Compatibilization of low-density polyethylene/plasticized starch blends by reactive compounds and electron beam irradiation

Blends based on various compositions of low‐density polyethylene (LDPE) and plasticized starch (PLST) were prepared by melt extrusion and molding in the form of sheets under hot press. The rheology properties during mixing were studied in terms of torque and temperature against mixing time. The structural properties of LDPE/PLST blends before and after electron beam irradiation was characterized by IR spectroscopy, tensile mechanical testing, and scanning electron microscopy (SEM). The torque‐time curves during the mixing process showed that the values of torque in the first region of mixing for pure LDPE or LDPE/PLST blends are higher in the presence of the compatibilizer PEMA than that in the presence of EVA. In addition, the stability of mixing was attained after a short time in the presence of PEMA. The IR spectroscopy suggests that the compatibilization by EVA and PEMA compounds proceeds through the formation of hydrogen bonding during mixing and this compatibility was improved after electron beam irradiation. The stress–strain curves of pure LDPE and its blends with PLST showed the behavior of tough polymers with yielding properties. The SEM micrographs of the fracture surfaces give supports to the effect of EVA and PEMA as compatibilizers and the effect of electron beam irradiation. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers