CMC & PAC KNOWLEDGE
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CMC Product Overview
 
CMC stands for carboxymethyl cellulose. However, CMC is more correctly the Sodium salt of carboxymethyl cellulose. Carboxymethyl cellulose (CMC) is a cellulose derivative with carboxymethyl groups (-CH2-COOH) bound to some of  the hydroxyl groups of the glucopyranose monomers that make up the cellulose  backbone. It is often used as its sodiumsalt, sodium carboxymethyl cellulose.
 
It is synthesized by the alkali-catalyzed reaction of cellulose with chloroacetic acid. The polar (organic acid) carboxyl groupsrender the cellulose soluble and chemically reactive.
The functional properties of CMC depend on the degree of substitution of the cellulose structure (i.e., how many of the hydroxyl groups have taken part in the substitution reaction), as well as the chain length of the cellulose backbone structure and the degree of clustering of the carboxymethyl substituents.
 
In fact Carboxymethyl cellulose (CMC) acts as thickener, rheology modifier, water retention aid, filtration reducer, binder, dispersant, protective colloid, floating aid, crystallization inhibitor, ions exchanger, etc. This wide range of properties makes CMC virtually useful everywhere water is involved in a process and more typically in food, detergency, drilling fluids, mining, paper, ceramics, coatings, textiles (sizing and printing)... . 
 
Besides CMC is physiologically inert,chemically stable, odorless and tasteless, not dangerous for health and environment.
 
Carboxymethyl cellulose (CMC) is a water-soluble anionic linear polymer. In food, Pharmaceutical and cosmetic applications, highly purified types (99.5%+) are required and are referred to as cellulose gum. 
 
Technical grades (90-99.5%) are used in adhesives, coatings, pulp and paper, textiles and other industrial applications.
 
Industrial (50-90%) grades of CMC, which contain large amounts of sodium chloride and sodium glycolate, are used in a number of detergent, mining and petroleum outlets.
 
Commercial products come in some 500 different grades differing on impurity level, molecular weight, Food and Drug regulation, degree of substation (DS) and several other factors. The DS level can range from 0.4 to 1.4 but most products have a DS of 0.7. Viscosity ranges from 6000 centiPoise (cP) in 1% solution to 10 cP in 2% solution
 
CMC TECHNOLOGY 
There are many processes to make CMC, depending on DS level and the quality of the desired product. The most common technology is the reaction of wood pulp with sodium chloroacetate in the presence of an inert water-miscible diluent such as isopropanol tertiary butyl alcohol, ethanol or a mixture of diluents at 50-70°C. At the end of the reaction, the excess alkali is neutralized and the crude product is purified or partially purified with methanol or another 
 
Solvent In an alternative process, wood pulp is wetted out with aqueous sodium hydroxide. One way to do this is to steep sheeted cellulose in aqueous sodium hydroxide and then press out the excess. The sheets are then shredded and sodium chloroacetic acid is added. The latter process is frequently used for industrial grades of CMC. Wood chips and cotton linters are also used for low active ingredient industrial grade and high quality purified CMC, respectively.
 
PAKAGING AND STORAGE
1. Woven sacks with PE liner. Paper-plastic compound bag with PE liners, net weight 25KG. 
2. Bulk bag is available. 
3. CMC could easily absorb water. During storage, care should be taken to ensure that packing sacks are not damaged and to avoid contact with water. Product should be stored in a dry and ventilated area.
 
 
PAC KNOWLEDGE 

PAC,Polyanionic cellulose is a water-soluble polymer produced only from cellulose chemically reacted with carboxy-methyl (anionic) groups. The product obtained is further purified to significantly increase the active polymer content. The product is a free-flowing and/or granular powder and its water solution is transparent viscous liquid .and in the oil-drilling industry as an ingredient of drilling mud, where it acts as a thickener, rheology modifier and water retention agent. As anionic cellulose, it features high purity, high replacement and well distribution and water soluble polymer.
PAC, polyanionic cellulose is both chemically and physically distinguished from CMC. The primary difference between the CMC and PAC production processes is in the radicalization step. CMC is definitely a carboxylic acid, where PAC is another. Although CMC and PAC are manufactured from the same raw materials, by adjusting the type of cellulose and stoichiometry of the reactants, different final products may be produced. 
PAC spread easily in all water-based drilling fluid, it can be applied to different drilling fluid system, Especially in salt water drilling, seawater drilling, saturation salt water drilling, In the low solid phase and no solid-phase drilling fluid, it can significantly reduce the amount of filtration loss and thinning thickness of the mud cake, and strongly restrain shale hydration. 
 
Our company’s PAC have strong water-soluble, high mud yield and excellent anti-salt, anti-calcium and magnesium, anti-high temperature resistance (150℃),reduce filtration loss capacity, and all have a very good role in filtration loss. 
 
XUEFENG® PAC is designed to be cost-effective, inherently biodegradable,and meet the standards of OCMA ,API SPEC 13A, GB/T5005-2001, SY5093-92.
 
 

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