Synthesis and thermal analysis of sugar based polyesters as candidate of high performance biopolymers

Synthesis and characterization of polyesters based on isosorbide/isoidide derived AB-monomers were reported. The homopolymers were prepared respectively by melt polycondensation of isosorbide 2(4-carbomethoxybenzoate), isosorbide 5(4-carbomethoxybenzoate) and isoidide (4-carbomethoxyphenyl ether). The chemical structure and properties of the synthesized polyesters were characterized by proton nuclear magnetic resonance spectroscopy (¹H NMR), differential scanning calorimetry (DSC) and X-ray diffraction. It was found that these renewable bio-based thermoplastics present promising high Tg and excellent crystallinity. By increasing the maximum temperature attained in the polymerization, the molecular weight of polyesters went up with their increased Tg. Because of their thermal stability, it provides the opportunity of melt processability of those homopolymers, which is often the major challenge arising from processing biopolymers on industrial scale. Meanwhile, the monomers can also be used as backbone modifier for many commercial polymers such as PET or PLA etc. Those high performance copolyesters with their processing versatility could be utilized in many different applications such as hot filling food packaging, implantable catheters and orthopedic prosthesis. In this article, transesterification of isosorbide 5(4-carbomethoxybenzoate) with PET was done and showed the Tg of PET could be raised by adding a small amount of those sugar derived AB monomers.