Nanoparticles prepared by the sol–gel method and their use in the formation of nanocomposites with polypropylene

Abstract

Hybrid layered aluminosilicate nanoparticles (HLNP) containing octadecylamine (ODA) as the organic part, and silica nanoparticles with spherical morphology containing ODA (HSNP) or without ODA (SNP) were prepared by the sol–gel method and used for the formation of nanocomposites with polypropylene. The polypropylene matrices, of different molecular weight and polydispersity, were prepared using polymers obtained via Ziegler–Natta or metallocene catalysts. A strong influence of the morphology and the presence of ODA on the surface of the nanoparticles was found on the formation and characteristics of the nanocomposites. The mechanical properties and thermal stability of these materials were determined and compared with those of nanocomposites prepared with 2:1 phylosilicate clays such as montmorillonite and hectorite in similar polymer matrices. X-ray diffraction, transmission electron microscopy, and the study of mechanical properties showed that the use of HLNP allows nanocomposites with considerably improved mechanical properties to be obtained, compared with nanocomposites prepared with exfoliated clays. In the case of nanocomposites prepared with spherical particles functionalized with ODA (HSNP), materials with high specific strength combined with high elongation before rupture were obtained. The thermal stabilization of polypropylene matrices containing the synthesized nanoparticles (HLNP, HSNP or SNP) occurs about 50 °C higher than that attained with clays.

A facile synthesis of highly water-soluble, core–shell organo-silica nanoparticles with controllable size via sol–gel process

“…In the measurement range of IR (4000-650 cm À1 ), there are three characteristic IR absorption peaks for the pure inorganic SiO 2 nanoparticles appearing around 1078 (strong), 952 (weak), and 805 (weak) cm À1 , respectively. The most prominent peak at 1078 cm À1 is ascribed to the Si-O-Si stretching band of silica nanoparticles [28,29], while the O-Si-O bending band is located at 805 cm À1 [29]. The absorption at 952 cm À1 is due to the silanol groups (Si-OH) on the surface of the nanoparticles [28,29], and this peak is unique as it only can been observed in the sample of silica nanoparticles, especially when they are prepared by the sol-gel process.…”

“…The most prominent peak at 1078 cm À1 is ascribed to the Si-O-Si stretching band of silica nanoparticles [28,29], while the O-Si-O bending band is located at 805 cm À1 [29]. The absorption at 952 cm À1 is due to the silanol groups (Si-OH) on the surface of the nanoparticles [28,29], and this peak is unique as it only can been observed in the sample of silica nanoparticles, especially when they are prepared by the sol-gel process. For all the organo-silica nanoparticle samples, these three peaks are easily identified at 1090, 950, and 800 cm À1 with the same relative intensity, respectively.…”

Effects of water depth and laser pulse numbers on size properties of colloidal nanoparticles prepared by nanosecond pulsed laser ablation in liquid

“…In using nanoparticles for different applications, the size properties (mean size and size distribution) of nanoparticles have significant role in their performance. Colloidal nanoparticles historically were produced by chemical techniques [3,4]. While the chemical techniques have been quite successful for producing a large variety of nanoparticles, they have some limitations in terms of composition and surface contamination.…”

Effect of morphology on the permeability, mechanical and thermal properties of polypropylene/SiO2 nanocomposites

“…For thermal properties, on the other hand, the incorporation of nanometer‐sized inorganic particles into the polymer matrix typically enhances the thermal stability by acting as a superior insulator and mass transport barrier to the volatile products generated during decomposition . Moncada et al reported that the addition of spherical and layered silica nanoparticles synthesized by the sol‐gel method increases the thermal stability of PP under oxidative conditions . Furthermore, it has been found that the addition of spherical nanoparticles of ca 70 nm can dramatically improve the thermal degradation of PP .…”