Characterization of layered silicate-reinforced blends of thermoplastic starch (TPS) and poly(butylene adipate-co-terephthalate)

Effect of pine resin derivatives on the structural, thermal, and mechanical properties of Mater‐Bi type bioplastic

“…The results showed that the polymeric matrix used in this study (Mater‐Bi) presents a three‐step degradation process: the first step centered at 317 °C, corresponding to the plasticized starch degradation; the second step centered at 349 °C, attributed to either the degradation of the compatibilizing agents usually present in Mater‐Bi formulations or to interpenetrating networks formed by starch with the aliphatic aromatic polyesters; the third step, with a maximum degradation peak at 412 °C, corresponding to the degradations of the PBAT . This peak could be overlapped with the degradation peak of PCL, because it has similar degradation temperature, and also because its fraction on Mater‐Bi is less than 10 wt % .…”

“…All these behaviors show that pine resin derivatives cause an important plasticizing effect on the base polymeric matrix, more specifically with the PBAT portion of the Mater‐Bi. Furthermore, this behavior suggests that all the pine resin derivatives studied are compatible with PBAT fraction of the Mater‐Bi . Analyzing the melting temperature ( T m plasticized starch ) and the melting enthalpy (Δ H m plasticized starch ) linked to the plasticized starch fraction, it is possible to verify a slight interaction between pine resins derivatives and the plasticized starch fraction of the formulations.…”

“…In addition, large discontinuities with flakes shape are observed, confirming this lack of cohesion due to a low miscibility between the components of the Mater‐Bi polymeric matrix (PBAT, plasticized starch, and PCL). This morphology is also characteristic of ductile fractures in poor cohesion materials, mainly observed in binary or ternary blends with low miscibility [Figure (a)] . Specifically, small spheres attributed to the minor portion of PCL are observed .…”

“…The DSC cooling assessment in Mater‐Bi, shown in Figure (b), exhibits a peak at 92.5 °C attributed to the crystallization of the PBAT fraction. This peak was also observed by Borchani et al ., who used a similar Mater‐Bi in their study, and by Lendvai et al . and Muthuraj et al ., who worked with TPS‐PBAT blends and with an hydrolytically degraded PBAT, respectively.…”

“…In addition, if the trend of storage modulus ( G ′) with temperature [Figure (b)] is observed, in the curve corresponding to the neat Mater‐Bi, two important losses of G ′ are observed . The first one corresponds to the combination of the glass transition of the PBAT and the one of the plasticized starch portion of the Mater‐Bi ( T gPBAT and T g plasticized starch ) having associated with a peak in tan δ at −28 °C . The second major loss of G ′ is associated with a peak of tan δ at 60 °C, corresponding to the PCL and additives portion, which represents 10% of the Mater‐Bi polymeric matrix, as discussed before on FTIR and DSC analyses .…”