Study On Preparation And Properties Of Sliding Graft Copolymer/Nitrile Butadiene Rubber Composites

Rrubber isolation bearing is the key part of the building and bridge. Lead core can effectively improve the damping property of rubber bearings, but there are some other problems, such as low self recovery capability, narrow bandwidth, high cost and environmental pollution. In this paper, a novel polymer-sliding graft polymer (SGC) was used. SGC as a high damping is added to the nitrile butadiene rubber (NBR) matrix to prepare the SGC/NBR composites. We studied the effect of SGC precrosslinked condition (temperature, time) and ratio on the microstructure, damping property and mechanical properties of the composites. Including the following aspects:(1) Crosslinked SGC shows excellent damping properties. Its damping performance is excellent which is tested by RPA.For example, the loss factor of the sample SGC is up to 0.3 under dynamic strain scanning and the loss factor is up to 0.7 in the 0.08-7Hz frequency scanning range. This can be attributed to the unique "pulley effect" of SGC. Under the action of "pulley effect", the crosslink points in SGC can slide along the main chain, which can cause the loss of energy and relieve the stress concentration effect in the process of sliding.(2) We studied the effect of SGC precrosslinked temperature on the properties of SGC/NBR composites. With the increase of SGC precrosslinked temperature, the damping propertie and the mechanical propertie of SGC/NBR composites increase first and then decrease. When the precrosslinking condition of SGC is 160?,3 h, the properties of SGC/NBR composites are optimized.(3) The effects of the amount of SGC on the damping and mechanical properties of SGC/NBR composites were studied, we can find that the microstructure of the two composites show obvious island structure. The size of the dispersed phase SGC in composite prepared by SGC only reach 500nm. With the increase of SGC, the damping property of the composite is gradually increased. The loss factor is increased from 0.08 to 0.24 under the strain scanning and the loss factor is increased from 0.15 to 0.26 in the 0.08-7Hz frequency scanning range. The tensile strength of the composites increased from 3.2MPa to 6.7MPa and the elongation at break increased from 328% to 418%.(4) The effects of the amount of precrosslinked SGC on the damping and mechanical properties of SGC/NBR composites were studied. With the increase of SGC, the mechanical propertie of SGC/NBR composites increase first and then decrease. In this process, there is a phenomenon of tensile orientation. When adding 20 phr of SGC, the mechanical properties of composites reach the optimal value. Its tensile strength reaches 8.1 MPa and elongation at break reaches 494%. SGC is a kind of high damping material, so the more SGC added, the damping effect of composite is more excellent. The loss factor is increased from 0.08 to 0.20 under the strain scanning, and the loss factor is increased from 0.15 to 0.28. in the 0.08-7Hz frequency scanning range. Contrast with (3), the damping properties of the composites which is prepared by precrosslinked SGC is basically unchanged, but the mechanical properties were significantly improved. The reason is that the crosslinking density of SGC after precrosslinked is improved, so the effect of the" pulley effect" is improved.(5) We prepared Poly cap rolactone (PCL)/NBR composite and studied its properties. With the increase of PCL, the damping property of the composites increases gradually. The loss factor is increased from 0.08 to 0.16 under the strain scanning, and the loss factor is increased from 0.15 to 0.23. in the 0.08-7Hz frequency scanning range. The tensile strength of the composites increased from 5.3MPa to 9.6MPa and the elongation at break increased from 338% to 371%.