The melt flow index (MFI) was evaluated using a CAEST type CA-MAN-001, according to ISO 1131-1991 (PN-93/C-89069). 5g of samples (granules) were dried in the vacuum oven over a night. The temperature of the device was set at 125°C with 2.16 kg of load, and the time for cutting the extruded melt was set at 30 seconds. The MFI was calculated according to Equation ( ):