abstract
Biopolymeric microspheres containing corrosion inhibitor benzotriazole (BTA) were prepared by a spray-drying technique using carboxymethylcellulose (CMC-Na) as encapsulating material. The resulting microspheres were characterized by FTIR, TGA, SEM and TEM analysis. Microspheres containing BTA have an average diameter of 1.1 mu m. FTIR analysis confirmed the presence of the core and encapsulating components. The release studies by UV - Vis spectrophotometry showed that the mechanism of inhibitor release from CMC-Na biopolymeric matrix is based on a hydrogel-swelling-driven mechanism triggered by water presence. Electrochemical impedance spectroscopy (EIS) measurements on bare carbon steel in NaCl solution revealed that the presence of CMC-Na does not affect the corrosion inhibition mechanism associated with BTA. Furthermore, the microcapsules were added to an epoxy coating and its active corrosion protection performance was also investigated by EIS. The results obtained indicate that capsules loaded with BTA do not affect negatively the barrier properties of the coating, and contribute for the enhancement of the corrosion protection of the metallic substrate. Therefore, this work shows the potential application of carboxymethylcellulose microspheres for development of new environmentally-friendly microcontainers for corrosion inhibitors.
keywords
INHIBITION; COATINGS; RELEASE; MICROCAPSULES; MICROENCAPSULATION; NANOCONTAINERS; SPECTROSCOPY; BEHAVIOR; DESIGN; MEDIA
subject category
Chemistry; Materials Science
authors
Calegari, F; da Silva, BC; Tedim, J; Ferreira, MGS; Berton, MAC; Marino, CEB
our authors
João Tedim
Assistant Professor
Mário Guerreiro Silva Ferreira
Retired ProfessorProjects
acknowledgements
This work was developed in the scope of the project PVE-CAPES (no 88881.064969/2014-01), financed by national agency CAPES. The authors gratefully acknowledge the support of UFPR, SENAI-PR and UA for the infrastructure, CNPq for the productivity fellowships and CAPES for financial support. This work was also supported by Portugal 2020 through European Regional Development Fund (ERDF) in the frame of Operational Competitiveness and Internationalization Programme (POCI), in the scope of the project MAGICOAT POCI-01-0145-FEDER016597/PTDC/CTM-BIO/2170/2014 and in the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID/CTM/50011/2013), and co-financed by national funds through the FCT/MEC.