Nano Silicate Research Articles

Nano Silica as A Promising Alternative in Control Sytophillus oryzae (L) (Coleoptera: Curculionidae)

Sitophilus oryzae (L.) is a serious primary insect pest of the stored rice, wheat and maize grain. The present study aims to determine the efficiency of the three nano- candidates (hydrophilic, hypophilic and lipophilic silicate). These nano silicate products were tested against the rice weevil Sitophilus oryzae under laboratory conditions. Results showed that the number of mortality of S. oryzae were 51.0 ± 9.1, 70. 4 ± 9.6 and 73.0 ± 6.2 individuals after investigated with 5 mg/kg-1, the number of mortality scored a higher mortality reached to 99.0 ± 6.7, 89.0 ± 4.2 and 93.00 ± 2.2 with 10 mg/kg-1. In 20 mg/kg-1 treatments the number mortality of S. oryzae were significantly increased to 100.0 ± 0.0, 100.0 ± 0.0 and 100.0 ± 0.0 14 days post application, as compared to 1.0 ± 2.8, 1.0 ± 5.1 and 0.0 ± 3.1, respectively in the control and 79.0 ± 3.2, 69 ± 2.1 and 98 ± 3.1 with deltamethrin treatments. Number of emerged adults and the original activity remaining OAR% were calculated where it gave with 20 mg/kg-1 treatments 95.55, 95.16, 94.59, 74.24, 44.82 and 39.93 OAR% while it gave 94.07, 92.25, 88.54, 42.80, 26.20 and 0.00 OAR% with hydrophobic silicate. With lipophilic silicate the OAR% scored 94.81, 95.16, 92.36, 29.09, 16.55 and 7.29 after 20, 40, 60, 80, 100 and 120 days post treatment in comparison to 95.92, 94.51, 92.01, 60.20, 27.24 and 12.15 with deltamethrin. LC50 found to be 160, 220 and 330 mg/kg -1 for hydrophilic, hypophilic and lipophilic silicate; respectively while it is 40 mg/kg -1 in case of Deltamethrin. This investigation lead to open up newer pathway of using nanomaterial-based technology using hydrophilic nano silicate at 20 mg/kg-1 as an efficient candidate to control the rice weevil.

Surface composition and role of hydrophilic diamonds in foam separation

The article presents new test results on structural and chemical properties of mineral formations on the surface of natural hydrophilic diamonds using Raman, X-ray phase and Auger spectroscopy methods. Analysis of morphological features of nano formations involved scanning electron microscope Jeol-5610 and analyzer INCA. Based on the studies into phase composition of diamonds non-recovered in the circuit of kimberlite ore processing, two types of mineral formations are discovered on their surface: microformations as silicate nature globules less than 1 μm in size and silicate nano films more than 5 nm thick. The tests detect also presence of layered talc silicates that make diamond surface hydrophilic.

Interaction of novel fluorescent nanoscale ionic silicate platelets with biomaterials for biosensors.

The nano silicate platelets (NSPs) of 100 × 100 × 1 nm(3) in dimension were previously derived from the exfoliation of naturally occurring sodium montmorillonite clay, and their affinity to the surface of bacteria was revealed. The unique characteristics of ionic charges (≡Si-O-Na(+)) and the presence of siloxanol functionalities (≡Si-OH) allowed the organic modification of NSP to form NSP-tethering poly(hydroxyethyl methacrylate) (PHEMA) pendants through a sol-gel and living polymerization. By attaching nathphalimide-type fluorescence onto NSP-PHEMA, a new class of fluorescent organic-inorganic hybrid (NSP-PHEMA-HA), was prepared and its photoluminescence (PL) and bacterial trapping properties were characterized. The investigation of PL emission revealed that the fluorescent NSP hybrids could be used to detect bacteria and possess the potential for the biosensor applications.

New heat resistant nanocomposites reinforced silicate nanolayers containing triazine rings based on polyamide: Synthesis, characterization, and flame retardancy study

N1,N1′‐(6‐methoxy‐1,3,5‐triazine‐2,4‐diyl)dibenzene‐1,4‐diamine (MTDA) containing triazine ring structure was synthesized and characterized. A new, montmorillonite (Mt) modified by MTDA (MTDA‐Mt), was prepared by ion‐exchange of sodium montmorillonite (Na+‐Mt) with protonated form of MTDA. It was confirmed by Fourier transform infrared spectroscopy and X‐ray powder diffraction (XRD) techniques. The results of XRD indicated that MTDA had intercalated with Na+‐Mt. A new polyamide (PA) containing triazine ring was synthesized by direct polycondensation reaction of 4,4′‐(6‐methoxy‐1,3,5‐triazine‐2,4‐diyl)bis(azanediyl)dibenzoic acid and 4,4′‐diaminodiphenylether and characterized. PA/MTDA‐Mt nanocomposites containing 4 and 8 mass% of MTDA‐Mt were prepared via blending of MTDA‐Mt with the PA by solution intercalation technique in N‐methyl‐2‐pyrrolidone. The nanostructures and properties of the PA/MTDA‐Mt nanocomposites were investigated using different techniques. Transmission electron microscopy and XRD results revealed the good dispersion nano silicate layers in the polymer matrix. Thermal properties and flame retardancy of the resulting PA/MTDA‐Mt nanocomposites were investigated by thermal gravimetry analyses and microscale combustion calorimetry techniques. The results showed that the addition of MTDA‐Mt enhanced the flame retardancy of PA, reflecting the decrease in heat release rate from 111 W/g for PA to 91 and 77 W g−1 for PA/MTDA‐Mt nanocomposites. POLYM. COMPOS., 188–198, 2016. © 2014 Society of Plastics Engineers

에폭시/층상실리케이트 나노콤포지트의 주파수 가속열화에 따른 부분방전 저항성

Frequency accelerated partial discharge resistance (PDR) aging of epoxy/layered silicate nanocomposite with 1.5wt % additions of layered silicate was investigated in comparison with that of epoxy without layered silicate in terms of PD(partial discharge) erosion depth. It was found that the change in the erosion depth is far smaller in specimens with layered silicate than those without layered silicate nano particles. Frequency acceleration can be done from 60Hz to 1000Hz. But the depth of erosion is less proportional to frequency. Acceleration factor is almost 2 times between 500Hz and 1000Hz, but it is much less than about 8.3 times between 60Hz and 500Hz. This superior PD resistance is caused by the presence of nanofillers, anano-effect due to closely packed nanofillers, and strong chemical bonds at layered silicate nanofillers /resin interfaces.

Synthesis, characterization and photo behavior of new poly(amide-imide)/ montmorillonite nanocomposite containing N,N'-pyrromellitoyl-bis-L-alanine

Two new samples of poly(amide-imide)-nanocomposites were synthesized by insertion nano silicate particles in poly(amide-imide) (PAI) chains using a convenient solution intercalation technique. PAI as a source of polymer matrix was synthesized by the direct polycondensation reaction of N,N'-pyrromelitoyl-bis-L-alanine with 4,4'-diamino diphenyl ether in the presence of triphenyl phosphite (TPP), CaCl2, pyridine and N-methyl-2-pyrrolidone (NMP). Morphology and structure of the resulting PAI-nanocomposite films with 5 and 10% silicate particles were characterized by FTIR spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effect of clay dispersion and the interaction between clay and polymeric chains on the properties of nanocomposites films were investigated by using UV-Vis spectroscopy, thermogravimetric analysis (TGA) and water uptake measurements. KEY WORDS: Nanocomposite, Poly(amide-imide), Silicate particle, Polycondensation, Thermal behavior Bull. Chem. Soc. Ethiop. 2013, 27(3), 459-467.DOI: http://dx.doi.org/10.4314/bcse.v27i3.15

New thermally stable nanocomposites reinforced silicate nanoparticles containing phosphine oxide moiety based on poly(amide-imide): synthesis, characterization and flame retardancy study

New type of nanocomposite materials were produced using a poly(amide-imide) (PAI) matrix and novel organoclay as a reinforcing agent by solution intercalation technique in N-methyl-2-pyrrolidone (NMP). The organoclay was prepared from Cloisite Na+ and protonated form of bis(3-amino phenyl)phenyl phosphine oxide via ion-exchange reaction. It was confirmed by Fourier transform infrared spectroscopy and X-ray powder diffraction techniques. A new PAI containing phenylacetic acid moiety was synthesized by direct polycondensation reaction of 2,2′-(5,5′-oxybis(1,3-dioxoisoindoline-5,2-diyl))bis(2-phenylacetic acid) as a new diacid and 4,4′-diaminodiphenylsulfone. Poly(amide-imide)/nanocomposites (PAIN)s containing 4 and 8 % of new organoclay were prepared via solution intercalation method through blending of organoclay with the PAI solution. The nanostructures and properties of the PAINs were investigated using different techniques. Transmission electron microscopy and XRD results revealed the good dispersion nano silicate layers in the polymer matrix. Thermal properties and flame retardancy of the resulting PAINs were investigated by thermal gravimetry analyses and microscale combustion calorimetry techniques. Organoclay shows a good effect on improving the flame retardancy of the PAI, reflecting the decrease in heat release rate (HRR) from 250 W/g for PAI to 185 and 157 W/g for PAINs, while the thermal stability of the PAI nanocomposites only increased slightly compared to the neat polymer.

Correction to Evaluation of the Antibacterial Activity and Biocompatibility for Silver Nanoparticles Immobilized on Nano Silicate Platelets

Correction to Evaluation of the Antibacterial Activity and Biocompatibility for Silver Nanoparticles Immobilized on Nano Silicate Platelets

Evaluation of the Antibacterial Activity and Biocompatibility for Silver Nanoparticles Immobilized on Nano Silicate Platelets

Silver nanoparticles (AgNPs) are known for their bactericidal abilities. The antibacterial potency is dependent on the particle size and dispersion status. In this study, we synthesized AgNP/NSP nanohybrids in two different weight ratios (1/99 and 8/92) using the fully exfoliated clay, i.e., nanosilicate platelets (NSP), as a dispersing agent and carrier for AgNPs. Due to the size of NSP, the immobilized AgNPs do not enter cells readily, which may lower the risk associated with the cellular uptake of AgNPs. The biocompatibility, immunological response, and antimicrobial activities of AgNP/NSP hybrids were evaluated. The results revealed that AgNP/NSP hybrids elicited merely mild inflammatory response and retained the outstanding antibacterial activity. The hybrids were further embedded in poly(ether)urethane (PEU) to increase the biocompatibility. At the same silver content (20 ppm), the PEU-AgNP/NSP nanocomposites were nontoxic to mouse skin fibroblasts, while simultaneously exhibiting nearly complete bacterial growth reduction (99.9%). PEU containing the same amount of free AgNPs did not display such an effect. Our results verify the better biosafety of the AgNPs/NSP hybrids and their polymer nanocomposites for further clinical use.

The biocompatibility and antimicrobial activity of nanocomposites from polyurethane and nano silicate platelets

Nanocomposites from a polyether-type waterborne polyurethane (PU) and 0.1 wt % of silicate materials were prepared. The individual silicate materials were natural clays (montmorillonite and mica), their exfoliated clays [nano silicate platelets (NSP) and nano mica platelets], and NSP modified with C18 fatty amine (NSP-S). The physico-chemcical properties and antimicrobial activity of the nanocomposites were characterized in vitro. The biostability and biocompatibility of the nanocomposites were evaluated in vivo. The nanocomposites exhibited various surface morphologies with phase separation of hard and soft domains in nanometric scales. The nanocomposite containing NSP (PU-NSP) showed better endothelial cell attachment and gene expression. The better biocompatibility of PU-NSP and PU-NSP-S was evidenced by the lower thickness of foreign body capsules in rat subcutaneous implantation. PU-NSP had the least surface degradation in vivo as demonstrated by the electron microscopy and infrared spectroscopy. This may be associated with the different surface structure. PU-NSP and PU-NSP-S showed strong bacteriostatic effects, which suggested that the nano clay in the polymer matrix may still interact with the microbes.

Non-sticky silicate replica mold by phase conversion approach for nanoimprint lithography applications

We have developed a transparent, non-sticky silicate nano mold with high mechanical strength and excellent releasing properties through a simple phase conversion process of polyvinylsilazane (PVSZ) replica mold. This inexpensive inorganic polymer derived silicate mold does not require extra surface modification and could be used as an ideal mold with low adhesion force for nanoimprint lithographic applications. The silicate hard nano mold allows fabrication of sub-100 nm patterns down to 30 nm. The mold can be used for both UV and thermal NIL duplication processes in a repeated manner. The economic efficiency of the mold fabrication as well as the high durability and excellent releasing properties could be quite valuable to physical contact nanolithography for high-throughput fabrication of nano-devices.

Mechanical behavior of activated nano silicate filled cement binders

This investigation aimed to develop structural blended cement pastes with high mechanical properties for building envelope purposes. The effect of nano silicate (NS) replacement on the properties of blended white cement pastes as compared with the control paste have been studied through the measurements of indirect tensile strength (ITS). NS was thermally activated at 850 °C for 2 h and used to partially replace Portland white cement (PWC) at different ratios. The activation effect of NS on the ITS have also been studied. The cement pastes were prepared using water of consistency. The pastes were removed from the mold after 24 h and then immersed in a water bath for hydration. The 7-day aged pastes were tested after drying for 24 h at 105 °C. Different physical properties such as thermal resistivity, solar reflectivity, water absorption and apparent porosity were measured. It was found that, activation of NS decreases the porosity allowing the blended cement paste to be denser, consequently increasing the ITS. Increasing the replacement content of unactivated NS upto 2%, improved the ITS by about 40% compared with the control paste. Also, the thermal activation of the NS has a very good influence in enhancing the ITS to about 50% with respect to the 2% unactivated blended paste. The results also showed that increasing the replacement content generally increases the water absorption and the porosity of blended white cement pastes, while, slightly improving the thermal resistivity. Activation of NS reduced the solar reflectivity of blended pastes as compared with unactivated blended pastes. An optimum replacement of around 2% can be concluded from the current work.

Influence of Mixed Field Radiation and Gamma Radiation on Nano Adhesive Bonding of HP Polymer

In this investigation, attempts are made to fabricate high performance polymer such as polybenzimidazole (PBI) (service temperature ranges from -260°C to +500°C) by nano silicate epoxy adhesive and to see its performance under space radiation. The polybenzimidazole sheets are fabricated by high performance nano adhesive i.e., by dispersing silicate nano powder into the ultra high temperature resistant epoxy adhesive (DURALCO 4703, the service temperature of the adhesive is -260°C to +350°C) with 2 to 20% weight ratios with the matrix adhesive. Prior to fabrication of polybenzimidazole sheet, the surface of the polybenzimidazole is ultrasonically cleaned by acetone followed by its modification through low-pressure plasma by using 13.56 MHz RF Glow Discharge with 30, 60, 120, 240 and 480 seconds at 100 W of power using nitrogen as process gas. It is observed that polar component of surface energy leading to total surface energy of the polymer increases with exposure time of low pressure plasma up to 120 seconds and then it saturates. Nano adhesive bonding of high performance polymer is exposed to two types of radiations (i) mixed field radiation for 24 hours at a dose rate of 37kGy/hr in the pool of a SLOWPOKE-2 (safe low power critical experiment) nuclear reactor and (ii) Co-60 irradiation with 100 % gamma radiation at a dose rate of 4 kGy/hr for 60 hours. Tensile lap shear strength reveals that when the polymer surface is modified by low pressure plasma, joint strength increases from 1 MPa to 13 MPa and increases further up to 23 MPa when the polymer is fabricated by nano silicate epoxy adhesive with increasing weight ratios of silicate nano powder up to 10% and then it deteriorates with the increasing weight ratio of silicate nano powder. When this nano silicate epoxy adhesive joint is exposed to high-energy radiation of mixed field, there is a further considerable increase in joint strength up to 30 MPa. However, when the nano silicate epoxy adhesive joint is exposed to 100 % gamma rays condition, joint strength deteriorates. Therefore, this is possible that mixed field radiation; basically increase the crosslink density of the adhesive resulting in increase in adhesive joint strength and in the second case: gamma radiation is detrimental and which could essentially makes chain scission to the basic adhesive and resulting in significant deterioration of joint strength. Finally, to understand the behaviour of nano silicate epoxy adhesive bonding of Polybenzimidazole, the fractured surfaces of the joints are examined by scanning electron microscope.

Magnetic Nanoparticles with Core/Shell Structures

Oxidized paraffin wax was used as a compatibilizer in composites of linear low-density polyethylene and layered nano silicate clays. X-ray diffraction analyses were carried out to investigate the crystalline morphology of five types of clays, oxidized wax, and their composites with LLDPE. The composites exhibited different X-ray diffraction and dynamic mechanical behaviour in the presence of different clays. Generally, the composites retained the partially crystalline behaviour of LLDPE, and no exfoliation was observed. Increased amount of wax did not change the morphology in most cases. The incorporation of clay resulted in an observable increase in the storage modulus of LLDPE. These values also increased with the addition of oxidized wax for most of the composites. The loss modulus increased with the amount of clay, irrespective of its nature. In most cases these values also increased with the incorporation of wax. The composites with 10% clay and 10% oxidized wax showed the highest storage and loss moduli, irrespective of the nature of the clay. The tan delta values did not change considerably with the addition of clay or wax.

Oxidized Wax as Compatibilizer in Linear Low-Density Polyethylene-Clay Nanocomposites: X-ray Diffraction and Dynamic Mechanical Analysis

Oxidized paraffin wax was used as a compatibilizer in composites of linear low-density polyethylene and layered nano silicate clays. X-ray diffraction analyses were carried out to investigate the crystalline morphology of five types of clays, oxidized wax, and their composites with LLDPE. The composites exhibited different X-ray diffraction and dynamic mechanical behaviour in the presence of different clays. Generally, the composites retained the partially crystalline behaviour of LLDPE, and no exfoliation was observed. Increased amount of wax did not change the morphology in most cases. The incorporation of clay resulted in an observable increase in the storage modulus of LLDPE. These values also increased with the addition of oxidized wax for most of the composites. The loss modulus increased with the amount of clay, irrespective of its nature. In most cases these values also increased with the incorporation of wax. The composites with 10% clay and 10% oxidized wax showed the highest storage and loss moduli, irrespective of the nature of the clay. The tan delta values did not change considerably with the addition of clay or wax.

Structure and characterization of Chinese fir (Cunninghamia lanceolata) wood/MMT intercalation nanocomposite (WMNC)

With water-soluble phenol-formaldehyde resin as an intermediate, Chinese fir (Cunninghamia lanceolata) wood/montmorillonite nanocomposite (WMNC) was prepared through vacuum impregnation and characterized with XRD, SEM, FTIR and TG-DTA analyses. The XRD analysis indicated that the wood crystallinity of WMNC decreased, the MMT exfoliated and some nano silicate layers entered into the non-crystallized microfibrillar region of the wood cell wall. Wood structure is anisotropic and its impregnation is anisotropic. Due to the nonuniformity of the MMT organic modification, PF intercalation and wood impregnation, the MMT configuration and distribution in wood were diverse. The SEM graphs of WMNC showed that some silicate grains were blocked in the wood cell lumen, some silicate layers adhered to the inner surface of the wood cell wall, and some exfoliated MMT layers even penetrated the wood cell wall. The obtained hydroxyl of WMNC increased and its ether linking decreased. It was considered that MMT and wood interacted not only with hydroxyl bonds, but also involved some chemical linking. Compared with untreated wood and the PF-impreg, the pyrolysis process of WMNC changed; its starting decomposing temperature decreased and its pyrolysis weight loss at high temperatures greatly decreased. The WMNC indicated certain nanoeffects of the composition of the inorganic MMT nanolamellae.

Effect of oxidized paraffin wax on the thermal and mechanical properties of linear low-density polyethylene–layered silicate nanocomposites

Oxidized paraffin wax was used as a possible compatibilizer in composites containing LLDPE and layered nano silicate clays. The samples were analysed using X-ray diffraction (XRD), tensile analysis, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). There was no exfoliation or intercalation of the clay layers in the absence of wax, while an obvious increase in d-spacings was observed when the samples were prepared with wax present. Generally, the modulus increased with both clay and wax contents, while the tensile strength generally decreased. The type of modifier in the clay determined the extent of the changes in these properties. The thermal stability of linear low-density polyethylene (LLDPE) generally improved with increasing clay content, but the presence of wax seems to slightly reduce the thermal stability, although these samples were still more thermally stable than pure LLDPE. Both clay and wax had an obvious influence on the crystallization behaviour of LLDPE, which was also determined by the type of modifier in the clay.

Preparation and characterization of wood/montmorillonite nanocomposites

With montmorillonite (MMT) organically modified as organophilic MMT (OMMT) and water-soluble phenol formaldehyde resin (PF) as intermediate, Chinese fir (Cunninghamia lanceolata) wood/MMT nanocomposites (WMNC) were prepared via nano intercalation compounding and characterized by XRD, SEM and FTIR. Results show that: 1) the preparation of OMMT is very successful; 2) the self-made PF can effectively intercalate into MMT to increase markably its gallery distance and even exfoliate its nano silicate laminae; 3) the XRD analysis indicates that some exfoliated MMT enters the non-crystallized region of microfibrils in wood cell walls and the crystallinity degree of wood in WMNC decreases; 4) the SEM graphs show that multiform MMT exists in WMNC. Some grains block in wood cell lumen, some layers adhere to the wood surface of the inner cell wall and some exfoliated nanolaminae even insert into wood cell walls; and 5) the FTIR analysis suggests that MMT and wood in WMNC perhaps interact via certain chemical bonding.