Properties and compression morphological characteristics of hydrogenated nitrile rubber filled with nano-fillers

The performances of hydrogenated nitrile rubber(HNBR) filled with carbon black N 330,N 550,N 770,N 990,zinc dimethacrylate(ZDMA) and N 770/ZDMA were studied,and the filler dispersion,morphological change and their relationships with the compression set were analyzed by using the rubber process analyzer and transmission electron microscope(TEM).The results showed that the mechanical properties of the rubber decreased,and the Payne effect of the polymer reduced with the increase of the particle size of carbon black,that was the better the carbon black dispersed,the smaller the compression set was.The rubber filled with carbon black had better thermal aging resistance and oil aging resistance.Among them,HNBR filled with carbon black N 770 had the best all-round properties.When 30 phr carbon black N 770 and suitable level ZDMA were filled into the HNBR,the tensile strength and elongation at break of HNBR vulcanizates increased significantly,and the compression set also increased as the level of ZDMA increased,however,the Payne effect of vulcanizate had little change.TEM images indicated that the carbon black particles aggregated,and the distance between them got shortened after compressed for a long time under high temperature,but the particles themselves were not deformed.The compression set of HNBR vulcanizate filled with carbon black was basically due to the variations of molecular structures of the rubber,aggregation of carbon black particles and changes in their distribution.The dispersion of nano-fillers of poly-ZDMA in the HNBR was excellent.The polymer particles were easy to slip,deform and obviously aggregate,and their impediment to elasticity recovery of the macromolecular network was much higher than that of carbon black after compressed,so that the compression set was higher than that of carbon black filled HNBR.