High performance polyethylene/thermoplastic starch blends through controlled emulsification phenomena.

The emulsification efficacies of a range of compatibilizers for polyethylene/thermoplastic starch blends have been studied and a detailed morphological and mechanical analysis has been conducted. It is shown that polyethylene-maleic anhydride terpolymers containing elastomeric segments provided excellent emulsification of PE/TPS blends with a fine morphology (volume diameter of 1.4 μm; number average diameter of 600 nm). The blends compatibilized with these copolymers exhibit a very high elongation at break of about 800%, the highest value ever reported for PE/TPS systems. Also, significant improvement in notched impact strength performance at interfacial saturation was found for these systems leading to specimens with an equivalent performance to pure polyethylene. An excellent correlation was found between the critical concentration for interfacial saturation and the mechanical properties, indicating the key role of morphology.