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]. Organically modified bentonites (Figures 6b, 6d) exhibited four-stage decomposition: free water vaporization (~80°C, ~200°C), CTAB decomposition (200-500°C), and aluminosilicate dehydroxylation (~500°C), potentially linked to surfactant carbon [Zidelkheir and Abdelgoad, 2008].
RkJQdWJsaXNoZXIy MTM0Mzk2