Effect of halloysite nanotubes and organically modified bentonite clay hybrid filler system on the properties of natural rubber

Abstract

<jats:p> The versatility and potential have framed natural rubber (NR) nanocomposites as the focal point in the polymer research field and industry. Currently, NR nanocomposites filled with hybrid nanostructures is an interesting area than single filler or conventional filler systems. Halloysite nanotube (HNT) and bentonite clay are well-studied potential fillers of polymers. This work is an attempt to study the effect of hybrid filler system of HNT and organically modified bentonite nanoclay (NC) in the properties of NR. NR/HNT-NC systems with varied filler concentrations were prepared in a two-roll mixing mill. Properties such as cure characteristics, morphology, mechanical, thermal, and transport behavior were analyzed in detail. The prepared composites had better wear properties than gum vulcanizates. Improvement in physical properties was observed due to the increased contact surface area between the filler and the matrix. The nanocomposite with 2 wt% hybrid filler shows a 31% decrease in abrasion loss compared to neat NR composite. Apparently, 4 wt% of hybrid filler could improve modulus at 300% strain and tear by approximately 57% and 14%, respectively. The ability to withstand high strain was evident from the improved crack growth resistance as observed in micrographs. Lorenz–Park plots were employed to analyze the rubber–filler interaction. The activation energy of thermal degradation was calculated using Coats–Redfern equation. </jats:p>

Flame‐retardant behavior and mechanism of theSBR/MMTcomposites modified by melamine matrix modifier

“…The Bragg equation was used to calculate the d‐spacing of the modified clay. The increase in d‐spacing supports the intercalation of modifier molecules between nano‐clay flakes 11,14 . The distance between the MMT lamellae increased from 1.89 to 2.26 nm, indicating that the MQAS modifier has successfully entered the silicate layer of the MMT, and the MMT has been peeled off to a certain extent 8,38 .…”

“…The flame‐retardancy of the polymer were improved because of the uniform dispersion of nanofillers and the good interface compatibility between the filler and the matrix 11 . The rubber processing analyzer test can be used study the chain mobility and behavior under various stress, temperature, and conditions to reveal the interaction between the matrix and the filler 37 .…”

“…However, when the frequency exceeded 10.0 Hz, the network structure was completely destroyed, the molecular chain friction increased, and tan δ increased. In comparison with the pure SBR and SBR/FOSM, the SBR/MMT composite had the highest tan δ , because the agglomeration of the MMT powders in the matrix increased the internal voids, pores production, and molecular chains mobility 11 . Losses occurred when polymer chains slide against each other or through the fillers 9 .…”

“…Montmorillonite (MMT) is a kind of layered silicate clay for rubber fillers because of its high specific surface area, high cation exchange capacity, and good mechanical stability 8,9 . The remarkable enhancement of the mechanical properties and thermal stability of composites is attributed to the dispersion of MMT in the rubber matrix 10–12 . However, the presence of active hydroxyl and alkoxy functional groups on the nanofiller makes it inherently acidic and hydrophilic, resulting in poor polymer‐filler interaction between the rubber hydrocarbon and the nanofiller 13 .…”

Mechanical and rheological properties of partial replacement of carbon black by treated ultrafine calcium carbonate in natural rubber compounds

“…The difference between these constants reveals the excellent matrix load interaction and synergism between loads [52]. According to Lorentz and Park [52], constant values greater than 0.7 indicate "a" strong interaction of calcium carbonate with rubber, making it di cult for solvent to penetrate the composite.…”