In this study, hydrogenated acrylonitrile butadiene rubber (HNBR, ZETPOL-2010L) and nitrile butadiene rubber (NBR, NIPOL-DN4555) were blended at different ratios in a Haake melt blender at 130°C. The HNBR and the NBR were of very similar acrylonitrile content and Mooney viscosity. The melt miscibility and solid-state properties were investigated by rheological, thermal, and mechanical testing and scanning electron microscopy (SEM) techniques. The dynamic viscosity of the blends followed the log-additivity rule, while the flow activation energy closely followed the inverse additivity rule. On the other hand, the storage modulus showed synergistic effects at all compositions, suggesting the presence of emulsion morphology at both ends of the composition range. For the 50/50 HNBR/NBR blend, the SEM micrographs suggest a uniform elongated structure. The thermal analysis showed the presence of two glass transitions, representing the pure components, at all blend ratios, suggesting the absence of segmental miscibility of the blends. The small-strain mechanical properties such as tensile modulus and yield stress followed linear additivity. However, HNBR and HNBR-rich blends were observed to strain harden at a rate higher than that of NBR. Induced crystallization of HNBR was suggested to be the reason for the strain hardening. The different rheological, thermal, and mechanical testing techniques agree in suggesting that the structurally similar HNBR and NBR are not thermodynamically miscible but mechanically compatible. Polym. Eng. Sci. 44:2346–2352, 2004. © 2004 Society of Plastics Engineers.

Study of the miscibility and mechanical properties of NBR/HNBR blends

The thermomechanical modification of hy- drogenated nitrile butadiene rubbers (HNBR) of different molecular parameters was investigated by rheological and light scattering techniques. The influences of acrylonitrile content, degrees of hydrogenation, and Mooney viscosity were examined. A melt blender with Banbury-type mixing blades was used to condition the rubber samples in the temperature range from 190 to 260°C. Light scattering was used to determine the effect of conditioning on MW and hydrodynamic radius of the rubber molecules. Dynamic viscosity () and storage modulus (G) were measured for the as-received and conditioned samples. Experimental re- sults showed that degradation in these rubbers occurred through chain scission and crosslinking. Depending on the molecular parameter, it was found that one of these two mechanisms dominated the degradation process in most brands. Addition of adequate amounts of antioxidants (Ir- ganox 1010 and Irgafos 168) was successful only in prevent- ing degradation by crosslinking. Compared to thermal deg- radation, thermomechanical degradation was found to be much more severe and progressed at much higher rates. Rheology was found to be a very sensitive technique to structural parameters of the polymers and could be used to detect and identify the mechanism of degradation. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1432-1441, 2005

https://faculty.kfupm.edu.sa/che/ihussein/rehanjaps2005.pdf

Influence of molecular parameters and processing conditions on degradation of hydrogenated nitrile butadiene rubbers

Effects of gamma irradiation on poly(vinyl chloride)/polystyrene blends: Investigation of radiolytic stabilization and miscibility of the mixture

Rheological and morphological characteristics of polyvinylchloride/polychloroprene blends––effect of temperature and mixing speed

In this study, compatibility of butyl/ethylene-propylene-diene rubbers in different ratios was investigated byviscometric technique. For evaluating polymer compatibility, the parameters Δb suggested by Krigbaum&Wall, ΔB and μ that were suggested by Chee were calculated. Data obtained from viscometric study were used for preparing new compound recipe. Mechanical and rheological properties of the new compounds were measured and the changes in the properties before and after thermal aging were determined. Replacement of ethylene-propylene-diene rubber with butyl rubber in appropriate ratio improved the fatigue resistance of the vulcanizates. Improvement of dynamic mechanical properties of polymer blends is expected only in the case of blending compatible polymers in appropriate ratios. The compatibility of blends in different ratios has been studied by viscometric technique and mechanical measurements and obtained very similar results. It has been concluded that viscometric determination of butyl/ethylene-propylene-diene rubbers compatibility could be used as a simple technique for predicting the mechanical properties of the same rubber blend that was related with solid phase compatibility. POLYM. COMPOS., 31:1869–1873, 2010. © 2010 Society of Plastics Engineers.

Swapan Saha

Papers

Miscibility of polyvinylchloride and polychloroprene blends: Viscometric and light scattering studies of dilute solutions