Peptization usefulness

Peptizers. Using of such peptizer as acetic acid instead of HNO3 would be desirable to eliminate NO emission at calcination stage. However, the samples obtained with addition of HAc into forming masses have a somewhat decreased mean radius and total pore volume (cf. lines 2 and 4, Table 5) that seems to be connected with a lower optimum water content in these pastes. Though in kinetic region the catalysts thus prepared have higher activities, at elevated temperatiu the diffusion limitations are expected to be more essential. Therefore, a choise between these two acids has to be determined also by conditions of exploitation. 

As indicated earlier, there is a delicate balance between the concentration of resins and asphaltenes in petroleum fractions. Any interruption in the ratio of asphaltenes resins can cause operational problems because of asphaltene precipitation (coke formation) and plant shutdown. It is therefore crucial, if coke formation is to be minimized, to monitor the ratio of asphaltenes resins during the thermal processing of bitumens and heavy oils. Clarke and Pruden developed a heat transfer analysis technique that can detect the onset of asphaltene precipitation. They showed that precipitated asphaltenes could be re-peptized using polynuclear aromatic compounds such as phenanthrene. It has been demonstrated in the 5000 bbl/d CANMET hydrocracking unit... 

Fig. 9. Viscosity versus peptizer level for in batch peptization using a short, high-rotor-speed, high-ram-pressure mixing cycle. Symbols as in Fig. 8. The top two curves represent the viscosity of the masterbatch stage in each case...

To improve processing and to plasticize the mbber compound, numerous processing agents have been used over the years, eg, petroleum and ester plasticizers, resins and tars, Hquid mbber peptizers, peptizers, fatty acids and derivatives from vegetable oils, and polyethylene and hydrocarbon waxes. 

The initial sulfur copolymer that is formed is often high conversion and gelled. Molecular weight is reduced to the required level by cleaving some of the polysulfide Linkages, usually with tetraethylthiuram disulfide. An alkaU metal or ammonium salt (30) of the dithiocarbamate, an alkaU metal salt of mercaptobensothiasole (31), and a secondary amine (32) have all been used as catalysts. The peptization reaction results in reactive chain ends. Polymer peptized with diphenyl tetrasulfide was reported to have improved viscosity stabiUty (33). 

Neoprene WHV-A. It is a non-peptizable and mercaptan-modified polychloro-prene elastomer. It is a slow-crystallizing, high molecular weight type and contains only 85% trans-, 4 structure. It is generally used in blends with low molecular weight crystallizing polychloroprene types to increase solution viscosity. 

Cathodic protection is a useful supplement to other forms of water treatment, as a general corrosion inhibiting device in HW boilers, or where specific design configurations can lead to inadequately protected localized metal in steam boilers. Where BW makeup demands are minimal and boiler output is fairly constant, cathodic protection devices can also provide some measure of protection against hardness scales. Calcium carbonate salt is formed as a floc-culant or soft sludge rather than a hard scale, due to the peptizing effects of a zinc hydroxide complex formed from zinc ions in alkaline BW. 

Hydrothermal synthesis of titanium dioxides using acidic and basic peptizing agents and their photocatalytic activity on the decomposition of orange II... 

In the literature the term soluble Prussian blue introduced by Keggin and Miles [5] to determine the KFeFe(CN)6 compound is still widely used. However, it is important to note, that the term soluble refers to the ease with which the potassium ion can be peptized rather than to the real solubility of Prussian blue. Indeed, it can be easily shown by means of cyclic voltammetry that the stability of Prussian blue films on electrode supports is nearly independent of their saturation by potassium cations. Moreover, Itaya and coworkers [9] have not found any appreciable amount of potassium ions in Prussian blue, which makes doubtful structures like KFeFe(CN)6. Thus, the above equation fully describes the Prussian blue/Prussian white redox reaction. 

Differential refraction( ) and colorimetric measurements ) were used to determine the amount of carbohydrate polymer adsorbed from solution. A Phillips X-ray diffractometer was used to quantify the degree of interlayer expansion(60. The cation exchange capacity of the peptized sodium and potassium... 

Figure 7.5 Image of two precursor solutions prepared using different methods (a) simple mixing of GPTMS and a Yoldas sol (b) mixing of GPTMS and A1(OBu)3 followed by peptization in water. (Reproduced from ref. 5, with permission.)...

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