Manipulation of mechanical properties of short pineapple leaf fiber reinforced natural rubber composites through variations in cross-link density and carbon black loading

ABSTRACT Replacing synthetic fillers, which are commonly used to reinforce rubber, with bio-fillers has potential to improve the sustainability of rubber products. Eggshell (ES) (a powder with a maximum particle diameter of 9.4 μm and a median of 1.1 μm) was added to guayule natural rubber (GNR) composites to partially or fully replace bifunctionally silanized, high surface area, precipitated silica (BSS). The mixing energy consumption, mechanical properties, cross-link density, filler dispersion and final particle size, fracture surface morphology, and dyeability of GNR composites were characterized. ES filler effectively reinforced vulcanized GNR compared with unfilled vulcanized GNR. Energy consumption, modulus at 300% strain (M300), and hardness generally decreased with increasing ES fraction (decreasing BSS), but tensile strength, gel fraction, and elongation at break increased even where cross-link density and M300 were similar. Thus, composite cross-link density was not solely influenced by silane content as the ratio and loading of ES and BSS changed. The production of the composites reduced particle size to submicron size. Even a small amount of ES improved the dispersion of BSS filler particles in the composites and hence the mechanical properties. The contributions of the two fillers to the composite properties are explained. Linear mixed models were built to predict the mechanical properties of a broader range of GNR–ES–BSS composites, and r2 (the quality of the model predictability) was above 0.9 for all models. ES filled GNR, with or without BSS, can be dyed different colors for specific applications. The lower-cost, renewability, dyeability, and excellent performance of ES–GNR composites addresses the need for sustainable rubber products with low carbon footprint.

Download Full-text

Impact of a nanomixture of carbon black and clay on the mechanical properties of a series of irradiated natural rubber/butyl rubber blend

e-Polymers ◽

10.1515/epoly-2021-0051 ◽

2021 ◽

Vol 21 (1) ◽

pp. 662-670

Author(s):

Dalal M. Alshangiti

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Carbon Black ◽

Natural Rubber ◽

Theoretical Models ◽

Butyl Rubber ◽

Clay Nanoparticles ◽

Vinyl Silane ◽

Link Density ◽

Cross Link Density

Abstract A series of natural rubber/butyl rubber NR/IIR blend loaded with N660 carbon black (CB) and triethoxy vinyl silane treated clay nanoparticles (TCNPs) were prepared using gamma irradiation in the presence of a polyfunctional monomer, trimethylolpropane triacrylate (TMPTA). The effect of incorporating different contents of N660 CB and five parts per hundred of rubber (phr) of treated clay on the mechanical properties of the prepared nanocomposites has been investigated. The addition of TCNP to CB/rubber composites markedly increase their tensile strength due to the increase of the cross-link density. These results indicated that the TCNP may be enclosed or trapped in the occluded structure of CB. The effect of CB and the TCNP content on the tensile strength (σ), elongation at break (ε b, %), and modulus of elasticity (E, MPa) of natural rubber/butyl rubber NR/IIR blend have been investigated. The incorporation of 5 phr of TCNP into 30 phr CB-loaded NR/IIR composites results in the increased tensile strength value by about 60%. Finally, theoretical models were used to interpret the experimental results.

Download Full-text