Mass Fraction Of Silica Research Articles

Determination of the Nanoscale Silica Mass Fraction by AF4/ICP-MS with Isotope Dilution Analysis Using 29Si-Enriched Silica Nanoparticles.

A methodology based on the use of asymmetrical flow field-flow fractionation (AF4) coupled to ICP-MS with size fraction-targeted isotope dilution analysis (IDA) has been developed, validated, and applied for the first time to determine the mass fraction of nanoscale silica (SiO2). For this purpose, 29Si-enriched SiO2 nanoparticles, to be used as an IDA spike/internal standard, were synthesized and characterized in-house. Double IDA was used to quantify an aqueous suspension of Stöber silica particles of similar characteristics to those of the 29SiO2 nanoparticle (NP) spike using a representative test material of natural Si isotopic composition as the calibrant. For fumed SiO2 NP in a highly complex food matrix, a methodology based on single IDA with AF4/ICP-MS using the same 29SiO2 NP spike was developed and validated. Relative expanded measurement uncertainties (k = 2) of 4% (double IDA) and 8% (single IDA) were achieved for nanoscale silica mass fractions of 5143 and 107 mg kg-1 in water suspension and food matrix, respectively. To assess the accuracy of AF4/ICP-IDMS for the characterization of SiO2 NP in a food matrix, standard addition measurements on samples spiked with Aerosil AF200, also in-house characterized for Si mass fraction, were undertaken, with an average recovery of 95.6 ± 4.1% (RSD, n = 3) obtained. The particle-specific IDA data obtained for both SiO2 NP-containing samples were also compared with that of post-AF4 channel external calibration using inorganic Si standards. The mass fractions obtained by IDA agreed well with those obtained by external calibration within their associated measurement uncertainties.

Interfacial nanolayer effect on thermophysical properties of silica-paraffin phase change material - A molecular dynamics simulation

Thermophysical properties of composite phase change materials (PCMs) are influenced by the interfacial nanolayer. Molecular dynamics (MD) method is used to study the effect of interfacial nanolayer on thermophysical properties of silica-paraffin composite PCM. The simulation results show that the melting enthalpy is reduced from 197.9 J·g−1 to 29.1 J·g−1, and the thermal conductivity is enhanced from 0.142 W·m−1·K−1 to 0.268 W·m−1·K−1, when the silica thickness is increased from 0 to 15.0 Å. The interfacial nanolayer is observed in composite PCM, and its thickness increases with the increase of silica wall thickness. In the composite PCM with 7.0 Å silica wall, a loss of 62.9% in the melting enthalpy is observed, with 32.6% attributed to the silica mass and 30.3% attributed to the nanolayer. Based on that, a modified model is proposed to predict the melting enthalpy of composite PCMs by considering the effects of both silica mass fraction and nanolayer. To reveal the thermal conductivity enhancement mechanism, the total heat flux is decomposed into three terms (namely, kinetic energy term, potential energy term and interaction energy term). It is found that the interaction energy term has the largest contribution to the total heat flux. The presence of nanolayer strengths the interactions, leading to the thermal conductivity enhancement.

Measurement science meets the reproducibility challenge

Measurement science is particularly well equipped not only to meet reproducibility challenges arising within the field of metrology, but also to suggest strategies and best practices for how such challenges can be met in other fields. This contribution illustrates three such challenges, in three different fields, and proposes ways to address them that can supplement the only way in which reproducibility challenges in science can be resolved definitively: by validated scientific advances that point toward the truth. The first example concerns a large interlaboratory, international comparison of the measurement of the mass fraction of silica in a granite reference material, using classical methods of wet analytical chemistry, carried out in the 1940s. The results delivered a shock to analysts worldwide about the state of the art at the time. The challenge was magnified by the fact that none of the measured values was qualified with an evaluation of measurement uncertainty. We offer an approach developed by Andrew Rukhin from NIST, for how to compute a meaningful consensus value in such case, and explain how the associated uncertainty can be characterized. The second example is about the currently hot topic of the Hubble tension, which refers to the mutual inconsistency of the measurement results, obtained by different methods, for the Hubble-Lemaître constant, which expresses the rate of expansion of the Universe. We suggest that such tension can be quantified in terms of the dark uncertainty that figures as a parameter in a laboratory random effects model, thus providing an objective metric whereby progress toward resolving such tension can be gauged. The third example discusses two sources of lack of reproducibility: on the one hand, the fact that different laboratories produced strikingly discrepant values for the mass fraction of arsenic in kudzu; on the other hand, that different models can be fitted to these data, each producing its own set of results. Here we use a Bayesian model selection criterion to choose one from among four models that are natural candidates to address this double reproducibility challenge. This third example also affords us the opportunity to deflate two widespread myths: that one needs at least four observations to obtain a Bayesian evaluation of standard uncertainty, and that sample standard deviations of small samples are systematically too small.

Investigation of Impact Performance of STF Impragnated Composites

It is important to achieve high strength, high modulus of elasticity, good energy damping for lightweight armor materials. For this purpose, two or more similar or different materials are combined at the macro level. In this way, a new structure emerges that we call composite material. A composite is a new structure in which the good properties of the components in its structure become evident in the material. Research on the production and mechanical properties of composites that meet the needs of the developing technology continues. Military personnel, armored vehicles and many security elements are tested in the field with a lot of threats (such as mines, armor piercing ammunition, explosives etc.). Therefore, the armor used by security elements should be strengthened without compromising features such as lightness, cost and long-term use. This study covers the development of Kevlar's ballistic properties by impregnating Shear Thickening Fluid (STF). STF is composed of silica (AEROSIL 200) and polyethylene glycol (PEG 400). STF-impregnated Kevlar fibers have been subjected to impact testing at low and high speeds. Low-speed tests were carried out with a drop tower. High-speed tests were carried out according to NIJ 0101.06 Level II standards. The mass fraction of silica in the STF was determined as the research parameter. The change in the behavior of the materials with the change of silica ratio was investigated; Although improvements were observed in energy dissipation in low-speed impacts, it was noted that ballistic behavior improved up to a certain point, and then the improvement in behavior decreased.

Mechanical properties of shear thickening fluid filled warp-knitted spacer fabrics

This paper reports the compressive behavior and low-velocity impact behavior of warp-knitted spacer fabrics (WKSFs) filled with shear thickening fluid (STF) when subjected to quasi-static compression and low-velocity impact loadings, respectively. In the steady rheological test, the STF experiences a shear thickening transition at a critical shear rate. Besides, the critical shear rate decreases with the increase of silica mass fraction. The compression curves of WKSFs filled with STF composites were consistent with those of WKSFs, including initial, elastic and compaction stage. As the compression speed increases, the overall compression load values of WKSF and WKSFs filled with STF composite increase. Moreover, the compression load of composite increases with the increase of silica mass fraction. Compared with WKSFs, WKSFs filled with STF composite composites need more work to deform under the same strain. The impact result reveals that STF-filled WKSF would absorb more energy and keep the peak load at a lower level than WKSF under the same impact loadings. In a certain range, the energy absorption of composites becomes more excellent with the increasing silica mass fraction. However, over a certain range, the energy absorption of the composite decreases with the increase of the mass fraction of silica. It was concluded that the STF-filled WKSF composite could be expected as a damping or energy-absorptive material for human body protection.

EXPERIMENTAL RESEARCH AND DEVELOPMENT OF A METHOD FOR CALCULATING THE PARAMETERS OF BOREHOLE HYDROMONITOR DISINTEGRATION OF RICH IRON ORE IN PLACE

Purpose. Study and development of a rational methodology for calculating the parameters of the process of downhole hydrodisintegration of martite ore massifs by pressure rotating water jets. Methods. Mine experimental-methodical and experimental-experimental works on: stage-by-stage study of the engineering and geological situation of ore deposits and selection of experimental sites; development of technological schemes for the hydrodisintegration of the ore in place and the creation of appropriate experimental equipment; selection of means for providing hydro-extracting operations; the choice of methods for monitoring and measuring the parameters of the hydrodisintegration process; generalization and analysis of the results of experiments and development of recommendations for the creation of technology and equipment, taking into account the achieved indicators. Results. A technique for calculating the parameters of hydrodisintegration of rich martite ores martite ore in places has been developed based on the study of the features of the formation of rotating compact water jets by borehole hydromonitors. Scientific novelty. Relationships between the structural and morphological characteristics and jointing of martite ores (porosity, the ratio of the grain composition of the ore, the ultimate uniaxial compression strength of ore and lumpiness) and the parameters of the hydromonitoring effect (water pressure, the initial diameter of the jet and the speed of its movement along the exposure of the face), which make it possible to determine rational technological parameters of hydrodisintegration products. Practical implication. Borehole hydromonitor disintegration of martite ores in place is a combined ore preparation process, including enrichment grinding operations and classification of destruction products according to their granulometric composition during their erosion. At the same time, there is a selective opening of ore-forming minerals that improve the quality of the ore by 0.5–1.5% compared to natural, a decrease in the mass fraction of silica from 2.0–1.2 to 0.5–0.3%, which ensures the production of iron ore raw materials of the highest quality – superconcentrates with an iron content of 69.0–69.5%. Control of the granulometric composition of hydrodisintegration products is achieved by adjusting the initial water pressure at the outlet of the jet nozzle, the speed of the jet along the face exposure and the orientation of the jet relative to the elements of occurrence and texture of the ores.

Melt Migration and Chemical Differentiation by Reactive Porosity Waves

AbstractMelt transport across the ductile mantle is essential for oceanic crust formation or intraplate volcanism. However, mechanisms of melt migration and associated chemical interaction between melt and solid mantle remain unclear. Here, we present a thermo‐hydro‐mechanical‐chemical (THMC) model for melt migration coupled to chemical differentiation. We consider melt migration by porosity waves and a chemical system of forsterite‐fayalite‐silica. We solve the one‐dimensional (1D) THMC model numerically using the finite difference method. Variables, such as solid and melt densities or MgO and SiO2 mass concentrations, are functions of pressure (P), temperature (T), and total silica mass fraction (). These variables are pre‐computed with Gibbs energy minimization and their variations with evolving P, T, and are implemented in the THMC model. We consider P and T conditions relevant around the lithosphere‐asthenosphere boundary. Systematic 1D simulations quantify the impact of initial distributions of porosity and on the melt velocity. Larger perturbations of cause larger melt velocities. An adiabatic or conductive geotherm cause fundamentally different vertical variations of densities and concentrations, and an adiabatic geotherm generates higher melt velocities. We quantify differences between melt transport (considering incompatible tracers), major element transport and porosity evolution. Melt transport is significant in the models. We also quantify the relative importance of four porosity variation mechanisms: (a) mechanical compaction and decompaction, (b) density variation, (c) compositional variation, and (d) solid‐melt mass exchange. In the models, (de)compaction dominates the porosity variation. We further discuss preliminary results of 2D THMC simulations showing blob‐like and channel‐like porosity waves.

A Facile and Rapid Approach to Lotus‐Seedpod‐Structured Electronic Skin for Monitoring Diverse Physical Stimuli

AbstractAlthough the burgeoning Internet of Things has created soaring demand for electronic skin (e‐skin), a facile and eco‐friendly approach towards the scalable fabrication of the hierarchical active layer for such a system is still limited in the stage of development. Herein a sensing layer with lotus‐seedpod‐like structures is reported that is readily prepared by multi‐melt multi‐injection molding (M3IM). Because of the shear flow and thermodynamic factors in M3IM, silica microspheres in the core layer of the polyethylene/silica composite are inclined to migrate to the interface between the skin layer of ethylene‐α‐octene block copolymer/carbon nanotube composite and core layer, resulting in lotus‐seedpod‐like structures consisting of micro‐pits and asperities formed on the surface of the peeled skin layer. The sensitivity of the fabricated e‐skin is significantly affected by the number of micro‐pits on the lotus‐seedpod‐like structure, which mainly depend on the silica mass fraction in the composites. For instance, the e‐skin made from the composites with 66.67 wt% silica exhibits a sensitivity of 19.87 kPa−1 over a wide linear range of 0.017–11.5 kPa and demonstrates excellent durability and reproducibility, enabling multiple signal detection. This work sheds light on the rapid and scalable fabrication of sensors using a polymer melt processing strategy.

Relationship between Microstructure and Thermal Conductivity in Coal Slags with Variable Silica and Alumina

For achieving a stable operation of coal gasification, it is crucial to understand the relationship between the microstructure and thermal conductivity of coal slags. Thermal conductivity measurements were carried out on a SiO2–Al2O3–CaO–Fe2O3–MgO slag system with a mass fraction of silica and alumina (SiO2 + Al2O3) ranging from 35 to 85 wt % using a nonstationary hot wire method. The crystallization tendency was obtained by a differential scanning calorimetry signal. Raman spectroscopy and X-ray diffraction (XRD) were combined to investigate the microstructure. The addition of (SiO2 + Al2O3) leads to a significant increase in the thermal conductivity of slags when (SiO2 + Al2O3) is higher than 55 wt %. The XRD results show that a gradual increase in the silica and alumina contents causes crystalline phase transition, resulting in an increase of bridging oxygen in the slag system. The degree of polymerization Q with variable (SiO2 + Al2O3) is quantified by Raman spectroscopy. The positive linear relations...

Beyond conventional metrics: Comprehensive characterization of respirable coal mine dust

Conventional practice in monitoring and control of respirable coal mine dust has focused on the total mass concentration and the crystalline silica mass fraction of personal exposures. For decades under this approach, as dust exposures in US mines declined, so did the incidence of occupational lung diseases. In the late 1990s, however, disease rates began to rise significantly with little or no apparent increase in the conventional dust metrics. Based on the geographic clustering of disease reports in parts of central Appalachia, several contributing factors have been suggested, including possible changes in dust characteristics as thin-seam mining has become increasingly common. However, data on anything beyond conventional dust metrics is almost non-existent. The current study represents an ongoing effort by the authors to comprehensively characterize respirable coal mine dust. Here, samples from eight mines in central and northern Appalachia were analyzed to determine: particle size and mineralogy distributions across a wide size range (~100–10,000 nm); potentially bioaccessible and total acid-soluble mass concentrations of metals and trace elements; and mass concentrations of polyaromatic hydrocarbons including 1-nitropyrene, which may be indicators of diesel exhaust. Results showed that dust characteristics can vary widely between and within mines. But several general observations were noted, such as a predominance of sub-micron particles, including those associated with both diesel exhaust and dust generated from cutting geologic strata in the mine or application of rock dusting products. Additionally, there appeared to be an inordinate amount of dust generated from cutting rock strata, as compared to coal strata. A correlation analysis was also conducted on a total of 40 dust characteristic variables, which may provide further insights to the source(s) of some constituents.

Nanocomposite electrolytes for lithium batteries with reduced flammability

We report a family of flame-retardant electrolytes for lithium batteries based on ionic nanocomposites. The nanocomposites are synthesized in one pot by dispersing SiO2 nanoparticles charge-balanced by both Li ions and mono-amino-terminated polyether (PEO-b-PPO-NH3+) in an oligomeric PEO matrix. The Li+ and PEO-b-PPO-NH3+ ions lead to enhanced Li+ transference number and compatibility with the PEO matrix, respectively. The nanocomposite electrolyte containing 40% mass fraction of silica shows a notable electrochemical stability window of more than 6 V in contact with Lithium and high Li+ transference number over 0.5. Rheology measurements demonstrate the tunability of the system from liquid to gel-like as the silica mass fraction percentage increases from 0 to 40% while the conductivity remains almost constant. Thermal gravimetric and microscale combustion calorimeter measurements of the nanocomposites show decreased rate of mass loss and heat release rate compared to neat electrolyte. Finally, the fire retardancy of the nanocomposites measured by directly observing the formation and sustainability of flame, when exposed to direct fire, make them promising candidates in the ever-growing quest for safe lithium batteries.

Improving the tracking and erosion resistance performance of alumina trihydrate-free addition-cure liquid silicone rubber

Aiming to improve tracking and erosion resistance performance of addition-cure liquid silicone rubber (ALSR) without alumina trihydrate, A- and B-series ALSR samples with different fumed silica mass fraction and platinum catalyst concentration were prepared respectively. The tracking and erosion resistance performance of all the samples were evaluated. Also, the thermal decomposition products were detected. Basing on the comparative analysis of thermal decomposition characteristics, morphology, crystal structure, the improvement mechanism was discussed. Results showed that increasing the concentration of platinum catalyst and the mass fraction of fumed silica both can improve the tracking and erosion resistance performance, whereas the former was more effectively. Further analysis considered that platinum catalyst played a very important role in thermal decomposition process of ALSR, increasing the platinum catalyst content can not only promote the crosslinking reaction between the methyl groups, but also suppress backbone decomposition.

A Standard Characterization Methodology for Respirable Coal Mine Dust Using SEM-EDX

A key consideration for responsible development of mineral and energy resources is the well-being of workers. Respirable dust in mining environments represents a serious concern for occupational health. In particular, coal miners can be exposed to a variety of dust characteristics depending on their work activities, and some exposures may pose risk for lung diseases like CWP and silicosis. As underscored by common regulatory frameworks, respirable dust exposures are generally characterized on the basis of total mass concentration, and also the silica mass fraction. However, relatively little emphasis has been placed on other dust characteristics that may be important in terms of identifying health risks. Comprehensive particle-level analysis to estimate chemistry, size, and shape distributions of particles is possible. This paper describes a standard methodology for characterization of respirable coal mine dust using scanning electron microscopy (SEM) with energy dispersive X-ray (EDX). Preliminary verification of the method is shown based several dust samples collected from an underground mine in Central Appalachia.

Partial discharge behavior of mineral oil based nanofluids

A previous study showed that both mineral oil based nanofluids with 0.01% silica mass fraction and with 0.1% fullerene mass fraction have a higher AC breakdown strength than mineral oil. Breakdown occurs following discharge initiation and propagation in the oil. The breakdown strength value alone provides little information on the discharge process. Therefore, it is important to investigate the details of the discharge mechanisms in mineral oil and in nanofluids. Hence, this study focuses on the partial discharge (PD) behavior of mineral oil, silica and fullerene nanofluids. The total charge, voltage and pulse shape were recorded with the help of a high bandwidth PD measuring system. The discharge mechanism in mineral oil appeared to depend strongly on the polarity of the applied DC voltage. Under positive DC voltage, the silica and the fullerene nanofluids show increased inception voltage and a reduction of the total discharge magnitude compared to the reference mineral oil. Under negative polarity, inception voltage and discharge magnitude of the nanofluids and the reference mineral oil are virtually the same.

Microfibrillated cellulose-SiO2 composite nanopapers produced by spray deposition

Microfibrillated cellulose (MFC)-SiO2 nanopapers were prepared using a rapid spray deposition technique. Large area (~310 cm2) composite nanopapers with thickness and SiO2 content varying from 16 to 92 µm and 0 to 33 %, respectively, were prepared in less than 30 min with nearly complete nanoparticle retention in the cellulose mat. In the presence of an excess of MFC, SiO2 nanoparticles formed large clusters embedded in a dense and continuous cellulose matrix which conferred to the composite an extremely low permeability to air, i.e., below 2 nm2. For silica mass fraction above 20 %, SiO2 clusters induced a net increase in air permeability and ionic conductivity up to 12 nm2 and 1.5 mS cm−1 for a SiO2 content of 33 %. Despite the addition of an inert phase, composite nanopapers displayed mechanical properties, viz. Young’s modulus and internal cohesion higher than 2.2 GPa and 913 J m−2, outperforming those of most conventional papers. This study demonstrates that MFC-SiO2 nanopapers fabricated by spray deposition can be an alternative to PE/PP membranes as separators in Li-ion batteries and, in general, that spray deposition is a promising method for the rapid fabrication of large area composite nanopapers.

Preparation and properties of imidazole-containing polyimide/silica hybrid films

Imidazole-containing polyimide/silica(PI/SiO2) hybrid films were prepared from 3,3′,4,4′-biphenyltetra-carboxylic dianhydride(BPDA) and 2,2′-di(p-aminophenyl)-5,5′-bibenzimidazole in N,N-dimethylacetamide(DMAc) by sol-gel method and thermal imidization. The hybrid film with high silica mass fraction up to 40% was transparent. Scanning electron microscope(SEM) and transmission electron microscope(TEM) results of the film indicate a homogeneous dispersion of silica nanoparticles in the polyimide matrix. One hybrid film PI/SiO2 with 15% SiO2 exhibits better mechanical properties with a tensile strength of 222 MPa, an elongation at break of 12%, and a tensile modulus of 5.66 GPa. The reinforced mechanism on mechanical properties was also studied.

Gas separation properties of polyvinylchloride (PVC)-silica nanocomposite membrane

Researchers have focused on improving the performance of polymeric membranes through various methods, such as adding inorganic nanoparticles into the matrix of the membranes. In the present study, the separation of oxygen, nitrogen, methane and carbon dioxide gases by PVC/silica nanocomposite membranes was investigated. Silica nanoparticles were prepared via sol-gel method. Membranes were prepared by thermal phase inversion method and characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermal gravimetry (TGA) analyses. The FTIR and SEM analyses demonstrated a nano-scale dispersion and good distribution of silica particles in the polymer matrix. According to TGA results, thermal properties of PVC membranes were improved and DSC analysis showed that glass transition temperature of nanocomposite membranes increased by adding silica particles. We concluded that the permeability of carbon dioxide and oxygen increased significantly (about two times) in the composite PVC/silica membrane (containing 30 wt% silica particles), while that of nitrogen and methane increased only 40 to 60 percent. Introducing 30 wt% silica nanoparticles into the PVC matrix, increased the selectivity of CO2/CH4 and CO2/N2 from 15.9 and 21 to 18.2 and 27.3, respectively. The diffusion and solubility coefficients were determined by the time lag method. Increasing the silica mass fraction in the membrane increased the diffusion coefficients of gases considered in the current study.

Development of photoluminescent glass derived from rice husk

In this study, rice husk was used as a biomass raw material as a substitute for commercial silica in glass making. The mass fraction of silica in rice husk ash (RHA) derived from rice husk powder by combustion at 1000 °C for 2 h was found to be as high as 96%, comparable to that of commercial silica. To make the rice husk glass a more value-added product, the addition of green photoluminescent (PL) pigments into rice husk glass was attempted. Green PL pigment was found to withstand high temperatures while maintaining its photoluminescent properties. Experiments were performed to add the PL pigment using two different methods, namely layering and mixing techniques. For the layering technique, the PL rice husk glass was produced by spreading the PL pigment between two layers of casted rice husk glass, resulting in a sandwich-like structure. On the other hand, through the mixing technique, the PL pigment was mixed directly into the molten glass. PL rice husk glass produced using the layering technique yielded a more preferable product. Some PL pigments were decomposed at high temperature during the glass making process, causing the pigment to lose its PL properties. As a result, the layering technique, which involved a lower level of decomposition of the PL pigment, was preferred to produce a PL rice husk glass with better PL properties compared to the mixing technique, which exposed more PL pigment to high temperature attack.

Preparation of Mesoporous Carbons from Acrylonitrile-methyl Methacrylate Copolymer/Silica Nanocomposites Synthesized by in-situ Emulsion Polymerization

Acrylonitrile-methyl methacrylate (AN-MMA) copolymer/silica nanocomposites were synthesized by in-situ emulsion polymerization initiated by 2,2′-azobis(2-amidinopropane) dihydrochloride absorbed onto colloidal silica particles, and the mesoporous carbon materials were prepared through carbonization of the obtained AN-MMA copolymer/silica nanocomposites, followed by HF etching. Thermogravimetric analysis of AN-MMA copolymer/silica nanocomposites showed that the carbon yield of copolymer was slightly decreased as silica particle incorporated. N2 adsorption-desorption, scan electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the structure and morphology of the mesoporous carbon materials. Both SEM and TEM results showed that disordered mesopores were formed in the obtained carbon material mainly through templating effect of silica nanoparticles. The diameter of mesopores was mainly distributed in the range from 5 nm to 15 nm. The mean pore diameter and total pore volume of the material increased as the mass fraction of silica in the nanocomposites increased from 0 to 24.93%. The significant increase of the mean pore diameter and the decrease of surface area for the carbon material prepared from the nanocomposite with 24.93% silica were caused by partial aggregation of silica nanoparticles in the polymer matrix.

Application of shear thickening fluid in ultra high molecular weight polyethylene fabric

AbstractAn advanced stab‐resistant material composed of shear thickening fluid (STF) and ultra high molecular weight polyethylene (UHMWPE) fabric was investigated. STF was prepared by dispersing nanosilica (SiO2) into ethylene glycol. The shear thickening behavior of STF with the increase of the shear rate was observed by PhysicaMCR301. STF/UHMWPE composite fabric was synthesized by impregnating UHMWPE fabric in STF dilution. Stab resistant experiment was conducted on a self‐made stab test machine with knife and spike as stab tool. The results demonstrate that the stab resistant property of the UHMWPE fabric is greatly improved by impregnating STF. The stab resistant property is greatly increased with the increase of mass fraction of silica in STF. Especially, when the mass fraction of SiO2 in STF is 38%, the stab resistance force and energy absorption of STF/UHMWPE are optimal for knife and spike threats. With the same stab resistant properties, the flexibility of UHMWPE fabric impregnated with STF is higher than that of the neat fabric. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013