RAFT polymerization of fatty acid containing monomers: controlled synthesis of polymers from renewable resources.

Abstract

The incorporation of bio-renewable resources such as fatty acids into the polymer chain allows tailoring the properties of products, for their widespread applications. A series of methacrylate monomers with side-chain fatty acids (FAMA) were synthesized by esterification of 2-hydroxyethyl methacrylate (HEMA) and fatty acids, such as caprylic, capric, lauric, mysritic, palmitic and stearic acid. Consequent polymerization of FAMAs via reversible addition-fragmentation chain transfer (RAFT) gave side-chain fatty acid-containing well-defined polymers (PFAMA) with targeted molecular weights, narrow molecular weight distribution and precise chain-end functionality. The PFAMAs were subsequently used as macro-chain transfer agents (macro-CTA) for the polymerization of 2-(2-methoxyethoxy)ethyl methacrylate (MEO2MA) to obtain block copolymers. Homopolymers with fatty acid pendants display crystalline behaviour depending on the chain length of the fatty acids, evidenced by differential scanning calorimetry (DSC), polarized optical microscopy, small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS) techniques.