Dry Mixing Techniques Research Articles

Fiber Showdown: A Comparative Analysis of Glass vs. Polypropylene Fibers in Hot-Mix Asphalt Fracture Resistance

Cracks in asphalt mixtures compromise the structural integrity of roads, increase maintenance costs, and shorten pavement lifespan. These cracks allow for water infiltration, accelerating pavement deterioration and jeopardizing vehicle safety. This research aims to evaluate the impact of synthetic fibers, specifically glass fiber (GF) and polypropylene fiber (PPF), on the crack resistance of Hot-Mix Asphalt (HMA). An optimal asphalt binder content of 5% was used in all sample designs. Using the dry mixing technique, GFs and PPFs were incorporated into the HMA at dosages of 0.50%, 1.00%, and 1.50% by weight of the aggregate. The effects of these fibers on the mechanical fracture properties of the HMA were assessed using Semi-Circular Bending (SCB), Indirect Tensile Asphalt Cracking Tests (IDEAL-CTs), and Three-Point Bending (3-PB) tests. This study focused on fracture parameters such as fracture work, peak load, fracture energy, and crack indices, including the Flexibility Index (FI) and Crack Resistance Index (CRI). The results from the SCB and IDEAL-CT tests showed that increasing GF content from 0.5% to 1.5% significantly enhances the flexibility and crack resistance of HMA, with FI, CRI, and CT Index values increasing by 247.5%, 55%, and 101.35%, respectively. Conversely, increasing PPF content increases the mixture’s stiffness and reduces its crack resistance. The PP-1 mixture exhibited higher FI and CT Index values, with increases of 31.1% and 10%, respectively, compared to the PP-0.5 mixture, based on SCB and IDEAL-CT test results. The SCB, IDEAL-CT, and 3-PB test results concluded that fibers significantly influence the fracture properties of bituminous mixtures, with a 1% reinforcement dosage of both PPFs and GFs being optimal for enhancing performance across various applications.

Preparation of ablation-resistant ethylene propylene trioxide/polyimide staple fiber composite insulation layer by solution wet mixing process

This research developed a solution wet mixing process for creating Ethylene propylene diene monomer/polyimide staple fiber composites (EPDM/PISF), overcoming the uneven fiber distribution seen in traditional dry mixing techniques. By uniformly dispersing PISF within the EPDM matrix, the wet mixing process improves the composite's performance. This is evidenced by an 18.08 % reduction in ΔG′, a 14.29 % lower linear ablation rate (0.042 mm/s), enhanced thermal stability, a higher charring rate, and a denser carbonized layer. Optimal overall performance was achieved using a PISF content of 10phr in the wet mixing process. This advancement significantly enhances the ablation resistance of EPDM/PIS, making them a promising choice for high-performance and durable insulation in solid rocket motors.

Organic-inorganic hybrids of BiI3-polymers with embedded conductive carbon fillers displaying high SNR for direct X-ray imaging detectors

Organic polymers are light weight, low toxic and environmentally stable candidates of interest in X-ray detection application. But low attenuation and high recombination rate of charge carriers cause low sensitivity is major limitation of these detectors. In this work, organic polymers (PS/PMMA) composites were prepared with high-Z inorganic BiI3 by simple dry mixing technique. The organic-inorganic hybrid further embedded with conductive carbon filler (MWCNT, CB, GP) to improve the charge collection of the samples. Resistivity and mobility of the samples were studied with help of Hall measurements and mobility-lifetime was calculated by Hecth equation and found (2.1 ± 0.2) × 10−3 cm2V−1. The elemental analysis of the samples had been done by XPS analysis. The X-ray investigations done by using dental X-ray source and the sensitivity of the samples increases from 3.4 to 200 μGy−1 cm−3 by incorporating CB filler with a low leakage current of order of 33.3 pA/cm2.

Enhancing HMA properties with polypropylene-based face mask integration: A qualitative comparison of wet mixing and dry mixing techniques

<span lang="EN-US">In the wake of the emergence and widespread dissemination of the COVID-19 coronavirus, scientifically identified as SARSCoV-2, the utilization of medical equipment, specifically tri-layered polypropylene (PP)-based face masks, has experienced significant proliferation. The extensive adoption of single-use polymer-based face masks has raised notable environmental concerns, given their extended degradation period of up to 480 years and their substantial threat to ecosystems, particularly aquatic organisms, due to pervasive littering practices. Hence, this study is dedicated to assessing the influence of incorporating polypropylene (PP)-based face masks into asphalt formulations. The incorporation of PP-based face masks into asphalt was executed at three distinct weight percentages, employing both dry and wet mixing techniques. Comprehensive performance evaluations were carried out utilizing the Marshall test, indirect tensile fatigue test, and Hamburg wheel tracking rutting experiments and the best value for each. Remarkably, augmenting the PP content yielded improvements in both fatigue life and rutting resistance of the asphalt mixtures, and the maximum improvement was recorded at 0.3% replacement. Notably, asphalt specimens prepared using dry mixing techniques outperformed their wet mixing counterparts, demonstrating superior cohesion attributes.</span>

Performance Evaluation of Hot Mix Asphalt (HMA) Containing Polyethylene Terephthalate (PET) Using Wet and Dry Mixing Techniques

This study evaluates the performance of Polyethylene Terephthalate (PET)-modified hot mix asphalt. Aggregate, bitumen of grade 60/70 and crushed plastic bottle waste were utilized in this study. Polymer Modified Bitumen (PMB) was prepared using a high shear laboratory type mixer rotating at a speed of 1100 rpm with varying PET content of 2%, 4%, 6%, 8% and 10%, respectively. Overall, the results of preliminary tests suggested that bitumen hardened with the addition of PET. Following optimum bitumen content determination, various modified and controlled HMA samples were prepared as per wet and dry mixing techniques. This research presents an innovative technique to compare the performance of HMA prepared via dry and wet mixing techniques. Performance evaluation tests, which include the Moisture Susceptibility Test (ALDOT-361-88), Indirect Tensile Fatigue Test (ITFT-EN12697-24) and Marshall Stability and Flow Tests (AASHTO T245-90), were conducted on controlled and modified HMA samples. The dry mixing technique yielded better results in terms of resistance against fatigue cracking, stability and flow; however, the wet mixing technique yielded better results in terms of resistance against moisture damage. The addition of PET at more than 4% resulted in a decreased trend for fatigue, stability and flow due to the stiffer nature of PET. However, for the moisture susceptibility test optimum PET content was noted to be 6%. Polyethylene Terephthalate-modified HMA is found to be the economical solution for high volume road construction and maintenance, besides having other significant advantages such as increased sustainability and waste reduction.

Fresh State, Rheological and Microstructural Characteristics of Alkali-Activated Mortars Developed Using Novel Dry Mixing Technique under Ambient Conditions

Ambient cured alkali-activated mortars (AAMs) are developed through the activation of supplementary cementitious materials (SCMs) by powder form reagents with silica sand using a novel dry-mixing method. The fresh state, rheological, compressive strength and microstructural characteristics of eight AAM mixes are comprehensively investigated. The effects of binary/ternary combinations/proportions of SCMs, different combinations/dosages of powder form reagents and the fundamental chemical ratios (SiO2/Al2O3, Na2O/SiO2, CaO/SiO2 and Na2O/Al2O3) present in the precursors and the reagents are investigated. The AAM mixes obtained compressive strengths ranging from 34 to 42.6 MPa with initial and final setting times between 122 and 458 min and 215 and 483 min, respectively. The yield stress and viscosity of the mixes decreased with the increase in the slump flow spread. All the mixes demonstrated pseudoplastic behavior. The microstructural analysis revealed the formation of more longer polymeric chains comprising Si-Al linkages in N-C-A-S-H/N-A-S-H gels for reagent one (calcium hydroxide:sodium metasilicate = 1:2.5) mixes, which resulted in a lower slump flow, higher yield stress, higher plastic viscosity and quicker setting times compared to their reagent two (calcium hydroxide:sodium sulfate = 2.5:1) counterparts.

Optimizing Precursors and Reagents for the Development of Alkali-Activated Binders in Ambient Curing Conditions

Alkali-activated binders (AABs) are developed through the activation of aluminosilicate-rich materials using alkaline reagents. The characteristics of AABs developed using a novel dry-mixing technique incorporating powder-based reagents/activators are extensively explored. A total of forty-four binder mixes are assessed in terms of their fresh and hardened state properties. The influence of mono/binary/ternary combinations of supplementary cementitious materials (SCMs)/precursors and different types/combinations/dosages of powder-based reagents on the strength and workability properties of different binder mixes are assessed to determine the optimum composition of precursors and the reagents. The binary (55% fly ash class C and 45% ground granulated blast furnace slag) and ternary (25% fly ash class C, 35% fly ash class F and 40% ground granulated blast furnace slag) binders with reagent-2 (calcium hydroxide and sodium sulfate = 2.5:1) exhibited desired workability and 28-day compressive strengths of 56 and 52 MPa, respectively. Microstructural analyses (in terms of SEM/EDS and XRD) revealed the formation of additional calcium aluminosilicate hydrate with sodium or mixed Ca/Na compounds in binary and ternary binders incorporating reagent-2, resulting in higher compressive strength. This research confirms the potential of producing powder-based cement-free green AABs incorporating binary/ternary combinations of SCMs having the desired fresh and hardened state properties under ambient curing conditions.

The Impact of Preparation Techniques on the Properties of Magnesium Aluminate Spinel

In this work, two different methods namely; dry mixing and ball milling followed by the cold isostatic press were employed to synthesize Magnesium aluminate spinel (MgAl2O4). The phase diffraction and morphological characteristic of the sintered product were analyzed using X-Ray diffraction (XRD), Scanning Electron Microscopy (SEM). The Archimedes principle for determining viscosity and porosity of MgAl2O4. The main aim of this study to compare preparation techniques on the properties of the final spinel product. The results show that the ball milling method has an advantage over the dry mixing technique. In this technique, bigger crystals, well-compacted grains, higher density, and lesser reduction size and porosity were observed. an increase in the period of milling process was found to improve all these characteristics of MgAl2O4 spinel.

Composite sulfur cathode for Li-S batteries comprising hierarchical carbon obtained from waste PET bottles

Waste PET bottles have been processed towards carbonaceous material through pyrolysis at 500 °C in nitrogen atmosphere followed by chemical activation with K2CO3. The obtained carbon was found to feature hierarchical pore structure, as evidenced by nitrogen sorption isotherm analysis. Composite sulfur-carbon electrode has been prepared using this carbon by means of simple dry-mixing technique and subjected to electrochemical testing in model Li-S cells with electrolyte being 0.5 M lithium trifluoromethanesulfonate (LiTf) and 0.5 M lithium nitrate (LiNO3) in mixture of 1,2dimethoxyethane (DME) and 1,3-dioxolane (DOL). The Li-S cells assembled with obtained composite sulfur-carbon cathode demonstrated a large initial specific discharge capacity of about 829 mA h g−1 at 0.05 C current rate and delivered ca. 712 mA h g−1 after subsequent 50 charge and discharge cycles, which corresponds to 86% capacity retention. Generally, the investigated Li-S cells have exhibited good cycling stability and excellent reversibility. Thus, the obtained waste-derived activated porous carbon can be considered as a promising component for the composite cathode material of Li–S batteries.

The role of different dry-mixing techniques on the mechanical and biological behavior of UHMWPE/alumina-zirconia composites for biomedical applications

The structural, morphological, mechanical characterization and cells interaction of ATZ (Alumina Toughened Zirconia)-UHMWPE composites containing 2.5 wt% of ceramic filler obtained with different dry-mixing techniques are discussed, in order to assess their feasibility as biomedical supportive function materials. The results indicate that, by changing the dry-mixing techniques used for preparing composites, it is possible to tune the structural and morphological characteristics of the composites that, in turn, affect the mechanical parameters.All the composites show good cell interaction and promote higher cell viability at 24 h than the unfilled polymer. The biological behavior is not directly correlated with wettability and microroughness, but it seems dependent on the presence of ATZ filler.

Large Batch Coating Process for Improving Thermal Stability of NCM622 Cathode

Nickel-rich cathodes such as LiNi0.6Co0.2Mn0.2O2 (NCM622) have received considerable attention as a result of their high delivered capacity. However, owing to high nickel content, NCM622 cathodes suffer from reduced cycle life and thermal stability compared to lower nickel content NCM523 and NCM333 cathodes. (1) Traditional approaches to coating and doping, including exploration of various coating (Al2O3, AlF3, SiO2) and dopant (Al3+, Mg2+, F-) species which either act as a passivating layer between the cathode surface and reactive electrolyte or to stabilize the structure of the material, have been employed in the past to improve the performance of Ni-rich cathodes. (2-9) This presentation demonstrates the effectiveness of a large batch (i.e. 500 grams) coating process to deposit either AlF3 or ZnO on NCM622 cathode material. The process is a dry mixing technique wherein the coating is applied using powerful mechanical energy to induce mechano-chemical reactions between the surface of NCM622 and AlF3 or ZnO. SEM imaging and EDX mapping illustrate that the size or morphology of the secondary particles is not affected by the process and the coating species is well-distributed among the bulk. Differential scanning calorimetry (DSC) and temperature-depending X-ray diffraction (XRD) were conducted to monitor the thermal stability of AlF3 and ZnO coated NCM622. Temperature-dependent XRD shows the structural degradation of the layered NCM622 structure to a non-layered rock-salt structure as a function of temperature. The peak positions in the DSC correspond directly to the c lattice parameter decreasing, which is caused by oxygen release, and the conversion to a rock-salt phase. These results indicate how AlF3 and ZnO coatings alter the collapse and phase transition of the delithiated NCM622 during heating. References (1) Liu, W.; Oh, P.; Liu, X.; Lee, M.-J.; Cho, W.; Chae, S.; Kim, Y.; Cho, J. Chem. Int. Ed. 2015, 54, 4440-4457. (2) Mohanty, D.; Dahlberg, K.; King, D. M.; David, L. A.; Sefat, A. S.; Wood, D. L.; Daniel, C.; Dhar, S.; Mahajan, V.; Lee, M.; Albano, F. Reports 2016, 6, 26532. (3) Han, B.; Paulauskas, T.; Key, B.; Peebles, C.; Park, J. S.; Klie, R. F.; Vaughey, J. T.; Dogan, F. ACS Appl. Mater. Interfaces 2017, 9, 14769-14778. (4) Liao, J.-Y.; Manthiram, A. Power Sources 2015, 282, 429-436. (5) Du, K.; Xie, H.; Hu, G.; Peng, Z.; Cao, Y.; Yu, F. ACS Appl. Mater. Interfaces 2016, 8, 17713-17720. (6) Zhou, P.; Zhang, Z.; Meng, H.; Lu, Y.; Cao, J.; Cheng, F.; Tao, Z.; Chen, J. Nanoscale 2016, 8, 19263-19269. (7) Woo, S.-U.; Yoon, C. S.; Amine, K.; Belharouak, I.; Sun, Y.-K. Electrochem. Soc. 2007, 154, A1005-A1009. (8) Hu, G.; Zhang, M.; Liang, L.; Peng, Z.; Du, K.; Cao, Y. Electrochimica Acta 2016, 190, 264-275. (9) Krishna Kumar, S.; Ghosh, S.; Ghosal, P.; Martha, S. K. Power Sources 2017, 356, 115-123.

DEVELOPMENT AND CHARACTERISATION OF NATURAL RUBBER - GELATIN BLENDS WITH IMPROVED BIODEGRADABILITY

Natural rubber (NR) blends with different concentrations of gelatin (GLN) were successfully prepared through solution casting and dry-mixing techniques. The gelatin content was varied from 0 to 20 phr. The blends were cured at 150 C to their respective optimum cure times. Biodegradability was evaluated using soil burial test and was found to have improved with gelatin content. A gelatin loading of 10 phr was sufficient to impart a significant extent of biodegradation. The blends were also investigated for mechanical and dynamic mechanical properties, morphology and thermal and solvent resistance. Enhanced cure rate, increased cross-link density and improved mechanical properties, without any deterioration in thermal stability, could be achieved through the blending process. The blend realizes fabrication of a biodegradable substitute for vulcanized natural rubber without compromising mechanical and thermal properties.

Copper-Doped Cobalt Spinel Electrocatalysts Supported on Activated Carbon for Hydrogen Evolution Reaction.

The development of electrocatalysts based on the doping of copper over cobalt spinel supported on a microporous activated carbon has been studied. Both copper–cobalt and cobalt spinel nanoparticles were synthesized using a silica-template method. Hybrid materials consisting of an activated carbon (AC), cobalt oxide (Co3O4), and copper-doped cobalt oxide (CuCo2O4) nanoparticles, were obtained by dry mixing technique and evaluated as electrocatalysts in alkaline media for hydrogen evolution reaction. Physical mixtures containing 5, 10, and 20 wt.% of Co3O4 or CuCo2O4 with a highly microporous activated carbon were prepared and characterized by XRD, TEM, XPS, physical adsorption of gases, and electrochemical techniques. The electrochemical tests revealed that the electrodes containing copper as the dopant cation result in a lower overpotential and higher current density for the hydrogen evolution reaction.

Pharmaceutical and pharmacokinetic characterization of a novel sublingual buprenorphine/naloxone tablet formulation in healthy volunteers

Context: Bitter taste, as well as dissolve time, presents a significant challenge for the acceptability of formulations for oral transmucosal drug delivery.Objective: To characterize a novel sublingual tablet formulation of buprenorphine/naloxone with regards to pharmacokinetics, dissolve time and formulation acceptability.Methods: Dry mixing techniques were employed to produce a small and fast dissolving buprenorphine/naloxone sublingual tablet formulation, OX219 (Zubsolv®), using sucralose and menthol as sweetener and flavor to mask the bitter taste of the active ingredients. Two cross-over studies were performed in healthy volunteers to evaluate pharmacokinetics, dissolve time and acceptability of OX219 5.7/1.4 mg tablets compared to the commercially available buprenorphine/naloxone formulations Suboxone® tablets and films (8/2 mg).Results: Buprenorphine exposure was equivalent in OX219 and Suboxone tablets. Sublingual dissolve times were significantly shorter for OX219 than for Suboxone tablets and were similar to Suboxone films. The OX219 formulation received significantly higher subjective ratings for taste and overall acceptability than both Suboxone formulations. OX219 was preferred over Suboxone tablet and film formulations by 77.4% and 88.9% of subjects, respectively.Conclusions: A sublingual tablet formulation with an improved acceptability has been successfully developed.

Characterization of UHMWPE/wood composites produced via dry‐blending and compression molding

AbstractIn this study, composites made from wood flour and ultra‐high molecular weight polyethylene (UHMWPE) were produced and characterized. In particular, the composites were initially prepared using a simple dry mixing technique and then compression molded. The effect of wood content on the mechanical properties was determined up to 30wt%. Characterization included scanning electron microscopy to investigate wood dispersion and interfacial bonding quality, while the mechanical tests included tensile, torsion, and flexion. The results show that good dispersion and adhesion was achieved and wood flour addition increased substantially (up to 97%) all the moduli in the range of conditions tested. Finally, it was found that hardness increased by about 5 Shore D points by adding 30% wood flour in UHMWPE. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers

Direct synthesis of platelet KNbO3 particles using KNb3O8 precursor and KNO3 self-flux

Platelet KNbO3 particles having perovskite single phase have been successfully synthesized by a new simple procedure based on the dry-mixing technique and self-flux method using KNO3 source that required no washing and filtration process. Well-crystalline edge-shaped platelet KNb3O8 particles were first obtained by the reaction between KNO3 and Nb2O5. Next, they were reacted with second KNO3 to form platelet KNbO3 particles by the topochemical conversion method. The platelet KNbO3 particles synthesized at 800°C demonstrated a relatively high aspect ratio of around 5 with edge lengths of about 2–10 and 10–40 µm in size for the tabular and thickness directions, respectively. The topochemical conversion mechanism from KNb3O8 to KNbO3 was also proposed in this study.

Fabrication and Characterization of High Temperature Resin/Carbon Nanofiber Composites

Multifunctional composites present a route to structural weight reduction. Nanoparticles such as carbon nanofibers (CNF) provide a compromise as a lower cost nanosize reinforcement that yields a desirable combination of properties. Blends of PETI-330 and CNFs were prepared and characterized to investigate the potential of CNF composites as a high-performance structural medium. Dry mixing techniques were employed and the effect of CNF loading level on melt viscosity was determined. The resulting powders were characterized for degree of mixing, thermal and rheological properties. Based on the characterization results, samples containing 30 and 40 wt.% CNF were scaled up to approximately 300 g and used to fabricate moldings 10.2 cm ′ 15.2 cm ′ 0.32 cm thick. The moldings were fabricated by injecting the mixtures at 260-280°C into a stainless steel tool followed by curing for 1 h at 371°C. The tool was designed to impart high shear during the injection process in an attempt to achieve some alignment of CNFs in the flow direction. Moldings were obtained that were subsequently characterized for thermal, mechanical and electrical properties. The degree of dispersion and alignment of CNFs were investigated using high-resolution scanning electron microscopy. The preparation and preliminary characterization of PETI-330/CNF composites are discussed.

Incorporation of multi-walled carbon nanotubes into high temperature resin using dry mixing techniques

As part of an ongoing effort to develop multifunctional advanced composites, blends of PETI330 and multiwalled carbon nanotubes (MWNTs) were prepared and characterized. Dry mixing techniques were employed and the maximum loading level of the MWNT chosen was based primarily on its effect on melt viscosity. The PETI330/ MWNT mixtures were prepared at concentrations ranging from 3 to 25 wt %. The resulting powders were characterized for homogeneity, thermal and rheological properties and extrudability as continuous fibers. Based on the characterization results, samples containing 10, 15 and 20 wt % MWNTs were chosen for more comprehensive evaluation. Samples were also prepared using in situ polymerization and solution mixing techniques and their properties were compared with the ball-mill prepared samples. The preparation and characterization of PETI330/ MWNT nanocomposites are discussed herein.

Development of particulate treatments and coatings to reduce SiC degradation by liquid aluminum

SiC-particulate-reinforced aluminum alloys are potentially attractive materials for structural applications. Among the fabrication possibilities, the molten metal mixing technique is one of the most promising in terms of cost and production capacity. Degradation of SiC by chemical reaction with molten aluminum is a problem that could be, at least partially, overcome by treatments or coatings of the reinforcements. This article describes the various techniques that have been used to coat particles and presents results ob-tained during remelting of composites. Prior oxidation of particles, oxide coating by sol-gel, or dry mixing techniques are thus presented. Oxidation of particles and TiO2 coatings slow the degradation of SiC. Analytical electron microscopy was used to characterize the interfacial reactions that occurred during fabrication and remelting of composites. Possible mechanisms of protection are then presented and discussed.

Reactive Multicomponent Powder Mixtures Prepared by Microencapsulation: Pb(Mg1/3Nb2/3)O3 Synthesis

Microencapsulation of ceramic powders using metalloorganic stearate soaps was investigated as an economical means to increase solid‐state reactivity of multicomponent mixtures. The specific system investigated was lead magnesium niobate (PMN); however, the process may be applicable to a wide range of other compositions. The physical and chemical characteristics of the unfired powder mixtures and reactivity during subsequent calcination were studied as a function of batch composition and mixing method. Batch composition was varied by molar substitution of magnesium stearate for magnesium carbonate. Mixing method was investigated by comparing a dry‐mixing technique developed for particle coating (mechanofusion) with conventional wet ball milling. Both mixing processes resulted in surface coating of the ceramic particles by the stearate soap. In addition, the mechanofusion process produced densely packed spherical granules of coated particles (multicored microcapsules) in the 50‐ to 200‐μm range. Solid‐state reactivity was measured in terms of perovskite phase yield, increased yields being indicative of a more reactive mixture. The highest perovskite yields (95 to 98 vol%) were achieved at 100 mol% substitution of magnesium stearate for magnesium carbonate, independent of mixing method. However, when magnesium stearate was only partially substituted for magnesium carbonate, the mechanofusion process produced consistently higher perovskite yields than did ball milling. Compared to conventional mixed‐oxide processing, the increased reactivity of the microencapsulated mixtures can be attributed to higher chemical activity of the metallo‐organic precursor, finer scale of mixing achieved by particle coating, and a further reduction in segregation scale due to the dense intragranule packing of multicore microcapsules.