Miscibility and degradation of polymer blends based on biodegradable poly (butylene adipate-co-terephthalate)

The aim of this work is to analyse the effect of the preparation method on the miscibility of poly(butylene adipate-co-terephthalate) (PBAT) and poly(hydroxy ether of bisphenol A) (PH) blends and to provide a better understanding on the effect of a non-degradable component (PH) in the degradation of biodegradable PBAT. Blends have been prepared by different methods and the miscibility has been studied in a deeper way by means of differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and infrared spectroscopy (FTIR). Depending on the preparation method miscible or partially miscible blends are obtained. Furthermore, for miscible blends the hydrolytic degradation has been carried out for 405 days. It has been observed that adipate sequences on poly(butylene adipate-co-terephthalate) copolymer are more prone to degradation which leads to changes on glass transition temperature, crystallinity and chemical structure. The degradation rate is decelerated with the addition of PH, however the rate is similar or higher than other biodegradable polymers. Therefore the degradation rate can be controlled varying the composition of the blend and tailored materials with adequate properties can be obtained.