Biobased co-polyesters poly(butylene succinate-co-butylene furandicarboxylate) (PBSF) is prepared by transesterification and polycondensation of dimethyl succinate (DSMu), dimethyl 2,5-furandicarboxylate (MDFD) and 1,4-butanediol (1,4-BDO). GPC analysis shows that PBSF has high molecular weight with weight average molecular weight (M w ) up to 11 Â 10 4 g/mol. Due to the low -COOH content, PBSF also has excellent thermal stability, which is beneficial to the polyester processing. Differential scanning calorimetry (DSC) analysis shows that PBSF are semi-crystalline materials, with T m ranging from 116 to 101 C. Tensile tests showed that theses polymers possess high tensile strength (30-22 MPa) and elongation at break as high as 562%, which is prominently higher than that of commercial poly(butylene succinate) (PBS) and most biodegradable packaging materials. It should be noted that the increase of BF units improves the UV shielding properties of polyester materials. Moreover, the incorporation of furan ring promoted the enzymatic degradation of PBS, and PBSF showed a significantly faster biodegradation rate when the BF unit content is 5%. PBSF polyester has excellent thermal properties, tensile properties, UV shielding properties and biodegradable properties. Therefore, these new bio-based polymers have great potential to be applied as environmentally friendly and sustainable plastic packaging.

The introduction of long-chain branched structures into biodegradable polyesters can effectively improve the melt strength and blow-molding properties of polyesters. In this study, pentaerythritol (PER) was used as a branching agent to synthesize branched poly(butylene dodecanedioate) (PBD), and the resulting polymers were characterized by Nuclear Magnetic Resonance Proton Spectra (1H NMR) and Fourier Transform Infrared spectroscopy (FT-IR). It was found that the introduction of a small amount of PER (0.25–0.5 mol%) can generate branching and even crosslinking structures. Both impact strength and tensile modulus can be greatly improved by the introduction of a branching agent. With the introduction of 1 mol% PER content in PBD, the notched impact strength of PBD has been increased by 85%, and the tensile modulus has been increased by 206%. Wide-angle X-ray diffraction and differential scanning calorimetry results showed that PER-branched PBDs exhibited improved crystallization ability compared with linear PBDs. Dynamic viscoelastics revealed that shear-thickening behaviors can be found for all branched PBD under low shear rates.

Novel poly(butylene succinate-butylene furandicarboxylate/polyethylene glycol succinate) (PBSF-PEG) was synthesized using two-step transesterification and polycondensation in the melt. There are characterized by intrinsic viscosity, GPC, 1H NMR, DSC, TGA, tensile, water absorption tests, and water degradation at different pH. GPC analysis showed that PBSF-PEG had high molecular weight with average molecular weight (Mw) up to 13.68 × 104 g/mol. Tensile tests showed that these polymers possessed good mechanical properties with a tensile strength as high as 30 MPa and elongation at break reaching 1500%. It should be noted that the increase of PEG units improved the toughness of the polyester material. In addition, the introduction of PEG promoted the water degradation properties of PBSF, and the copolymer showed a significantly faster water degradation rate when the PEG unit content was 20%. This suggests that the amount of PEG introduced could be applied to regulate the water degradation rate of the copolymers. Hence, these new polymers have great potential for application as environmentally friendly and sustainable plastic packaging materials.