Influence of the Multiple Injection Moulding and Composting Time on the Properties of Selected Packaging and Furan-Based Polyesters

In recent years, there has been a trend toward replacing petrochemical raw materials with so-called “bio” plastics, i.e. plastics from renewable sources. Herein, the susceptibility of degradation in the compost heap of three types of packaging polyesters, by means of PET and biobased PEF and PLA, with other thermoplastic polyesters with more methylene groups (three and six) bio—(PTF and PHF, respectively) and petrochemically-based (PTT and PHT, respectively) has been studied. Two series of polymer materials based on ethylene, propylene, and hexamethylene glycols and two diesters (dimethyl terephthalate and dimethyl 2,5-furandicarboxylate) were thus obtained and compared with “double green” PLA. Moreover, the assessment of the influence of the subsequent processing cycle (injection moulding) on the utilitarian properties of these materials, constitutes the analogy to the subsequent recycling cycle. The susceptibility to degradation was assessed in the context of changes in the structure (analyzed by FTIR and DSC), intrinsic viscosity, and mechanical performance. In addition, chromatographic analysis of the solutions of the analyzed samples in methanol was carried out in order to determine whether and what low-molecular compounds were released from the analyzed polyesters. It has been shown that furan-based polyesters have great potential to replace materials based on dimethyl terephthalate-based polyesters.