722 saturated clays (Bofe and Chocolate) - montmorillonite and kaolinite 001 reflections: (a) natural, (b) Mgsaturated, (c) ethylene-glycol-solvated. (5) CTAB modified Organo clays: (a) Bofe, (b) Chocolate. 3.1.2 PLA biocomposites XRD patterns (Figure 5) show semi-crystalline characteristics of PLA and PLA/organoclay. Extruded samples exhibit fewer peaks, likely due to crystalline structure disruption during extrusion [Gonzáles-Seligra ET AL., 2017]. It occurs probably due to drying conditions were very different as well. The sheets were quickly dried at high temperatures and high shear stress during extrusion and the films were slowly dried at rest by casting at low temperatures. The casting process helps to promote more effective recrystallization in the matrix, while rapid drying at high temperatures and shear that occurs during the extrusion process causes the destruction of this crystalline structure. The properties of biocomposites may undergo changes due to the differences that occur between these two processes. Figure 5 - XRD patterns of PLA and PLA/organoclay composites:(a) neat PLA (casting), (b) neat PLA (extrusion), (c) PLA/Bofe organoclay (casting), (d) PLA/Bofe organoclay (extrusion), (e) PLA/Chocolate organoclay (casting), (f) PLA/Chocolate organoclay (extrusion). 3.2 TGA/DTA Analysis 3.2.1 Bentonite samples Natural bentonites showed two or three similar and important thermal degradation transitions as could be seen in Figure 6. The first one is present in the two samples (Figures 6a, 6c) around the range of 80 ˚C due to the volatilization of free water while the second one around 200ºC is low and can be noted at Bofe clay (Figure 6a) related to the water residing inside the interlayer space [Guzel ET AL., 2012]. The last transition observed near 500ºC is ascribed to the loss of dehydroxylation of the structural OH units of the clay minerals [Yu et al, 2014].
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