Furan-2,5- and Furan-2,3-dicarboxylate Esters Derived from Marine Biomass as Plasticizers for Poly(vinyl chloride)

Esters of furan dicarboxylic acids (DAFs) were synthesized by a one-pot reaction between marine biomass-derived galactaric acid and bioalcohol under solvent-free conditions and were fully characterized. The catalyst amount could be reduced without loss of reaction yields using p-xylene as the material separation agent. Also, a possible mechanism was proposed for the first time. Then the properties of four DAFs as plasticizers on the poly(vinyl chloride) (PVC) matrix were investigated. The experimental results showed that DAFs exhibit competitive efficiencies of plasticization when compared to the most commercialized plasticizer, DOP. It was found that the combination of DAFs and PVC produced homogeneous smooth-surface films, indicating miscibility between them. ATR-FTIR depicted the upshift of carbonyl absorption bands after mixing with the PVC matrix, with a magnitude of at most 18-21 cm^-1. TGA, DSC, and UTM data illustrated equivalent plasticization efficiencies. Due to their small molecular weights, the investigated DAFs are more volatile. However, due to bearing an oxygen atom in the aromatic furan ring, the degree of polarization of DAFs was boosted and helped inhibit leaching into the surrounding media. In brief, these synthetic compounds have promising feasibility as biobased plasticizers. Moreover, another interesting point is that the properties of furan-2,3-dicarboxylic acid derivatives were studied for the first time and herein reported.