Hyperbranched phenolic-alkyd resins with high solid content

Abstract

Abstract Hyperbranched phenolic-alkyd resins (HPARs) with high solid content (70 wt%) were obtained in this study, with the aim of obtaining new environmentally friendly materials. The HPARs were synthesized from hyperbranched polyester polyol of fourth generation (HBP), phenol, and tall oil fatty acids (TOFA). In all cases the proportions of HBP (75.40 g) and TOFA (69.60 g) were kept constant, and those for the phenol were 10 (HPAR1 resin), 20 (HPAR2 resin) and 30 wt% (HPAR3 resin). The structural, rheological, thermal and film properties of the HPARs were evaluated and compared with those of a hyperbranched alkyd resin (HBAR) obtained in our earlier work with the same proportion of HBP and TOFA employed in this study. The reaction between TOFA and phenol with the HBP was evidenced by acid value ( AV ), hydroxyl value ( OHV ) and nuclear magnetic resonance (NMR) analyses. The modification percentage of the HBP increased with the phenol content, which was higher than 60%. The conversion percentage of TOFA was higher than 90%. The molar mass of the HPARs determined by gel permeation chromatography (GPC) was upper than that of the HBP. Dynamic light scattering (DLS) analysis showed that the intensity distributions of the HPARs were monomodals except for the HPAR1 resin. HPARs gloss and hardness values increased with phenol content. Glass transition and thermal decomposition temperatures, viscosity and hardness values were higher for HPARs than HBAR.