Addition Of Binder Research Articles

The combined effects of binder addition and different sintering methods on the mechanical properties of bovine hydroxyapatite

Hydroxyapatite (HA) from bovine bones has been used as a biomaterial in dentistry due to its biocompatibility and bioactivity. However, dense HA bioceramics still present inadequate properties for applications that require high mechanical performance, such as infrastructure. Microstructural reinforcements and control of ceramic processing steps are methods to improve these shortcomings. The present study assessed the effects of polyvinyl butyral (PVB) addition in combination with two sintering methodologies (2-step and conventional), on the mechanical properties of polycrystalline bovine HA bioceramics. The samples were divided into four groups (with 15 samples per group): conventional sintering with binder (HBC) and without binder (HWC) and 2-step sintering with (HB2) and without binder (HW2). HA was extracted from bovine bones, turned into nanoparticles in a ball mill, and subjected to uniaxial and isostatic pressing into discs, according to ISO 6872 standards. All groups were characterized by x-ray diffractometry (XRD), differential thermal analysis (DTA) and Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and relative density. Besides, mechanical analyses (biaxial flexural strength (BFS) and modulus of elasticity) were also performed. The characterization results demonstrated that adding agglutinants or the sintering method did not affect HA's chemical and structural characteristics. Even so, the HWC group showed the highest mechanical values for BFS and modulus of elasticity being 109.0 (98.0; 117.0) MPa and 105.17 ± 14.65 GPa, respectively. The HA ceramics submitted to conventional sintering and without the addition of binders achieved better mechanical properties than the other groups. The impacts of each variable were discussed and correlated to the final microstructures and mechanical properties.

Effect of Particle Shape on The Behavior of Polymer-Improved Sandy Soil Used in Pavements Due to Freeze-Thaw Cycles

Freeze-thaw cycles have a significant negative effect on the engineering behaviour of soil in cold regions. In this study, the compressive strength of stabilized, poorly graded sandy soil used in road pavement that was subjected to different freeze-thaw cycles was studied. Samples with three different particle shapes were stabilized with a binder developed by mixing polyvinyl acetate (PVAc) and ethylene glycol monobutyl ether (EGBE). The PVAc/EGBE weight ratio was 2:1, and PVAc was added at 1%, 2%, and 3% of the dry weight of the soil, with the effect of up to ten freeze-thaw cycles evaluated. Results showed that the addition of binder decreased optimum moisture content and increased compressive strength. An increase in particle roundness results in a decrease in the magnitude of compressive strength but increases the soil composite ductility. Changing particle shape from angular to rounded resulted in a more significant decrease in compressive strength than changing from rounded to well-rounded. The decrease in compressive strength is most significant between the first and fourth freezing-thawing cycles and marginal between the fourth and tenth. The negative effect of increasing the roundness of particles is compensated by increasing binder percentages.

Increasing the Content of Reclaimed Asphalt in Asphalt Mixture by using Rejuvenators

Recycling pavements is beneficial on various levels, since using reclaimed asphalt (RA) has a positive effect on the economy and environmental protection at the same time. Removed old asphalt pavement is no longer considered as a waste material, which has to be landfilled, but a useful material for further applications. Leading to a reduction of the need for virgin materials and preserve the planet. At the start, RA was used for construction of embankments and unbound granular layers, later cold recycling became another effective solution. After years of experiments, the rate of RA has increased to reach even the 100 %. But typical RA content in hot asphalt mixtures is between 25 % to 40 %. The presence of RA in the asphalt mixture has a negative effect on the mixture properties. Two alternatives were used in order to soften the aged bitumen – use of softer binder or special additives, i.e., rejuvenators. This study evaluated the possibility of increasing the RA content (30 % and 50 %) in asphalt mixture by adding mainly bio-based alternative rejuvenators. Mechanical performance was evaluated by means of laboratory investigations for typical characteristics dedicated to durability, stiffness, and cracking potential.

Effect of Phyllosilicates As Toxin Binder On Productivity, Intestinal Morphology, and Liver Toxicity in Broiler Fed Afb1 Contaminated Feed

Aflatoxin B1 is a toxin produced by the fungus Aspergillus flavus which reduces the development and function of organs in broilers. The aim of this study was to determine the effect of adding binder toxin from different bentonite to feed contaminated with AFB1 on productivity, intestinal morphology, and liver toxicity in broilers. A total of 60-day old chick male broilers were placed in 12 pens. Each treatment consisted of three replicates, each replicate containing five broilers. Treatment in the study consisted of P0 (control, basal diet, without the addition of AFB1), P1 (P0 + 100 µg/kg AFB1 + 4 g/kg calcium bentonite Type A), P2 (P0 + 100 µg/kg AFB1 + 4 g/kg calcium bentonite Type B), and P3 (P0 + 100 µg/kg AFB1 + 4 g/kg calcium bentonite Type B + kerolite + saponite). Treatment diets were given to broilers from day 22 to 35 (finisher phase). The results showed that the toxin binder on AFB1 contaminated feed had no effect on feed consumption, body weight gain and feed conversion (p>0.05). Addition of toxin binder on AFB1 contaminated feed increased the relative weight of the duodenum (p=0.024), although P3 was not significantly different. Treatments had no effect on villus length, crypt depth, and ratio of villus length to crypt depth (p>0.05), but decreased villus width (p=0.013). The addition of toxin binder tended to decrease the villus area (p=0.055). SGOT and SGPT did not show differences between treatments. AFB1 contamination with the addition of toxin binder showed signs of toxicity on liver histopathological observations. Based on the research, it can be concluded that the addition of binder toxin in feed contaminated with AFB1 can reduce the negative effect on the development of intestinal villus and chemical effect to the liver. Toxin binder Type B has the best efficacy for reduce the negative effect

Molecular Dynamics Simulations of the Thermal Decomposition of RDX/HTPB Explosives.

The addition of binders to energetic materials is known to complicate the thermal decomposition process of such materials. To assess this effect, the present work studied the thermal decomposition of cyclotrimethylene trinitramine (RDX)/hydroxy-terminated polybutadiene (HTPB) mixtures and of pure RDX over the temperature range of 2000-3500 K by combining the classical reaction and first-principles molecular dynamics methods. The incorporation of HTPB as a binder was found to significantly reduce the decomposition rate of RDX. At 3500 K, the decay rate constant of RDX in the RDX/HTPB system is 2.0141 × 1012 s-1, while it is 2.7723 × 1012 s-1 in the pure RDX system. However, the binder HTPB had little effect on the initial decomposition mechanism, which involved the rupture of N-NO2 bonds to produce NO2. The HTPB was predicted to undergo dehydrogenation and chain breaking. The free H resulting from these processes was predicted to react with low-molecular-weight intermediates generated by the RDX, resulting in greater equilibrium quantities of the final products H2O and H2 being obtained from the mixed system compared with pure RDX. HTPB-chain fragments were also found to combine with the primary RDX decomposition product NO2 to inhibit the formation of N2 and CO2.

Weathering characteristics of asphalt modified by hybrid of micro-nano tire rubber and SBS

Tire rubber has been considered as the ideal candidate for improving aging durability of styrene–butadienestyrene copolymers (SBS) modified asphalt pavement. However, crosslink characteristic of tire rubber affected its dispersion in SBS modified asphalt binder (SMB) and restricted high addition dosage. In this study, microscale and nanoscale tire rubber (MNTR) hybridized SMB with the high dosage was prepared for studying its structural evolution during weathering and physical property variation. Results of gel permeation chromatography and infrared spectroscopy showed that MNTR stabilized the molecular weight distribution and decreased oxidative condensation reaction of asphalt matrix during weathering, and yet did not prevent the SBS degradation. Structural characteristics revealed that the dissolved rubber and core–shell structured carbon black nanoparticles in MNTR were implanted into the colloid structure of asphalt, inhibiting the weathering reaction including asphalt condensation and asphalt oxidation. Fraass brittleness temperature and modulated differential scanning calorimetry results verified that the hybrid modified asphalt had more stable crack resistance compared with SMB at low temperature, and dynamic shear rheometer experiment proved its stable deformation resistance and excellent elasticity at high temperature during weathering. Accordingly, the addition of high content MNTR strongly improved natural weathering resistance of SMB based on the highly hybridized colloid structure.

Application of optimized bamboo fibre reinforced mortar in prefabricated bamboo reinforced wall panels as a sustainable building component

The natural resources are getting exploited due to increase in population for the manufacture of regular construction materials like steel, bricks and cement. This leads to increase in the cost of these materials and worsen the environment by releasing more harmful greenhouse gases. This phenomenon leads to development of alternative sustainable construction. This article gives out a sustainable building element – a bamboo reinforced prefabricated wall panels. The flexural strength, rebound hammer test and the cost analysis were carried out on the panels to investigate its potential for its use in the low cost building projects. Along with the bamboo reinforcement for the panels, the other waste bamboo materials like bamboo Fibre (BF) and Bamboo Stem Ash (BSA) are used as additive and complementary binder respectively in the mortar. The optimum dosage is obtained and validated by adapting Taguchi’s approach. The experimental results proved that bamboo reinforced wall panel is 11% lighter and 16% cheaper than the conventional steel reinforced wall panels and the load carrying capacity reached to 72% of the conventional steel reinforced wall panel. The advantage of this panel over the conventional brick wall was enormous and there can be an alternative solution for low cost housing.

Tannic acid as a binder and electronic conductor precursor in silicon electrodes for Li-ion batteries

State of-the-art Si electrodes for Li-ion batteries typically require the addition of an advanced polymeric binder and a conductive carbon additive to the active material in order to circumvolve the issues associated with silicon, namely its poor conductivity in the oxidized state, and its high volume variation upon lithiation which give rise to several failure mechanisms. Here, we demonstrate that both additives can be replaced by a cheap, naturally available, polyphenol, tannic acid (TA). We show that Si/TA electrodes (80/20 wt%), even with a high loading (∼2 mg_Si cm−2), can retain a specific capacity above 2000 mAh g−1 after 50 cycles. This unexpected result appears to result from the irreversible reduction of TA during the first cycle, into a conducting, likely polymeric, species.

Effects of flour, dye and binder types on the proximate properties of analog rice

Various types of non-rice food in Indonesia can be used produced analog rice, which is more nutritious than rice to support diversification programs in Indonesia. Taro flour and breadfruit flour are local carbohydrate sources that can be processed into analog rice. To improve the attractiveness of analog rice and enrich its nutritional content, natural food dyes are usually added. Binders are also used to modify the texture and cohesiveness of analog rice. The aimed of this research to determine the proximate properties of analog rice made from taro and breadfruit flours with addition of natural dyes and binders. This study tested three variables namely: the type of flour (taro and breadfruit), type of dye (beetroot and butterfly pea flower), and type of binder (CMC and carrageenan). The results showed that analog rice had an average water content of 3.25%, ash content of 2.72%, protein content of 7.66%, fat content of 2.00%, and carbohydrate content of 82.64%. The best formula was analog rice prepared from a combination of breadfruit flour, beetroot, and CMC with moisture, ash, fat, protein, and carbohydrate contents of 3.17%, 2.96%, 1.41%, 8.17%, and 82.65%, respectively. Based on the results obtained, the carbohydrate source of taro and breadfruit flour with the addition of natural dyes of beetroot and butterfly pea flower, as well as using CMC and carrageenan can produce analog rice that has good nutritional content (proximate properties).

ANN model using MATLAB in CFS -concrete

This paper presents the ANN studies on concrete by using Cenosphere as a partial replacement of binder and filler addition with foundry sand. This study contains mechanical properties that includes ANN analysis in Cenosphere with Foundry Sand (CFS) Concrete. Cenosphere and waste foundry sand are extensively available in manufacturing industries. The resulting materials have adequate strength and greater durability characteristics. The various proportion of trial mixes are studied with Cenosphere namely 0% 5%, 10%, 15%, and 20% with replacement of OPC 53 grade, and waste foundry sand with 20%, 30%, 40%, 50%, and,60% with partial replacement of sand added to the concrete. The strength and durability were tested for 7, 14, 28, 56 and 91 days. The waste foundry sand is used as alternate for fine aggregate and Cenosphere used as cement partial mixing for the dosages. Since Cenosphere is a very fine material of the colour of cement it can be used in replacing cement instead of PPC. Ash Cenospheres are hollow lightweight microspheres formed from fly ash generated during the burning of pulverised coal for power production. The particle size and characteristics are very similar to the pozzolanas with comparatively low density. It containsSiO2and Al2O3 in larger quantity and the content of components, such as SiO2, Fe2O3, MgO, CaO and K2O,which help for the enhancement of strength. The waste foundry sand is available in greater quantity and so it can be used for making concrete. The test results show good workability and mechanical behavior of concrete. This concrete increases 25 to 50 percentage of strength and have the best workability. It controls pores and crack in concrete. Micro cracks and pores are controlled better compared to conventional mixing concrete. This study includes the Artificial neural network (ANN) to predict the numerical experiments to review the effects of variable proportions on the concrete mix.

Analytical Study on the Effect of Electric Arc Furnace Dust (EAFD) on the Rutting of Asphalt Concrete Mixtures

As a byproduct of the steelmaking process, significant amounts of hazardous electric arc furnace dust (EAFD) are produced. Utilizing the solidification/stabilization technology with asphalt mix is one way to safeguard the environment from its negative effects. Rutting was used as an indicator to assess the asphalt mixture with EAFD since it is an important factor in pavement design. This study's major goal is to ascertain how EAFD affects the rutting of asphalt-concrete mixtures. To evaluate the ideal asphalt content, the Marshall test method was applied to asphalt concrete mixtures. EAFD was added to the asphalt cement in four different volume percentages as a binder addition. Then, using the Universal Testing Machine, participants were exposed to a replica of the rutting test (UTM). Experiments were conducted at 25, 40 and 55oC, and at frequencies of 1, 4 and 8 Hz. Rutting was measured for each specimen. Tests results showed that while rut depth has negative correlation with of EAFD% and positive correlation with the temperature. The use of EAFD has dual advantages, protecting the environment from the adverse impact of EAFD and reducing the cost of asphalt mix without jeopardizing the pavement performance.

ОСОБЕННОСТИ СТРУКТУРООБРАЗОВАНИЯ КОМПОЗИЦИОННЫХ ГИПСОВЫХ ВЯЖУЩИХ С КОМПЛЕКСОМ МИНЕРАЛЬНЫХ И ОРГАНИЧЕСКИХ ДОБАВОК

For the dynamically developing low-rise construction industry, there is a growing need to expand the range of building materials, including fast-hardening types of binders. Composite gypsum binders are effective, including a carefully selected mixture of gypsum binder, Portland cement and active mineral additives. Materials based on them harden quickly and gain the required strength. An increase in the performance characteristics of this type of binders is achieved when mineral and chemical additives are used in a complex. This helps to regulate the processes of their structure formation and hardening, depending on the activity of the components, changes in water demand, as well as the peptizing, adsorption and air-entrapping effects of chemical additives. The article presents the results of a study of the effect of chemical additives – superplasticizers MARF SU 84, MELFLUX 5581 F and the retarder of the setting time of PlastRetard PE – on the physico-mechanical properties of a hardened composite gypsum binder, including gypsum binder, Portland cement and a complex of mineral components (fine quartz sand, metacaolin VMK-45, limestone dust). The issues of management of its structuring processes are considered. It has been established that finely dispersed mineral additives from quartz sand, VMK-45 metacaolin and limestone dust are effective components for the production of composite gypsum binders. The developed complex chemical additives MARFSU 84 (0.1%)+PlastRetard PE (0.08%) and MELFLUX 5581 F (0.1%)+ PlastRetard PE (0.08%) can significantly slow down the beginning and end of setting of gypsum cement mixtures up to 45...48 min and increase the compressive strength of the hardened KGV after 28 days by 1.5 ...1.6 times (up to 18.3...20.4 MPa), respectively.

Mechanical properties and microstructural characteristics of 316L stainless steel fabricated by laser powder bed fusion and binder jetting

In this work, the tensile test coupons and lattice structure of 316L stainless steel (SS) samples were manufactured by two powder bed-based additive manufacturing (AM) techniques-laser powder bed fusion (LPBF) and binder jetting (BJ) processes. The microstructure and mechanical properties of these components were investigated through a scanning electron microscope, hardness measurement, tensile tests, and compression tests. The results showed that the grain size of the LPBF sample was smaller than that of the BJ sample. This difference led to the microhardness of LPBF and BJ samples being 239.16 ± 4.90 HV and 208.71 ± 4.15 HV, respectively. The relative density of LPBF samples was 99.20 ± 0.30% and the BJ samples was 96.54 ± 0.54%. The LPBF samples had better mechanical properties, with tensile strength and compressive yield strength of 669.92 ± 18.68 MPa and 75.65 ± 5.77 MPa, respectively, while the tensile strength and compressive yield strength of the BJ samples were 437.55 ± 10.11 MPa and 78.65 ± 3.57 MPa, respectively. The experimental data showed good consistency with the simulation results (error within 10%) in both the compression modulus and yield strength for the lattice structures. These findings look promising for the future design of lattice structures with high mechanical properties using LPBF and BJ techniques.

Mechanical and Thermal Properties of Extrudates Produced from Discarded Coal Fines and Recycled Plastics as Binders

This study focuses on the extrusion of discarded coal fines from the Highveld coalfield together with recycled low-density polyethylene (LDPE) and polypropylene (PP) which are used as binders to produce agglomerates with better handling properties than the coal fines for industrial use. The binder content varied between 5 and 100 wt %. The barrels of the twin screw extruder were kept at a temperature of 220 °C to melt the binders while forcing the mixture through a 10 mm die. The extrudates containing 10% or more binder were strong and homogeneous, while a 5% binder addition proved to be too low to produce homogeneous extrudates. The extrudates containing 10% LDPE and 10% PP showed compressive strengths of 17.5 and 7.9 MPa before breaking, respectively. The rest of the extrudates (>10% plastic addition) did not break but merely flattened as the plastic load increased. The compressive strength of all the extrudates showed no significant difference after being exposed to water. Furthermore, the extrudates absorbed less than 5% water after being submerged for 24 h. Thermogravimetric analysis of the extrudates was conducted under a nitrogen atmosphere up to 900 °C. Three iso-conversional methods, Kissinger–Akahira–Sunose, Starink, and Flynn–Wall–Ozawa, were used to determine the activation energy of the extrudates and raw materials. The lower activation energy and conversion temperatures found for the extrudates indicate a synergy between plastic and coal fines when the extrudates are pyrolyzed. Results from this study suggest that the co-extrusion of recycled plastic with coal fines will produce solid carbonaceous fuels with high hydrophobicity, heating value, and high mechanical strength compared to coal fines.

RESPONSE OF BROILER CHICKENS FED AFLATOXIN MAIZE-BASED DIETS SUPPLEMENTED WITH VARIOUS LEVELS OF MYCOTOXIN BINDER

The efficacy of varying levels of mycotoxin binder supplementation on growth performance, carcass characteristics and serum metabolites of broiler chickens fed aflatoxin maize-based diets was assessed. A total of four hundred and thirty-two (432), one-day-old Hubbard Cobb hybrid broilers were used for the experiment. The chicks were equally weighed and allotted to 12 dietary treatments in a 3 x 4 factorial arrangement of an activated clay toxin binder at three different inclusion levels (0 g/kg, 0.1 g/kg and 0.2 g/kg) of feed challenged with 4 levels of aflatoxin B, (0, 40, 60 and 80 ppb). Thirty-six chicks were allocated to each treatment group and replicated three times with 12 chicks per replicate in deep litter for eight weeks. At the end of the feeding trial, the birds were starved overnight prior to blood collection, three birds per treatment were selected on the basis of average pen weight. Blood samples were collected for serum and haematological analysis. Data collected were subjected to One-way analysis of variance (ANOVA) using SAS software. Results revealed significant (p < 0.05) differences in the total protein (TP) content across the dietary treatments. Interaction between aflatoxin and binder levels showed a significant (p < 0.05) effect only on the Alanine amino transferase (ALT) of the birds. Addition of mycotoxin binder (clay type) to aflatoxin contaminated diets was able to ameliorate the effect of aflatoxin on birds regardless of the level at which it was supplemented. Inclusion of 1 % binder in the diets is therefore recommended and feed ingredients for feed formulations be always subjected to test for aflatoxins.

Effect and mechanism of action of glass waste powder as an additional binder on the properties of recycled concrete

Effect and mechanism of action of glass waste powder as an additional binder on the properties of recycled concrete

Electrochemical performance of aqueous electrolytes in porous carbon derived cassava peel electrode material-based for sustainable symmetrical supercapacitor

Electrolytes have been generally recognized as one of the most important components in enhancing the electrochemical performance of supercapacitors. On the other hand, aqueous electrolytes are considered prime candidates for the development of the next generation of symmetric supercapacitors due to their low-cost, environmentally friendly, high ionic conductivity, fine ionic size, and high capacitance. Herein, the symmetrical supercapacitor of the sustainable porous carbon-based electrode material was confirmed through various aqueous electrolytes consisting of neutral, basic, and acidic Na2SO4, KOH, and H2SO4. Activated carbon is obtained from high potential biomass sources of cassava peel waste. Activated carbon synthesis was performed with a comprehensive approach in order to obtain abundant pore structure, high porosity, and improved wettability through a combination of high-temperature chemical and physical activation. in addition, the electrode material is designed to resemble a solid disc without the addition of a synthetic binder. The evaluation of the disc dimensions showed high porosity in the obtained activated carbon. Furthermore, the symmetrical supercapacitor of the optimized electrode material exhibit excellent specific capacitances of 112, 150, and 183 F g-1 at 1 mV s-1 in the electrolytes Na2SO4, KOH, and H2SO4, respectively. In addition, the highest rate capability of 70% was confirmed in the H2SO4 acid electrolyte. Moreover, their coulombic efficiency can be maintained around 89% with low equivalent series resistance 0.21-0.42 ?. Therefore, the activated carbon-based supercapacitor symmetric cell device from cassava peel shows high performance for developing high-performance supercapacitor applications with guaranteed stability in aqueous electrolytes.

Effect of Torrefaction on the Physiochemical Properties of White Spruce Sawdust for Biofuel Production

Torrefaction pretreatment is a mild form of pyrolysis that has the potential to produce a high-quality raw material for making biofuel that serves as a replacement for coal in the bioenergy industry. Microwave-assisted torrefaction was conducted on white spruce sawdust (WSS) at temperatures of 200 °C, 250 °C, and 300 °C and retention times of 5 min, 7 min, and 9 min in an inert environment. The torrefaction process produces a solid carbon, commonly known as biochar, and condensable (torrefaction liquid (TL)) and non-condensable gases. In this study, torrefaction characteristics were investigated to observe its effects on the thermal and physiochemical properties of the pellets produced. During the torrefaction process, a significant mass loss associated with the decomposition of hemicellulose was observed. The hemicellulose content drastically reduced to approximately 1.8% and the cellulose content was reduced by approximately 10%, while the lignin gained approximately 35% as the severity increased. This led to an improvement in the higher heating value (HHV), hydrophobicity, bulk, particle density, pellet dimensional stability, and pellet density. However, the pellet tensile strength decreased as the torrefaction severity increased. Pellet tensile strength is a critical indicator of biomass pellets that expresses the force required to crush or damage a pellet. Therefore, to enhance the tensile strength of the pellets, the introduction of a binder was necessary. Torrefaction liquid and sawdust were used as additives at different proportions during pelletization. The addition of binders (torrefaction liquid and sawdust) to the pellet formulation increased the tensile strength of the torrefied WSS by approximately 50%. The OH groups in the biomass break down to a limited degree due to dehydration. This hinders the formation of H bonds, thereby increasing the chances that the pretreated biomass will become hydrophobic. The SEM graphs showed that the torrefied WSS pellets demonstrated more firmly glued surfaces with fewer pores spaces when set side by side with the raw pellets. The thermogravimetric analysis conducted showed that the torrefaction of WSS slightly reduced its thermal stability.

Investigating the role of dry compaction and layer-wise agglomeration to control the dissolution of granular urea fertilizer

Pore size distributions and degree of anisotropy (pore channel orientation) affect the mechanical properties, fragmentation, and dissolution kinetics of granular composites. Especially in porous solids such as granular urea fertilizers, uncontrolled dissolution leads to soil and water contamination from nutrient leaching. In this work, a dry compaction method and a bilayer granulation process were compared to investigate their ability to control the nutrient release from granular urea fertilizers. Urea and binary mixtures of urea and a xanthan and konjac gum binder were dry compacted. The compacts were then milled to specific particle sizes producing core granules. The core granules were drum granulated along with a known percent of fines and water to produce bilayer granules. The drum granulation parameters were optimized based on the granules' particle size distributions and color analysis. Dissolution and porosity distributions of core and bilayer granules were investigated and compared to market urea granules. Core granules with or without a binder compacted at 100 MPa had smaller pore size distributions compared with core granules compacted at 50 MPa, bilayer granules, and market urea granules. Core granules compacted at 100 MPa showed a significant decrease in the dissolution rate compared to less dense systems, such as core granules at 50 MPa, bilayer, and market urea granules. The addition of gums as binder caused an additional delay in the dissolution rate, indicating that formulation design is essential in controlling nutrient release. Less porous structures, i.e., higher compaction pressure to produce core granules, along with binder addition resulted in delayed dissolution rates due to binder migration and gelation at the solid-liquid interface. These results show that densification and formulation design can help control the release of urea from granular fertilizers with the potential of reducing leaching losses and pollution.

Investigating the Influence of Polymer Binders on Liquid Phase Transport and Tortuosity Through Lithium-Ion Electrodes

Quantifying the tortuosity of porous lithium-ion electrodes is important for understanding the rate capability of cells and for optimizing their design, particularly when designing high energy density cells such as those desired for electric vehicles. However, quantifying tortuosity may be difficult, and results often disagree with the commonly used Bruggeman relation. Here, we discuss the observation that PVDF binder, a polymer used to mechanically hold the electrode together, has a direct effect on the rate capability of NMC111 cathodes. Using a pseudo-two-dimensional (P2D) physics-based model of the system, we fit the electrode tortuosity to the cycling data and determine that increased binder volume fraction in an electrode leads to increased electrode tortuosity. Using a TiO2-based blocking electrode, we further support these findings using electrochemical impedance spectroscopy (EIS) measurements and transmission line models. Finally, using pulsed field gradient nuclear magnetic resonance (PFG-NMR) experiments on these blocking electrodes, we propose a mechanism involving liquid phase Li ion “choke-points,” formed by the addition of PVDF binder, which dominates electrode tortuosity. We provide an empirically derived relationship that serves as a binder volume correction to the Bruggeman relation, and this finding motivates further work on the impact of different electrode components on transport through porous electrodes.