Synthesis of linear aliphatic polysulfides and their corrosion inhibiting effects

Polythioether that have aliphatic backbones and chelating groups may be used to provide a hydrophobic coating by forming a pseudopassive layer on a steel surface. To verify this assumption, binary condensation copolymers of 1,2-ethane dithiol and 1,3-propane dibromide, 1,4-butane dibromide and 1,6-hexane dibromide were prepared. Yield ranged from 55 to 89% with molecular weight of 1 to 2 x 104. The polymers were synthesized via phase transfer polycondensation process with and without the presence of water. The polymers were characterized by DSC, FT-IR, 1H and 13C NMR spectroscopy. The synthesized polymers were then used as corrosion inhibitors. Their corrosion inhibiting properties were studied through the effect of their adsorptions from a dilute solution onto mild steel and through their use as surface pretreatment. Corrosion tests using salt-fog cabinet, Q-UV condensation cycle, and flash-rust test using 98% humidity chamber were carried out. The result indicated that these polymers had a high degree of crystallinity which was detrimental to its use as a corrosion inhibiting additive. In addition, a new method to evaluate the flash-rust test utilizing an integrating visible color spectroscopy was also developed to overcome the subjective and limited existing method which uses human eyes as the measuring instrument. The quantitative measurement done by this new method indeed showed a better accuracy and reproducibility in evaluating flash-rusting. --Abstract, page iii

Synthesis of Linear Aliphatic Polysulfides

The three new polymers were synthesized via a modification of the phase transfer approach: Poly(1,4-dithiaheptane), PDTH; poly(1,4-dithiaoctane), PDTO; and poly(1,4-dithiadecane), PDTD. A description is given of the synthesis and characterization of the three new polymers. Methods for preparing the polymers and characterization methods are outlined

Linear Aliphatic Polysulfides: Synthesis and Characterization

Binary condensation copolymers of 1,2-ethane dithiol and 1,3-propane dibromide, 1,4-butane dibromide, and 1,6-hexane dibromide were prepared. Yields ranged from 55 to 89% with molecular weights of 1-2 × 104 Daltons. the polymers were synthesized via an SN2 process with and without the presence of water. the polymers were characterized by DSC, viscosity, FT-IR, and 1H- and 13C-NMR spectra

Ironing Out Stains

Flash rusting of waterborne coatings can result in staining and reduced adhesion. Common inhibitors may leach out of applied coatings, sometimes causing blistering. Compounds which prevent oxidation by forming a tight chelated complex with the metal substrate are shown to offer potential as flash rust inhibitors

Development and Evaluation of a New Spectrophotometric Integration Technique for Flash Rust Staining Determination

Flash rusting was evaluated using a newly developed procedure that utilized a color meter or a color computer to integrate color changes. Flash rusting was measured with the new method as well as the accepted ASTM method. The new technique was evaluated as to its reproducibility. To facilitate the development of the test method, five commercially available inhibitors at several levels were used in evaluation of the technique. Additionally, four different drying conditions were employed to mimic typical exposure conditions