Search

Activated (AS) and carboxymethylated (CMS0.24) cassava starch derivatives were studied as corrosion inhibitors for carbon steel XC35 in a 200 mgL-1 NaCl solution. They were characterized by back titration and Fourier Transform Infrared Spectroscopy (FTIR). Electrochemical techniques were used to evaluate the inhibitive properties of starches at room temperature and the chemical composition of the protective films was determined by X-Ray Photoelectron Spectroscopy (XPS). Electrochemical measurements revealed that AS acts as mixed inhibitor, whereas CMS0.24 mainly inhibits the anodic reaction. In both cases, the protection increased with the inhibitor concentration; nevertheless, after 24 hours of immersion, the CMS0.24 loses its properties, while AS molecules still maintains them. XPS analyses show that the inhibitive films are composed of an iron oxide/hydroxide mixture in which starch molecules are incorporated. Results were explained taking into consideration the hydrophilicity and the strength of the ionic interaction of the starches with the metal surface.

The thermal behavior of melt‐mixed polypropylene (PP)/poly(ε‐caprolactone) (PCL) blends was investigated with differential scanning calorimetry, and it was quantitatively related to the morphology observed through scanning electron microscopy. The PP/PCL blends were immiscible in the whole composition range; however, some interesting phenomena were found. Blends with low PP contents crystallized in a fractionated fashion. By applying a self‐nucleation procedure, we demonstrated that this occurred because of a lack of highly active heterogeneities within the confined PP domains. On the other hand, PP acted as a nucleating agent for PCL, and when the PP content was reduced, the higher surface/volume ratio increased its nucleating activity. The nucleating effect was improved when the PP was self‐nucleated because of the better nucleating effect of PP annealed crystals. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1365–1379, 2007 [ABSTRACT FROM AUTHOR]