bare electrolyte (1 M NaClO4/PC/5% FEC). Moreover, the NFM cathode shows better kinetics, with the specific discharge capacity increasing from 22 to 67 mAh g-1 at 300 mA g-1. It also demonstrates greatly improved rate capability, cycling stability, and Coulombic efficiency under various operating conditions, including high temperature (55 °C) and high cutoff voltage (2.0-4.3 V vs Na+/Na).

Structural and optical properties of silicon oxycarbide thin films using silane based precursors via sol-gel process

Silicon oxycarbide (SiCxOy) is a candidate material for white luminescence. This work investigates the formation of SiCxOy thin film coating by sol-gel route using various silanes namely, methyltrimethoxy silane (MTMS) with or without using tetraethyl orthosilicate, vinyltrimethoxysilane and polydimethyl siloxane, followed by calcination at 1000 °C/1 h under Ar atmosphere. The structural and optical properties of the developed films were studied by X-ray diffractomete (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), electron paramagnetic resonance (EPR) spectroscopy and Photoluminescence (PL). XRD plot shows amorphous nature of silicon oxycarbide (SiCxOy) while FTIR reveals Si-C band at 795 cm−1 and Si-O-Si band at 1085 cm−1 confirming the presence of SiCxOy. XPS analysis of MTMS derived coating revealed stoichiometry of SiC0.3O2.25 which is comparable to SiCxOy (0.2<x<0.6, y<1.6). EPR spectra analysis shows presence of Si-dangling bond which could be the probable cause of luminescence center in SiCxOy as observed from PL study. FESEM shows uniform coating of thickness ∼200 nm. PL spectra shows blue and green emission peaks at ∼ 403–452 and ∼ 483–560 nm, respectively.

Surface-Modified Electrospun Glass Nanofibers from Silane Treatment and Their Use for High-Performance Epoxy-Based Nanocomposite Materials.

As a new and promising reinforcing filler, electrospun glass nanofibers (EGNFs) have attracted attention in the field of polymer composite materials. However, the reinforcing effectiveness of surface-modified EGNFs using different silane coupling agents in epoxy resin is still not quite clear. In this research, a series of silane coupling agents with increasing chain lengths in the order of methyl trimethoxysilane (MTMS), (3-aminopropyl) triethoxysilane (APTES), (3-glycidyloxypropyl) trimethoxysilane (GPTMS), and dual silane coupling agent APTES-GPTMS were employed to carry out surface treatment on the EGNFs. The pristine and silane functionalized EGNFs were then incorporated into epoxy resin as reinforcing fillers at low loading levels, i.e., 0.25 wt.%, 0.5 wt.%, and 1 wt.%, and the mechanical properties of the resultant epoxy nanocomposites, including strength, stiffness, ductility, and toughness, were evaluated. A commercial product of glass nanoparticles (GNPs) was used as a control to compare the reinforcing effectiveness of the EGNFs and the GNPs. This study revealed that the EGNFs could provide significant reinforcing and toughening effects at ultra-low loading (0.25 wt.%) in epoxy nanocomposite materials. Furthermore, surface modification of the EGNFs with silane coupling agents with long chain lengths, e.g., by using dual silane coupling agents, APTES-GPTMS, could enhance the interfacial bonding between the EGNFs and the epoxy matrix and further increase the mechanical performance of the EGNF-reinforced epoxy nanocomposite materials. Through this research, we realized epoxy nanocomposite materials with much-improved mechanical properties, i.e., 37%, 24%, 18%, 57% improvement in strength, stiffness, ductility, and toughness, respectively, with respect to those of the cured neat epoxy material with an ultra-low loading (0.25 wt.%) of APTES-GPTMS-EGNFs. Our research paves the road for developing lighter and stronger epoxy nanocomposite materials with EGNFs.

An ultra-thin and highly efficient electromagnetic interference shielding composite paper with hydrophobic and antibacterial properties

Facing the increasing electromagnetic interference (EMI) pollution in the living environment, it is a new trend to explore an efficient EMI shielding material with facile fabrication and a wide range of application scenarios. A hydrophobic composite paper composed of silver nanowires (AgNWs) and kapok microfibers cellulose (MFC) was modified by methyl trimethoxy silane (MTMS) through a simple method. As a result, the composite paper has a good EMI shielding effectiveness (EMI SE) of 61.7 dB with electrical conductivity of 695.41 S/cm. The modification of MTMS improved the thermal stability performance of composite paper, which also increased its water contact angle to 113°. The free silver ions (Ag+) released from AgNWs can kill surrounding microbial bacteria, endowing the composite paper with good antibacterial property. Water resistance and antibacterial property enable MTMS/AgNWs/MFC composite paper to cope with complex application environments.

Enhanced hydrophobic ZSM–5 with high capacity for toluene capture under high-humidity conditions

Industrial volatile organic compounds (VOCs) have the characteristics of large displacement and high humidity. The problem of water resistance of the adsorbent in treating VOCs by adsorption method under high humidity conditions needs to be solved urgently. Herein, methyl triethoxysilane (CH3Si(C2H5O)3) and methyl trimethoxysilane (CH3Si(CH3O)3) are used for hydrophobic modification of ZSM-5, and its adsorption properties for toluene are studied under high-humidity conditions. Fourier infrared spectroscopy and X-ray photoelectron spectroscopy indicate that the hydrophobic groups –CH3 and –CH2– are successfully grafted onto the surface of the ZSM-5. The adsorption–desorption results of toluene show that the hydrophobicity of the modified ZSM-5 is remarkably improved, and the adsorption capacity for toluene is almost 6.5 times higher than that of original ZSM-5 at 80 % relative humidity. The mechanism of surface hydrophobicity modification of ZSM-5 was further investigated and found that the silicone hydroxyl group on the surface of the material reacted with the modifier to graft the hydrophobic group onto the surface of the material, which improved the hydrophobic property of the material. Moreover, the universality of the hydrophobic modification method has been proved feasible in commercial ZSM-5. Therefore, this work provides an important theory and reference for improving the hydrophobic properties of ZSM–5 molecular sieve.

Self-catalyzed Gelling Synthesis of Aerogels with Inorganic and Organic Nanocomponents for Thermal Insulation and CO2 Capture

Silica aerogels have already been recognized as potential candidates in the fields of thermal insulation, sorption, and separation, but the intrinsic brittleness and cumbersome preparation process limit their broad applications. In this work, a simple self-catalyzed gelling strategy was applied to prepare organic–inorganic in situ hybrid aerogels (OIHAs) derived from bis[3-(triethoxysilyl)propyl]amine (BTPA) and methyltrimethoxysilane (MTES). The Si–CH3 groups from MTES make it possible for OIHAs to be prepared through ambient drying and exhibit good hydrophobicity. Owing to the alkalinity of the amine groups from BTPA, self-catalyed hydrolyzation and condensation reactions occur between two silicon precursors to build a uniform pearl-chain nanoporous structure. The high specific surface area and amine groups existing on the nanoskeleton surface of the obtained OIHAs endow them with fascinating CO2 capture ability up to 5.89 mmol/g at 298 K and 100 kPa, which are significantly higher than the values of other aerogels reported under the similar conditions. Furthermore, ultralow thermal conductivity (as low as 20.1 mW/(m·K) at 25 °C), high strength (up to 2.38 MPa), and great elasticity (fully recoverable elastic strain of 14%) are achieved together for the OIHAs due to the organic–inorganic in situ cross-linked architecture. The as-prepared OIHAs with versatile properties have great application prospects in the fields of building thermal insulation and CO2 capture. The self-catalyzed gelling strategy provides an alternative routine for the simple preparation of silica-based aerogels.

Quantitative and convenient protocol for analysis of surface‐modified silica nanoparticles using 29Si‐NMR and near‐infrared diffuse reflection spectroscopy

Near‐infrared (NIR) diffuse reflection spectroscopy combined with solid‐state 29Si‐nuclear magnetic resonance (NMR) was applied to surface‐methylated silica nanoparticles for rapid determination of the degree of modification of silanol group. 29Si‐NMR with direct polarization method was employed to quantify the amounts of methyl and silanol groups from the areas of the T2, T3, Q2, and Q3 sites for referential samples modified with different amounts of trimethoxymethylsilane (TMMS). The degree of modification obtained by NMR was correlated with the corresponding NIR spectra by partial least squares (PLS) regression, where CH overtone and combination bands of the methyl group played a key role. Validity of the regression model was demonstrated for the mixtures of modified and unmodified samples at different ratios and for the samples prepared using excess amount of TMMS. This protocol will enable a high‐throughput characterization of surface‐modified silica nanoparticles used as a filler for polymer composites and a nucleating agent for polymer foams.

Characterization and Analysis of Intelligent Eco-Friendly Coating for Porcelain Insulator Flash-Over Protection

Among all the astonishing equipment found in power transmission and distribution networks, the insulator plays a vital role by providing mechanical support and electrical protection to power system. Despite all these noteworthy facts, the breakdown of insulators owing to surface contaminants appears to be particularly fascinating in today’s scientific world. Researchers provide a plethora of methods to eradicate this problem. Amidst the methods, superhydrophobic coating for insulators which is one of the widely used method, provide better solution as it offers resistance to moisture, wetness, dust and ice. This unique property of superhydrophobic coated insulators require further investigation. Hence to achieve this purpose, preparation of eco-friendly superhydrophobic solution of PDMS (Poly di methyl siloxane) with MTMS (Methyl tri methoxy silane) composites was made and analysed. In this study superhydrophobic coatings were prepared by using sol-gel method and spray coating technique. Authors performed characterization studies by using goniometer to measure the contact angle (CA) for superhydrophobic coating on insulator surface and it was found to be from 165° to 170° and sliding angle was from 5° to 10° confirming superhydrophobic property. Fourier Transforms Infrared Spectroscopy (FTIR) analysis validates the chemical composite of the coatings. Scanning Electron Microscope (SEM) analysis was used to observe the surface morphology of coating with estimated thickness L = 2 μm.Thermogravimetric analysis (TGA) was conducted to study about thermal withstanding limit of the coating above 600 °C. Finally, in an intentional contaminated conditions based on solid layer method of IEC60507 standards and IEC 60587 standards insulation resistances were tested using a megger instrument and self-cleaning ability of coating was also determined in this research.

Lightweight and multifunctional super-hydrophobic aramid nanofiber/multiwalled carbon nanotubes/Fe3O4 aerogel for microwave absorption, thermal insulation and pollutants adsorption

Lightweight and multifunctional aerogel has attracted increasing attention in microwave absorption, thermal insulation and pollutant recovery due to the increase of electromagnetic radiation and pollution, global warming and environmental pollution, which is an ideal material to meet the technical needs of today's society. In this study, aerogel composites (M-AMF), consisted of aramid nanofiber, multiwall carbon nanotubes and Fe3O4 nanoparticles modified by methyl trimethoxy silane, are prepared via a combination of a facile vacuum assisted filtration, freeze drying and vapor deposition, which show superhydrophobic property, low density and high mechanical properties. M-AMF32 aerogel composite as microwave absorber shows that a minimum reflection loss can reach up to ‐45.83 dB at microwave frequency of 5.46 GHz and a maximum effective absorption bandwidth is 4.0 GHz. Moreover, surface temperature of M-AMF aerogel composite as thermal insulation material is only 50 °C after placed on heating plate of 100 °C. The adsorption capacity of M-AMF32 aerogel can still maintain at about 30 g/g after 100 cycles for oil. Moreover, M-AMF aerogel exhibits excellent thermal insulation performance and certain selective absorbability to non-polar liquids, which can be applied in the harsh environment applications and the treatment of pollutants.

Preparation of self-healing superhydrophobic cotton fabric based on silica aerogel for self-cleaning and oil/water separation

Self-healing superhydrophobic coatings with excellent self-cleaning ability have received a lot of attention. A self-healing superhydrophobic cotton fabric was obtained by coating SiO2 aerogel and polydimethylsiloxane (PDMS) on a cotton fabric via the spraying process. Sol-gel reaction and ambient pressure drying (APD) were used to prepare hydrophobic SiO2 aerogel utilizing methyl trimethoxy silane (MTMS) as a precursor and water as a solvent in the presence of surfactant. Spraying a mixture of SiO2 aerogel and polydimethylsiloxane onto cotton fabric created the self-healing superhydrophobic cotton fabric. The surface morphology and chemical composition of superhydrophobic cotton fabrics were characterized respectively. The results showed that the treated cotton fabrics exhibited the superhydrophobic property with water contact angle (WCA) and water shedding angle (WSA) 161.1° ± 0.9° and 4° ± 0.5°, respectively, due to the simultaneous introduction of typical three-dimensional network porous structure caused by SiO2 aerogel and low surface tension PDMS layer on cotton fabrics. The treated cotton fabrics had not only excellent self-cleaning and anti-fouling properties, but also self-healing properties. The treated cotton fabrics showed excellent friction durability and laundering durability attributed to stable and firm PDMS adhesive layer. After 20 laundering cycles, 600 friction cycles or 8 cycles of etching-self-healing, the treated cotton fabrics were still superhydrophobic. The treated cotton fabric manifested desirable oil-water separation performance with a separation efficiency of 96.0%. These durable superhydrophobic fabrics with self-cleaning and liquid repellency may find various potential applications and display promising prospects.

One‐step flame retardant/hydrophobic finishing on cotton fabric with ammonium salt of hexamethylenediamine ‐ N, N, N′, N′ ‐ tetra (methylphosphonic acid) doped silica sol

AbstractWith the rapid development of textile technology, single‐function textile finishing is difficult to meet the current needs of people for textiles. Textiles with flame retardancy, superhydrophobicity, UV resistance, and other functions are increasingly favored by people. At present, most of the preparation processes of multifunctional textiles are complex and time‐consuming. In this work, a flame retardant hexamethylenediamine tetramethylene phosphate ammonium salt of hexamethylenediamine ‐ N, N, N′, N′ ‐ tetra (methylphosphonic acid) (AHDTMPA) was synthesized using hexamethylenediamine tetramethylene phosphate (HDTMPA) and urea with aqueous solution as solvent. Then AHDTMPA and cetyltrimethoxysilane were added into the solution with methyl trimethoxysilane (MTMOS) and tetraethyl orthosilicate (TEOS) as precursors to obtain a multifunctional sol. Finally, the multifunctional cotton fabric can be obtained by immersing the cotton fabric in the multifunctional sol in one‐step. The limiting oxygen index (LOI) and water contact angle (WCA) value of the finished cotton fabric was 27.6% and 131.4°, respectively. The FT‐IR characterization results and the SEM analysis verified the synthesis of AHDTMPA. The micro calorimeter combustion (MCC) and thermo gravimetric (TG) analysis indicated that the finished samples had less heat release capacity and less weight loss. The smoke density test showed good smoke suppression of the finished cotton fabric. Moreover, the whiteness of finished samples was nearly unchanged. In this work, the flame retardant and hydrophobic multi‐functional cotton fabric was prepared by one‐step, and the method is simple and efficient. The prepared functional cotton fabrics can be widely used in home textile fabrics, automotive interior fabrics, clothing fabrics, flags, tents, and protective clothing.

Preparation and evaluation of organosilica nanocapsules encapsulating DCOIT by using the response surface optimization

AbstractAntifouling agent 4, 5‐dichloro‐2‐n‐octyl‐4‐isothiazolin‐3‐one (DCOIT) in a one‐stage process based on the self‐catalytic reaction between methyl trimethoxysilane (MTMS) and 3‐aminopropyl trimethoxysilane (APS) in an aqueous system without any surfactants and catalysts have been developed. The optimal preparation process parameters of organosilica nanocapsules encapsulating DCOIT (DCOIT@SiNC) were determined using response surface methodology (RSM) based on the single‐factor experimental results. The results of RSM optimization showed that 49.51% encapsulation efficiency (EE [%]) would be achieved with a shell–core mass ratio of 5.59:1, a MTMS‐APS mole ratio of 1.52:1, and a reaction temperature of 31°C. DCOIT@SiNC prepared according to the RSM optimal process exhibited a decent uniform sphericity with an average particle diameter of 660.50 nm. The encapsulation was characterized by Fourier‐transform infrared and X‐ray diffraction. The loading efficiency and thermal stability were verified via thermogravimetric analysis. Compared to DCOIT, DCOIT@SiNC had better controlled release performance, and the release kinetics investigated by Riger‐peppas model indicated that the release of DCOIT was diffusion‐controlled.

One Stone for Multiple Birds: A Versatile Cross-Linked Poly(dimethyl siloxane) Binder Boosts Cycling Life and Rate Capability of an NCM 523 Cathode at 4.6 V.

Increasing working voltage is a promising way to increase the energy density of lithium-ion batteries. Cycling and rate performance deteriorated due to excessive electrolyte decomposition and uncontrolled formation of a cathode-electrolyte interface (CEI) layer at a high voltage. A new concept is proposed to construct a high-voltage-stable electrode-electrolyte interface. An elastomeric poly(dimethyl siloxane) (PDMS) binder is incorporated into the electrode to modify the LiNi0.5Co0.2Mn0.3O2 (NCM 523) particle surface via an in situ cross-linking reaction between hydroxy-terminated PDMS and methyl trimethoxy silane promoted by moisture at ambient conditions (MPDMS). Improved electrochemical performance is achieved with the MPDMS binder in terms of reversible capacity (201 vs 185 mAh·g-1 at 0.2C), capacity retention (80 vs 68%, after 300 cycles at 1C), and rate performance (55.6% increase at 5C), as demonstrated by the NCM 523||Li half-cell. The NCM 523||graphite full-cell also shows improved performance at 4.6 V (147 vs 128 mAh·g-1, 82 vs 76%, after 200 cycles at 1C). The mechanism studies indicate that MPDMS exerts multiple effects, including cathode surface passivation, solvation structure tuning, electrolyte uptake enhancement, and mechanical stress relief. This work provides an inspiring route to realize high-voltage application of lithium-ion battery technology.

Sorbitol cross-linked silica aerogels with improved textural and mechanical properties

It is well known that although organically modified silica aerogels have enhanced mechanical properties, the specific surface area decreases due to the larger pore size. However, cross-linking with sorbitol enhances the mechanical properties while maintaining the highly textural structure, low density, and the thermal conductivity of silica aerogel. Herein, we report the silica aerogels reinforced with sorbitol via facile sol-gel polymerization. The sorbitol improved mechanical properties while maintaining the textural structure of the silica aerogels. Sorbitol with surface hydroxyl groups was covalently cross-linked with either tetraethoxysilane (TEOS) or methyl trimethoxysilane (MTMS) precursor. The two possible combinations of sorbitol-TEOS or sorbitol-MTMS aerogels were systematically prepared by varying mol% of the precursor and aerogels to obtain different properties. The sorbitol-MTMS aerogel with a 90:1 M ratio of methanol to precursor attained a large surface area (1193 m2/g), good mechanical strength (205.9 kPa) during compression testing, a small pore volume (2.2 cm3/g), and low thermal conductivity (0.041 Wm−1K−1). The thermal stability of sorbitol-TEOS and sorbitol-MTMS cross-linked silica aerogels in air was up to ∼418 °C, as ascertained from their thermo-gravimetric profiles. The results indicate that using small linear organic molecules for cross-linking with an inorganic silica precursor is highly useful for obtaining aerogels with a high surface area and improved mechanical properties.

Methyltrimethoxysilane (MTM) as a Reagent for Direct Amidation of Carboxylic Acids.

Methyltrimethoxysilane [MTM, CH3Si(OMe)3] has been demonstrated to be an effective, inexpensive, and safe reagent for the direct amidation of carboxylic acids with amines. Two simple workup procedures that provide the pure amide product without the need for further purification have been developed. The first employs an aqueous base-mediated annihilation of MTM. The second involves simple product crystallization from the reaction mixture providing a low process mass intensity direct amidation protocol.

Preparation and Properties of Hydrophobically Modified Whey Protein Isolate-Pullulan Composite Aerogel

Objective: To modify hydrophobicity of protein/ polysaccharide aerogels and evaluate their properties. Methods: The whey protein isolate (WPI)- pullulan (PUL) composite aerogels were treated by low temperature plasma treatment. After exposure to hydroxyl groups, silane coupling agents were used for surface grafting. Hydrophobic composite aerogels were obtained, and their hygroscopicity, hydrophobicity, oil content, compression resistance, thermal weightlessness, loading and slow release properties of essential oils were studied. Results: the equilibrium moisture absorption rate of the composite aerogel modified by methyltrimethoxy silane (methyltrimethoxysilane, MTMS) was 9.67%±0.323%, eighteen alkyl trimethoxy silane (octadecyltrimethoxysilane, OTMS) modified composite aerogel equilibrium moisture absorption rate of 9.34%±0.276%, compared with before modification (11.41±0.506%).It was significantly reduced; Before modification, the contact angle of composite gas gel was 40.14°±2.16°, The oil contact angle was 28.07°±2.43°; The contact angle of water after MTMS modification was 82.10°±4.78°, the oil contact angle was 56.14°±3.25°; The contact angle of water after OTMS modification was 85.21°±4.61°, the oil contact angle was 74.63°±3.08°; The hydrophobic and oil drainage properties of the modified products were improved, and the effect of OTMS was better. Compression modulus of modified composite aerogel (21.745±1.982) MPa, (17.655±3.034) MPa after MTMS modification, (18.412±3.513) MPa after OTMS modification. The compressive strength of the modified material decreased slightly, but it did not affect the normal use. The maximum loading rate of the modified composite aerogel clove essential oil was 254.26%±5.585%, after MTMS hydrophobic modification, the maximum loading rate of clove essential oil was 241.57%±5.214% and OTMS group 223.31%±4.436%. The loading rate of clove essential oil had decreased, but the sustained release property had been improved, and the MTMS modified slow-release effect was better. The thermal stability of OTMS group was better. Conclusion: Silane graft hydrophobic modification can significantly enhance the hydrophobicity and enhance the hydrophobicity of composite aerogels. It is suitable for loading and slow releasing applications of active oils, which widens the application field of WPI-PUL composite aerogels.

Fabrication of highly efficient nano core–shell structure for the development of super-hydrophobic polymeric coating on mild steel

This research work deals with the development of a polymeric super-hydrophobic surface involving nano silica–titania core–shell particles. This core–shell structure enhanced the properties of two different materials in a single nanoparticle in an outstanding manner; polymeric coatings containing core silica and shell titania have improved the mechanical behavior and hydrophobicity of coating surfaces, respectively. This nano core–shell was synthesized through two different methodologies which were prepared at high and low processing temperature separately, that is, called sol–gel and peptization synthesis. Further surface properties of the prepared nanoparticles were investigated individually in solvent-based emulsions and water-based emulsions. Nanocoating formulations were developed on mild steel substrate for analysis on the mechanical behavior of the coating and contact angle measurement. In the coating formulation, nano core–shell concentrations ranged from 1% (wt) to 6% (wt), and used nanoparticles were functionalized with methyl trimethoxy silane for better surface properties. Based on the results of the experiment, core–shell nanocoatings have been found mechanically robust and superhydrophobic (∼145.1° ± 2°) coating.