# Thermal and Thermomechanical Characterization of Polypropylene-Seed Shell Particles Composites
## 3 Results  
### DSC Results  
The DSC thermogram for pristine PP is presented in Figure 2, all the PP-JA and PP-PI composites showed the same behavior, and from them were obtained the crystallization temperature (Tc), the crystallization enthalpy (\(\Delta\)H\({}_{\rm c}\)), the melting temperature (Tm), the melting enthalpy (\(\Delta\)H\({}_{\rm m}\)), and the % crystallinity of the PP-JA and PP-PI composites are reported in Table 2. An important variable that affects the crystallization of PP is the melt index [22], in our case the PP melt flow is medium. From the data obtained, PP's Tc is 111 \({}^{\circ}\)C with minimum variation, and when JA is added, there is no appreciable variation in this value. In general, the addition of JA slightly decreases \(\Delta\)H\({}_{\rm c}\) however, with the increase in the particle content, this value also increases, PP-6-JA being the composite with the highest \(\Delta\)H\({}_{\rm c}\). The addition of lignocellulosic causes an increase in the crystallization temperature of pristine PP [21]. Other reports indicate that the addition of lignocellulosic fibers does not have a significant effect on the melting temperature of pristine PP [26; 27; 28]. On the other hand, the addition of PI presented a similar behavior in regard to T\({}_{\rm c}\), which remains unchanged. However, with respect to \(\Delta\)H\({}_{\rm c}\), there is a slight increase at low concentrations (PP-2-PI, PP-4-PI), higher than that of PP; however, at a higher content of particles, the enthalpy decreases to values lower than pure PP. [PERSON] et al. [24] reported a T\({}_{\rm c}\) value of 113\({}^{\circ}\)C, a value similar to that reported in our work, despite the fact that a PP \begin{table}
\begin{tabular}{l l l l l l} \hline \hline
**Composite** & **Tc**\({}^{\circ}\)C & **\(\Delta\)H\({}_{\rm c}\), **/g** & **Tm**\({}^{\circ}\)C & **\(\Delta\)H\({}_{\rm m}\), **/g** & **\% Xc** \\ \hline PP & 111 & 92.11 & 171 & 62.48 & 30.18 \\ PP-2-JA & 113 & 84.6 & 165 & 63.14 & 30.5 \\ PP-4-JA & 111 & 81.36 & 164.7 & 65.52 & 31.65 \\ PP-6-JA & 111 & 89.74 & 164.8 & 73.23 & 35.37 \\ PP-8-JA & 112 & 83.24 & 163.7 & 64.63 & 31.22 \\ PP-10-JA & 112 & 87.88 & 166 & 71.26 & 34.4 \\ PP-2-PI & 111 & 92.45 & 167 & 68.78 & 33.22 \\ PP-4-PI & 112 & 98.47 & 165 & 78.36 & 37.85 \\ PP-6-PI & 112 & 86.8 & 165 & 65.87 & 31.82 \\ PP-8-PI & 112 & 85.85 & 167 & 65.67 & 31.72 \\ PP-10-PI & 113 & 78.25 & 166 & 62.68 & 30.28 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Thermal data obtained by DSC for PP, PP-JCSP and PP-PSP composites. with a lower melt index (12 g/10 min) was used in their study. These results are similar to those reported by [PERSON] and [PERSON] [29] who evaluated that PP irradiated with UV light did not undergo changes in its crystallization behavior. Furthermore, [PERSON] et al., [30] reported that the crystallization process of PP with lignocellulosic materials can be modified with a chemical treatment or with the presence of coupling agents. Regarding the T\({}_{\text{m}}\) value, it showed a decrease of up to 6 \({}^{\circ}\)C compared to the T\({}_{\text{m}}\) of pure PP (171\({}^{\circ}\)C), which is indicative of an affectation in the crystalline structure of PP. This T\({}_{\text{m}}\) value differs from some previous works, which report a T\({}_{\text{m}}\) of 166 \({}^{\circ}\)C and 164 \({}^{\circ}\)C, but with a melt flow PP of 17 g/10 min and 12 g/10 min, respectively [21,22].The crystallinity of the PP was calculated from the \(\Delta\)H\({}_{\text{m}}\) of 62.48 J/g, and a % of crystallinity of 30.18% was determined, a value close to that reported in previous work with a similar melt flow value of PP [27] On the other hand, it was reported that the melt flow value has a significant effect on the crystallinity of the PP [22].