Aminosilane Coupling Agent Research Articles

Effect of silane treatment loading on the flexural properties of PLA/flax unidirectional composites

Abstract Matrix/fiber interfacial bonding, is one of the most significant issues that needed to be addressed, for the wider acceptance of natural fiber reinforced composites to outdoor applications. The hydrophilic nature of the specific fibers is a major obstacle for the bonding with the hydrophobic polymer matrices , thus the formation of poor interface between the two components is inevitable. In this study, unidirectional flax fiber reinforced Polylactic Acid (PLA) composites (Flax/PLA)were fabricated through “film stacking method”, resulting to panel samples. Flax fibers were treated with amino-silane coupling agent, at different silane content values, in order to optimize the composite properties regarding this parameter. The effect of the amount of treatment onPLA/Flax composites has been studied in terms of their flexural response, both static and creep, in order to evaluate their long-term performance as a function of the silane treatment. Results about the effectiveness of silane-treated flax fibers on the mechanical performance of the bio-composite under investigation have been obtained. It has been found that silane loading over a specific number, results to deterioration of the composite’s properties.

PLA and single component silicone rubber blends for sub-zero temperature blown film packaging applications

Abstract The poly(lactic acid) (PLA) blend with single component silicone rubber in the presence of reactive amino silane coupling agent and polyester polyols plasticizer were studied. The manufacturing of film packaging for sub-zero temperature applications from the PLA blend was the main objective. The mechanical properties, especially the impact strengths, of PLA/silicone blends were significantly depended on the silicone loading. The outstanding impact strengths, tested at sub-zero temperature, of the blend having silicone content of 8.0 phr was achieved. It was chosen as the best candidate for the processability improvement. Adding the talc filler into the PLA/silicone blend to enhance the rheological properties was investigated. The ductility of the talc filled blends were decreased with increasing the filler contents. However, the shear viscosity of the blend was raised with talc loading. The blend loaded with 40 phr of talc filler was justified as the optimal formula for the blown film process testing and it was successfully performed with a few difficulties. The obtained blown film showed relative good flexibility in comparison with LDPE but it has low transparency.

Sodium alginate-grafted submicrometer particles display enhanced reversible aggregation/disaggregation properties

In this article, we demonstrate that submicrometer particles with surface-grafted sodium alginate (SA) display enhanced and reversible aggregation/disaggregation properties in aqueous solution. 300 nm silica particles were first functionalized with an aminosilane coupling agent, followed by the grafting of pH-sensitive SA, as confirmed by zeta potential, XPS and FTIR analyses. The SA-modified particles show enhanced aggregation properties at acidic pH compared to unmodified silica, with a 10 times increase in average aggregate diameter. The process is reversible, as the aggregates can be broken and dispersed again when the pH is increased back to 7.0. As a result, the sedimentation rate of SA-modified particles at pH 3.0 is both significantly faster and complete compared to the unmodified particles. This enhanced aggregation is most likely due to the formation of intermolecular hydrogen bonds between neighboring SA-modified particles. This work illustrates how surface-grafted macromolecules of natural origins can be used to tune interparticle interactions, in order to improve separation processes.

Designing a multi-functionalized clay lamellar-co-graphene oxide nanosheet system: An inventive approach to enhance mechanical characteristics of the corresponding epoxy-based nanocomposite coating

Abstract Clay nano-platelets (NC) and Graphene oxide nanosheets (GO) are functionalized by the aid of 1,4- butanediol diglycidyl ether (BDDE) through an aminosilane coupling agent, i.e. 3-Triethoxysilyl propylamine (APTES). The products obtained from the modification process are characterized by visual assessment, FTIR, XRD, TGA, UV–vis, AFM and FE-SEM analyses. The results clearly demonstrate the epoxide ring of BDDE is chemically attached on the surface of the fillers. Furthermore, the process is causing the stacks of layers expand and d-spacing increases. The functionalized NC and GO, i.e. MNC and MGO, are then impregnated into an undiluted clear di-functional bisphenol A/epichlorohydrin derived liquid epoxy resin at 0.3% weight concentration by simple mechanical mixing. The films are also morphologically studied by FE-SEM. Dynamic and static mechanical properties are investigated by DMA and tensile testing. The outcomes demonstrate that there exists an optimum mixing ratio of MGO and MNC to obtain the best mechanical properties, i.e. MGN (70:30). Besides, almost all the modified samples show improved mechanical properties compared to their unmodified counterparts.

Multiple enhancement of PVC cable insulation using functionalized SiO2 nanoparticles based nanocomposites

Manufacturing of a new insulation material for power cables has become necessary in order to withstand electrical and mechanical stresses. The current study aims to enhance the dielectric and mechanical properties of Polyvinyl Chloride (PVC), one of the wide used power cable insulation, by the insertion of chemically modified silica (silicon dioxide, SiO2) nanoparticles. The surface functionalization of the inserted SiO2 nanoparticles was performed using amino silane coupling agent, and the PVC/SiO2 nanocomposites were synthesized with different concentrations of nanoparticles. The surface morphology and chemical structure of the prepared samples were characterized by field emission scanning electron microscopy (FE-SEM) and Fourier transformation infrared spectroscopy (FT-IR). The mechanical properties of the obtained nanocomposites showed that the insertion of functionalized nanoparticles is able to increase the tensile strength and the Young’s modulus of samples, however it decreases their elongation. In addition, the dielectric properties of PVC/SiO2 nanocomposites, such as relative permittivity (εr) and dielectric loss (tan δ), were also measured in a frequency range of 20Hz–1MHz. Moreover, AC breakdown voltage of the prepared samples was measured under uniform and non-uniform field, and AC dielectric strength was evaluated using finite element method (FEM) for non-uniform and uniform field. For further evaluation, DC dielectric strength was also measured under uniform field. The obtained data revealed that PVC/SiO2 nanocomposites with functionalized SiO2 nanoparticles exhibited better dielectric properties compared to that with un-functionalized one or that of neat PVC. The physical mechanisms behind the obtained enhancements have been discussed.

PDA-meditated green synthesis of amino-modified, multifunctional magnetic hollow composites for Cr(VI) efficient removal

Abstract Employing mussel-inspired concept, a controllable “Sol-Gel-like” condensation of dopamine (DA) and aminosilane coupling agents (A1, A2, A3 represent APTMS, TSPED and TPDA, respectively) was undertaken to synthesize magnetic hollow composites (Fe 3 O 4 @A/PDA), aiming for removing Cr(VI) from wastewater. Compared to reported magnetic amino-functionalized composites for heavy metal removal, it is a new green process via post-grafting pathways that can avoid using organic solvents and high-temperature treatment. Structural characterization and batch experiments are correlated to illustrate the adsorption performance of resultant composites. Upon screening resultant adsorbents, Fe 3 O 4 @A2/PDA exhibited the highest adsorption capacity; the maximum Cr(VI) removal amount could be up to 284.1 mg g −1 at 298 K and pH 2.0. The pseudo-second-order and Langmuir model preferably fitted the adsorption process, besides, the activation energy is 7.17 kJ/mol −1 . The hollow composites could be easily separated from solutions by a magnet, and over 70% Cr(VI) could be removed even after five cycles. Electrostatic attraction and reduction reaction could be used to explain the adsorption mechanism that on the basis of XPS analysis. According to thermodynamic analysis, the adsorption is a spontaneous endothermic process. The high Cr(VI) adsorption capacity, fast adsorption kinetics and easy separation properties of hollow Fe 3 O 4 @A2/PDA composites make it be potential to alleviate Cr-containing aqueous solutions.

A water durable resistive humidity sensor based on rigid sulfonated polybenzimidazole and their properties

A water-durable, polymeric resistive humidity sensor was designed using rigid sulfonated polybenzimidazole (SPBI) with tetramethylammonium (Me4N+) as the counter cation. The Me4N–SPBI structure based on the imidazole group was used to obtain a cross-linkable moiety to attach the humidity-sensitive polyelectrolyte film to an alumina substrate pretreated with an aminosilane coupling agent using an epoxy cross-linker. The SPBI in Me4N+ structure is derived from 3,3′-diaminobenzidine (DAB), sodium 6,6′-oxybis(3-carboxybenzenesulfonate) (SOCBS) and 4,4′-oxybisbenzoic acid (OBBA), followed by quaternization, which allows for easy fabrication, higher sensitivity and better adhesion between the film and the substrate. The effect that cross-linking and anchoring the Me4N–SPBI films had on the humidity-sensing properties and water durability of sensors were investigated. The SPBI films with Me4N–DAB/SOCBS/OBBA=100/100/0 and 100/70/30 exhibited a linear response with a resistivity of 6.11–1.19kΩ and 7.60MΩ–2.51kΩ between 20 and 95% RH, respectively. Consequently, cross-linking and anchoring the film to the substrates with a coupling reagent significantly improves the water durability and stability at a high humidity and high temperature.

Functionalized TiO2 nanoparticles by single-step hydrothermal synthesis: the role of the silane coupling agents.

A simple, robust and versatile hydrothermal synthesis route to in situ functionalized TiO2 nanoparticles was developed using titanium(IV) isopropoxide as Ti-precursor and selected silane coupling agents (3-aminopropyltriethoxysilane (APTES), 3-(2-aminoethylamino)propyldimethoxymethylsilane (AEAPS), and n-decyltriethoxysilane (DTES)). Spherical nanoparticles (ca. 9 nm) with narrow size distribution were obtained by using DTES or by synthesis performed without silane coupling agents. Rod-like nanoparticles along with 9 nm spherical nanoparticles were formed using aminosilane coupling agents because of a combination of oriented attachment of nanoparticles and specific adsorption of the aminosilane on crystallographic faces of anatase nanoparticles. The nanoparticles were functionalized in situ and became hydrophobic as silanes reacted to form covalent bonds on the surface of TiO2. The versatility of the aqueous synthesis route was demonstrated, and by selecting the type of silane coupling agent the surface properties of the TiO2 nanoparticles could be tailored. This synthesis route has been further developed into a two-step synthesis to TiO2–SiO2 core–shell nanoparticles. Combustion of the silane coupling agents up to 700 °C leads to the formation of a nanometric amorphous SiO2 layer, preventing growth and phase transition of the in situ functionalized nanoparticles.

Fire Retardancy Characteristics and Mechanical Properties of High-Density Polyethylene/Ultrafine Fly Ash/MWCNT Nanocomposites

ABSTRACTNanocomposites of high-density polyethylene along with ultrafine fly ash and acid-functionalized multiwalled carbon nanotubes have been developed. To enhance the interfacial adhesion, an epoxy-functionalized high-density polyethylene has been added, while the ultrafine fly ash has been surface modified using aminosilane-coupling agent. Improvement in mechanical properties using both ultrafine fly ash/multiwalled carbon nanotubes was seen and was further analyzed using micromechanical models. The addition of ultrafine fly ash and multiwalled carbon nanotubes together exhibited synergism leading to lowering of peak heat release rate. The nanocomposites showed enhanced thermal stability and lowered crystallinity percentage values of the high-density polyethylene phase due to improved interfacial interactions.

Preparation of nanosilica-immobilized antioxidant and the antioxidative behavior in low density polyethylene

This article reports a study of the preparation of nanosilica-immobilized antioxidant (SiO2-APTMS-AO) and the thermal oxidative stability of low density polyethylene (LDPE) nanocomposites containing SiO2-APTMS-AO. SiO2-APTMS-AO was prepared based on the fumed nanosilica which was firstly modified with an aminosilane coupling agent and then reacted with 3,5-Di-tert-butyl-4-hydroxybenzoic acyl chloride. Infrared spectroscopy, X-ray photoelectron spectroscopy and thermogravimetric analysis measurements confirmed that the antioxidant group was chemically immobilized onto nanosilica. LDPE/silica nanocomposites were prepared by melt mixing and then pressed into different films. The thermal oxidative stability of the nanocomposites was evaluated by thermogravimetric analysis in air atmosphere, oxidation induction time (OIT) and long-term accelerated thermal aging. The results showed that the SiO2-APTMS-AO can significant improve the thermal oxidative stability of LDPE nanocomposite. Because SiO2-APTMS-AO is based on inorganic nano-filler, in comparison to organic antioxidants, it might have advantages in thermal stability and migration stability during processing and application.

Functionalization of epoxy resin and the performance of the resultant magnesium-rich primer

Abstract A magnesium (Mg)-rich primer can provide cathodic protection for an aluminum (Al) alloy due to the lower potential of Mg. However, the Mg-rich primer prepared by simple blends shows poor flexibility and impact resistance. In this paper, bisphenol-A type epoxy resin E-20 was graft modified by hydroxyl silicon oil (HS), amino silane coupling agent and diphenyl-methane-diisocyanate (MDI) by three different ways. Then Mg-rich primer was prepared by direct blends of modified resins. Results indicate that the introduction of siloxane groups could improve the comprehensive performance of the coating especially the flexibility and impact resistance. Furthermore, Mg-rich primer prepared from MDI modified epoxy resin even possesses excellent salt spray and aging resistance.

Morphology and photoluminescence properties of phenolic epoxy resin coating on KH550-modified SrAl2O4: Eu2+, Dy3+ powder in the presence of triarylsulfonium hexafluoroantimonate

In this study, the amino silane coupling agent (KH550)-modified SrAl204: Eu2+, Dy3+ phosphor powder coated with phenolic epoxy resin (EOCN) in the presence of triarylsulfonium hexafluoroantimonate catalyst was prepared using the combination of organic–inorganic composite dip-coating and UV curing coating methods. The results of SEM, TEM, and FTIR showed that the organic coating was a layer of compact membrane with a thickness of 20–50 nm, which can be named silane-modified epoxy monomer generated by the KH550 and the EOCN. Furthermore, it was observed that afterglow and spectrum properties of the coated phosphor powder had good long-afterglow luminescence properties, and revealed two emission peaks at 435 nm and 520 nm under the same excitation wavelength of 360 nm, respectively. More interesting, the emitting color of the coated sample was located in the area of cyan light on CIE1931 chromaticity diagram, which led to a slight blue shift rather than the yellow–green color of the pure SrAl204: Eu2+, Dy3+ phosphor powder.

A new amino silane coupling agent for old corrugated container fibers/high density polyethylene composites

The effects of a silane coupling agent such as (N‐(n‐butyl)−3‐aminopropyltrimethoxy silane) on old corrugated container (OCC) fibers, as a recyclable material, were studied on the ultimate strength of the prepared OCC fibers/high density polyethylene composites. Raw materials were mixed in a counter‐rotating twin‐screw extruder and injection molding machine was used to make samples. Various characterization methods, based on ASTM standard, were conducted to evaluate physical properties (water absorption and thickness swelling) and mechanical behavior (tensile, flexural, impact, hardness, and elongation‐at‐break) of the composites. Also, the thermal properties of the specimens were recorded by differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA). Finally the results of the treated samples were compared with the non‐treated and pure polymer specimens. The obtained results showed that increasing coupling agents by a maximum of 2 wt% enhanced mechanical behavior (including flexural and tensile strengths), thermal stability, and increased crystallinity of the composites. Moreover, water absorption and thickness swelling of composite materials declined. Morphological studies by scanning electron microscopy methods (SEM) indicated that fiber pull‐out decreased in treated samples and coupling agent facilitated strong adhesion in fiber/polymer interface. The highest flexural strength and modulus were obtained in composites with 2 wt% silane coupling agent and 30 wt% OCC fibers. POLYM. COMPOS., 39:2054–2064, 2018. © 2016 Society of Plastics Engineers

Amine-graphene oxide/waterborne polyurethane nanocomposites: effects of different amine modifiers on physical properties

To study the dispersity of different amine-graphene oxide (amine-GO) in polymer matrix and the interfacial interactions between functionalized graphene oxide and matrix, two kinds of modifiers—organoamine- and aminosilane-coupling agents—were used to functionalize graphene nanosheets to obtain functionalized graphene oxide/waterborne polyurethane nanocomposites by in situ polymerization. The chemical structure, morphology, and interlayer space of amine-GO nanoplatelets were confirmed by FT-IR, Raman, TGA, XPS, TEM, AFM, and XRD. The dispersity behaviors between different amine-GOs and polymers were evaluated by FESEM. The thermal, mechanical, and hydrophobic properties of the nanocomposites were investigated by TGA, tensile testing machine, and water contact angle test, respectively. It was found that the tensile strength of nanocomposites was increased from 10.13 to 27.79 and 28.96 Mpa after the addition of amine-GO functionalized by APTMS and APTES, respectively. The better thermal stability and hydrophobicity of nanocomposites were also achieved by the addition of amine-GO, especially those modified by aminosilane-coupling agents. This study paves a new route for designing and developing chemically converted graphene oxide nanosheets/polymer nanocomposite materials by altering suitable amine-modifier to functionalize graphene oxide nanosheets and then optimizing the interphases between graphene oxide nanosheets and polymer matrices.

High-Performance PEBA2533-Functional MMT Mixed Matrix Membrane Containing High-Speed Facilitated Transport Channels for CO2/N2 Separation

A novel mixed matrix membrane was fabricated by establishing montmorillonite (MMT) functionalized with poly(ethylene glycol) methyl ether (PEG) and aminosilane coupling agents in a PEBA membrane. The functional MMT played multiple roles in enhancing membrane performance. First, the MMT channels could be used as high-speed facilitated transport channels, in which the movable metal cations acted as carriers of CO2 to increase the CO2 permeability. Second, due to mobility of long-chain aminos and reversible reactions between CO2 and amine groups, the functional MMT could actively catch the CO2, not passively wait for arrival of CO2, which can facilitate the CO2 transport. At last, PEG consisting of EO groups had excellent affinity for CO2 to enhance the CO2/N2 selectivity. Thus, the as-prepared functional MMMs exhibited good CO2 permeability and CO2/N2 selectivity. The functional MMM doped with 40 wt % of MMT-HD702-PEG5000 displayed optimal gas separation with a CO2 permeability of 448.45 Barrer and a CO2/N2...

Radiolabeled D-Penicillamine Magnetic Nanocarriers for Targeted Purposes.

The aim of this study is to synthesize D-Penicillamine (D-PA) conjugated magnetic nanocarriers for targeted purposes. Magnetic nanoparticles were prepared by partial reduction method and surface modification was done with an amino silane coupling agent's (structural properties), AEAPS, the particles were characterized by Scanning Electron Microscope (SEM), X-ray Diffraction (XRD). After that D-PA was linked with the magnetic nanoparticles (MNPs) and has been radiolabeled with [99mTc(CO)3]+ core. Quality controls of [99mTc(CO)3-MNP-D-PA] were established by Cd(Te) detector. The radiolabeling efficiency of magnetic nanoparticles ([99mTc(CO)3-MNP-D-PA]) was about 97.05% with good in vitro stability during the 24 hour period. As a parallel study, radiolabeled D-PA complex ([99mTc(CO)3-D-PA]) was prepared with a radiolabeling yield of 97.93%. At the end, biologic activities of binding complexes were investigated on MCF7 human breast cancer cells. Our results show that, radiolabeled magnetic nanoparticles with core [99mTc(CO)3]+ ([99mTc(CO)3-MNP-D-PA]) showed the highest uptake on MCF7 cells which were applied magnetic field in the wells. In that case, result of this study emphasizes that radiolabeled magnetic nanoparticles with core [99mTc(CO)3]+ would support new occurrences of new agents.

Use of amino silane coupling agent to improve physical and mechanical properties of UF-bonded wheat straw (Triticum aestivum L.) poplar wood particleboard

We evaluated the potential use of amino silane coupling agent (SiNH) to improve physical and mechanical properties of UF-bonded wheat straw (Triticum aestivum L.) poplar wood particleboard. We examined the effects of varied content of silane coupling agent content and ratios of straw to poplar wood particles on particleboard properties. The ratios of straw to poplar wood particles were 100:0, 85:15, 70:30 and 55:45. Silane coupling agent content was tested at three levels, 0, 5 and 10 %. The experimental panels were tested for their mechanical strength, including modulus of elasticity (MOE), modulus of rupture (MOR), internal bonding (IB) and physical properties according to procedures specified in DIN 68763 (Chipboard for special purposes in building construction: concepts, requirements, testing, 1982–03, 1982). All board properties were improved by the addition of silane coupling agent. The use of poplar wood particles had a positive effect on the mechanical properties of wheat straw particleboard but had a negative effect on physical properties (thickness swelling and water absorption).

Nanosilica‐immobilized UV absorber: synthesis and photostability of polyolefins

AbstractA nanosilica‐immobilized UV absorber (SiO2‐APTMS‐UVA) was prepared by the following methods: the fumed nanosilica was first modified with an aminosilane coupling agent 3‐aminopropyltrimethoxysilane (APTMS) and then reacted with hydroxy‐benzoyl chloride. Several measurements confirmed that the UV absorber was chemically immobilized on the surface of the nanosilica. SEM observation showed that SiO2‐APTMS‐UVA was homogeneously dispersed in the matrix of low density polyethylene (LDPE) and polypropylene (PP). The photo‐degradation of the nanocomposites was evaluated by an accelerated aging test. It was found that the SiO2‐APTMS‐UVA has a great effect on preventing the degradation of LDPE or PP under UV exposure. © 2015 Society of Chemical Industry

High density polyethylene/cenosphere composites reinforced with multi-walled carbon nanotubes: Mechanical, thermal and fire retardancy studies

Nanocomposites of high density polyethylene (HDPE) along with lightweight hollow fly ash cenospheres and acid functionalized multi-walled carbon nanotubes (MWCNT) have been developed. In order to enhance the interfacial adhesion, an epoxy functionalized HDPE has been added to the composites while the cenospheres have been surface modified using aminosilane coupling agent. Improvement in mechanical properties for the nanocomposites using both cenospheres and MWCNT was seen and were further analysed using micromechanical models. The addition of both cenospheres and MWCNT together exhibited synergism which led to lowering of peak heat release rates as observed by cone calorimetry. A uniform char layer was formed by using both the fillers together. The nanocomposites showed enhanced thermal stability. Differential scanning calorimetric analysis indicated lowered crystallinity percentage values of the HDPE phase due to improved interfacial interactions.

Wide spectral response and enhanced photocatalytic activity of TiO2 continuous fibers modified with aminosilane coupling agents

N–Si co-doped TiO2 continuous fibers were prepared by a modified sol–gel method combined with centrifugal spinning. Three aminosilane coupling agents, namely γ-aminopropyltriethoxysilane (APTES), γ-aminopropyltrimethoxysilane (APTMS) and N-(2-aminoethyl)-3-aminopropyltriethoxysilane (AEAPTES), were selected as novel different Si and N dopants. The fibers were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), N2 adsorption–desorption, and UV–vis diffuse reflectance spectroscopy (DRS). The results indicated that Si and N were incorporated into the lattice of TiO2. Si doping enhances surface area, delays the phase transformation from anatase to rutile and improves the UV photocatalytic activity, while N doping improves visible light absorption. In the case of APTES as a modifier at a Si/Ti molar ratio of 0.15, TiO2 fibers with a mixed crystalline phase at an anatase/rutile ratio of 77:23 and the largest Brunauer–Emmett–Teller (BET) specific surface area were obtained at 900°C. It displayed the highest wide spectral responsive photoactivity, and the degradation rate of the azo dye reactive brilliant red X-3B in aqueous solution reached 96.6% for 90min and 96.4% for 180min under UV and visible light irradiation, respectively. In addition, the degradation efficiency was still maintained at>90% for 5 cycles. The resulting wide spectral responsive fibers possess enormous advantages in water treatment.