*3.2.3.2. Thermogravimetric analysis (TGA)*

TG and DTG curves for PP and PP-bagasse biocomposites are shown in **Figure 15a** and **b**, respectively. Neat PP degradation occurs in a single-step process with an onset temperature (To) located at 371°C and a Tmax of 449°C. Regarding biocomposites, TG and DTG show that degradation occurs in a two-step process. The first degradation step is associated with the decomposition of fiber constituents with a To located between 264 and 311°C for neat bagasse and silane-modified bagasse, respectively. This result indicates that chemical treatments

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The second degradation step corresponds to the decomposition of PP matrix. As shown in **Table 2**, To increases between 51 and 53°C.Also, Tmax increase between 4 and 9°C in comparison

improve the thermal stability of bagasse fibers.

**Figure 15.** (a) TG and (b) DTG curves of neat PP and PP-bagasse biocomposites.

**Figure 14.** First heating DSC curves for neat PP and PP-bagasse biocomposites.

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**Figure 14.** First heating DSC curves for neat PP and PP-bagasse biocomposites.

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

mechanical performance against stresses produced by bending loads.

*3.2.3. Thermal characterization*

144 Characterizations of Some Composite Materials

*3.2.3.1. Differential scanning calorimetry (DSC)*

the melting processes of the PP matrix.

*3.2.3.2. Thermogravimetric analysis (TGA)*

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

The first heating runs of PP and PP-bagasse biocomposite were shown in **Figure 14**. Both samples exhibit an endothermic peak between 163 and 165°C corresponding to the melting of the PP matrix. These results indicate that the addition of the bagasse fibers does not disturb

TG and DTG curves for PP and PP-bagasse biocomposites are shown in **Figure 15a** and **b**, respectively. Neat PP degradation occurs in a single-step process with an onset temperature (To) located at 371°C and a Tmax of 449°C. Regarding biocomposites, TG and DTG show that degradation occurs in a two-step process. The first degradation step is associated with the

**Figure 15.** (a) TG and (b) DTG curves of neat PP and PP-bagasse biocomposites.

decomposition of fiber constituents with a To located between 264 and 311°C for neat bagasse and silane-modified bagasse, respectively. This result indicates that chemical treatments improve the thermal stability of bagasse fibers.

The second degradation step corresponds to the decomposition of PP matrix. As shown in **Table 2**, To increases between 51 and 53°C.Also, Tmax increase between 4 and 9°C in comparison


**4. Conclusions**

**Acknowledgements**

**Conflict of interest**

**Author details**

Miguel Ángel Hidalgo-Salazar1

Occidente, Cali, Colombia

The chemical composition and thermal behavior of neat and chemically modified sugar bagasse fibers were studied. The biocomposites of bagasse fiber incorporated into a PP matrix were prepared by a melt-extrusion, injection, and thermocompression processes. The effects of bagasse fibers and chemical modification on the properties of the biocomposites were explored. Flexural characterization showed that bagasse fiber incorporation induces a significant improvement of flexural properties of PP. Also, the impact tests showed that the addition of silanized bagasse increases the capacity of PP to absorb energy. The DMA experiments show that bagasse fiber addition improves the maximum service temperature of the PP matrix. It was also observed that silanization process didn't improve the viscoelastic properties compared to the alkalinization treatment. However, the alkalization treatment generates an improvement against the damping of the PP matrix. Thermal studies show that bagasse fiber addition did not disturb the melting process and improves the thermal stability of the PP matrix. This study offers an environmentally friendly alternative for utilizing waste bagasse

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The authors acknowledge the Autónoma de Occidente University, Cali-Colombia, for the technical and financial support; the nanocharacterization center of Virginia Commonwealth University, Virginia-United States, for EDX and SEM spectra; Santiago de Cali University, Cali-Colombia, for its support in the use of FAAS; Servicio Nacional de aprendizaje (SENA), Cali-Colombia, for the financial support through the System of Research, Technological Development and Innovation (SENNOVA). In addition, we wish to thank the company

The authors of this manuscript declare that they do not hold any conflicts of interest that

\*, Fernando Luna-Vera<sup>2</sup>

1 Research Group for Manufacturing Technologies GITEM, Universidad Autónoma de

2 Research Group for Development of Materials and Products GIDEMP, National Center for

and Juan Pablo Correa-Aguirre1

might have any bearing on research reported in their submitted manuscript.

fiber generated by the sugar industry for the production of biocomposites.

"Sucromiles" Colombia, for providing the sugarcane bagasse.

\*Address all correspondence to: mahidalgo@uao.edu.co

Technical Assistance to Industry (ASTIN-SENA), Cali, Colombia

**Table 2.** Thermal degradation data of the samples at 10°C/min in nitrogen atmosphere.

to neat PP. This increment in the thermal stability of the biocomposites has been previously observed in different studies [36, 37], indicating that the incorporation of fibers in the material induces spherulite nucleation points, increasing the crystallinity of the polymer and improving its thermal properties.

#### **3.3. Morphology**

**Figure 16** shows SEM images of fractured surfaces from PP-Bag and PP-Bag+NaOH+Silane biocomposites. Gaps between the bagasse fibers and the surrounding PP matrix can be clearly observed in **Figure 16a**, which indicates a poor interfacial adhesion between the PP matrix and the bagasse fibers [38]. For **Figure 16b**, with the chemical treatments, we can see that the gaps between bagasse and PP were reduced significantly and exhibited improved interface for the composite. This result confirms that chemical treatments expose the bagasse fibers and provided links between the cellulosic fibers and the surrounding polymer long chains, which improved the interfacial property of the hydrophobic PP matrix and the hydrophilic bagasse.

**Figure 16.** SEM pictures for a) PP-Bagasse and b) PP-Bag + NaOH+Silane biocomposites.
