Synthesis and characterization of allyl fatty acid derivatives as reactive coalescing agents for latexes

Abstract

This work evaluated the use of allyl fatty acid esters derived from vegetable oil (palmitic acid, soybean and sunflower oils) as reactive coalescing agents in a waterborne latex system. Allyl fatty acid derivatives (AFAD) from vegetable oils were synthesized by two different processes. The synthesis was monitored by IR-spectroscopy and the final product characterized by FT-IR, GC-MS, H-1 and C-13 NMR. The presence of conjugated double bonds in the aliphatic chain was confirmed, which is a determinant for the proposed autoxidative latexes drying mechanism. Each of the AFAD were subsequently added to a standard acrylic emulsion, in order to study its potential as reactive coalescing agent. The minimum film-forming temperature (MFT), glass transition temperature (T (g)), drying time and rubbing resistance to solvents were evaluated. The results showed that, when added to water-borne acrylic resins, an AFAD acts as a non-volatile plasticizer capable of autoxidative crosslinking with itself.