Thermal Stability and Kinetic Study of Isotactic Polypropylene/Algerian Bentonite Nanocomposites Prepared via Melt Blending

Abstract

Isotactic polypropylene (iPP)/bentonite nanocomposites were prepared via melt blending using bentonite clay originated from Maghnia (Algeria). This clay was, at a first stage, used in its pure form (PBT) and then organically modified by Hexadecyl ammonium chloride (OBT). The effect of Maghnia bentonite dispersion on the iPP matrix was investigated by X-ray diffraction (XRD) and transmission electronic microscopy (TEM). DSC results evidenced that unmodified or organomodified bentonite can act as a nucleating agent increasing the rate of crystallites formation. Moreover, a thermogravimetry analysis confirmed a significant enhanced thermal stability of IPP/clay nanocomposites compared to pure IPP. The Flynn-Wall-Ozawa and Tang methods were applied to determine the activation energy Ea of the degradation process. The apparent activation energy Eα of thermal degradation for IPP/clay nanocomposites was much higher than that of virgin iPP. Comparatively to PBT, results indicate that OBT has an important effect on pure iPP thermal stability. Tensile modulus, tensile strength, and elongation at break were also measured and compared with those of pure iPP.

Non-isothermal crystallization kinetics and its effect on the mechanical properties of homopolymer isotactic polypropylene

“…The deduced values of the activation energy vary between -100 kJ mol −1 and -176.35 kJ mol −1 , which covers a wide range of activation energy. Other studies concerning the iPP have revealed a similar variation with a range from -61.3 kJ mol −1 to -210 kJ mol −1 [46,47]. The isoconversional methods take into account the variation in the activation energy with crystallization phases.…”

Polymer blend nanocomposites: effect of mercapto silane modified kaolin clay on the thermal properties of Polypropylene/Polystyrene blend

“…studied the effect of the incorporation of pure bentonite or organically modified bentonite into iPP matrix on the degradation mechanism of iPP. The activation energy (Ea) of degradation of pure iPP and iPP/PBT or iPP/OBT nanocomposites was first estimated by the well‐known equation of Ozawa, Flynn, and Wall and Tang, and they found out that the Ea of nanocomposites were higher than that of pure iPP …”

Flammability and Thermal Kinetic Analysis of UiO-66-Based PMMA Polymer Composites

“…With the melting of PMMA, UiO-66 migrates to the polymer surface, forms an effective diffusion barrier, and thus hinders the diffusion of formed gases from the thermal decomposition of PMMA. These results suppose that the shielding effect of UiO-66 could increase the activation energy of the polymer degradation [ 39 ].…”