Properties And Modification Of Hydrogenated Nitrile Rubber

NBR was hydrogenated in a 5 liter reactor by using a new Rh-Ru bimetallic complex catalyst developed in this lab. Some basic properties of the hydrogenated NBR(HNBR) obtained were compared with corresponding products from German Bayer corporation and Japanesse Zeon corporation. Results show that the vulcanizate of the HNBR has better tensile properties and heat-resistance, while other properties such as oil resistance, rheological property are similar.Liquid nitrile rubber(LNBR) was hydrogenated using the Rh-Ru bimetallic catalysts, and its degree of hydrogenation reached over 82%. For the first time, liquid hydrogenated nitrile rubber (LHNBR) was applied as a plasticizer in HNBR vulcanizates. Compared with HNBR plasticized with LNBR, LHNBR has higher tensile strength, elongation and heat resistance, and has less effect on vulcanization behavior of HNBR.HNBR was blended with EPDM and VMQ seperately, the result of DSC indicates that EPDM is compatible with HNBR to some extent. When blended with about 15% of EPDM, the low temperature property of HNBR can be improved, and the compression set is lowered as well, while some other properties such as hardness, tensile strength and oil-resistance are not significantly affected. Although the low temperature properties and heat-resistance of HNBR can be improved by blending with VMQ, the compression set is increased, and the tensile properties were deteriorated.The effection of vulcanization process and the recipe for HNBR vulcanizates on the low temperature properties and the compression set was studied. The compression set of HNBR or its covulcanizates can be reduced if it was post vulcanizated, and the low temperature properties were improved as well. When the amount of peroxide in HNBR vulcanizates is increased, the compression set can be decreased, but the glass transition temperature was increased, and the low temperature properties were deteriorated.Heat-resistance of HNBR and its covulcanizates are studied by thermogravimetric method, and some kenetic parameters were calculated. HNBR or its covulcaniates have good heat-resistance if it had higher activation energy in decomposition reaction.Percolation model can be used for analyzing the phenomenon of significant change of the tensile strength of HNBR covulcanizates versus its composition schematically, and the model was simulated with computer by Monte Carlo methed.