Amino Silane Research Articles

Role of curing conditions and silanization of glass fibers on carbon nanotubes (CNTs) reinforced glass fiber epoxy composites

Curing behavior of amino-functionalized carbon nanotubes (ACNT) used as reinforcing agent in epoxy resin has been examined by thermal analysis. Experiments performed as per supplier’s curing conditions showed that modification of the curing schedule influences the thermo-mechanical properties of the nanocomposites. Specifically, the glass transition temperature (Tg) of ACNT-reinforced composites increased likely due to the immobility of polymer molecules, held strongly by amino carbon nanotubes. Further, a set of composites were prepared by implementing the experimentally determined optimal curing schedule to examine its effect on the mechanical properties of different GFRP compositions, while focusing primarily on reinforced ACNT and pristine nanotube (PCNT) matrix with silane-treated glass fibers. From the silane treatment of glass fibers in ACNT matrix composition it has been observed that amino silane is much better amongst all the mechanical (tensile and flexural) properties studied. This is because of strong interface between amino silane-treated glass fibers and modified epoxy resin containing uniformly dispersed amino-CNTs. On the other hand, PCNT GFRP composites with epoxy silanes demonstrated enhanced results for the mechanical properties under investigation which may be attributed to the presence of strong covalent bonding between epoxy silane of glass fiber and epoxy–amine matrix.

Multiresidue determination of 29 pesticide residues in pepper through a modified QuEChERS method and gas chromatography-mass spectrometry.

This study describes the development and use of a modified quick, easy, cheap, effective, rugged and safe (QuEChERS) method coupled with gas chromatography with mass spectrometry to determine 29 pesticide residues in green, red and dehydrated red peppers. Pesticides were extracted with acetonitrile (1% acetic acid), partitioned with sodium chloride and purified with primary secondary amino and octadecyl silane in acetone. The QuEChERS extraction conditions were optimized, and the matrix effects that might influence recoveries were evaluated and minimized using matrix-matched calibration curves. Under the optimized conditions, the calibration curves for 29 pesticides showed good linearity in the concentration range of 0.1-10 μg/mL with determination coefficient R(2) >0.998. The limits of quantification of the 29 pesticides were 0.006-0.06 mg/kg for green pepper, 0.005-0.039 mg/kg for red pepper and 0.014-0.25 mg/kg for dehydrated red pepper. These values are below the suggested regulatory maximum residue limits. The mean recoveries ranged between 70.1 and 110%, and the relative standard deviations were <13%. The developed method was successfully applied to commercial samples. Some samples were found to contain the 29 pesticides with levels below the legal limits. Copyright © 2016 John Wiley & Sons, Ltd.

Formation of Reversible Clusters with Controlled Degree of Aggregation.

We develop a reversible colloidal system of silica nanoparticles whose state of aggregation is controlled reproducibly from a state of fully dispersed nanoparticles to that of a colloidal gel and back. The surface of silica nanoparticles is coated with various amino silanes to identify a silane capable of forming a monolayer on the surface of the particles without causing irreversible aggregation. Of the three silanes used in this study, N-[3-(trimethoxysilyl)propyl]ethylenediamine was found to be capable of producing monolayers up to full surface coverage without inducing irreversible aggregation of the nanoparticles. At near full surface coverage the electrokinetic behavior of the functionalized silica is completely determined by that of the aminosilane. At acidic pH the ionization of the amino groups provides electrosteric stabilization and the system is fully dispersed. At basic pH, the dispersion state is dominated by the hydrophobic interaction between the uncharged aminosilane chains in the aqueous environment and the system forms a colloidal gel. At intermediate pH values the dispersion state is dominated by the balance between electrostatic and hydrophobic interactions, and the system exists in clusters whose size is determined solely by the pH. The transformation between states of aggregation is reversible and a reproducible function of pH. The rate of gelation can be controlled to be as fast as minutes while deaggregation is much slower and takes several hours to complete.

Processing of Functionalized and Pristine Carbon Nanotube Epoxy Composites with Silane-Treated Glass Fiber

In this work, an attempt has been made to study the bonding between the silane coupling agents and the glass fiber (GF) surface. The mechanical properties of the composites so obtained have been specifically analyzed. It has been experimentally found that epoxy silane (ES)-treated GF mat in a neat epoxy matrix showed considerable improvement compared to amino silane (AS)-treated GF. The effect of heat treatment on GF has also been looked into. Moreover, a new processing technique has been explored, which involves the use of amino functionalized nanotube (ACNT) and pristine nanotube (PCNT), homogeneously and uniformly dispersed in an epoxy matrix. Additionally, the effect of ES- and AS-treated GF in the presence of PCNTs and ACNTs has been studied and it has been found that AS shows strong interfacial adhesion in the ACNT matrix, whereas ES shows improved mechanical behavior in the PCNT matrix. The findings from this study have certainly helped us design improved fiber reinforced nanocomposites with enhanced mechanical properties suitable for marine structures.

Flame retardants based on amino silanes and phenylphosphonic acid

The sol-gel approach offers a new class of flame retardants with a high potential for textile applications. Pure inorganic sol-gel systems do, however, typically not provide an effect sufficient for a self-extinguishing behavior on its own. We therefore employed compounds with nitrogen and phosphorous containing groups. Especially the combination of compounds with both elements, using the synergism, is promising for the aim to find well-applicable, environmental friendly, halogen-free flame retardants. In our approach, the sol-gel network ensured on the one hand the link to the textile as non-flammable binder. On the other hand, the sol-gel-based networks modified with functional groups containing nitrogen groups provided flame retardancy. In this way, a flame retardant finishing for textiles could be obtained by simple finishing techniques as, e.g., padding. Besides a characterization with various flame tests (e.g., according to EN ISO 15025 – protective clothing), we used a combination of cone calorimetry, thermogravimetry coupled with infrared spectroscopy analysis and scanning electron microscopy to analyze the mechanism of flame retardancy. Thus, we could show that the main mechanism is based on the formation of a protection layer. This work provides a model system for sol-gel-based flame retardants and has the potential to show the principle feasibility of the sol-gel approach in flame retardancy of textiles. It therefore lays the groundwork for tailoring sol-gel layers from newly synthesized sol-gel precursors containing nitrogen and phosphorous groups.

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.

New self assembly monolayer onto SiGe as a selective biosensor for single-strand DNA

An important step of fabrication of selective DNA probe/receptor is the functionalization of semiconducting surfaces with a self-assembled monolayer (SAM) with an appropriate surface termination to interact with DNA. In this work, we studied an immobilization of single-strand DNA (ssDNA) onto self-assembly monolayer of both the heavily exploited aminopropyltriethoxy silane (APTES) and n-(2-aminoethyl)-11-aminoundecyltrimethoxysilane (NAATS), a bi-functional amino silane onto the surface of SiGe substrate. X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) techniques were employed to characterize the silanization of SAMs on SiGe surface. The immobilization process was confirmed using fluorescence intensity measurements. The coverage values of APTES and NAATS SAMs were estimated to be 71.3 and 83 XPS% at 78°, respectively from the C/Ge ratio. Comparing the performance towards both specific and non-specific ssDNA complements for both silanes, it was observed that a higher selectivity and sensitivity was obtained by using NAATS SAM. This work highlighted the importance of SAM chain length by comparing one short alkyl chains, APTES with that long-chain counterpart, NAATS.

2-Deoxy-D-Glucose Modified Magnetic Nanoparticles with Dual Functional Properties: Nanothermotherapy and Magnetic Resonance Imaging.

Superparamagnetic iron oxide nanoparticles (SPIONs) with appropriate surface chemistry have attracted wild attention in medical and biological application because of their current and potential usefulness such as magnetic resonance imaging (MRI) contrast enhancement, magnetic mediated hyperthermia (MMH), immunoassay, and in drug delivery, etc. In this study, we investigated the MRI contrast agents and MMH mediators properties of the novel 2-deoxy-D-glucose (2-DG) modified SPIONs. As a non-metabolizable glucose analogue, 2-DG can block glycolysis and inhibits protein glycosylation. Moreover, SPIONs coated with 2-DG molecules can be particularly attractive to resource-hungry cancer cells, therefore to realize the targeting strategy for the SPIONs. SPIONs with amino silane as the capping agent for amino-group surface modification were synthesized by the chemical co-precipitation method with modification. Glutaraldehyde was further applied as an activation agent through which 2-DG was conjugated to the amino-coated SPIONs. Physicochemical characterizations of the 2-DG-SPIONs, such as surface morphology, surface charge and magnetic properties were investigated by Transmission Electron Microscopy (TEM), ζ-Potential and Vibrating Sample Magnetometer (VSM), etc. Magnetic inductive heating characteristics of the 2-DG-SPIONs were analyzed by exposing the SPIONs suspension (magnetic fluid) under alternative magnetic field (AMF). U-251 human glioma cells with expression of glucose transport proteins type 1 and 3 (GLUT1 and GLUT 3), and L929 murine fibroblast cell as negative control, were employed to study the effect of 2-DG modification on the cell uptake for SPIONs. TEM images for ultra-thin sections as well as ICP-MS were applied to evaluate the SPIONs internalization within the cells. In vitro MRI was performed after cells were co-incubated with SPIONs and the T2 relaxation time was measured and compared. The results demonstrate that 2-DG-SPIONs were supermagnetic and in spherical shape with -10 nm diameter. Possessing ideal magnetic inductive heating characteristics, which can generate very rapid and efficient heating while upon AMF exposure, 2-DG-SPIONs can be applied as novel candidature of magnetic nanothermotherapy for cancer treatment. Modification of 2-DG can greatly promote the cell uptake of SPIONs and such cellular uptake of 2-DG-SPIONs was time dependent. Surface coating by 2-DG can remarkably enhance the MR imaging ability for the SPIONs on the cells of U251 cancer cells. In summary, our investigation provides a novel glucose analogue modified SPIONs with potential application in the targeting cancer nanothermotherapy and MR imaging.

表面修饰对钛酸钡与聚酰亚胺复合材料结构和介电性能的影响

如何更好的控制相界面来提高介电性能是目前高分子介电复合材料的研究热点之一。本文采用氨基硅烷、油酸和对氨基水杨酸对纳米钛酸钡进行表面修饰，然后通过原位聚合制备了纳米BaTiO3/聚酰亚胺(PI)复合材料。对表面修饰钛酸钡进行了表征，测量了其复合材料的介电性能。研究发现：三种改性剂均能促进BaTiO3在聚酰亚胺中的分散，并且改善复合材料的介电性能。当BT体积分数为15%时，在频率为1K Hz下，复合材料的介电常数达到30，而介电损耗为0.02。 How to well control the phase interfaces to improve dielectric performance is one of the research hotspots in polymer dielectric composites. In this paper, nanometer barium titanate (BT) was modified by amino silane (KH550), oleic acid (OA), and p-aminosalicylic acid (ASA), then their composites with polyimide (PI) were prepared by in-situ polymerization. The modified BT powders were characterized by various techniques, and their composites were tested with respect to the dielectric properties. The results show that these three organic molecules enable the improvement of the dispersity of nanometer BT in PI host, and thus the dielectric properties of the resulting composites. When PI is loaded with 15 vol% nanometer BT, dielectric constant and loss of the composites is 30 and 0.02, respectively.

Fusion-bonded epoxy composite coatings on chemically functionalized API steel surfaces for potential deep-water petroleum exploration

Corrosion of oil and gas pipelines significantly reduces the service life of the pipelines, thus increasing costs, and more seriously, it can cause catastrophic environmental accidents. More recently, the exploitation of oil in ultra-deep seawater fields is facing new technological challenges in material selection owing to the extreme production conditions. Thus, the development of organic coatings as protective layers for steel pipelines is of crucial importance against highly corrosive environments. In this work, fusion bonded epoxy (FBE) coatings were deposited onto chemically functionalized carbon steel surfaces with organosilanes to investigate the potential applications in protection against corrosion and degradation in harsh marine environments. Carbon-steel API 5L X42 (American Petroleum Institute Standard grade) was chemically functionalized with two organosilanes, 3-APTES [(3-Aminopropyl)triethoxysilane], and 3-GPTMS [(3-Glycidyloxypropyl)trimethoxysilane], followed by the deposition of FBE composite coatings. The systems were extensively characterized with respect to each component as well as the steel-coating interface. The contact angle measurements and Fourier transform infrared spectroscopy (FTIR) results clearly indicated that the steel surface was effectively modified by the functional amine and glycidyl silane groups, leading to the formation of interfacial covalent bonds with increased hydrophobicity compared to bare steel surfaces. In addition, the morphological and chemical characterizations of FBE by scanning electron microscopy, atomic force microscopy, X-ray diffraction, and FTIR showed that it is composed of an epoxy-based organic matrix of bisphenol-A diglycidyl ether (DGEBA) reinforced with uniformly dispersed inorganic phases of calcium silicates and TiO2 particles. Moreover, the chemical functionalization of the steel surfaces with amino and glycidyl silanes significantly altered the interfacial forces with the FBE coatings, resulting in higher adhesion strength for 3-APTES-modified steel compared to 3-GPTMS-steel; however, both mostly showed cohesive rupture mode in the FBE component.

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).

Preparation and mechanical properties of carbon nanotube grafted glass fabric/epoxy multi-scale composites

In the present paper, carbon nanotubes (CNTs) were chemically grafted onto surfaces of the amino silane treated glass fabric by a novel chemical route for the first time to create 3D network on the glass fibers. The chemical bonding process was confirmed by Fourier transform infrared spectroscopy and scanning electron microscopy. The glass fabric/CNT/epoxy multi-scale composite laminates were fabricated with the CNT grafted fabrics using vacuum assisted resin infusion molding. Tensile tests were conducted on fabricated multi-scale composites, indicating the grafting CNTs on glass fabric resulted a decrease (11%) in ultimate tensile strength while toughness of the multi-scale composite laminates were increased up to 57%. Flexural tests revealed that the multi-scale composite laminates prepared with CNT grafted glass fabric represent recovering after first load fall. The interfacial reinforcing mechanisms were discussed based on fracture morphologies of the multi-scale composites.

Comparative Study of Corrosion Protection of Sol–Gel Coatings with Different Organic Functionality on Al-2024 substrate

Abstract In this paper we have studied the effect of addition of amino silane and sulfur silane by 2 wt% into a reference coating solution by using two basic silane coupling agents methyl-tri-ethoxy silane (MTEO) and glycidoxy-propyl-tri-ethoxy silane (GPTS) in 1:1 molar ratio by sol–gel technique. The change in hydrophobicity due to the addition of amino group and thiol group was investigated by contact angle study and sol–gel kinetics was studied by Fourier transform infrared spectroscopy. The thermal resistance and surface morphology was analyzed by thermo gravimetric method and scanning electron microscope. The anti corrosion property of all three coatings were evaluated by potentiodynamic polarization study, AC impedance and salt spray method. X-ray photoelectron spectroscopic method was used to monitor the bonding mechanism of coating matrix with the metal surface. All type of investigations revealed that, addition of thiol group containing silane coating to the reference coating solution has caused remarkable improvement in hydrophobicity and corrosion resistance properties where as amine group rendred the surface less hydrophobic and showed no sign of improvement in corrosion protection. The most probable reason behind this improved performance is due to the additional hydrophobicity imparted by much less polar thiol group. But amino silane provided comparatively poor performance due to the presence of polar amine group.

Introduction of thiol moieties, including their thiol–ene reactions and air oxidation, onto polyelectrolyte multilayer substrates

We describe the derivatization of uncross-linked and cross-linked layer-by-layer (LbL) assemblies of polyelectrolytes (polyallylamine hydrochloride and polyacrylic acid) with sulfydryl groups via Traut’s reagent (2-iminothiolane). This thiolation was optimized with regards to temperature, concentration, and pH. The stability of the resulting –SH groups in the air was determined by X-ray photoelectron spectroscopy (XPS). This air oxidation has obvious implications for the use of thiol–ene reactions in materials chemistry, and there appears to be little on this topic in the literature. Three main S 2s signals were observed by XPS: at 231.5eV (oxidized sulfur), 227.6eV (thiol groups), and 225.4eV (thiolate groups). Due to their rapid oxidation, we recommend that thiolated surfaces be used immediately after they are prepared. As driven by 254nm UV light, thiol groups on polyelectrolyte multilayers react with 1,2-polybutadiene (PBd), and residual carbon–carbon double bonds on adsorbed PBd similarly react with another thiol. In the case of a fluorinated thiol, surfaces with high water contact angles (ca. 120°) are obtained. Modest exposures to light result in derivatization, while longer exposures damage the assemblies. Polyelectrolyte–thiol–PBd–thiol assemblies delaminate from their substrates when immersed for long periods of time in water. Surface silanization with an amino silane prevents this delamination and leads to stable assemblies. These assemblies withstand various stability tests. Techniques used to analyze the materials in this study include X-ray photoelectron spectroscopy (XPS), spectroscopic ellipsometry (SE), atomic force microscopy (AFM), and contact angle goniometry.

Synthesis and evaluation of radiolabeled, folic acid-PEG conjugated, amino silane coated magnetic nanoparticles in tumor bearing Balb/C mice

Abstract To design a potent agent for positron emission tomography/magnetic resonance imaging (PET/MRI) imaging and targeted magnetic hyperthermia-radioisotope cancer therapy radiolabeled surface modified superparamagnetic iron oxide nanoparticles (SPIONs) were used as nanocarriers. Folic acid was conjugated for increasing selective cellular binding and internalization through receptor-mediated endocytosis. SPIONs were synthesized by the thermal decomposition of tris (acetylacetonato) iron (III) to achieve narrow and uniform nanoparticles. To increase the biocompatibility of SPIONs, they were coated with (3-aminopropyl) triethoxysilane (APTES), and then conjugated with synthesized folic acid-polyethylene glycol (FA-PEG) through amine group of (3-aminopropyl) triethoxysilane. Finally, the particles were labeled with 64Cu (t 1/2 = 12.7 h) using 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid mono (N-hydroxy succinimide ester) DOTA-NHS chelator. After the characterization of SPIONs, their cellular internalization was evaluated in folate receptor (FR) overexpressing KB (established from a HeLa cell contamination) and mouse fibroblast cell (MFB) lines. Eventually, active and passive targeting effects of complex were assessed in KB tumor-bearing Balb/C mice through biodistribution studies. Synthesized bare SPIONs had low toxicity effect on healthy cells, but surface modification increased their biocompatibility. Moreover, KB cells viability was reduced when using folate conjugated SPIONs due to FR-mediated endocytosis, while having little effect on healthy cells (MFB). Moreover, this radiotracer had tolerable in vivo characteristics and tumor uptake. In the receptor blocked case, tumor uptake was decreased, indicating FR-specific uptake in tumor tissue while enhanced permeability and retention effect was major mechanism for tumor uptake.

Aspects of Interfacial Structure of Silane Coupling Agents in Particulate-Filled Polymer Composites and the Reinforcement Effect: A Critical Review

In order to form an effective interphase in a polymer composite, the preparation and characterization of silane structure on particle surface and in the interfacial layer in the composite are reviewed. The polycondensation of silane is affected by the concentration and pH of silane solution and the pH of inorganic particle. Pulsed 1H nuclear magnetic resonance (pulsed NMR) analysis is useful to characterize the structure of silane layer on the particle surface. It is found that the linear chain structure formed from dialkoxy type silane is flexible, whereas the network structure formed from trialkoxy type silane is rigid. To form an effective interphase, the linear chain structure formed from dialkoxy type is more useful than the network structure formed from trialkoxy type in the silica-filled rubber composites. The pre-treatment method and the integral blend method are compared in the silica-filled rubber composites. As a result, the dialkoxy type is found to be suitable for the pre-treatment method, whereas the trialkoxy type is suitable for the integral blend method. In the pre-treatment method, the linear silane chains form entanglements with the rubber chains in the interfacial region and improve the reinforcement effect. In the integral blend of trialkoxy type, the formation of the silane network and the entanglement proceed simultaneously during the preparation process and a well-entangled interfacial region is formed. Pulsed NMR analysis for the silica-filled unvulcanized rubber composites is useful to analyze the interfacial layer in the composites. The surface treatment of CaCO3 with a mixture of amino and mercapto functional silanes is found to be useful to improve the reinforcement effect in rubber/CaCO3 composites.

On-line micro column preconcentration system based on amino bimodal mesoporous silica nanoparticles as a novel adsorbent for removal and speciation of chromium (III, VI) in environmental samples.

BackgroundChromium (VI) has toxic and carcinogenic effects. So, determination and speciation of chromium in environmental samples is very important in view of health hazards. In this study, solid phase extraction (SPE) based on bulky amine-functionalized bimodal mesoporous silica nanoparticles (NH2-UVM-7) as a novel nanoadsorbent was applied for preconcentration and speciation of chromium (III, VI) in water samples.MethodsUVM-7 was synthesized via atrane route and subsequently functionalized with amino silane via grafting method. In SPE procedure, polymer tubing as a micro-column was filled with NH2-UVM-7 adsorbent. Preconcentration and speciation of Cr (III) and Cr (VI) ions with NH2-UVM-7 were obtained in water samples due to the fact that only Cr (VI) ions can be complexed with-NH2 groups at optimized pH. Finally, chromium concentration was determined by flame atomic absorption spectrometry (F-AAS).ResultsTEM, XRD, and SEM results confirmed the beneficial properties of NH2-UVM-7 as the adsorbent for chromium extraction. Under the optimal conditions, linear calibration curve, detection limit and preconcentration factor were obtained 6–320 μg/ L, 1.2 μg/L and 66.7, respectively (RSD < 5 %). The efficiency of nanoadsorbent for preconcentration and extraction of Cr (VI) was 96 %, whereas it was less than 5 % for Cr (III).ConclusionsThe developed NH2-UVM7-based SPE/F-AAS method has enough sensitively and simplicity for speciation and determination of Cr (VI) and Cr (III) ions in real water samples. Good recoveries, with low detection limits and good preconcentration factors are the main advantages of this procedure.

Group 1 Complexes of an (Amido-amino)silane and Their Use in the Synthesis of the Bi(III) Amide, Bi(Me2Si{NAr}{N(H)Ar})Cl2 (Ar = 2,6-i-Pr2C6H3)

The synthesis of sodium and potassium salts of the monoanionic, (amido-amino)silane, [Me2Si{NAr}{N(H)Ar}]− (Ar = 2,6-i-Pr2C6H3), and their use as ligand transfer reagents to bismuth are presented. Initial attempts to form Li(Me2Si{NAr}{N(H)Ar) (2) using equimolar amounts of n-BuLi and the neutral compound Me2Si{N(H)Ar}2 (1) gave mixtures of the unreacted di(amino)silane and the known dianion, Li2(Me2Si{NAr}2), on workup. Reaction of 1 with NaH and KH, however, afforded the desired anion in the soluble, crystalline compounds Na(Me2Si{NAr}{N(H)Ar})(THF)3 (3(THF)3) and K(Me2Si{NAr}{N(H)Ar}) (4). The crystal structure of 4 shows a cyclic hexamer [4]6, containing intra- and intermolecular K···π-aryl interactions. Reaction of 3 or 4 with BiCl3 demonstrated that both compounds are effective ligand transfer reagents, affording the bismuth compound Bi(Me2Si{NAr}{N(H)Ar})Cl2 (5). The crystal structure of 5 showed a primary monodentate κ1-N-bonding mode for the ligand with a close Bi···N contact to the neutral amino nitrogen atom. Long range Bi···Cl interactions associate these molecules into dimers, [5]2.

The Effects of Coupling Agents on the Mechanical and Thermal Properties of Eucalyptus Flour/HDPE Composite

The aim of this research was to study the effects of the coupling agents, FusabondTM E-528 (polyethylene-grafted maleic anhydride; PE-g-MA, MA) and Amino Silane (Si), on the thermal properties, and mechanical properties of Eucalyptus flour-HDPE composite. Variation of the Eucalyptus flour contents in the HDPE resulted in properties of the composite. With increasing in the contents of Eucalyptus flour in polymer matrix, the mechanical properties of the HDPE composite decreased in EU-MA series samples while they were gradually decreased in EU-Si series samples. SEM micrographs showed the fracture surface of the HDPE/Eucalyptus composite at different ratios of Eucalyptus flour. SEM micrograpgh exhibited the dispersion of EU flour in polymer matrix. The samples of both coupling agents showed an increase in interfacial adhesion, observed for the considerable decreased of gaps between the matrix and the dispersed phase. However, the EU-MA sample appeared to be more uniformly than the EU-Si sample.

Polymerization of Oriental Lacquer (Urushi) with Epoxidized Linseed Oil as a New Reactive Diluent

A hybrid lacquer (HBL) paint prepared by combining a natural kurome lacquer (KL) paint and an amino silane reagent, for example,N-(2-aminoethyl)-3-aminopropyl triethoxysilane (AATES), produced a polymerized film faster than the KL paint alone. However, the viscosity of the HBL paint was too viscous for easy handling. Addition of 10 wt% of an epoxidized linseed oil, ELO-6, with 6.4 mol% epoxidation as a reactive diluent to the HBL paint decreased the viscosity by 1/2 from 25476 mPa·s to 12841 mPa·s and improved the ease of coatability. The polymerization mechanism was elucidated by NMR measurements of extracts from the resulting polymerization films, suggesting that amino groups in the HBL paint reacted with epoxy groups of ELO-6 in the lacquer matrix, and then the complex reacted with double bonds of the urushiol side-chain by autooxidation and cross-linking reactions to give a hard polymerized film with a high quality of color and gloss. These results indicate that the addition of ELO-6 improved the polymerizability of both KL and HBL paints without decreasing the quality of the resulting films.