Investigation of mechanical properties and biodegradability of compatibilized thermoplastic starch/ high impact polystyrene blends reinforced by organophilic montmorillonite

This work consists of preparation and characterization of composites produced from thermoplastic starch (TPS) and high impact polystyrene (HIPS). Due to the immiscibility of the system (TPS/HIPS), it was necessary to incorporate concentrations of 1, 2 and 3% of an organophilic montmorillonite (MMT) to improve the properties of the mixtures, in particular their rigidity. The composites thus prepared were characterized using XRD, FTIR, mechanical test, degree of swelling in water and biodegradability. The results show that the addition of MMT improves the mechanical properties of the mixtures such as the tensile strength and the Young’s modulus by 5% and 10%, respectively. In contrast, the resilience of the system has significantly decreased. Moreover, for 3% of MMT, the composites biodegradability is enhanced by 15% when compared to the TPS/HIPS mixture without MMT.

Effect of sequence of melt mixing on the properties and morphology of blends of polypropylene, styrene–ethylene–butylene–styrene copolymer grafted with maleic anhydride, and organophilic montmorillonite clay

Styrene–ethylene–butylene–styrene (SEBS) copolymer, grafted or not, with maleic anhydride and organophilic montmorillonite clay was melt mixed with polypropylene (PP) using different mixing sequences to understand its effect on properties and morphology. The addition of clay changed the blend morphology from large elongated domains to droplets. The nanocomposites without maleic anhydride presented clay in the intercalated form. In the formulation containing maleic anhydride, clay is exfoliated on the blend, indicating that the maleic anhydride group acted to increase the interaction between the clay lamellae and the polymer chains. The best balance of mechanical properties was achieved in the formulation in which the clay was first melt mixed in SEBS without maleic anhydride and afterward melt mixed with clay and PP. It is reported in the literature that nanocomposites with exfoliated structures have better mechanical properties than nanocomposites with intercalated structure. However, in this study, an opposite trend was found, which may be related to the higher amount of crystalline phase formed in the intercalated structure nanocomposites, since the clay intercalation phenomenon in the polymer chains favored the polymer crystallization process.

Preparation and characterization of poly(3-glycidoxypropyltrimethoxysilane) nanocomposite using organophilic montmorillonite clay (Mag-cetyltrimethylammonium)

Nanocomposites of linear poly(3-glycidoxypropyltrimethoxysilane) based on Algerian natural organophilic clay: montmorillonite–cetyltrimethylammonium named Maghnite-CTA were prepared by enhancing the dispersion of the matrix polymer in sheets of the organoclay. The effect of the organoclay, used with different amounts (3, 5, and 7% by weight) and the preparation method were studied in order to determine and evaluate their structural, morphological and thermal properties. X-ray diffraction analysis of obtained nanocomposites showed a significant change in the distance interlayer of montmorillonite–cetyltrimethylammonium. Therefore, interlayer expansion and exfoliation of linear poly(3-glycidoxypropyltrimethoxysilane) between layers of montmorillonite–cetyltrimethylammonium were observed. The thermal properties of the prepared nanocomposites were given by thermogravimetric analysis. The structure and morphology of the obtained materials were determined respectively by Fourier transform infrared spectroscopy and scanning electronic microscopy. The results obtained have approved the privilege of the intercalation of linear poly(3-glycidoxypropyltrimethoxysilane) in the interface of montmorillonite–cetyltrimethylammonium and the best quantity of organoclay required to prepare nanocomposite with a high thermal stability is 5% (by weight).