2.2 Compounding procedures
LDPE incorporated with 0%, 2.5%, 10%, 20 %wt. EVA, and neat EVA were melt-compounded in a co-rotating twin screw extruder (SHJ-25, ENMACH) with a screw speed of 60 rpm. Because of air cooling, the temperatures along the extruder were ranged from 90 °C to 130 °C and 100 oC at die zone in order to prevent the loss of plant extract and remain low melt flow index in mixture. After that the extruded were removed from the twin screw extruder and were grinded to pellet. Likewise LDPE incorporated with 10%wt. EVA containing the 3 kinds of plant extract (0.5, 2 and 4% wt.) were prepared under the same conditions as the above paragraph which had no presence of any EO.