Liquid tailored properties

Ionic liquids offer a broad spectrum of solvent properties that can be readily distinguished from those of the typical conventional organic solvents. The possibilities for tailoring properties of ionic liquids by the selection of their structures are particularly attractive. 

Coal is not a viable option in many urban areas because of very stringent emission standards for nitrogen oxides and particulate emissions. However, coal derived liquid feuls with tailored properties could be used to meet these requirements. 

In recent years devices based on liquid crystal displays have become an inseparable part of our daily life. Flat panel LCD-TV, PC monitors, notebook computers, cellular phones, and PDA would not exist without fluorine-containing liquid crystals. The use of fluorinated substructures, supported by computational methods and the development of novel preparative methods, enables targeted design and synthesis of new materials vith a broad range of custom-tailored properties. 

RTlLs exhibit a variety of desirable properties, such as negligible vapour pressure, which makes them interesting for various applications. In particular, the option of fine-tuning chemical and physical properties by an appropriate choice of cations and anions has stimulated much of the current excitement with respect to these compounds and has led to the term designer solvents . An alternative, complementary strategy to tailor properties is not only to mix two (or more) ionic liquids but also to mix ionic liquids with molecular solvents. 

Further, they exhibit other desirable properties, e.g., good hydrolytic stability, high glass transition temperatures, low dielectric constants, and good mechanical properties. Flexible PODA films can be obtained only if the inherent viscosities of the pol5miers are higher than 2.7 dl PODA can be tailored to impart liquid crystalline properties. 

Due to the tailored properties of liquid phase sintered silicon carbide (LPSSiC) it is used as dewatering elements in the paper machinery and as rings for highly stressed gas seals. It is a price competitive alternative to silicon nitride materials and outperforms alumina and tungsten carbide materials. In addition, LPSSiC is proposed as neutral matrix in ceramic matrix composites containing plutonium to burn the world s stockpiles of military plutonium in thermal or fast reactors [278]. 

Plasticizers are most commonly liquid esters of low volatUity, which are blended into rigid thermoplastic polymers to make them soft and flexible. Most are esters of phthatic, phosphoric, and adipic acids. Major use is in polyvinyl chloride (PVC) elastoplastics. Another major use, rarely mentioned in the literature, is the addition of hydrocarbon oils to rubber to improve processability. Plasticizers are also used to improve melt processabUity and toughness of rigid plastics such as cellulose esters and ethers, and they are used in a variety of specialized apphcations. In some cases, they perform dual functions such as thermal stabilization or flame retardance. This gives the individual processor the ability to tailor properties for each produet. 

The final chapter by Dr Coles concerns a topic at the very forefront of active development. In the few years since their initial synthesis, side-chain liquid crystal polymers have excited interest firstly because of their response to electric and magnetic fields and thence to potential applications in areas such as information storage, which is discussed here. What has been opened up, however, is a powerful means of tailoring properties to applications by synthesis of suitable molecules. This has long been an aim of materials science and this field will surely be the source of future developments. 

Physical Properties. Physical properties of importance include particle size, density, volume fraction of intraparticle and extraparticle voids when packed into adsorbent beds, strength, attrition resistance, and dustiness. These properties can be varied intentionally to tailor adsorbents to specific apphcations (See Adsorption liquid separation Aluminum compounds, aluminum oxide (alumna) Carbon, activated carbon Ion exchange Molecular sieves and Silicon compounds, synthetic inorganic silicates). 

Molecular orientation results in increased stiffness, strength, and toughness (Table 8-12) as well as resistance to liquid and gas permeation, crazing, microcracks, and others in the direction or plane of the orientation. The orientation of fibers in reinforced plastics causes similar positive influences. Orientation in effect provides a means of tailoring and improving the properties of plastics. 

All composite liquids are produced by the chemical processing industries, and chemical engineers face continuing challenges in tailoring their end-use properties. Some of these challenges are illustrated in the following examples ... 

A modern refinery is a complicated collection of conversion processes, each tailored to the properties of the feed it has to convert. The scheme shown in Fig. 9.1 summarizes the most important operations some reasons for these processes are given in Tab. 9.2, along with relevant catalysts. First the crude oil is distilled to separate it into fractions, varying from gases, liquids (naphtha, kerosene and gas oil), to the heavy residue (the so-called bottom of the barrel ) that remains after vacuum distillation. 

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