Oil resistance controlled by phase morphology in natural rubber/nitrile rubber blends

Abstract

Rheological properties, morphology, and oil resistance in natural rubber (NR)/nitrile rubber (NBR) blends were investigated as functions of blending conditions and viscosity ratios of the blends. As for the blending condition effects, Mooney viscosity of the blends depended more strongly on blending time than rotor speed. Size of the NR dispersed phase was approximately independent of rotor speed but decreased with increasing blending time up to 25 min. As blending time further increased, NR dispersed phase size increased. The results of relative tensile strength, which is an indicator for oil resistance, in this study were in agreement with those of the blend morphology, indicating that the oil resistance in 20/80 NR/NBR blend depended strongly on the phase morphology of the blend. The smaller the size of NR dispersed phase was, the higher was the resistance to oil of the blend. However, a decrease in the size of the dispersed phase by the modification of the viscosity ratio via the use of low-molecular-weight rubber (i.e., liquid natural rubber and epoxidized liquid natural rubber) did not result in an improvement in the oil resistance.

Composite natural rubber based latex particles: a novel approach

“…However, a high proportion of synthetic rubber is normally required for the blending with NR in solid form for satisfactory improvement of oil resistance of NR [16], whereas the use of latex blending would consume less energy and time because there would be no need of mastication. We, therefore, studied the heterocoagulation involving agglomeration of small particles of polar rubber latex onto a large core NR particle.…”

Elastomer nanocomposites based on NBR/BR/nanoclay: morphology and mechanical properties

“…The tan δ peak intensity is weaker for both NBR and BR phases with increasing the nanoclay content. Higher degrees of falling trend are representative of better nanoclay dispersion within the elastomeric phase [1] . This effect is more intensively observed on NBR compared to BR.…”

“…As the dispersion state of fillers within the elastomer matrix has been always a challenging factor in achieving acceptable composite properties, several works investigating elastomer/filler interactions could be found in the literature. Sirisinha et al [1] studied the effect of two different carbon black grades (N330 and N660) and their dispersion on the microstructure and properties of NBR/BR elastomer blends with a 50/50 fixed component ratio. Callan and co-workers [2] suggested the effectiveness of several factors, such as compounding method, filler/ matrix interactions, rubber matrix polarity and its saturation level on the dispersion state of filler within the NBR/ BR blends.…”

Mechanical Properties and Swelling Behavior of Cross-Linked Natural Rubber/Chitosan Blends

“…[1][2][3] Natural rubber has excellent mechanical properties and heat resistance but poor solvent resistance. 4 Uncured rubber is sticky, can easily deform when warm, and is brittle when cold. In this state, it cannot be used to make articles with a good level of elasticity.…”