*2.4.4.2. Temperature ramp tests*

After finding the linear viscoelastic zone, temperature ramp tests were performed to observe the behavior of the PP matrix at different temperatures. These tests were performed between −60°C and 170°C, at 1 Hz, 3°C/min, and 0.01% of strain.

#### *2.4.5. Morphology*

**2.4. Characterization of the biocomposites**

134 Characterizations of Some Composite Materials

**Figure 1.** Injected specimens of PP and a PP-bagasse biocomposite.

as the average value of five samples.

Three-point bending flexural tests were performed with an INSTRON universal testing machine model 3366 according to the ASTM D 790–17. The tests were carried out on bars of rectangular cross section at 23°C and at a rate of crosshead motion in 1.3 mm/min. This rate was determined based on the dimensions of the specimen. Also, the distance between the supports was 50 mm, and the tests were conducted up to 5% strain. All the results were taken

The impact strength of PP and biocomposites were determined with an Izod Tinius Olsen impact pendulum equipped with a 4.53 N pendulum. Prior to the test, the materials were subjected to conditioning for 48 h at 50% relative humidity and a temperature of 25°C. The specimens were made following the standard ASTM D256, and the starting angle of the test

Differential scanning calorimeter (DSC) and TGA test of the neat PP and biocomposites were carried out using a TGA/DSC 2 STAR system, from Mettler Toledo. DSC tests were carried out

with a sample of 10 mg in aluminum pans. Melting temperatures (Tm) were determined from the first heating scans. TGA was carried out on 10 mg samples using a TA Q500 thermogravimeter at 10°C/min from 23 to 600°C under nitrogen flow. The thermal degradation temperatures con-

Polymers and composites have a different response to mechanical loads in comparison with other materials. They can be studied as materials that in some cases behave as elastic solids

at 50 mL/min) from 20 to 200°C at a scanning rate of 10°C/min,

) and the temperature of maximum weight loss rate (Tmax).

was 55.80°. All the results were taken as the average value of five samples.

*2.4.1. Flexural properties*

*2.4.2. Impact properties*

*2.4.3. Thermal characterization*

under nitrogen atmosphere (N2

sidered were the onset of inflection (T0

*2.4.4. Dynamic mechanical analysis*

Scanning electronic microscopy (SEM) of biocomposites was carried out on the cryogenic fracture surfaces of the specimens using a Quanta FEG 250 microscope operating at a voltage of 10 kV.

The samples were previously sputter-coated with gold to increase their electric conductivity. The cross-sectional diameters of the dispersed phase were measured using ImageJ 1.8v (Wayne Rasband, National institutes of health, USA). Determinations were performed in different areas of the SEM images.

#### *2.4.6. Statistical analysis*

Flexural and impact properties of the materials were subjected to analysis of variance (ANOVA), and the Tukey's test was applied at the 0.05 level of significance. All statistical analyses were performed using Minitab Statistical Software Release 12 (Pennsylvania, USA).
