Thermal degradation of biobased polyesters: Kinetics and decomposition mechanism of polyesters from 2,5-furandicarboxylic acid and long-chain aliphatic diols

Abstract

In the present study, biobased furan dicarboxylate polyesters have been prepared using 2,5-furandicarboxylic acid (FDCA) and diols with high number of methylene groups (long chain diols), namely 8, 10 and 12, which are named as poly(octylene 2,5-furanoate) (POF), poly(decylene 2,5-furanoate) (PDeF) and poly(dodecylene 2,5-furanoate) (PDoF), respectively. Semi-crystalline polyesters with number average molecular weight ranging from 34,000 to 39,000g/mol have been prepared and their chemical structure was proved by 1H NMR spectroscopy. A systematic investigation of the thermal stability and decomposition kinetics of these polyesters was performed, using thermogravimetric analysis (TGA) and pyrolysis-gas chromatography/mass spectroscopy (Py-GC/MS). From TGA curves it was found that all polyesters have high thermal stability since their decomposition starts around 340°C and completes near 500°C. The decomposition mechanism of the prepared polyesters was also studied with pyrolysis-gas chromatography/mass spectroscopy (Py-GC/MS). From the identified decomposition products after pyrolysis at 350 and 450°C, it was found that the decomposition of these polyesters is taking place mainly via β-hydrogen bond scission and in lower extent with homolytic >CC< radical decomposition and with α-hydrogen scission.