Waterborne polysiloxane–urethane–urea for potential marine coatings

Waterborne polysiloxane–urethane–ureas (WBPSUU) were prepared through a prepolymer process using siloxane polyol, namely polydimethylsiloxane (PDMS) and polyether polyol, namely poly(tetramethyleneoxide glycol) (PTMG) as the soft segments. The goal of this study was to explore the potential use of polysiloxane–urethane–urea in marine coatings in order to boost the flexibility, adhesion, erosion, and foul-release property with respect to PDMS/PTMG ratio (PDMS wt%). The structural elucidation of the synthesized waterborne polyurethane and WBPSUU was carried out by FTIR, ¹H NMR, and ²⁹Si NMR spectroscopic techniques. The XPS and AFM analyses indicate that the polymer surface can be silicone enriched with the optimum PDMS content (15.76 wt%). The antifouling property of the coatings was investigated by the immersion test under a marine environment for 90 days. The fouled area was calculated for all the samples and the fouled area (%) decreased with increasing PDMS content. After 90 days the lowest fouled area (5%) was observed in the sample using WBPSUU4 (PDMS 15.76 wt%) among all of the samples.