*3.2.2.2. Temperature ramp tests*

**Figure 9** shows the thermograms obtained in the DMA for the PP matrix and its biocomposites. In these graphs the values of the storage modulus (E'), loss modulus (E"), and tan delta are shown. Neat PP tan delta plot shows two relaxations located near 6°C (β relaxation or Tg) and 60°C (α relaxation) [35]. It is also observed that the values of E´ are temperature dependent. At 25°C the value of E´ is 2708 MPa, while at 75°C, this value is 1199 MPa, which represents a decrease of 55%.

In the tan delta plot of the biocomposite PP-Bag (**Figure 10**), a Tg of 5.3°C is observed, while the α relaxation increased 17.5°C compared to the neat PP. Also, E'values at 25°C is 2454 MPa,

**Figure 8.** Strain sweep test curves for neat PP at 0, 30, and 60°C.

**Figure 9.** Dynamic mechanical analysis (DMA) curves of neat PP.

**Figure 10.** Dynamic mechanical analysis (DMA) curves of PP-Bag biocomposite.

while at 75°C, this value is 1169 MPa. E'values' decrease in this temperature range was 52%. This result shows that the addition of bagasse fiber improves the stability of the storage module of the PP matrix with the temperature. The increase in the value of α relaxation and the stability of E´ with the temperature was also observed in biocomposites PP-Bag + NaOH and PP-Bag + NaOH+Silanes (**Figures 11** and **12**).

**Figure 13** shows the summary of the temperature sweep tests for biocomposites. The tan delta graphics show that there are no significant changes in the Tg of the biocomposites compared to the PP matrix. The values of Tg range between 3.7°C and 6.5°C. Also, these graphs show a reinforcing effect in the PP-bag biocomposite. Tan delta values varied 19.8% compared to the PP matrix. In the case of biocomposite PP-Bag + NaOH, this variation was 32.64% while in the

**Figure 12.** Dynamic mechanical analysis (DMA) curves of PP-Bag + NaOH+Silane biocomposite.

**Figure 11.** Dynamic mechanical analysis (DMA) curves of PP-Bag + NaOH biocomposite.

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biocomposite PP-Bag + NaOH+ Silane was 32.95%.

Biocomposites from Colombian Sugarcane Bagasse with Polypropylene: Mechanical, Thermal… http://dx.doi.org/10.5772/intechopen.80753 143

**Figure 11.** Dynamic mechanical analysis (DMA) curves of PP-Bag + NaOH biocomposite.

**Figure 9.** Dynamic mechanical analysis (DMA) curves of neat PP.

142 Characterizations of Some Composite Materials

**Figure 10.** Dynamic mechanical analysis (DMA) curves of PP-Bag biocomposite.

PP-Bag + NaOH+Silanes (**Figures 11** and **12**).

while at 75°C, this value is 1169 MPa. E'values' decrease in this temperature range was 52%. This result shows that the addition of bagasse fiber improves the stability of the storage module of the PP matrix with the temperature. The increase in the value of α relaxation and the stability of E´ with the temperature was also observed in biocomposites PP-Bag + NaOH and

**Figure 12.** Dynamic mechanical analysis (DMA) curves of PP-Bag + NaOH+Silane biocomposite.

**Figure 13** shows the summary of the temperature sweep tests for biocomposites. The tan delta graphics show that there are no significant changes in the Tg of the biocomposites compared to the PP matrix. The values of Tg range between 3.7°C and 6.5°C. Also, these graphs show a reinforcing effect in the PP-bag biocomposite. Tan delta values varied 19.8% compared to the PP matrix. In the case of biocomposite PP-Bag + NaOH, this variation was 32.64% while in the biocomposite PP-Bag + NaOH+ Silane was 32.95%.

**Figure 13.** Dynamic mechanical analysis (DMA) curves of neat PP and its composites.

With temperature increase, a second peak is observed around 60°C for neat PP. This peak can be related to an alpha transition. In the case of biocomposites, this alpha transition can be spotted at higher temperatures. This suggests that the service temperature of the biocomposites with alkaline and silanized treatments would allow a better performance of the material. In this experiment observed that the addition of silane to bagasse does not generate an improvement in the viscoelastic properties compared to the alkalinization treatment. It is emphasized that the alkalization treatment generates an improvement against the damping. This improvement can be positive for biocomposite applications that require an enhanced mechanical performance against stresses produced by bending loads.

#### *3.2.3. Thermal characterization*
