Morphological and rheological properties of (low‐density polyethylene)/thermoplastic starch blend: investigation of the role of high elastic network

Rheological and morphological properties of low‐density polyethylene (LDPE) and thermoplastic starch (TPS) with low‐density polyethylene‐grafted‐maleic anhydride as a compatibilizer were investigated. The results showed that the circularity of the droplets decreased with increasing TPS content. The presence of compatibilizer led to finer morphology and higher continuity. The rheological analyses showed that TPS and compatibilizer can increase elasticity and viscosity of the blend dramatically. In addition, the compatibilizer enhanced the compatibility of the blends, as evidenced by the shifting of the relaxation time peak of TPS to longer times. The rheological properties of the neat components and their blends were discussed by the Carreau‐Yasuda and fractional Zener models. The fractional Zener model results proved the existence of network structure in the compatibilized blends. The transient properties of blends showed that TPS and compatibilized blends had strong overshoot compared with the uncompatibilized blend, owing to the formation of high elastic network in their structure. J. VINYL ADDIT. TECHNOL., 20:250–259, 2014. © 2014 Society of Plastics Engineers