Stability and Biological Responses of Zinc Oxide Metalworking Nanofluids (ZnO MWnF™) using Dynamic Light Scattering and Zebrafish Assays

Zinc oxide nanoparticles (ZnO NPs) have demonstrated the ability to improve lubrication and thermal conductivity and are promising metalworking lubricant and coolant additives due to their low cost compared to other NPs. Though nanomaterials are a focus of research due to their potential to enable advanced technologies, little is known about their effects on the environment and human health. This research investigates two main characteristics of ZnO metalworking nanofluids (MWnF). First, the stability of ZnO NPs (20 nm) is investigated using dynamic light scattering (DLS) for mixtures of a microemulsion (TRIM MicroSol 585XT) and several dispersants, all of which are commercially available. Second, toxicological assessments using a zebrafish assay method are conducted to survey the effect of ZnO NPs on MWnF safety. The research revealed that none of the dispersants enhanced the stability of ZnO NPs more than the prepared microemulsion alone. The work also revealed that ZnO MWnF had a significantly higher toxicity than the prepared microemulsion. This demonstrates the need for precautionary development of metalworking nanofluids.     

Preparation and evaluation of some eco-friendly olethio-amide derivatives as lube oil additives

Eco-friendly synthesis of organic compounds is a major trend in green chemistry. Thus, we aim at producing some of the lube oil additives through the use of green chemistry. Dispersant lube oil additives are remarkable additives that regulate the formation of deposits throughout the process. Antioxidants do not prevent the oxidation reactions but only delay the rate of this process. In the present work, some additives for lube oil based on thiourea derivative were prepared by one-step reaction, which is the reaction of octadeca-7-enoy) chloride with ammonium thiocyanate in addition to different amines such as ethylenediamine, diethylene triamine, and tetraethylene pentamine as three-component system in order to prepare thioamide derivatives (A, B, and C). Infrared spectroscopy, elemental analysis, nuclear magnetic resonance, determination of molecular weights, and yield determination verified the chemical structure of all synthesized molecules. All the compounds produced are tested as lube oil additives (dispersants and antioxidants), and it has been found that all the compounds prepared are good as dispersants but have poor effect as antioxidants. The theoretical result is the same as the experimental result of antioxidants through the use of the quantum chemical calculations by calculating the energy gap (EHOMO-ELUMO). The best dispersant lube oil additive is (C).     

The effects of dispersants on sinterability and microwave dielectric properties of Zr0.8Sn0.2TiO4 ceramics

This study investigated the effects of dispersants (deionised water and ethanol) on the sinterability, phase compositions and microwave dielectric properties of Zr_0.8Sn_0.2TiO₄ ceramics prepared by a solid-state reaction. Results showed the presence of impurity phases in low-density ceramics with ethanol as dispersant sintered from 1500?°C to 1550?°C. However, pure phase was detected in samples prepared with deionised water as dispersant when sintering temperature ranged from 1512?°C to 1550?°C. The microwave dielectric properties of the samples with deionised water significantly improved compared with those with ethanol. Thus, deionised water was suitable for preparing Zr_0.8Sn_0.2TiO₄ ceramics with a high density of approximately 98%, ε_r of 39.83, Q ×?f of 33,700?GHz and τ_f of +?3.5?ppm/°C.     

Controlling particle dispersion in latex paints containing associative thickeners

Latex paints contain several types of particles including polymer binder, primary pigment, extenders, and colorants. When the paints contain associative thickeners, control of particle dispersion can be very complicated due to the interaction of the particles with dispersants, surfactants, and the associative thickener itself. In particular, dispersion of the pigments can act independently of dispersion of the binder particles. The consequences of this situation are manifested in the physical properties of the paint and of the films it forms. This paper describes these interactions in terms of their colloid chemistry and shows the consequences of additive choices on the particle dispersion and also the optical properties of model paint films. Presented at the 2006 FutureCoat! conference, sponsored by the Federation of Societies for Coatings Technology, in New Orleans, LA, on November 1–3, 2006.     

Selection of dispersants for the dispersion of carbon black in organic medium

The dispersion of the carbon black pigment in non-aqueous medium requires the use of dispersant additives. Two carboxylic dispersants of different chemical nature and molar masses have been investigated regarding this purpose. Their adsorption behavior has been evaluated by means of adsorption isotherms. The molecular interactions taking place at the surface have been inferred from IR and ¹³C RMN spectroscopies. The rheological behavior of the dispersions has considerably been improved by the presence of the copolymer dispersant of higher molar mass. It might adsorb at the surface by hydrogen bindings while taking a flat conformation with tails and possibly few loops that contributed to the steric stabilization of particles. The consequences of the deflocculation of the suspension on the colorimetric properties are an enhanced tinting strength and improved color stability.     

Parameter effects on wet ultrafine grinding of limestone through slurry rheology in a stirred media mill

Wet ultra-fine grinding of a limestone powder (< 100 μm) has been investigated in a stirred media mill with respect to the effect of slurry rheology. The grinding results obtained by various parameters (i.e., molecular weight of a dispersant, solids concentration, additive dosage, addition method and beads load) are evaluated in terms of energy efficiency and the fineness of a product. A polymeric dispersant called Dispersant S40 with a molecular weight of 5500 gives the best grinding results. For a certain level of beads load, an optimal solids concentration exists. In the case of the additive dosage of Dispersant S40 at 0.1 wt.% or more, a smaller additive amount of Dispersant S40 gives a higher energy efficiency and a smaller median size at a lower level of specific energy input. However, the excessive amount of the dispersant could cause a cushion layer formed on milling beads and thus lowers stress intensities from the collisions of milling beads, leading to an inefficient milling operation. This can be avoided by either the multi-point addition of the dispersant or a higher beads load (≥ 83 vol.%). In addition, it was found that the higher the beads load, the better the cumulative energy efficiency, and the smaller the product size at the same specific energy consumption. For a given solids concentration, the relationships between the specific surface area and the particle size of an FP product and the additive amount of Dispersant S40 are explored, respectively. Furthermore, an empirical particle size-energy model provides a good fit (R² > 0.991) to the grinding results under the experimental conditions investigated.     

Studies On Competitive Interactions and Blending Order of Engine Oil Additives by Variable Temperature 31P-NMR and IR Spectroscopy

Interactions between various engine oil additives including dispersant, detergent, antiwear/antioxidant, and viscosity index improvers have been investigated through changes in the ³¹P-NMR and IR spectra. Significant changes in the ³¹P-NMR and IR spectra of zinc dialkyldithiophosphate (ZDDP) have been observed by varying the blending order of additives. Dispersant-detergent (polyisobutylene succinimide-calcium overbased sulfonate) and viscosity index improver-detergent (dispersant olefin copolymer-calcium overbased sulphonate) interactions were found to be strong and irreversible in nature. Variable temperature ³¹P-NMR spectra have provided enough evidence to suggest that the actual performance of an additive may not be decided by its bulk interactions with other additives at room temperature, and that tribochemical reactions occurring at higher temperature play a greater role.     

油井水泥分散剂的降滤失作用

分散剂是石油固井常用的油井水泥外加剂。本文采用水泥浆性能测定、电镜扫描等方法，研究了分散剂在水泥浆中的降滤失作用，探讨了分散剂的降滤失机理。     

吐哈油田油井水泥外加剂应用概况

介绍了吐哈油田历年来应用的油井水泥外加剂，包括减轻剂、分散剂、缓凝剂、防气窜剂和降失水剂的组成，性能和应用情况。     

用分散剂NM-1优化东鞍山磁选粗精矿提质降杂工艺

东鞍山选矿厂原正浮选菱铁矿、反浮选分离赤（磁）铁矿与石英的工艺已不能适应采出矿石菱铁矿含量上升的情况,故以NM-1为微细粒菱铁矿的分散剂,对东鞍山磁选粗精矿进行了单一反浮选工艺研究。结果表明,在NM-1作用下,采用1粗2精1扫、中矿顺序返回的单一反浮选工艺流程处理该粗精矿,可获得铁品位为66.37%、回收率为75.00%的铁精矿;优化后的工艺流程更简洁,在精矿铁品位下降1.47个百分点的情况下铁回收率提高了5.53个百分点,达到了优化工艺流程、提高经济技术指标的效果。