Dynamic Mechanical Analysis and Elastic Recovery Behavior of Carbon Black/NBR Co-reinforced with Precipitated Silica and Sillitin for Hydraulic Applications

Abstract

This work studied dynamic mechanical thermal properties and elastic recovery behavior ofsilica based fillers in acrylonitrile-butadiene rubber (NBR) for hydraulic applications. The effect of silicabased fillers, including sillitin and precipitated silica with silane surface treatment, on the properties wasstudied. The loading of the fillers used ranged from 0 to 50 parts per hundred rubber (phr) added into theNBR containing 50 phr carbon black as main reinforcement filler, and 10 phr aromatic oil filled NBR wasinvestigated. The shape and particle size were characterized by Fourier Transform Infrared spectroscopy(FT-IR), X-Ray Fluorescence spectroscopy (XRF) and Scanning Electron Microscope (SEM). The scorchtime, cure time, and mechanical properties; compression set and dynamic mechanical thermal propertieswere of our main interests. The experimental results suggested that the addition of silica based fillers inthe NBR vulcanizates had no effect on scorch time and cure time. The silitin gave better compression setproperties of the carbon black/NBR vulcanizates than the precipitated silica. In addition, the vulcanizateswith precipitated silica filler had higher storage modulus and lower tan delta values than those with thetreated silitin. The glass-transition temperature of the NBR with precipitated silica was higher than thatwith sillitin. Finally, under the actual dynamic hydraulic test for seals, the selected NBR vulcanizates filledwith precipitated silica and sillitin were produced in form of U-CUP seals and the results suggested thatthe properties of the seals produced in this work were comparable with the commercial seal product.

Keywords : Compression Set / Silica / NBR Rubber / Dynamic Mechanical Thermal Analysis