Self-curing poly (2, 6-dimethyl-1, 4-phenylene oxide)-organic titanium chelate resin for thin anticorrosive coatings

- Redistributed PPO (RPPO) and GBA were firstly used to form a self-curing, thermosetting resin.
- The RPPO-GBA resin could be cured by heating without any curing agents.
- Thin coating with 10 μm-thickness was developed via the reaction between chelate bonds and phenolic hydroxyl groups in RPPO-GBA resin.
- No degradation was found after 72 h immersion tests in boiling water, seawater and boiling butanone.
- The self-curing RPPO-GBA resin can be a good candidate for anticorrosive coatings.

Poly (2, 6-dimethyl-1, 4-phenylene oxide) (PPO) has been extensively investigated as an outstanding engineering plastic. Functionalized PPO with low molecular weight has been widely studied to expand its applications, while there are relatively few reports on PPO-containing coatings. In this work, a terminal phenolic hydroxyl group PPO (RPPO) with low molecular weight was synthesized by redistribution of high molecular weight commercial PPO with bisphenol A via benzoyl peroxide as an initiator. The self-curing, thermosetting RPPO-organic titanium chelate resins were first developed via the reaction between phenolic hydroxyl groups in RPPO and isopropoxy groups of diisopropoxy titanium bis (acetylacetonate). Thin coatings with 10 μm thickness could be obtained by heat curing without any curing agents. Characterization using Fourier transform infrared spectroscopy and 13C nuclear magnetic resonance showed evidence of the successful preparation of the self-curing, thermosetting resins. The curing behavior and thermal stability were assessed via differential scanning calorimetry and thermo-gravimetric analysis. The mechanical properties of the cured coating were discussed and the chemical resistance was tested using accelerated immersion tests. Benefited by the self-curing mechanism, issues of non-uniformity, bubbles, and low storage stability caused by curing agents were avoided. It was found that the thin coating possessed good thermal and mechanical properties. Owing to the rigid aromatic chain structure and strong Ti-O bond in the crosslinked structure, the glass transition temperature was improved and the thermal degradation temperature could reach up to 402 °C. No degradation was found after 72 h accelerated immersion tests in boiling water, boiling seawater and boiling butanone, which should be critical to the resin's potential application for anticorrosive coating.

Self-curing poly (2, 6-dimethyl-1, 4-phenylene oxide)-organic titanium chelate resin were prepared for building thin anticorrosive coatings. Contribution of both RPPO and GBA facilitated the coating with good mechanical properties, excellent thermal stability as well as outstanding water and chemical resistance.72