Addition Of SiO2 Research Articles

Dynamic Interfacial Properties and Foamability of DoTAB/SiO2 Mixtures

The interaction between nanoparticles and cationic surfactants is an exciting and emerging field in interfacial science. This area of research holds significant promise, linking fundamental principles to practical applications in a variety of industries, including chemical processes, biomedical applications and the petroleum industry. This study explores the interaction between dodecyltrimethylammonium bromide (DoTAB) and silica (SiO2) nanoparticles, investigating their influence on dynamic interfacial properties and foam characteristics. Through equilibrium and dynamic surface tension measurements, along with examining the dilational visco-elasticity behavior, this research reveals the complex surface behavior of DoTAB/SiO2 mixtures compared to individual surfactant solutions. The foamability and stability experiments indicate that the addition of SiO2 significantly improves the foam stability. Notably, stable foams are achieved at low SiO2 concentrations, suggesting a cost-effective approach to enhancing the foam stability. This study identifies the optimal stability conditions for 12 mM DoTAB solutions, emphasizing the crucial role of the critical aggregation concentration region. These findings offer valuable insights for designing surfactant-nanoparticle formulations to enhance foam performance in various industrial applications.

Optimization of spraying process and stoichiometric stage of plasma‐sprayed Yb2Si2O7 environmental barrier coating

AbstractYtterbium disilicate (Yb2Si2O7) is a potential environmental barrier coating (EBC) material. In this paper, the microstructure and phase composition of plasma‐sprayed Yb2Si2O7 coatings with different spraying process were systematically investigated to optimize the spraying power and spraying distance. Furthermore, in order to obtain Yb2Si2O7 coating with single phase, a certain proportion of SiO2 was added to the Yb2Si2O7 powder to compensate for the volatilization of SiO2 during plasma‐spraying process, and the influence of spraying powder composition on the microstructure and phase structure (composition and content) of Yb2Si2O7 coatings were also characterized in detail. The results showed that the Yb2Si2O7 coating was dense with fewer pores and cracks at the spraying power of 40 kW and the spraying distance of 100 mm. Yb2Si2O7 coating with the “sandwich” structure was composed of Yb2Si2O7, Yb2Si2O7 + Yb2SiO5, and Yb2SiO5 three microstructures, which was mainly caused by the volatilization of SiO2 in Yb2Si2O7 spraying powder. The Yb2Si2O7 coating contained 90.68 mol.% Yb2Si2O7 phase and 9.32 mol.% Yb2SiO5 phase after crystallization at 1300°C for 20 h. The coating was composed of Yb2Si2O7 phase and amorphous phase after SiO2 addition. Yb2SiO5 phase precipitated from the coating after heat treatment at 1300°C, and its content decreased with the increase of SiO2 content. The content of the Yb2Si2O7 phase was as high as 99.41 mol.% when SiO2 content was 10 mol.%, which would provide a scientific basis for further research on stoichiometric Yb2Si2O7 EBCs with excellent properties.

Thermochemical heat storage performance and structural stability of SiO2-coated CaO particles under fluidization in CaO/Ca(OH)2 cycles

The decline in CaO/Ca(OH)2 heat storage performance of CaO-based material with the number of cycles due to its fast expansion and fragmentation is an problem in the fluidized bed reactor. In this paper, a novel SiO2-coated CaO particle was manufactured from limestone and silica sol via wet-mixing method. Exothermic performance (such as exothermic temperature, effective hydration conversion and volumetric energy density) and structural stability of SiO2-coated CaO particles in a fluidized bed reactor were studied. The effects of SiO2 addition and calcination temperature on the exothermic performance and structural stability were analyzed, respectively. The results show that the mass ratio of limestone to silica sol of 1:1 and calcination temperature of 850 °C are recommended for the preparation of SiO2-coated CaO. The SiO2 layer is observed on the surface of the CaO. SiO2-coated CaO particles exhibit superior structural stability than uncoated CaO particles. The SiO2 coating reduces the increase of average particle size during 10 cycles from 33 % to 11 %. After 10 heat storage cycles, SiO2-coated CaO particles achieve a reduction of 45.4 % in expansion rate and 48.5 % in attrition rate compared with uncoated CaO particles, respectively. The volumetric energy density of SiO2-coated CaO particles after 10 cycles is 33.2 % higher than that of uncoated CaO particles. The highest exothermic temperature of SiO2-coated CaO particles after 10 cycles reaches 455.4 °C (steam partial pressure @ 60 kPa). The SiO2-coated CaO seems a promising candidate for the CaO/Ca(OH)2 thermochemical heat storage in the fluidized bed rector.

Effect of Micro and Nano Particles of Al<sub>2</sub>O<sub>3</sub> and SiO<sub>2</sub> on Electrical Tree Inhibition in Epoxy Resin Insulator

Electrical tree is a topic that has been extensively studied in recent years. Electrical tree is considered a deterioration of the electrical insulator due to the high voltage field's distortion. Solid insulating materials used in high voltage applications, such as epoxy resin are widely employed due to their high dielectric strength and excellent mechanical properties. This research studies the effect of micro and nanoparticles of Al2O3 and SiO2 on electrical tree inhibition in epoxy resin insulators. Electrical tree inhibition is achieved by incorporating micro and nanoparticles into the polymer material, which possess different properties. Following ASTM D 3756-97, the experiment is conducted with a constant 22 kV voltage and frequency of 50 Hz. Both Al2O3 and SiO2 possess the ability to inhibit the growth of the electrical tree. Experimental results revealed that the addition of Al2O3 and SiO2 to the epoxy resin affected the formation of electric trees. As the quantity of filler increases, fewer electric trees are produced. Additionally, It has an effect on the initial formation time of electric trees. The initial time of the electric tree with the addition of micro/nano(1/3) Al2O3 additives at a ratio of 0.1 wt% was 3.5 times longer when compare with pure epoxy resin.

Tribological Behavior and Wear Mechanism of Cu-SiO2 Sintered Composite under Different Sliding Speeds

In this paper, the tribological behavior of Cu-SiO2 composite against 1045 steel was studied. Based on the characterization of worn surface, worn subsurface and wear debris in morphology and composition, the friction layer effects on the tribological behavior of coupled materials and the wear mechanism were discussed. Abrasive wear and adhesive wear are the dominant mechanisms at the 0.56 m/s–1.12 m/s condition. Delamination wear and oxidation wear are the dominant wear mechanisms at the 1.68 m/s–2.24 m/s condition. Plastic and thermal deformation cause the evolution in morphology and structure of the tribolayer of Cu-SiO2. There is a certain correlation between the friction coefficient and the variation in friction temperature during sliding wear of Cu-SiO2 and 1045 steels. The addition of SiO2 induces the accumulation of frictional heat at the friction interface, which leads to an increase in the average temperature of the contact surface and transfer.

A First-Time Addition of Selenium to a Mg-Based Metal Matrix Composite for Biomedical Purposes

A magnesium-based metal matrix composite, Mg-5Se-2Zn-2SiO2, was synthesized using the Disintegrated Melt Deposition (DMD) method followed by hot extrusion. Elemental analysis revealed that the material experienced selenium loss which was attributed to the evaporation of selenium at high temperatures. Superior damping characteristics were exhibited while retaining similar Young’s modulus, and significant grain refinement also resulted in decisively superior mechanical properties such as hardness (32% increase), fracture strain (39% increase), as well as yield and ultimate compressive strength (157% and 54% increase, respectively). These were a consequence of SiO2 addition as well as presence of Mg2Si (and MgSe) intermetallic phases which were detected by X-ray characterization. Furthermore, while the material had lower corrosion resistance than pure magnesium, it retained acceptable corrosion resistance as well as structural integrity after the full immersion duration of 28 days. Overall, the material exhibits promising potential for applications in the biomedical field, especially in development of smaller and lighter implants where mechanical properties are paramount, with key lessons learned for the synthesis of Mg-materials containing selenium for the future.

Relationship between viscosity, foaming, and structure of CaO–SiO2–Al2O3–MgO–FeO slag with the addition of SiO2 and Al2O3

Optimizing the foaming characteristics of slag in electric arc furnaces (EAF) presents a challenging task, affecting electrode heating efficiency and increasing smelting cost. This study explores the impact of adding silicon dioxide (15–35 wt%) and a small quantity of alumina (5–10 wt%) on the viscosity and foaming properties of CaO–SiO2–Al2O3–MgO–FeO slag. Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) were employed to investigate structural changes in the slag melt. The findings reveal that higher levels of silica or a slight increase in alumina content enhance slag polymerization and foaming efficiency. Specifically, a 10 wt% alumina content, in contrast to 5 wt%, leads to high silica content, leading to faster polymerization but relatively lower viscosity. Structural analysis confirms that increasing alumina content, particularly when silica content is high, results in a less stable Al–O–Si structure, causing a shift from Q0 and Q1 units to Q2 and Q3 units, which ultimately reduces viscosity. When the alumina content remains at 5 wt% and silica content increases from 15 wt% to 35 wt%, foaming efficiency improves from 13.06 cm min to 94.97 cm min, a remarkable 627% rise. Moreover, when silica content is 30 wt% and alumina is slightly increased by 5 wt%, there is a notable enhancement in foaming efficiency, rising from 47.11 cm min to 89.16 cm min, while the effect on viscosity is not prominent.

A novel self-cleaning ceramic waste-slag geopolymer with nano-SiO2-TiO2 photocatalytic coating

In this investigation, a geopolymer based on ceramic waste (CW) and granulated blast furnace slag (GBFS) was synthesized. To confer the geopolymer with self-cleaning functionality, a nano-SiO2-TiO2 coating with hydrophobic and photocatalytic properties was applied onto the surface of CW-GBFS-based geopolymer. The effect of both the CW content and the alkali activator modulus (molar ratio of SiO2/Na2O) on the compressive strength of the geopolymer was evaluated. The highest compressive strength of 45.6 MPa was attained at 7 days with a composition containing 40 wt% of CW and an alkali activator modulus of 1.4. Furthermore, the geopolymer with the most desirable compressive strength was selected for the preparation of SiO2–TiO2/CW-GBFS-based geopolymer (ST/CGG). The effect of nano-SiO2-TiO2 dosage on the self-cleaning performance of ST/CGG was explored. The self-cleaning surface of the ST/CGG had a maximum water contact angle of 118° when the addition of SiO2 and TiO2 was 5.8 wt%. Moreover, the surface of the ST/CGG underwent testing for methyl orange degradation, ultraviolet–visible diffuse reflectance spectral analysis, oleic acid decomposition, and bauxite residue removal, validating its superior photocatalytic self-cleaning efficacy. Overall, this work not only highlights the potential of ceramic waste utilization for geopolymers, but also provides a feasible strategy for developing functional geopolymers with self-cleaning ability.

Effect of Silicon Dioxide Nanoparticles on the Sintering Properties of Beta-Tricalcium Phosphate Composites.

Composite sintered bodies comprising silicon dioxide (SiO2) nanoparticles dispersed in β-tricalcium phosphate (β-TCP) were prepared. The addition of nano-sized colloidal SiO2 to the β-TCP produced well-dispersed secondary phase nanoparticles that promoted densification by suppressing grain growth and increasing linear shrinkage of the sintered bodies. The SiO2 was found not to react with the β-TCP at 1120 °C and the substitution of silicon for phosphorous to produce a solid solution did not occur. This lack of a reaction is ascribed to the absence of available calcium ions to compensate for the increase in charge associated with this substitution. The SiO2 nanoparticles were found to be present near the intersections of grain boundaries in the β-TCP. β-TCP composite sintered body containing 2.0 and 4.0 wt% SiO2 exhibited a bending strength comparable to that of cortical bone and hence could potentially be used as a bone filling material.

Hierarchically porous cellulose-based carbon aerogels with N-doped skeletons and encapsulated iron-based catalysts for efficient tetracycline catalytic degradation

Three-dimensional interpenetrating and hierarchically porous carbon material is an efficient catalyst support in water remediation and it is still a daunting challenge to establish the relationship between hierarchically porous structure and catalytic degradation performance. Herein, a highly porous silica (SiO2)/cellulose-based carbon aerogel with iron-based catalyst (FexOy) was fabricated by in-situ synthesis, freeze-drying and pyrolysis, where the addition of SiO2 induced the hierarchically porous morphology and three-dimensional interpenetrating sheet-like network with nitrogen doping. The destruction of cellulose crystalline structure by SiO2 and the iron-catalyzed breakdown of glycosidic bonds synergistically facilitated the formation of electron-rich graphite-like carbon skeleton. The unique microstructure is confirmed to be favorable for the diffusion of reactants and electron transport during catalytic process, thus boosting the catalytic degradation performance of carbon aerogels. As a result, the catalytic degradation efficiency of tetracycline under light irradiation by adding only 5 mg of FexOy/SiO2 cellulose carbon aerogels was as high as 90 % within 60 min, demonstrating the synergistic effect of photocatalysis and Fenton reaction. This ingenious structure design provides new insight into the relationship between hierarchically porous structure of carbon aerogels and their catalytic degradation performance, and opens a new avenue to develop cellulose-based carbon aerogel catalysts with efficient catalytic performance.

New insight and countermeasure for sulfur poisoning on nickel-based catalysts during dry reforming of methane

Dry reforming of methane (DRM) is the method to convert two greenhouse gases to synthesis gas. The nickel-based catalysts used in the DRM are extremely easily poisoned by H2S in the feed gas, however, the associated poisoning process is not clear. In this work, a mechanism for poisoning the Ni/Al2O3 catalyst by elemental sulfur migration was proposed, and silica was added to the catalyst to prolong the sulfur tolerance of the catalyst. From the characterizations of the catalyst with different methods, it was noted that the main factor accelerating catalyst poisoning was the formation and migration of elemental sulfur. The catalyst Ni/Al2O3 with 1.0 % SiO2 exhibited improved sulfur tolerance. The addition of SiO2 inhibits the growth of Ni particles during the reduction process, and the smaller Ni particles lead to less coke and a longer period of sulfur tolerance.

Vitrification of lead–bismuth alloy nuclear waste into a glass waste form

AbstractLead–bismuth eutectic (LBE), a promising coolant in advanced nuclear systems, can be activated by neutrons during nuclear reactor operations. The decommissioning of nuclear facilities would generate lead–bismuth (Pb–Bi) alloy‐contaminated nuclear waste. The current metallic nuclear waste treatment approach involves remelting followed by cementitious solidification. This increases the waste volume and the risk of radionuclide migration in groundwater. Therefore, this study developed a method for vitrification of Pb–Bi alloy waste. Different amounts of SiO2 were added at 750–1100°C in the air to turn the simulated LBE waste into glass waste form. The values of the normalized elemental leaching rates (Pb, Bi, Si, Te, and Ni) determined using the 28‐day static leaching test were less than .2 g m−2 d−1 and varied with SiO2 addition. Furthermore, a three‐stage evolution of the glass structure with SiO2 addition was proposed according to the structural analysis performed using Raman and X‐ray photoelectron spectroscopies. The evolution stages were as follows: (i) the stage of heavy metal transition from covalent to ionic heavy metals (7.5 wt% < SiO2 < 15 wt%), (ii) the stage of increase in bridging oxygen (15 wt% < SiO2 < 20 wt%), and (iii) the stage of domination of the Si–O network (20 wt% < SiO2 < 25 wt%). The evolution of the glass structure resulted in varying glass chemical durability. Finally, the glass‐forming region of (20–48)PbO–(35–70)Bi2O3–(7.5–25)SiO2 (wt%) and the temperature needed to melt those glasses were determined through the melting test, where radionuclides and toxic heavy metals showed undetectable volatilization during vitrification. Hence, turning LBE waste into glass waste form will be a potential approach for treating Pb–Bi alloy nuclear waste.

De-chlorination of poly(vinyl) chloride using Fe2O3 and the improvement of chlorine fixing ratio in FeCl2 by SiO2 addition

Abstract A quantitative investigation of poly(vinyl) chloride (PVC) de-chlorination using Fe2O3, together with the impact of SiO2 addition on the co-pyrolysis of PVC and Fe2O3, was conducted below 673 K in an Ar atmosphere aiming to cut the emission of gaseous Cl⁻ products. It was found that chlorine in PVC can be fixed in FeCl2 by the reaction between PVC and Fe2O3. The co-pyrolysis of PVC and Fe2O3 proceeds in two stages with a temperature boundary of around 543 K. Below 543 K, a direct reaction occurs between PVC and Fe2O3, resulting in a small mass loss ratio and some extent of chlorine fixing ratio in FeCl2. However, above 543 K, PVC starts to decompose to release gaseous H2, HCl, etc., which react with Fe2O3 through two possible pathways to form FeCl2. In Pathway 1, first Fe2O3 is reduced to Fe3O4 by H2, followed by the chlorination of Fe3O4 to FeCl2 by HCl. In Pathway 2, first Fe2O3 is chlorinated to FeCl3 by HCl, followed by the reduction of FeCl3 to FeCl2 by H2. The chlorine fixing ratio in FeCl2 and the volatile generation ratio increase with decreasing PVC content in the initial mixtures. The addition of SiO2 promotes the chlorine fixing ratio in FeCl2 and volatile generation, and the impact gets stronger with decreasing PVC content in the mixtures. The chlorine fixing ratio is increased from 70.8 to 82.6% by SiO2 addition for the mixtures containing 25% PVC, whereas the difference in the chlorine fixing ratio in FeCl2 caused by SiO2 addition is negligible for the mixtures containing 90% PVC. Fayalite (Fe2SiO4) was not detected in the solid residues after the experiments. After separating FeCl2 using water leaching, the filter residue, a composite of iron oxide and conjugated polyene, can be used as a raw material for iron-making.

Synthesis, structural investigations and properties of Si-modified Li1.5Al0.5Ge1.5(PO4)3 glass-ceramics

The properties of the Li1.5Al0.5Ge1.5(PO4)3 glass-ceramics were modified by the partial substitution of P5+ by Si4+, and the synthesis process is optimized. The thermal behavior of the original Li1.5+хAl0.5Ge1.5SixP3-xO12 (0 ≤ x ≤ 0.5) glasses was investigated using differential scanning calorimetry (DSC), optical dilatometry and heating microscopy. The glass transition temperature (Tg) decreases from 525 to 457 °C with increasing additive content from x = 0 to x = 0.5. Single-phase glass-ceramics with the NASICON-type structure were synthesized up to x = 1, which was confirmed by X-ray diffraction (XRD), Raman and energy-dispersive X-ray (EDX) mapping data. It has been shown that the SiO2 addition has a beneficial effect on the electrical properties of glass-ceramics, crystallized at 700 and 750 °C. However, heat treatment at 820 °C leads to a smaller increase in conductivity. Therefore, Si-containing glass-ceramics should be produced at lower temperatures than pure LAGP, which is 750 °C and correlated with the thermal analysis results. The influence of the SiO2 addition on the bulk and grain boundary conductivity of the Li1.5Al0.5Ge1.5(PO4)3 has been studied in detail. The Li1.52Al0.5Ge1.5Si0.02P2.98O12 glass-ceramics has the highest total ionic conductivity of 4.55·10−4 S/cm at RT and negligible electronic conductivity of 7.5·10−10 S/cm, therefore can be considered as promising solid electrolytes for all-solid-state batteries.

Additively Manufactured SiO2 and Cu-Added Ti Implants for Synergistic Enhancement of Bone Formation and Antibacterial Efficacy.

Commercially pure titanium (CpTi), a bioinert metal, is used as an implant material at low load-bearing sites and as a porous coating on Ti6Al4V at high load-bearing sites. There is an unmet need for metallic biomaterials to improve osseointegration and inherent antimicrobial resistance. In this study, we have added 1 wt % SiO2 and 3 wt % Cu to the CpTi matrix and processed via metal additive manufacturing (AM). Si4+ ions promote angiogenesis and osteogenesis. CpTi-SiO2 composition exhibited 4.5 times higher bone formation at the bone-implant interface over CpTi in an in vivo study with a rat distal femur model. In vitro bacterial studies with Gram-positive Staphylococcus aureus bacterium revealed 85% antibacterial efficacy by CpTi-SiO2-3Cu than CpTi. CpTi-SiO2-3Cu did not show any inflammatory markers in vivo, indicating the absence of cytotoxicity, but displayed delayed osseointegration compared to CpTi-SiO2. CpTi-SiO2-3Cu displayed 3-fold higher mineralized bone formation than CpTi. Our results emphasize the synergistic effect of SiO2 and Cu addition in CpTi, promoting enhanced early stage osseointegration and inherent antibacterial efficacy, contributing toward implant longevity and stability in vivo.

Fabrication of thermal insulation sodium alginate/SiO2 composite aerogel with superior radiative cooling function for firefighting clothing

Purpose This study aims to evaluate the thermal performance of sodium alginate (SA) aerogel attached to nano SiO2 and its radiative cooling effect on firefighting clothing without environmental pollution. Design/methodology/approach SA/SiO2 aerogel with refractory heat insulation and enhanced radiative cooling performance was fabricated by freeze-drying method, which can be used in firefighting clothing. The microstructure, chemical composition, thermal stability, and thermal emissivity were analyzed using Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analyzer and infrared emissivity measurement instrument. The radiative cooling effect of aerogel was studied using thermal infrared imager and thermocouple. Findings When the addition of SiO2 is 25% of SA, the prepared aerogel has excellent heat insulation and a high radiative cooling effect. Under a clear sky, the temperature of SA/SiO2 aerogel is 9.4°C lower than that of pure SA aerogel and 22.1°C lower than that of the simulated environment. In addition, aerogel has more exceptional heat insulation effect than other common fabrics in the heat insulation performance test. Research limitations/implications SA/SiO2 aerogel has passive radiative cooling function, which can efficaciously economize global energy, and it is paramount to environment-friendly cooling. Practical implications This method could pave the way for high-performance cooling materials designed for firefighting clothing to keep maintain the wearing comfort of firefighters. Originality/value SA/SiO2 aerogel used in firefighting clothing can release heat to the low-temperature outer space in the form of thermal radiation to achieve its own cooling purpose, without additional energy supply. Graphical abstract

An investigation into the effects of ink formulations of semi-solid extrusion 3D printing on the performance of printed solid dosage forms.

Semi-solid extrusion (SSE) 3D printing has recently attracted increased attention for its pharmaceutical application as a potential method for small-batch manufacturing of personalised solid dosage forms. It has the advantage of allowing ambient temperature printing, which is especially beneficial for the 3D printing of thermosensitive drugs. In this study, the effects of polymeric compositions (single hydroxypropyl methylcellulose (HPMC) system and binary HPMC + polyvinylpyrrolidone (PVP) system), disintegrant (silicon oxide (SiO2)), and active pharmaceutical ingredients (tranexamic acid (TXA) and paracetamol (PAC)) on the printability of semisolid inks and the qualities of SSE printed drug-loaded tablets were investigated. Printability is defined by the suitability of the material for the process in terms of its physical properties during extrusions and post-extrusion, including rheology, solidification time, avoiding slumping, etc. The rheological properties of the inks were investigated as a function of polymeric compositions and drug concentrations and further correlated with the printability of the inks. The SSE 3D printed tablets were subjected to a series of physicochemical properties characterisations and in vitro drug release performance evaluations. The results indicated that an addition of SiO2 would improve 3D printing shape fidelity (e.g., pore area and porosity) by altering the ink rheology. The pores of HPMC + PVP + 5PAC prints completely disappeared after 12 hours of drying (pore area = 0 mm2). An addition of SiO2 significantly improved the pore area of the prints which are 3.5 ± 0.1 mm2. It was noted that the drug release profile of PAC significantly increased (p < 0.05) when additive SiO2 was incorporated in the formulation. This could be due to a significantly higher porosity of HPMC + PVP + SiO2 + PAC (70.3 ± 0.2%) compared to HPMC + PVP + PAC (47.6 ± 2.1%). It was also likely that SiO2 acted as a disintegrant speeding up the drug release process. Besides, the incorporation of APIs with different aqueous solubilities, as well as levels of interaction with the polymeric system showed significant impacts on the structural fidelity and subsequently the drug release performance of 3D printed tablets.

Retracted: Mechanical and Morphological Studies of Sansevieria trifasciata Fiber-Reinforced Polyester Composites with the Addition of SiO2 and B4C

Retracted: Mechanical and Morphological Studies of <i>Sansevieria trifasciata</i> Fiber-Reinforced Polyester Composites with the Addition of SiO₂ and B₄C

Super-tough poly(lactic acid)/silicone rubber thermoplastic vulcanizates: The organic and inorganic synergistic interfacial compatibilization

Polymer modification using silicone rubber represents a promising avenue for enhancing physico-mechanical properties. However, achieving optimal performance through direct blending is hindered by the poor interface compatibility between silicone rubber and the matrix. In this study, we prepared super-tough thermoplastic vulcanizates (TPVs) of polylactic acid/silicone rubber through dynamic vulcanization with PLA, methyl vinyl silicone rubber (MVQ), glycidyl methacrylate grafted MVQ (MVQ-g-GMA), and fumed silica nanoparticles (SiO2). The impact of the SiO2 addition in MVQ on the morphology, mechanical properties, crystallization, and thermal properties of the TPVs was investigated. The results showed that MVQ-g-GMA and SiO2 exhibited a synergistic compatibilization effect significantly improving the interfacial adhesion between PLA and MVQ. Therefore, the impact and tensile strength of the TPVs increased from 8.0 kJ/m2 and 22.2 MPa to 62.6 kJ/m2 and 36.7 MPa, respectively. Moreover, the TPVs also presented good low-temperature toughness with a maximum impact strength of 40.4 kJ/m2 at −20 °C. Additionally, improvements in thermal stability and crystallization rate were also observed. Overall, combining organic and inorganic synergistic compatibilization is a feasible and effective method to fabricate outstanding low-temperature toughness to PLA.

Setting Time, Compressive Strength, and Photon Attenuation Properties of Cement Mortars Produced with Nano-SiO2

In this study, initial and final setting time, compressive strength, and photon attenuation properties of cement mortar samples produced with 0.5%, 1%, 2%, and 4% nano-scale SiO2 addition were investigated. For this purpose, cement mortar samples were prepared and cured for 1, 2, 7, 28, and 90 days. Increases in compressive strength values were observed in the early curing ages, with a slight decrease of 3.17% and 0.33% for low nano-SiO2 rates (0.5% and 1%) in later ages. In addition, these results were evaluated with Scanning Electron Microscope (SEM) images. In the samples added 4% nano-SiO2, there was a 13.3% and 9.09% reduction in the initial and final setting times, respectively. Furthermore, mass attenuation coefficients were compared for different cure ages. It was aimed to determine the effect of the curing time on the photon attenuation property by adding nano-SiO2 to the concrete.