Silane Compounds Research Articles

Effect of The Amount of 3-(trimethoxysilyl) propyl methacrylate on Improving Surface’s Adhesive Properties of Zirconia

Abstract The objective of this research was silanize zirconium oxide (ZrO2) nanoparticles with 3-(trimethoxysilyl) propyl methacrylate (γ -MPS). Silanization is a surface treatment process of a material using silane compounds to improve the surface adhesive and compatibility of ZrO2 with other materials or coatings and to modify its surface. The surface modification of ZrO2 by 3-(trimethoxysilyl) propyl methacrylate as coupling agents under the influence of ultrasonic waves. The silanized ZrO2 was characterized Fourier Transform Infrared Spectroscopy (FTIR) and thermogravimetric analysis (TGA). The FTIR analysis indicated the interaction of the silane compound on the ZrO2 surface, showing characteristic peaks corresponding to Zr-OH, C-H stretching, carbonyl groups, and Zr-O-Si bonds, indicating successful grafting. The FTIR spectra for the ZrO2 nanoparticles, showing peaks at 1088 cm−1 showed the formation of Zr-O-Si covalent bonds. ZrO2 nanoparticles also exhibited a characteristic peak at 400 cm−1, indicating the deformation of Zr-O-Zr bonds. C=C, and C=O peaks are observed in the range of 1632-1714 cm−1. Thermogravimetric analysis (TGA) measures showed a higher weight loss of the silanized ZrO2 when higher amounts of silane were added.

Synthesis and antimicrobial activity testing of quaternary ammonium silane compounds

With increasing health awareness of the pathogenic effects of disease-causing microorganisms, interest in and use (of medical textiles, disinfectants in medical devices, etc.) of antimicrobial substances have increased in various applications, such as medical textiles and disinfectants (alcohol-based and nonalcoholic), in medical devices There are several concerns with alcohol-based disinfectants, such as surface deformation of medical devices due to high alcohol content and damage to skin tissue caused by lipid and protein denaturation of cell membranes. Quaternary ammonium compounds (quats) were preferred because they have the potential to prepare water-based disinfectants. In this study, novel (3-chloropropyl)triethoxysilane (CPTMO) and (3-chloropropyl)triethoxysilane (CPTEO) based quaternary ammonium silane compounds (silane-quats) were developed using quats with carbon chain lengths of C12, C14, C16 and C18. Titration (ASTM D2074) was used to calculate the yield of the synthesis and the structures of the products were characterised by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (13C NMR, 1H NMR) and gas chromatography-mass spectrometry (GC–MS).The in vitro antimicrobial activity of the synthesized samples was evaluated against Gram-positive (Staphylococcus aureus (S. aureus), Enterococcus hirae (E. hirae)) and Gram-negative (Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa)) bacteria and fungi (Candida albicans (C. albicans), Aspergillus brasiliensis (A. brasiliensis)) using the minimum inhibitory concentration (MIC) test. According to MIC tests, the silane-quats with the highest antimicrobial effects were dimethylhexadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (SQ3), which had an MIC of < 16 μg/ml (ppm) against E. coli, S. aureus, E. hirae, C. albicans, and A. brasiliensis and 32 μg/ml against P. aeruginosa. The MIC test results also showed antimicrobial activity at least 2 times greater than that of the commercially available disinfectant benzalkonium chloride (BAC). Findings suggest that SQ3 (C16) holds promise as an effective medical disinfectant, presenting a novel approach to combating microbial infections in healthcare settings.

Cu-Catalyzed Regioselective Silylation of Chloro-Substituted Allenyl-Bdan.

A copper-catalyzed efficient regioselective silylation reaction of chloro-substituted allenyl-Bdan was developed. Under mild reaction conditions, allenyl and propargyl silane compounds can be selectively obtained in moderate to high yields by adjusting the bases and solvents used in the reactions. This study offers direct and efficient methods for synthesizing multifunctionalized allenyl and propargyl silane compounds from the same initial material of chloro-substituted allenyl-Bdan.

CO2 gas-triggered wettability control of silylation-modified CNC films by manipulating the surface structure and introducing tertiary amino groups

Here, cellulose nanocrystal (CNC) films were chemically modified in a two-stage process to realize surface wettability control through the introduction of CO2 gas. In addition to controlling the surface structure of the silylation-modified CNC film, functional groups derived from silane compounds were installed, and the corresponding effects on the resulting chemical modification were investigated. In the first stage, methyltriethoxysilane (MTES) and hexyltriethoxysilane (HTES) combined with tetraethoxysilane (TEOS) were subjected to condensation under alkaline conditions. In the second stage, (3-(N,N-dimethylamino)propyl)trimethoxysilane (DMAPS) generated an amino group to control the surface wettability by adsorption CO2 gas. Then, the silylation-modified CNC film was fabricated on a glass substrate by spin coating. Fourier transform infrared (FT-IR), nuclear magnetic resonance (29Si-NMR), and X-ray photoelectron spectroscopy (XPS) inspection indicated that the silane compounds were bonded to the CNC film surface and that tertiary amino groups were successfully introduced. The surface structure of the silylation-modified CNC film was analyzed by atomic force microscopy (AFM), and the surface roughness calculating indicated a root-mean-square roughness (RMS) of 4.2 nm. The water contact angles before and after the CO2 gas treatment were evaluated as 73o and 22o, respectively.

Enhancing silicon-nitride formation through ammonolysis of silanes with pseudo-halide substituents.

Considering the challenges in reactivity, potential contamination, and substrate selectivity, the ammonolysis of traditional halosilanes in silicon nitride (SiN) thin film processing motivates the exploration of alternative precursors. In this pioneering study, we employed density functional theory calculations at the M06-2X/6-311++G(3df,2p) level to comprehensively screen potential pseudo-halide substituents on silane compounds as substitutes for conventional halosilanes. Initially, we investigated the ammonolysis mechanism of halosilanes, exploring factors influencing activation barriers, with the aid of frontier molecular orbital and charge density analyses. Subsequently, a systematic screening of silane substituents from group 14 to group 16 was conducted to identify pseudo-halides with low reaction barriers. Additionally, we examined the inductive effects on pseudohalide substituents. Using cluster models to represent the silicon surface validates the realistic prediction of ammonolysis barriers with a simplified model. Our findings indicate that pseudo-halide substituents from group 16, particularly those with electron-withdrawing groups, present as practical alternatives to traditional halosilanes in SiN thin film processing, including applications such as low-temperature atomic layer deposition (ALD) techniques.

Utilization of synthesized silane-based silica Janus nanoparticles to improve foam stability applicable in oil production: static study

This study investigated the effect of silane-based silica (SiO2) Janus nanoparticles (JNPs) on stabilizing the foam generated by different types of gases. Two types of SiO2 JNPs were synthesized through surface modification using HMDS and APTS silane compounds. Static analyses were conducted to examine the impact of different concentrations of the synthesized nanoparticles in various atmospheres (air, CO2, and CH4) on surface tension, foamability, and foam stability. The results indicated that the synthesized SiO2 JNPs and bare SiO2 nanoparticles exhibited nearly the same ability to reduce surface tension at ambient temperature and pressure. Both of these nanoparticles reduced the surface tension from 71 to 58–59 mN m−1 at 15,000 ppm and 25 °C. While bare SiO2 nanoparticles exhibited no foamability, the synthesis of SiO2 JNPs significantly enhanced their ability to generate and stabilize gas foam. The foamability of HMDS-SiO2 JNPs started at a higher concentration than APTS-SiO2 JNPs (6000 ppm compared to 4000 ppm, respectively). The type of gas atmosphere played a crucial role in the efficiency of the synthesized JNPs. In a CH4 medium, the foamability of synthesized JNPs was superior to that in air and CO2. At a concentration of 1500 ppm in a CH4 medium, HMDS-SiO2 and APTS-SiO2 JNPs could stabilize the generated foam for 36 and 12 min, respectively. Due to the very low dissolution of CO2 gas in water at ambient pressure, the potential of synthesized JNPs decreased in this medium. Finally, it was found that HMDS-SiO2 JNPs exhibited better foamability and foam stability in all gas mediums compared to APTS-SiO2 JNPs for use in oil reservoirs. Also, the optimal performance of these JNPs was observed at a concentration of 15,000 ppm in a methane gas medium.

Superhydrophobic melamine sponge-sorbent fabricated using WS2, halloysite nanotube, octyltriethoxysilane, tetraethoxysilane, and polydimethylsiloxane for the selective uptake of oil from water

Here, a novel coating formulation was developed using WS2, halloysite nanotube (HNT), octyltriethoxysilane (OTES), tetraethoxysilane (TEOS), and polydimethylsiloxane (PDMS) to fabricate a new melamine sponge (MS)-based superhydrophobic sorbent material for the treatment of wastewater polluted with oily substances and organic solvents. The innovative aspect of this study lies in the alteration of WS2 particle size within the sorbent material and the chemical modification of HNT with silane compounds through the formation of reactive -OH groups on the cylindrical outer surface of clay mineral by chemical activation. The effect of nano- and micro-WS2 particle sizes on the wettability of sorbent material was investigated systematically. Successful coating of MS with the developed coating formulation was confirmed using SEM, mapping, EDS, and FTIR analyses. Sorbent material showed remarkable superhydrophobicity (WCA: 170.3°), excellent thermal and mechanical stability, good chemical durability, high sorption capacity (34.0–73.8 g/g), good reusability, outstanding oil-water separation ability (>99.8 %) and flux (11,774 L/(m2.h)), and efficient separation ability for water-in-oil emulsions (up to 99.6 %). The results of this study exhibit that MS/WS2/HNT/OTES-TEOS/PDMS sorbent material is of a great potential for the selective and effective removal of oily substance and organic solvent spills from water.

Improving performance of natural rubber composites by the application of functional biofiller: horsetail modified with silane coupling agents

The growing ecological awareness of society and increasingly stringent legal requirements regarding environmental protection and the strategy of implementing the principles of sustainable development force the search for and continuous development of environmentally friendly solutions in the field of polymer materials technology. One of the directions is the use of raw materials from renewable sources. For this reason, the research object of the presented work was natural rubber composites containing a filler of plant origin in the form of ground horsetail (HT) biomass. Despite its health-promoting properties, it is commonly considered a weed. What’s more, the ubiquitous occurrence and surplus make it a valuable source of waste biomass for management. Taking into account the limitations resulting from the hydrophilic nature of the lignocellulosic filler, and the related poor adhesion to the non-polar elastomer matrix, the horsetail filler was modified with organoalkoxysilanes. The study used silane compounds containing groups that can affect the properties of vulcanizates in various ways, such as vinyltriethoxysilane (VTES), 3,3′-Tetrathiobis(propyl-triethoxysilane) (TESPTS), 3-(aminopropyl)triethoxysilane (APTES), 3-(chloropropyl)triethoxysilane (CPTES) and octyltriethoxysilane (OTES). The biomass in the form of field horsetail was previously modified with selected silanes. Then, the bioadditive prepared in this way was applied to rubber mixtures. The process of modifying the natural filler contributed to structural changes in the lignocellulosic material, which may indicate the effective attachment of silane compounds to the horsetail surface. The results of the contact angle analysis show that the treatment strongly influenced the surface characteristics of the fillers, making them more hydrophobic. The results show that the type of silane coupling agent affects not only the processing associated with the vulcanization process but also the mechanical properties of the NR vulcanizates. This phenomenon is probably the result of increased rubber-bioadditive interaction and improved filler dispersion. Moreover, all composites with modified HT, show a greater flame permanence time than the one using unmodified filler.Graphical abstract

Application of selected chemometric methods to describe and predict the properties of grafted ceramic membranes

Modification of a ceramic membrane surface for the purpose of hydrophobization can be achieved by the grafting technique involving the application of silane compounds and their derivatives. For the selection of the appropriate modifying compound, chosen chemometric methods can be implemented. In this study, the chemometric methods, i.e., hierarchical cluster analysis (HCA) and principal component analysis (PCA), were used for the evaluation of the properties of selected silane compounds applied as modifiers of ceramic membranes.The results of the calculations indicate that these methods are effective in predicting the properties of modifiers. Moreover, the PCA results provide additional information about the physicochemical properties of modifiers which influence grafted membrane properties. The data are essential when looking for (or synthesizing) new modifiers/linkers necessary for the preparation of ceramic membranes with the desirable properties It was found that physicochemical parameters such as molecular shape, atomic mass, total absolute charge, number of heavy atoms, polarizability, van der Waals volume, electronegativity as well as the number of H-bond acceptors are the most important. These parameters describe the observed properties of the grafting molecules and, simultaneously, the properties of the obtained modified ceramic membranes. It was also demonstrated that HCA and PCA can be used to interpret the previously obtained experimental results. For instance, HCA can limit the number of consecutive experiments aimed at estimating the stability of membranes in various organic solvents. Moreover, the applicability of multiple linear regression (MLR) analysis to predict the values of contact angle (CA) and water fluxes of modified membranes was also examined.

Bifunctional modification of graphene by phosphorus/nitrogen‐containing silane compounds for smoke suppression and flame retardancy of epoxy resins

AbstractEnhancing the flame retardancy with minimal impact on the mechanical and thermal performances of polymers remains a challenge. This study synthesized a phosphorus/nitrogen‐containing silane compound (D) using polyformaldehyde, KH‐550, and 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) as raw materials through the Kabachnik‐Fields reaction. After that, D was grafted onto the surface of graphene after hydrothermal treatment to obtain a nano hybrid flame retardant (D‐GR). And D‐GR/EP composites exhibited good flame resistance (LOI = 30.1% and UL‐94 reaches the V‐1 rating) even if the load on D‐GR was 1 wt%. Indeed, the total heat release, the peak heat release rate (PHRR), and the total smoke release of 1% D‐GR/EP dropped by 13.54%, 28.62%, and 44.32%, respectively, in comparison to pure EP. The mechanical performance of 1% D‐GR/EP was effectively maintained, as indicated by the results of impact, tensile and flexural tests. A systematic evaluation indicated that the accession of D‐GR effectively inhibited smoke and heat releases that are ascribed to the synergistic effect of phosphorus/nitrogen‐containing silane compound and graphene. In this study, a facile method was provided for the synthesis of halogen‐free flame‐retardant epoxy composites with superior performances. The combustion products of the as‐prepared composites complied with green and environmental protection standards.

Catalytic Asymmetric Dehydrogenative Si-H/N-H Coupling: Synthesis of Silicon-Stereogenic Silazanes.

Despite growing progress in the construction of silazanes, the catalytic asymmetric synthesis of silicon-stereogenic silazanes is significantly less explored and remains a considerable challenge. Herein, we report a highly enantioselective synthesis of silicon-stereogenic silazanes via catalytic dehydrogenative coupling of dihydrosilanes with anilines. The reaction readily produces a wide range of chiral silazanes and bis-silazanes in excellent yields and stereoselectivities (up to 99% ee). Further utility of this process is demonstrated by the construction of polycarbosilazanes featuring configurational main chain silicon-stereogenic chirality. In addition, the straightforward transformation of the enantioenriched silazanes delivers various chiral silane compounds in a stereospecific fashion, illustrating their potential utilities as synthons for the synthesis of novel silicon-containing functional molecules.

Vapor-phase grafting of functional silanes on atomic layer deposited Al2O3

Fundamental studies are needed to advance our understanding of selective adsorption in aqueous environments and develop more effective sorbents and filters for water treatment. Vapor-phase grafting of functional silanes is an effective method to prepare well-defined surfaces to study selective adsorption. In this investigation, we perform vapor phase grafting of five different silane compounds on aluminum oxide (Al2O3) surfaces prepared by atomic layer deposition. These silane compounds have the general formula L3Si–C3H6–X where the ligand, L, controls the reactivity with the hydroxylated Al2O3 surface and the functional moiety, X, dictates the surface properties of the grafted layer. We study the grafting process using in situ Fourier transform infrared spectroscopy and ex situ x-ray photoelectron spectroscopy measurements, and we characterize the surfaces using scanning electron microscopy, atomic force microscopy, and water contact angle measurements. We found that the structure and density of grafted aminosilanes are influenced by their chemical reactivity and steric constraints around the silicon atom as well as by the nature of the anchoring functional groups. Methyl substituted aminosilanes yielded more hydrophobic surfaces with a higher surface density at higher grafting temperatures. Thiol and nitrile terminated silanes were also studied and compared to the aminosilane terminated surfaces. Uniform monolayer coatings were observed for ethoxy-based silanes, but chlorosilanes exhibited nonuniform coatings as verified by atomic force microscopy measurements.

Surface Modification of Silica Particles with Adhesive Functional Groups or Their Coating with Chitosan to Improve the Retention of Toothpastes in the Mouth.

Silica is widely used in the oral care formulations to act as an abrasive and to give the products its distinct physical properties. In this study, silica particles were synthesized using a co-condensation of tetraethyl orthosilicate with a series of functional silane compounds [(3-mercaptopropyl)trimethoxysilane, (3-glycidyloxypropyl)trimethoxysilane, and (3-acryloxypropyl)trimethoxysilane)]. The surface of the particles based on tetraethyl orthosilicate and (3-glycidyloxypropyl)trimethoxysilane was then further modified with 3-aminophenylboronic acid. Commercial Aerosil R972 Pharma silica particles were also coated with chitosan. Additionally, commercially available (3-maleimido)propyl-functionalized silica particles were used in this study. All these functionalized silica particles were incorporated into toothpaste formulations, and their retentive properties were tested on ex vivo sheep tongue mucosa models using fluorescent microscopy-based flow-through techniques. Those surfaces with chitosan, phenylboronic acid, and acryloyl groups were shown to provide a significant improvement in the retention of the oral care formulations during the retention testing. The retention of toothpastes containing silica functionalized with maleimide and thiol groups was also superior compared to that of unmodified silica particles. This study synthesized and tested a range of silica particles and demonstrated that the functionalized silica incorporated into toothpastes can significantly improve the retention of these formulations on oral mucosal surfaces.

In situ preparation of compounds using silanized mPEG inspired by talc-like structures.

Composite materials show improved properties compared to pristine materials, in particular when the filler is dispersed homogeneously in the matrix. For polymer-clay composites, different strategies exist to improve clay mineral dispersion in the polymer matrix. In this study, an innovative approach is suggested which consists of forming a talc-like structure directly in a polymer matrix using a silanized polymer as the silicon source. Poly(ethylene glycol) methyl ether of different average molar masses (Mn = 350, 500, 750, 1900 g mol-1) were functionalized with (3-isocyanatopropyl)triethoxysilane and added to the ethanolic solutions of magnesium nitrate. 1H-29Si CPMAS solid state NMR experiments revealed partial condensation of silane compounds, and FTIR analysis confirmed the presence of both Si-O and Mg-O bonds, but an additional proof of the Si-O-Mg bond is needed to prove the formation of such a structure.

Carboxymethyl cellulose/montmorillonite bionanocomposite films incorporated with polyhedral oligomeric silsesquioxane

ABSTRACT In this work, carboxymethyl cellulose (CMC)/montmorillonite (MMT) bio-nanocomposite films were prepared by intercalating MMT with polyhedral oligomeric silsesquioxane (POSS) to promote the interfacial interactions between CMC and MMT and overcome limitations of CMC such as its moisture barrier property, thermal, and mechanical properties with maintaining its transparency, biocompatibility, and film-forming ability, etc. POSS combined with ammonium and imidazolium groups (POSS-ammonium and POSS-imidazolium) were prepared by the hydrolysis of organic silane compounds and intercalated into MMT via an ion-exchange reaction. MMT intercalated with POSS-ammonium and POSS-imidazolium are designated as MOAP and MOIP, respectively. MMT modified with POSS-imidazolium (MOIP) was adequately dispersed in the polymer matrix owing to the increased gap between the MMT layers and electrostatic interaction between POSS at the MMT edge and carboxylate moieties on CMC chain. The good compatibility and interaction between MOIP and CMC as well as higher thermal stability of heterocyclic compound in POSS-imidazolium endowed the bionanocomposite films with excellent mechanical properties and thermal stability. Furthermore, UV-barrier, moisture barrier, antibacterial, and antioxidant properties of the CMC bionanocomposite films were effectively improved with the introduction of MOIP.

Propylene Polymerization Performance with Ziegler-Natta Catalysts Combined with U-Donor and T01 Donor as External Donor

In propylene (C3) polymerization with Ziegler-Natta catalyst, not only internal donor but also external donor is very important to make isotactic polypropylene (PP) with higher yield. Most propylene-based polymers have been commercially produced with Ziegler-Natta catalysts combined with dialkyl-dialkoxy silane compounds (R2Si(OR)2) such as C-donor, P-donor, and D-donor as external donors. In this paper, we will introduce the propylene polymerization performance with aminosilane compounds, i.e., diethylamino triethoxy silane (U-donor) and bis(ethylamino) di-cyclopentyl silane (T01 donor), as external donor in Ziegler–Natta catalyst. The polymerization screening experiments were conducted using some triethoxyalkylsilanes compounds (1–7) and performances were compared with U-donor. The polymerization results of the binary donor system show improvement in stereoregularity. These aminosilane compounds exhibit high hydrogen response in propylene polymerization and high copolymerization performance of propylene (C3) and ethylene (C2) in ICP production compared with dialkyl-dialkoxy silane compounds. While using methanol as an additive along with external electron donor, as a serendipitous, the copolymerization activity, block ratio, EPR (ethylene-propylene rubber) content improve significantly for U-donor as compared with T01 donor and C-donor.

MICROSTRUCTURAL CHANGES OF THE PEO COATING INDUCED BY SILANE-BASED SOL–GEL TREATMENT

In this paper, the silane-based sol–gel treatment process was applied to the plasma electrolytic oxidation (PEO) ZM6 Mg-alloy. The microstructural characteristics and corrosion resistance of the PEO/organic composite coatings were studied by means of SEM and XRT in conjunction with electrochemical measurements. The results showed that the microdefects in the PEO coating could be effectively filled with the silane compounds, reducing the porosity of the PEO coating. The treated PEO coating had a hydrophobic property, which may be related to the siloxane network (Si–O–Si) formed on the PEO coating surface. The corrosiveness of the silane agent to the PEO coating and the generation of internal stress in the PEO coating resulted in the damage of microstructures of the PEO coating. The global and local electrochemical measurements showed that the corrosion-resistant performance of the PEO Mg-alloys after the silane-based sol–gel treatment was improved and its service life would be shortened by the balance of micropores without sealing and the damaged microstructure.

3D Printed Parahydrophobic Surfaces as Multireaction Platforms.

Parahydrophobic surfaces (PHSs) composed of arrays of cubic μ-pillars with a double scale of roughness and variable wettability were systematically obtained in one step and a widely accessible stereolithographic Formlabs 3D printer. The wettability control was achieved by combining the geometrical parameters (H = height and P = pitch) and the surface modification with fluoroalkyl silane compounds. Homogeneous distribution of F and Si atoms onto the pillars was observed by XPS and SEM-EDAX. A nano-roughness on the heads of the pillars was achieved without any post-treatment. The smallest P values lead to surfaces with static contact angles (CAs) >150° regardless of the H utilized. Interestingly, the relationship 0.6 ≤ H/P ≤ 2.6 obtained here was in good agreement with the H/P values reported for nano- and submicron pillars. Furthermore, experimental CAs, advancing and receding CAs, were consistent with the theoretical prediction from the Cassie-Baxter model. Structures covered with perfluorodecyltriethoxysilane with high H and short P lead to PHSs. Conversely, structures covered with perfluorodecyltrimethoxysilane exhibited a superhydrophobic behavior. Finally, several aqueous reactions, such as precipitation, coordination complex, and nanoparticle synthesis, were carried out by placing the reactive agents as microdroplets on the parahydrophobic pillars, demonstrating the potential application as chemical multi-reaction array platforms for a large variety of relevant fields in microdroplet manipulation, microfluidics systems, and health monitoring, among others.

Study on Controlling the Surface Structure and Properties of a Cellulose Nanocrystal Film Modified Using Alkoxysilanes in Green Solvents.

Film and sheet products made from naturally derived materials that exhibit high-performance surface functions are important as regards the environment. This study aimed to control the surface structure of a cellulose nanocrystal (CNC) film modified using methyltriethoxysilane and tetraethoxysilane coprecursors with environmentally friendly solvents (water and ethanol) during a spin-coating process. The surface-modified CNC film on the glass substrate was evaluated by microstructure analyses (Fourier transform infrared (FT-IR), nuclear magnetic resonance (NMR), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM)) and water contact angle (hydrophobicity) measurements. Through FT-IR, NMR, and XPS, it was confirmed that the silane compounds were chemically bonded to the surface of the CNC. The AFM images suggested that the local surface structure of the silylation-modified CNC film was formed along with the rod-like shape of the CNC. The water contact angle was approximately 90°, owing to the silylation of the hydroxy group and increased surface roughness of the CNC layer enabled by the sol-gel reaction.

Particle-resin systems for additive manufacturing of rigid and elastic magnetic polymeric composites

Fiber-reinforced polymeric composites (FRPCs) with selective fiber orientations are finding applications in building biological constructs, smart materials and energy devices. Field-assisted additive manufacturing (AM) has emerged as one of the promising methods for creating FRPC structures. Compared to other AM processes and due to the liquid form of the raw materials, vat photopolymerization has shown higher potential in building FRPCs with selective fiber orientation. Compared to other methods of controlling the fiber orientation during AM processes, magnetic field-assisted fiber reorientation, is a relatively easy-to-use contactless method that has been effectively paired with vat photopolymerization. One of the major issues in magnetic field-assisted vat photopolymerization is the dispersion instability of the particles in resin system, which leads to separation between the resin components and dispersed particles and results in non-uniform particle distribution during the printing process. In this study, ferromagnetic particle-loaded photocurable resins are developed through surface modification of the particles to achieve more uniform particle dispersion, more dispersion-stable resins systems and enhanced mechanical properties of FRPCs. Magnetite particles were functionalized under silanization reactions and mixed with two photocurable resins. Fourier-transform infrared spectroscopy (FTIR) analysis was used to select the matching composition of silane compounds and verify the functionality of the treated magnetite particles for each resin mixture. Dispersion stability of the developed resin system was verified by visual observation of the resin mixture and image analysis of microscope images. To provide a better guideline for 3D printing the developed resin system, cure depth of each resin system containing different particle fractions is studied. Tensile tests are devised to understand the effects of particle content, orientation, and surface treatment on mechanical properties of the 3D printed FRPCs. Results of this study suggest that an optimized particle-resin system can be developed through surface treatment of magnetite particles with functional groups.