*2.3. Rheology*

The melt flow index (MFI) of pure PLA at 190 ◦C is 3.7075 g/10 min (Figure 2). For the PLA composites with SS-Limonene the MFI value increased with increasing concentrations of the filler. The composite samples containing 2.5% concentration of the additive are characterized by slightly higher MFR value. On the basis of the data analysis, it can be concluded that SS-Limonene as an additive to the polymer matrix will have a positive e ffect on its processing.

A capillary rheometer was used to determine the relation between shear rate and viscosity (Figure 3). At low shear rates, the viscosities of all compositions are lower than those of neat PLA, as a consequence of SS-Limonene acting as a plasticizer.

**Figure 2.** Result of MFR measurements.

**Figure 3.** Viscosity measurement results.
