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Nano-TiO2-dispersed polymeric coatings have been extensively studied in recent years owing to their photocatalytic-induced self-cleaning characteristics. However, durability and long-term retention of self-cleaning performance of such coatings remain a challenge for practical applications. In the present work, we report the self-cleaning properties of nano-TiO2/silicone soya alkyd-based coating formulations comprising 0.5–5 wt% of nanofiller as well as conventional additives of rutile TiO2 and BaSO4. The nanocomposites were prepared by an in situ process involving dispersion of nano-TiO2 in soya oil, soya alkyd synthesis by alcoholic process, followed by silicone modification. The coatings prepared from the nanofiller-dispersed resin showed significant UV radiation-induced hydrophilicity and photocatalytic degradation of methylene blue (MB) solution. A coating formulation with 2 wt% of nano-TiO2 loading showed a decrease in water contact angle from 87° to

A hyperbranched polyol (HBP) was synthesized using dipentaerythritol as a core material and 2,2-bis(methylol) propionic acid as a chain extender. This was reacted with varying concentrations of soya fatty acid to make hyperbranched alkyd (HBA) resins. The HBA resins containing unreacted hydroxyl groups were reacted with isophorone diisocyanate at NCO/OH ratio of 1.6:1 to make high solid hyperbranched urethane alkyd (HBUA) resins. The excess NCO content in the HBUA resins was used to cure with atmospheric moisture, and thus moisture-cured HBUA coatings were formed. The resins were characterized by FTIR, and 13C NMR spectroscopic analysis. A series of such resins were made using different fatty acid/isocyanate ratios with respect to the hydroxyl groups present in the HBP. The effect of compositions on the mechanical and weathering properties of the cured resins was investigated. It was observed that there was an optimum fatty acid–isocyanate ratio in terms of the requirements of solvent, mechanical and weathering properties of the resin. The requirement of solvents for formulating HBUA coatings is much lower compared to linear alkyd-based coatings. The present study reveals that the moisture-cured HBUA resins can be used as a binder material in the field of low-pollution weather-resistance coatings.

Methyl esters substituted at β position with good leaving groups (nucleofugals) are smoothly hydrolysed by Pig Liver Esterase (PLE) in moderate to high yields.

Among the various hydrolases, Pig Liver Esterase (PLE) is possibly the most widely used enzyme, particularly for the preparation ~f chiral synthons *'2 and for chemo 3 and regioselective transfo .~6ations. Various active site models for PLE have been proposed' , the cubic space model of Jones et al. s having received most attention. We report the reactivities of methyl esters containing large hydrophobic substituents toward PLE catalysed hydrolysis, and discuss the results in the light of Jones' model.