Organophilic bentonites based on Argentinean and Brazilian bentonites: part 2: potential evaluation to obtain nanocomposites

Abstract

-This work describes the preparation of composites of polypropylene and organophilic bentonites based on Brazilian and Argentinean bentonites. During the processing of the samples in a twin screw microextruder, torque and pressures of the extruder were accompanied and the viscosity values were calculated. No significant changes in the torque, pressure and viscosity were found for composites prepared with different bentonites. The samples were characterized by XRD and TEM to evaluate the structure and dispersion of the organophilic bentonites. Composites with exfoliated, partially exfoliated and intercalated structures were obtained and correlations between the intrinsic properties of the sodium clays and organophilic bentonites and their influence on the composites were studied. The cation exchange capacity of the sodium bentonites and the swelling capacity of the organophilic bentonites were the most important properties to obtain exfoliated structures in composites. All bentonites showed the potential to obtain polymer nanocomposites, but the ones from Argentina displayed the best results.

Biopolymer blends based on polylactic acid and polyhydroxy butyrate-co-valerate: Effect of clay on mechanical and thermal properties

“…XRD has been successfully used for the evaluation of nanocomposite structure . The shift of the diffraction peaks of clays to lower angles due to increase of basal spacing indicates the formation of an intercalated structure while the disappearance of the diffraction peaks suggests the formation of an exfoliated structure . The XRD patterns of the samples are represented in Figure .…”

Estudo da influência de argilas organofílicas no processo de biodegradação do PLA

“…O aumento da distância interplanar é refletido no difratograma pela redução do ângulo de difração, e pode ser visualizado na forma do deslocamento dos picos de DRX para ângulos menores [30] . Este deslocamento foi observado nos difratogramas dos nanocompósitos de PLA e argilas Cloisite 20A e Cloisite 30B, em comparação aos difratogramas das argilas puras, indicando a intercalação de cadeias poliméricas entre as camadas de argila.…”

Modification and characterization of an Iranian montmorillonite as a corrosion/mechanical promoter for epoxy coatings

“…The type, size and polarity of surfactant (Guo et al , 2004; Fu & Heinz, 2010; Liu et al , 2013), surfactant/MMT mass ratio (Hojiyev et al , 2017), the CEC and the purity of MMT (Veiskarami et al , 2016) affect the final characteristics of organo-MMT. The CER of MMT and surfactant may be performed through various approaches, including ultrasonic and hydrothermal (Xi et al , 2005), solid/solid (Zhuang et al , 2015), semi-solid (Paiva et al , 2012; Paiva & Morales, 2012) and super critical CO 2 (Liu et al , 2014; Alves et al , 2016) methods. Kornmann et al (2001) prepared an epoxy/MMT nanocomposite using two MMTs with various CECs and investigated the effect of CEC of the MMT on the synthesis and structure of the epoxy/MMT nanocomposite.…”