###### Abstract  
Sodium carboxymethylcellulose (CMC-Na) microparticles, containing corrosion inhibitor benzotriazole (BTA), were prepared using different spray drying processing parameters, with the purpose of future application in protective coatings for the delivery of corrosion inhibitors. The effects of the processing parameters, such as inlet temperature and spray flow rate, are discussed herein. The biopolymeric CMC-Na microparticles obtained were characterized morphologically by SEM and TEM, and their release profile studied by UV-Vis. The results show that the prepared microparticles (microspheres) were homogeneous, spherically shaped and of a matrix-type nature. Additionally, it was observed that the inlet temperature and spray flow rate significantly influenced the release profiles and process yields. From the different process parameters tested, it was found that the best conditions to achieve higher process yields, higher encapsulation efficiencies and better release properties, were an inlet temperature of 170 \({}^{\circ}\)C, a pump rate of 2.5 mL/min, and a drying air-flow rate of 440 L/h. carboxymethylcellulose; microencapsulation; benzotriazole; spray drying; release studies +
Footnote †: journal: Applied  
**CIC  
new type of protective coating is based on the use of nano/microcontainers for corrosion inhibitor storage, dispersed in organic or hybrid coating matrices. Nano/microcontainers have the ability of smart delivery of inhibitors, but also prevent the negative interactions between inhibitors and coating formulations. Thus, corrosion inhibitors are released based on a stimulus-response mechanism and are also able to avoid the degradation of the protective coating barrier properties and the inactivation of the inhibitive corrosion compounds [5; 8]. This type of technology may also help to prevent spontaneous leaching of the inhibitor from the coating into the environment [2]. There are several methods described for nano/microreservoir development. Research has shown the use of chemical processes for corrosion inhibitor encapsulation, such as in situ and interfacial polymerization, as well as co-precipitation techniques [8; 9; 10]. Furthermore, physicochemical methods such as layer-by-layer and coacervation techniques have also been largely reported in the literature [1; 11]. Although rarely used for the development of nano/microreservoirs for corrosion inhibitor storage, spray drying is one of the most common techniques to perform microencapsulation in the pharmaceutical and food industries [12; 13]. Regarding the use of spray drying in corrosion applications, scarce work is available that describes the use of this technique to prepare polylactic acid microcapsules containing a corrosion inhibitor, to be used as an additive to concrete for protection against steel bar corrosion [14; 15]. Spray drying is a physical process and a well-established industrial encapsulation technique that presents several advantages, mainly due to its simplicity, relatively low cost, high encapsulation efficiency, large-scale production, and the possibility of using a totally aqueous system [16; 17]. With respect to the encapsulating material, synthetic organic polymers derived from petroleum--such as polyurea, polystyrene and poly (diallydimethylammonium chloride), among others--have been gradually replaced by inorganic particles such as CeO\({}_{2}\), SiO\({}_{2}\), ZnO, TiO\({}_{2}\), halloysite nanotubes and layered double hydroxides [6]. Another alternative, that has gained considerable attention for the encapsulation of corrosion inhibitors, relies on the use of biopolymers such as alginate, cellulose and chitosan as matrices [1; 18; 19].