Study on the Aging Behavior of Natural Rubber/Butadiene Rubber (NR/BR) Blends Using a Parallel Spring Model

Abstract

Natural rubber/butadiene rubber (NR/BR) blends are widely used in industrial areas for absorbing vibrations and shocks because of their excellent elastic stability. However, when an industrial-equipment surface is exposed to sunlight and oxygen over a long period of time, the rubber hardens. As a result, the tensile properties of the rubber material and the behavior of the strain-energy density function are changed, greatly reducing the performance of the rubber product. However, only a few experimental studies on the aging characteristics of NR/BR blends are available, and it is difficult to find a study that analyzes the organic relationship of the changes in the mechanical (stress-strain curves, strain-energy density, etc.) and chemical (cross-linked structure, crosslink density, etc.) properties. In this study, a swelling test was performed on an aged rubber compound, and the result was substituted into the Flory-Rehner equation to obtain the quantitative crosslink density. The results revealed a linear relationship between the strain-energy density (SED) and the crosslink density (CLD) when the cross-linked structure increase was represented by a parallel spring model. Finally, the relationship between the strain-energy density and the crosslink density was summarized as a formula, and a method for predicting the aging behavior of NR/BR blends using the crosslink density was proposed.

A Statistical Analysis on the Effect of Antioxidants on the Thermal-Oxidative Stability of Commercial Mass- and Emulsion-Polymerized ABS

“…These authors also verified that the emulsion-polymerized ABS showed better thermal stability, and associated these results with the presence of a cross-linked network in the PB fraction, which is expected to promote a reduction in the free volume and oxygen diffusion [22,23]. Such PB crosslinking also occurs during aging and processing forming gels; however, the addition of AOs can improve the stability, reducing crosslinking [14,24].…”

Preparation and Characterization of Rubber Blends for Industrial Tire Tread Fabrication

“…For composites with one matrix system, only the calculated interaction parameter (χ 1 ) of that matrix is used in the estimation of its crosslinking density (N) [28,29]. Researchers have adopted the use of the mixtures rule [30] for blend systems or a method of averaging χ 1 for each the polymer involved to compute the N of composites with many matrix phases [18,20,31]. In this present study, we also adopted the latter method of averaging χ 1 for the blend systems, for the computation of their respective N values.…”

Silica‐filled NR compounds prepared by dry and wet masterbatches with different mixing times

“…where β 1 is the lattice constant, usually 0.34, δ r is the solubility parameter of NR (8.12 [cal/cm 3 ] 1/2 ), and δ s is the solubility parameter of toluene (8.97 [cal/cm 3 ] 1/2 ). [32][33][34] The tensile properties of DNR and WNR compounds were determined from their strain-stress curves recorded using a universal tensile tester (Daekyung Co., DUT-500C) at ambient temperature with a crosshead speed of 500 mm/min according to ASTM D 412. Four dumbbelltype samples were used for each measurement.…”