Metal Stearates Research Articles

The synergistic influence of metal cations on the drying and viscosity of linseed oil assessed by means of model samples containing synthesised metal carboxylates

The recent multi-analytical study carried out on the Van Eyck’s Ghent Altarpiece showed the simultaneous presence of several kinds of metal carboxylates in oil-rich glaze layers. This outcome raised the question whether these carboxylates had already formed during the preparation of the oil binder by the artists. In the case of early-stage formation, they may have had an impact on the drying rate of the resulting oil, as well as on its handling properties. This hypothesis was investigated using a model system of in-house-prepared linseed oil containing incremental concentrations (2–5–10 wt.%) of relevant metal carboxylates (i.e. Ca-, Zn-, Cu-, and Pb oleates and stearates). This paper describes the influence of these type of molecules on the drying rate of linseed oil and, to an extent, on its viscosity. The drying time of the linseed oil, to which one or more metal carboxylates were added, was measured with a drying recorder while the viscosity was assessed with a rheometer. When introduced together, some of these metal carboxylates act in synergy to shorten the drying time with respect to the situation when the same metal carboxylates were added separately to linseed oil. Mixtures of Ca- and Zn-oleates proved to have a larger effect than other binary combinations. Addition of two metal oleates (combination of Ca/Zn/Cu/Pb) reduced the drying time even more. On the other hand, specific combinations of three metal stearates and/or oleates also demonstrated a significant synergistic effect towards increasing the viscosity of the binder. Especially combinations of Ca/Zn/Cu and Ca/Zn/Pb stearates and oleates gave rise to the highest level of linseed oil viscosity increase, when compared to the situation in which the same metal carboxylates were added separately.

Valorization of palm oil refining by-product for organotin mercaptide as a polyvinyl chloride thermal stabilizer: Synthesis, efficacy and comparison to mixed metal stearate

Organotin mercaptide-based thermal stabilizer is recognized for its effectiveness in enhancing thermal stability of polyvinyl chloride (PVC). In this study, we synthesized an organotin mercaptide-based thermal stabilizer from palm fatty acid distillate, which is a by-product of palm oil refining process, and then evaluated its thermal stabilizing effects on PVC and compared its efficacy and economics to those of mixed metal stearate. The synthesized thermal stabilizer manifests as methyltin mercaptoethyl carboxylate sulfides. Both dehydrochlorination and two-roll mill discoloration tests have demonstrated the high efficacy of the resulting thermal stabilizer in stabilizing PVC, surpassing the performance of mixed metal stearate, as evidenced by the lower dosage required. The synthesized PVC thermal stabilizer not only provides effective stabilization but also presents a competitive viable alternative.

The effect of coated calcium carbonate using stearic acid on the recovered carbon black masterbatch in low-density polyethylene composites

Abstract This research focuses on recycling rubber tire waste through pyrolysis to produce recovered carbon black (rCB). The rCB is combined with recycled low-density polyethylene (rLDPE), calcium carbonate (CaCO3), fatty acid, metallic stearate, and polyethylene (PE) wax to create an rCB masterbatch for household packaging. Surface modification of CaCO3 particles using stearic acid improves the compatibility with LDPE. The study investigates mechanical properties, morphology, melt flow index (MFI), X-ray diffraction, and thermogravimetric analysis in three systems: uncoated, coated, and a hybrid combination of coated and uncoated CaCO3 in LDPE/rCB masterbatch composites. The coated system demonstrates higher mechanical properties and improved compatibility between CaCO3 and LDPE. All three systems exhibit enhanced thermal stability and MFI compared to virgin LDPE, with the coated system showing the most significant improvement. The study showcases the potential of LDPE/rCB masterbatch composites for household packaging, with the coated system displaying the optimum performance across various characteristics.

On the Production of Poly(Lactic Acid) (PLA) Compounds with Metallic Stearates Based on Zinc, Magnesium and Cobalt. Investigation of Torque Rheometry and Thermal Properties

The addition effects of zinc (Zn), cobalt (Co), and magnesium (Mg) based metallic stearates into poly (lactic acid) (PLA) matrix were investigated through torque rheometry, thermogravimetry (TG) and in the Differential Scanning Calorimetry (DSC). PLA compounds/metallic stearates were processed using an internal laboratory mixer with 0.25 wt% Zn, Co, and Mg. Torque rheometry results indicated that PLA/stearate compounds showed higher thermomechanical degradation during processing related to PLA. PLA viscosity is reduced upon stearates addition, especially in the compound with Zn. This behavior suggested PLA chain scission in the presence of metallic stearates during processing, corroborating the decrease in the torque plots. PLA/Zn started to lose weight at lower temperatures than the other compounds, indicating higher pro-oxidant potential. It was observed that Co and Zn significantly reduced the glass transition temperature (Tg), as well as PLA’s crystalline parameters, which suggests PLA’s molecular scission during processing, heading to greater flexibility and reducing Tg. Zn stearate was the most aggressive to PLA’s thermomechanical degradation, suggesting a stronger pro-degradant effect.

Impact of the presence of common polymer additives in thermal and catalytic polyethylene decomposition

Chemical recycling of waste plastics has attracted growing global interest in recent years. However, the role that polymer additives play during these depolymerization reactions is still unknown. In this work, we investigate the impact of typical additives on the rate of reaction of pyrolysis and catalytic decomposition over zeolites. Further, we regenerate the spent catalysts after contact with additive-containing polymer and assess modifications to the catalyst structure and activity. All the tested additives were found to hinder the activity of ZSM-5 catalysts. We also unveil that some additives (amines, phenols) can be fully removed from the catalyst via calcination, whereas others (phosphites, metallic stearate) may permanently deposit and modify sites. The deposition of such impurities on zeolites may change their alkane cracking capabilities. After regeneration, zinc deposited on the catalyst (resulting from plastic degradation reactions) was able to increase hexane cracking conversion by over 7-fold when compared to fresh ZSM-5.

Formulating calcium carbonate masterbatches

Abstract The effects of filler content, filler particle size and surface coating, as well as the natures of the wax and metal stearate lubricants on the properties of calcium carbonate-filled linear low-density polyethylene compounds were investigated. The elongation at break decreased exponentially with filler loading irrespective of whether the filler was surface coated or not. The corresponding decline in the impact strength was more gradual but it dropped abruptly on reaching a filler loading of 70 wt%. The effect of shear rate on the apparent melt viscosity followed an empirically modified Carreau–Yasuda model which included the effect of filler content. It features the zero-shear viscosity and the flow consistency index as adjustable parameters. These characterize the viscosity trends at low- and high-shear rates, respectively. In the absence of additives, the melt viscosity at 60 wt% filler exceeded that of the neat polymer by a factor of three. Adding 3 wt% wax and 1.0 wt% zinc stearate returned the melt viscosity to levels just above that of the neat polymer. Calcium stearate and magnesium stearate were less effective at reducing the apparent melt viscosity but a blend of the latter with zinc stearate performed particularly well.

Evaluation of Alternative Metallic Stearates as Lubricants in Pharmaceutical Tablet Formulation.

Magnesium stearate (MgSt) is perhaps one of the most frequently used lubricants in tablet formulation due to its superior lubrication capacity, yet it could also negatively affect the critical quality attributes of pharmaceutical products. Therefore, we provided a rather comprehensive evaluation of another two FDA-approved metallic stearates, sodium stearate (NaSt) and calcium stearate (CaSt), as alternative tablet lubricants. The primary objective of the present study is to comparatively evaluate the physicochemical properties and lubrication efficiency of the three metallic stearates. In addition, it was also aimed to specify the most influential factor for ranking and differentiating the lubricity of various lubricants using principal component analysis. Unit ejection force could be used herein as a simple and the most powerful parameter to evaluate the lubrication performance instead of the friction coefficient. The results suggested that CaSt, MgSt, and NaSt had similar impacts on the mechanical strength of tablets. However, CaSt exhibited insufficient lubrication effects as the formulations containing CaSt showed low pressure transmission ratios, high unit ejection forces, and high friction coefficients. In contrast, both MgSt and NaSt displayed satisfactory lubrication efficiency without negatively impacting tabletability. Notably, the lubrication performance of the formulation containing 0.5 wt% NaSt was almost identical to that of the formulation with 1 wt% MgSt, indicating that NaSt had a remarkable lubrication capability probably due to its high specific surface area. In summary, the findings of this investigation should provide practical information and feasible methodologies to readily determine the lubricity and to sensibly select alternative lubricants for pharmaceutical tablet formulations.

Self-organization of stearic acid salts on the hemispherical surface of the aqueous subphase allows functionalization of matrix-assisted laser desorption/ionization mass spectrometry target plates for on-plate immobilized metal affinity chromatography enrichment

In this work we propose an approach for formation of periodic two-dimensional structures on a solid substrate via self-assembly of stearic acid molecules on an aqueous subphase drop containing metal ions. It was shown that when a saturated solution of stearic acid in n-hexane was applied to the hemispherical surface of an aqueous media containing barium ions, barium stearate monolayer was formed, which spontaneously collapsed during movement from the drop surface to the substrate. By means of infrared and Raman spectroscopy, light and scanning electron microscopy, atomic force microscopy and matrix-assisted laser desorption/ionization mass spectrometry it was proved that a multi-structure of collapsed metal stearate monolayers with a developed surface was formed on the substrate surface. Thin films formed by a single application of stearic acid solution in n-hexane to a drop of aqueous lanthanum nitrate solution were used for selective enrichment of human butyrylcholinesterase adducts with diisopropyl fluorophosphate.

Degradative Analysis of Sodium Salt of Poly(Ethylene-Co-Methacrylic Acid) Compatibilized LDPE-Starch- Mixtures Containing Metal Stearates

Degradative Analysis of Sodium Salt of Poly(Ethylene-Co-Methacrylic Acid) Compatibilized LDPE-Starch- Mixtures Containing Metal Stearates

Rheological, thermal and mechanical characterization of PBAT/PCL/Stearates blends

The slow degradation and the high environmental impact caused by inappropriate disposal of polymer products are the main factors prompting scientists to either substitute conventional polymers by biodegradable ones or to enhance biodegradation of short-lived polymer products, particularly those used in packaging. Polymer blends of conventional and biodegradable polymers is one of the alternative solutions found to improve mechanical properties and accelerate polymer degradation after disposal. This work investigates the effect of incorporating different metallic stearates (Zn and Mg) on the rheological, thermal and mechanical characteristics of 75PBAT/25PCL blends processed in an internal laboratory mixer. The results of torque rheometry suggest degradation during processing potentialized with the stearates incorporation, while that of DSC indicated that the crystallinity of the blends increased with the incorporation of additives. TG data showed a reduction in the thermal stability of the systems containing stearates. Incorporation of stearates resulted in strongly thermally degraded systems. Adding up to 0.25% of magnesium stearate to the blend 75PBAT/25PCL leads to a material that combines maintenance or improvement of properties combined with higher decomposition.

A molecular mechanics and molecular dynamics study of the structural organization of Cu(II), Ni(II), Co(II), and Fe(II) stearates as potential catalysts for in situ upgrading of heavy oil

Metal stearates may show a substantial catalytic effect in the thermal methods of in situ upgrading of heavy oil. Their good solubility in oil makes it possible to efficiently distribute them over oil reservoirs. Furthermore, in situ synthesis of metal oxide and metal sulfide nanoparticles is possible under conditions of steam injection or other thermal treatments. The initial molecular structure and arrangement of molecules of copper, nickel, cobalt, and iron transition metal stearates are elucidated using the molecular mechanics and molecular dynamics methods. All the simulated complexes are arranged into lamellar layers with additional arrangement of aliphatic chains and metal atoms in two-dimensional periodic arrays. According to the molecular dynamics simulation data, the disordering of hydrocarbon chains and the overall molecular organization takes place at high temperatures. The simulated structures can be further used for studying the solubility of the studied metal stearates in hydrocarbons and the mechanisms of nanoparticle formation from them under conditions used for in situ upgrading of heavy oil.

Thermal characterisation of metal stearate lubricant mixtures for polymer compounding applications

Metal stearate blends are potential lubricants and filler dispersants in polymer compounding. Therefore, the thermal phase behaviour of binary blends of calcium stearate and magnesium stearate with zinc stearate was investigated. Cooling curve studies indicated lower melting temperatures in both systems. X-ray diffraction studies revealed that this was due to the formation of solid solutions of variable composition rather than to eutectic formation. Rheology measurements showed that true fluidification only happened well above the apparent melting points established from cooling curves. Calcium carbonate filled polyethylene containing metal stearate mixtures showed lower melt viscosities than were achievable using only calcium- or magnesium stearate as the lubricant. These results suggest that metal stearate blends, in combination with a judiciously selected wax component, may offer advantages in lowering compound melt viscosity and facilitating better particle dispersion.

Improving the reliability and durability of the gear wheels of the main transmission of fi re trucks by improving the tribotechnical characteristics of transmission oils

The issues of increasing the reliability and durability for fi re trucks the use of highly соeffi cient lubricants in friction units of machines, improving the antiwear properties of hypoid oils used to lubricate the gear wheels of the main drive in transmissions of the trucks are considered. An antiwear additive based on soft metal stearates is proposed. The results tribotechnical tests of the developed antiwear additive, which indicate the effectiveness of its application, are presented.

Materials in Manufacturing and Packaging Systems as Sources of Elemental Impurities in Packaged Drug Products: An Updated Literature Review.

Elemental impurities in drug products arise from different sources and via a number of different means, including leaching of elemental entities (including the elements themselves or element-containing compounds) from the drug product's manufacturing or packaging systems. Thus, knowledge about the presence, level, and likelihood of leaching of elements in manufacturing and packaging systems is relevant to understanding how these systems contribute to a drug product's total elemental impurity burden. To that end, this manuscript updates a previous review of available literature on elemental entities in pharmaceutically relevant polymers and the presence of these elemental entities in material extracts and/or drug products. This updated review contains the information that has been published subsequent to the publication of the initial review and considers two questions: (1) What elemental entities are present in the relevant polymers and materials and at what levels are they present? (2) To what extent are these elemental entities leached from these materials under conditions relevant to the manufacturing and storage/distribution of solution drug products? The compiled recent data reaffirms the conclusions drawn from the original review: (1) Elemental entities are present in the materials used to construct packaging and manufacturing systems as these materials either contain these elemental entities as additives or are exposed to the elemental entities during their production. (2) Unless the elemental entities were parts of the materials themselves (e.g., SiO2 in glass) or intentionally added to the materials (e.g., metal stearates in polymers), their incidental amounts in the materials were generally low. (3) If elemental entities were present in materials and systems, generally only a very small fraction of the total available amount of the entity could be leached under conditions that were relevant to the packaged drug products. Thus, although sources of certain elemental impurities may be ubiquitous in the natural environment, they were not ubiquitous in materials used in pharmaceutical packaging and manufacturing systems and when they were present, they were not extensively leached under relevant conditions of use for those systems. This conclusion, supported by an ever-increasing body of literature, suggests that in general the manufacturing and packaging systems, by themselves, do not contribute sufficiently large quantities of elemental impurities that the impurities pose a meaningful threat to patient safety. Furthermore, this conclusion should be considered when standards are developed for the characterization and qualification of manufacturing systems, packaging systems, and their associated materials and components of construction.

Studies on the thermal stabilization for Polyvinyl chloride by some metal stearates

In this study, preparation of some metal stearates derived from stearic acid with metals ;Iron , Cobalt, Nickel, Copper and Zinc . They were used as thermal stabilizers for Polyvinylchloride. These metal stearates were identified by elemental analysis and infraredspectroscopy.I.R, spectroscopy within the rang 1500-1900 cm-1 was used to study the thermalstability for PVC containing prepared metal stearates , and that depending on thin filmstechnique . The variations in the absorption bands intensity of the groups C = O , C = C ,COO - at 195oC were studied at different times (15 ,30 ,45 , 60 min) from thermal stress.These variations resulted from the rule of the metal stearates in the stabilizing of polymer .U.V-V.S spectroscopy was used to study the thermal degradation of unstabilized PVC andthe reprecipitated PVC from the stabilizers .This study was carried out by the investigation ofthe polymer resulted from the evolving of HCl from the polymer chain at 275nm and 385 nmcorresponding to three and seven conjugated double bonds respectively .The results wereindicated that metal stearates and their synergistic mixtures have the ability to stabilize PVCby decreasing the conjugated double bonds in the polymer .The thermal stability of the unstabilized PVC and PVC containing different metalstearates was investigation by thermogravimetric analysis (TGA). Many functions werecalculated such as the decomposition temperature , rate of decomposition ,activation energy,char content ,and percentage of HCl evolving from the polymer chain . The results indicatedthat metal stearates was increasing the thermal stability for PVC . TGA was also used toevaluate the synergistic effect for some mixtures of the prepared metal stearates (Zincstearate with stearates of the Nickel ,Cobalt ,Copper , Iron ) , and it was found that thesemixtures have high stabilizing ability for the PVC .

Полный факторный эксперимент механосинтеза стеарата кальция на модифицированном шнековом оборудовании

Metal stearates are widely used in various industries: as a thickener, lubricants, auxiliary desiccant, emulsifier for cosmetics, chemical additives to synthetic rubbers and a stabilizing component in polyolefins (PE, PP), ABS plastic, polystyrene, polyamide and polyvinyl chloride ( PVC). The greatest interest in using the metal salt of stearic acid is stabilization of PVC. At present, technologies for the synthesis of divalent metal carboxylates have evolved in three directions: synthesis technology in solution, in the melt and in the solid phase. The latter was the most laborious at the end of the last century due to the lack of equipment that allowed the imposition of mechanical energy on the material in sufficient quantity to initiate chemical transformation. In the literature, experiments are carried out on planetary mills, attritors, rollers and Bridgman anvils. In devices of a similar design, the best conditions for the chemical process between the components of the reaction mixture are created. The chemical reaction proceeds as a result of the creation and subsequent relaxation of the stress field when applying a mechanical action to the reaction mixture. However, they did not give a high selectivity for the target product; therefore, the chemical industry of stabilizing additives focused on solution methods for producing metal carboxylates. The authors of the article have developed a new approach for the synthesis of calcium stearate in the solid phase on a modified screw apparatus. Screw machines, in turn, provide an increase in the number of contacts between reagents and, more significantly, the area of the contact interface. In addition, heat generation due to friction in the contact area can further intensify the process. The influence of the temperature range inside the material cylinder - the reactor, the screw rotation speed on the technical characteristics and the yield of calcium stearate was investigated. Mathematical processing of the results of the full factorial experiment was carried out. A comparison of the adequacy of the obtained linear equation and experimental data is carried out.

High performance metal stearates thermal stabilizers for poly vinyl chloride

Low thermal stability of poly vinyl chloride (PVC) is one of the most serious problems that facing its processing. In the present study some single and mixed metal stearate soaps were prepared, characterized and evaluated for their performance in enhancing and imparts the thermal stability of PVC. Accordingly, calcium stearate, barium stearate, zinc stearate and also the mixed metal stearate salt of calcium, zinc and barium were prepared by the double decomposition of sodium stearate and single or mixed metal acetate solutions. The prepared metal stearates were characterized via spectroscopic analysis (FT-IR and XRD) in addition to micro analysis and thermal gravimetric analysis (TGA). The results showed that the prepared metal stearates are good thermal stabilizers for PVC; also the thermal stability of the prepared (Ca/Ba/Zn) stearate was enhanced when melamine, ammonium poly phosphate, magnesium hydroxide and Ca/Zn phosphate are mixed with it.

A Study of the Regularities of the Solid-Phase Synthesis of Metal Stearates

Features of the solid-phase synthesis of metal stearates (calcium, barium, zinc, and silver stearates) on a Bridgman anvil-type device were studied. Factors of the solid-phase reaction between reagents were determined. The activation volumes of the reactions between stearic acid with calcium oxide and silver oxide were determined. The initial rates of the solid-phase synthesis of silver and calcium stearate were calculated. The rates of synthesis of metal stearates in liquid and solid phases were compared. The data showed that metal carboxylates could be synthesized in a solution-less medium.

All-Inorganic Perovskite Nanocrystals with a Stellar Set of Stabilities and Their Use in White Light-Emitting Diodes.

We report a simple, robust, and inexpensive strategy to enable all-inorganic CsPbX3 perovskite nanocrystals (NCs) with a set of markedly improved stabilities, that is, water stability, compositional stability, phase stability, and phase segregation stability via impregnating them in solid organic salt matrices (i.e., metal stearate; MSt). In addition to acting as matrices, MSt also functions as the ligand bound to the surface of CsPbX3 NCs, thereby eliminating the potential damage of NCs commonly encountered during purification as in copious past work. Quite intriguingly, the resulting CsPbX3-MSt nanocomposites display an outstanding suite of stabilities. First, they retain high emission in the presence of water because of the insolubility of MSt in water, signifying their excellent water stability. Second, anion exchange between CsPbBr3-MSt and CsPbI3-MSt nanocomposites is greatly suppressed. This can be ascribed to the efficient coating of MSt, thus effectively isolating the contact between CsPbBr3 and CsPbI3 NCs, reflecting notable compositional stability. Third, remarkably, after being impregnated by MSt, the resulting CsPbI3-MSt nanocomposites sustain the cubic phase of CsPbI3 and high emission, manifesting the strikingly improved phase stability. Finally, phase segregation of CsPbBr1.5I1.5 NCs is arrested via the MSt encapsulation (i.e., no formation of the respective CsPbBr3 and CsPbI3), thus rendering pure and stable photoluminescence (i.e., demonstration of phase segregation stability). Notably, when assembled into typical white light-emitting diode architecture, CsPbBr1.5I1.5-MSt nanocomposites exhibit appealing performance, including a high color rendering index ( Ra) and a low color temperature ( Tc). As such, the judicious encapsulation of perovskite NCs into organic salts represents a facile and robust strategy for creating high-quality solid-state luminophores for use in optoelectronic devices.

Superhydrophobic brass and bronze meshes based on electrochemical and chemical self-assembly of stearate

The preparation and characterization of superhydrophobic membranes formed on metal meshes (brass and bronze) by coating from stearic acid is presented. The membranes were prepared by two methods: electrolysis and acid etching. The electrolysis process is a one-step method performed by anodizing the mesh in ethanol solutions of stearic acid. Stearic acid concentration, support electrolyte concentration and electrolysis time were systematically varied. Nanostructures, including nanotubes, are induced on the metallic filaments. Analysis by FTIR, XRD, XPS and SEM of surfaces and precipitated material indicate that formed nanostructures are assemblies of metallic stearates on the surface (copper and/or zinc stearates). Superhydrophobicity (contact angles larger than 150°) was only achieved (in the electrolysis method) in cases where the formation of nanotubes was observed. On the other hand, the acid etching process is a two-step method: immersion of the meshes in acid solution of CuCl2 or FeCl3, oxidizing the surface with formation of inorganic salts nano crystals, followed by immersion in stearic acid solution. Organic nanostructures (nanoribbons and/or nanopetals) were observed after the second step. Superhydrophobic surfaces (contact angles between 150 and 170°) were obtained for all the membranes.Both kind of membranes (electrolysis and etching) resulted effective in oil-water separation.