Effects of Nanofillers Based on Cetyltrimethylammonium-Modified Clays in a Polypropylene Nanocomposite

Abstract

Nanocomposites of hydrophobic organo-clay/polypropylene (organo-clay/PP) were efficiently developed through a solution-blending technique. For this, we utilized various smectite clays as host agents; namely, Na-montmorillonite (Mt, ~1000 nm), Na-fluorine mica (Mica, ~1500 nm), and Na-hectorite (Ht, ~60 nm) with varied sizes, layer charges, and aspect ratios. Such clays were functionalized with cetyltrimethylammonium (CTA) bromide via an intercalation technique to obtain hydrophobic organic clays. The as-made clay particles were further mixed with a PP/xylene solution; the latter was removed to obtain the final product of the CTA-clay/PP nanocomposite. An X-ray diffraction (XRD) analysis confirmed that there were no characteristic (001) diffraction peaks for CTA-Mica in the PP nanocomposites containing CTA-Mica, assuring the fact that the Mica layers could be completely exfoliated and thereby homogenously composited within the PP. On the other hand, the CTA-Mt and CTA-Ht incorporated composites had broader (001) peaks, which might have been due to the partial exfoliation of CTA-Mt and CTA-Ht in the composites. Among the three CTA-clay/PP nanocomposites, the CTA-Mica nanohybrid showed an enhanced thermal stability by ~42 °C compared to the intact host polymer matrix. We also noted that when the CTA-Mica content was ~9 mass % in the nanocomposites, the Young’s modulus was drastically maximized to 69%. Our preliminary results therefore validated that out of the three tested clay-PP nanocomposites, the CTA-Mica nanofiller served as the best one to improve both the thermal and mechanical properties of the PP nanocomposites.

Evaluation of Mechanical and Thermal Properties of Polypropylene-Based Nanocomposites Reinforced with Silica Nanofillers via Melt Processing Followed by Injection Molding

“…The PP employed herein is a homopolymer (HHR102) of a commercial grade in the form of pellets, with the following properties: melt flow index (MFR) of 2 g /10 min, density of 0.905 g/cm 3 , and melting temperature (T m ) of 168 • C. Silicon dioxide (SiO 2 ) or NS nanopowder (spherical and porous, Sigma-Adrich, South Africa), having a size range of 5-20 nm and molecular weight of 60.08 g/mol, was used.…”

“…The automotive industry has made remarkable improvements in the type of material employed for a specific application or targeted function to achieve a durable lightweight material [1]. Specific attention has been given to polypropylene (PP) due to its cost-effectiveness, recyclability, high strength, good physical properties, chemically resistant characteristics, and outstanding processability, which allow for filler incorporation and property improvement [2,3]. Also, PP is characterized by a density of about 0.905 g/cm 2 , which can contribute to fuel reduction in automobiles.…”

“…Much research on polymer nanocomposites has been focused on modified nanoparticles/fillers, the incorporation of larger amounts of the ideal filler, or leveraging the synergetic effects of dual filler systems to improve polymer matrix properties. Among the various modified strategies, the modification of hydrophobic organic clay (9% mica) with cetyltrimethylammonium bromide has shown an enhanced modulus and thermal stability of the PP matrix [3]. PP nanocomposites containing dual filler systems based on MgFeAl-layered double hydroxide (2.5%, 5%, and 7.5% LDH) cause catalytic degradation effects during melt processing [24].…”