Production of thermoplastic starch and poly (butylene adipate-co-terephthalate) films assisted by solid-state shear pulverization

A novel processing technique involving Solid-State Shear Pulverization (SSSP) was used to produce thermoplastic starch (TPS) and Poly (Butylene Adipate-co-Terephthalate) (PBAT) films to improve processability and produce well-dispersed blends. Four different compositions (50−80 wt% TPS content) were processed using two different production routes. In one instance, the compositions were pre-treated by SSSP before melt extrusion (SSSPE). Secondly, starch was initially plasticized and thereafter blended with PBAT by melt extrusion (EXT) method. Flat films were produced using both routes and processability, visual and tactical aspects, mechanical and optical properties, crystallinity, and water absorption behavior were evaluated. High starch content films (70 and 80 wt%) prepared based on SSSP incorporation showed easier processability, and better visual aspect and mechanical integrity than EXT ones. However, EXT films with 50 and 60 wt% of starch presented higher elongation at break and lower water absorption due to finer dispersion of TPS and better starch plasticization.