Structural, molecular and thermal properties of cardanol based monomers and polymers synthesized via atom transfer radical polymerization (ATRP)

Abstract

Cardanol, a byproduct of the cashew processing industry, has been widely studied feeedstock for sustainable monomers and polymers. In this article, the Atom Transfer Radical Polymerization (ATRP) of three radically polymerizable monomers, namely, cardanyl acrylate (CA), hydrogenated cardanyl acrylate (PA) and hydrogenated cardanyl methacrylate (PMA), was studied. The monomers as well as the polymers were structurally characterized and studied by differential scanning calorimetry (DSC) to understad their thermal behavior. The PA monomer showed melting (Tm) at 35 °C and crsytallization (Tc) at −3.27 °C. The synthesized polymer shows Tm of 16.5 °C and the Tc increased to 7.2 °C. In PMA monomer, the Tm was observed at 15.21 °C and Tc at −11 °C and the correponding values for the polymer decreasing to 1 °C and −18 °C, respectively. The coressponding transitions of CA monomer and its polymer were broad and less defined. The homopoymerization of CA and PMA yielded good conversions but the PA polymer yield was low under identical conditions, probably due to the higher monomer crystallinity of PA. The effect of different ATRP ligands, viz, pentamethyldiethylenetriamine (PMDETA) and bipyridine (dNbpy), on the conversion, molecular weight and polydispersity was also investigated.