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Dispersants
Published in Leslie R. Rudnick, Lubricant Additives, 2017
As mentioned in Section 3.5, succinimide, phenol, and phosphonate are the common connecting groups used to make dispersants. Of these, succinimide and phenol are the most prevalent [2]. Succinimide group results when a cyclic carboxylic acid anhydride is reacted with a primary amino group. Alkenylsuccinic anhydride is the precursor for introducing the succinimide connecting group in dispersants. Alkenylsuccinic anhydride is synthesized by reacting an olefin, such as polyisobutylene, with maleic anhydride [2]. This is shown in Figure 3.4.
Effect of different ions present in fresh water on performance of polyvinylamine based ASA emulsion
Published in Journal of Dispersion Science and Technology, 2020
Ashish Kumar, Nishi K. Bhardwaj, Surendra P. Singh
Alkenyl succinic anhydride (ASA) is an alkaline sizing agent most widely used in a number of alkaline paper grades. ASA is also known as a cellulose reactive sizing agent that provides resistance to aqueous penetration at varying degrees to paper by diminishing the hydrophilic property of cellulosic fibers. ASA is a synthetic sizing agent recognized for its on spot sizing degree or on machine sizing behviour. It produces sizing in paper quicker than other sizing chemicals viz. rosin and alkyl ketene dimer (AKD). ASA undergoes hydrolysis by reacting with the surrounding water molecules or if the wet end conditions are not controlled properly.[1–3] ASA is reaction product of isomerized olefin and maleic anhydride. Formation of succinic anhydride takes place which is highly reactive and will make complex by reacting with the hydroxyl groups of cellulose, starch and water. The sizing takes place on the paper machine itself immediately without any excessive drying unlike AKD sizing.[4–7] Apart from the merits of its high reactivity there are some demerits of the high reactive ASA molecules. The two main problems with the ASA sizing are (a) low shelf life of ASA emulsion, and (b) the sticky actions of hydrolyzed ASA.[8,9] Alkenyl succinic acid is the byproduct of ASA hydrolysis which is formed by the reaction of ASA and water which is detrimental to sizing. Freshly prepared ASA emulsion should be consumed within short period of time i.e. within a few minutes.[10] The various factors affecting the quality and shelf life of ASA emulsion are pH, temperature, viscosity of the ASA sample and particle size distribution (PSD) of ASA emulsion.