Recyclability assessment of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/poly(butylene succinate) blends: Combined influence of sepiolite and compatibilizer

Blends of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and poly (butylene succinate) (PBS) (50:50 w/w) were prepared by melt mixing. 5 wt% of compatibilizing agent, obtained by grafting of maleic anhydride onto PHBV, was used to improve the miscibility between the blend components. The influence of the presence of both sepiolite and compatibilizer was studied by evaluating the effect of repeated extrusion cycles (up to 6) on the morphology and the functional properties of materials. Changes in thermal, morphological, rheological and mechanical properties were investigated. All the results showed that PHBV is the more sensitive component towards recycling due to thermomechanical degradation, but PBS as well as sepiolite and compatibilizer play a stabilizing role on PHBV due to improved morphology. The mechanical characteristics measured at different scales remain more or less constant compared to the initial ones revealing the preservation of the mechanical properties of the different samples after reprocessing. This paper highlights a synergistic effect induced by the presence of both compatibilizer and sepiolite leading to an improved recyclability of the resulting materials compared to neat polymers.