Blends of poly(2,5-dimethoxy aniline) and fluoropolymers as protective coatings

• Published in: Electrochimica acta 2004-09, Vol.49 (21), p.3507-3516
• Main Authors: Alvial, Gastón, Matencio, Tulio, Neves, Bernardo Ruegger Almeida, Silva, Glaura Goulart
• Format: Article
• Language: English
• Subjects: AFM; Applied sciences; Blends; Corrosion; Corrosion prevention; Exact sciences and technology; Fluoropolymers; Metals. Metallurgy; Poly(2,5-dimethoxy aniline)
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2004.03.021

This work presents the study of blends formed by a substituted polyaniline (PAni), poly(2,5-dimethoxy aniline) (PDMA), and the fluoropolymers poly(vinylidene fluoride) (PVDF) and poly(tetrafluoroethylene-co-vinylidene fluoride-co-propylene) (co-PTFE). PDMA was electrochemically synthesized from monomer 2,5-dimethoxy aniline (DMA) onto stainless steel surfaces. The polymers and the ternary blends were dissolved in N, N-dimethyl formamide and were deposited onto polished stainless steel plates. Thermal analysis (differential scanning calorimetry (DSC) and thermogravimetric analysis (TG)) and atomic force microscopy (AFM) were used in order to evaluate the properties of the materials. Ternary blends with good adhesion properties and thermal stability (with degradation over 400 °C) were obtained. Porous morphology with indication of PVDF enrichment on surface was observed. Preliminary open circuit potential (OCP) test showed an increase in this potential in the blends, compared with uncoated stainless steel. Therefore, blends with phase separation and very promising new protective properties were produced. Co-PTFE guarantees good adhesion, PDMA the special corrosion protection, and both fluoropolymers contribute to the large thermal stability.