Fully biobased, elastomeric and compostable random copolyesters of poly(butylene succinate) containing Pripol 1009 moieties: Structure-property relationship

Fully biobased random copolymers of poly(butylene succinate) (PBS) containing different amount of Pripol 1009 moieties were synthesized by melt polycondensation. Molecular characterization confirmed the chemical structure and the random distribution of counts (NMR) and indicated that high molecular weight samples were obtained (GPC). All the polymers under study were semicrystalline, developing the typical α-PBS crystalline phase, the melting temperature and the crystallinity degree regularly decreasing with the increase of Pripol content. Pripol moieties determined also an improvement of polymer chain flexibility, as proved by the glass transition temperature decreasing, and of thermal stability. Polymer mechanical response was nicely tuned by changing copolymer composition, the copolymer with the highest Pripol content showing the typical behavior of thermoplastic elastomers despite its random nature. Lastly, biodegradation rate in compost also increased with the content of Pripol due to the parallel decrease of sample crystallinity degree. Surprisingly, microorganisms present in the compost preferentially attack BS comonomeric units despite their semicrystalline nature.