Organoclay–natural rubber nanocomposites synthesized by mechanical and solution mixing methods

Abstract

This investigation describes two methods to obtain rubber composites based on natural rubber (NR) and organophilic layered silicates. In order to improve the exfoliation and compatibilization of the organoclays with the rubber matrix, a new approach which involves swelling of the organoclays with an elastomer solution prior to compounding has been used. The effect of the addition during swelling of a coupling agent, namely bis(trietoxysilylpropyl)tetrasulfan (TESPT), on the behaviour of the composites was also investigated. The results show that a low amount of organoclay (10 phr) significantly improves the properties of natural rubber. This suggests a strong rubber-organoclay interaction which is attributed to a high degree of rubber intercalation into the nanosilicate galleries, as was confirmed from X-ray diffraction. In addition, an ulterior improvement in the properties of the nanocomposites prepared by solution mixing is clearly observed, due to the better filler-rubber compatibility. An even further increase in the properties is observed by treating the silicate with a silane coupling agent. The silane functional groups modify the clay surface, thus reducing the surface energy, and consequently improving the compatibility with the rubber matrix.

Preparation and properties of natural rubber/organo-montmorillonite: from lab samples to bulk material

“…In order to achieve the desired dispersion of nanofillers, various methods for obtaining elastomeric nanocomposites, similar to those applied for thermoplastics-based nanocomposites, have been used, such as solution mixing [15][16][17], latex compounding [18][19][20] and melt mixing [21][22][23][24]. Among these, melt mixing is the most widely used due to its simplicity and potential industrial applicability.…”

Rubber‐Clay Nanocomposites

“…A reduction of the activation energy for sulphur based NR crosslinking was found by using a bentonite modified with octadecylamine chloridrate [83,88]. OC could thus present a warning, as they could lead to premature scorching but, at the same time, they could present the chance of performing vulcanization reactions at lower temperatures.…”

Fabrication and Characterization of Nanostructured Polymer Composites Prepared by Melt Compounding

“…On the other hand the repulsion between clay layers facilitates the entrance of polymer chains into the galleries of silicate Very recently, increasing attention has been paid on rubber/clay nanocomposites (RCNs). According to reports, Several RCNs based on one or two elastomers has been prepared via solution intercalation, melt intercalation, and rubber-latex compounding [6] - [15]. But to our knowledge, no studies have been published on NR/BR nanocomposites prepared by melt intercalation in the literature.…”

“…Rheological properties of nanocomposite materials is a great of interest and has been investigated by several researchers [2], [6], [8], [9]. The complex viscosity (η*) and elastic modulus (G') of prepared samples are shown in Fig 4. As seen, complex viscosity of prepared samples in sensibly higher than that of pure NR/BR.…”

“…When nanolayers have been exfoliated, the improvement in properties can be seen as an increase in tensile properties, as well as enhanced barrier properties, decreased solvent permeability, and increased thermal stability and flame retardance. [6], [7].…”