I have prepared Natural rubber- Multiwall CNT composite with weight % ratio of 99:1. But it is highly flexible. Now i want to improve its stiffness at minimum level. So what material should i add with this composite?
Stiffness of rubber products is directly related to its hardness.. 1% MWNT loading in NR is pretty low. Increase hardness by adding inert fillers (calcium carbonate etc.) or functional fillers like carbon black, silica etc.
Carbon black will increase thermal conductivity. If you want to use silica I recommend to use additional a functional silane as adhesion promoter like silane Si 69, (MeO)3Si-CH2-CH2-CH2-SSSS-CH2-CH2-CH2-Si(OMe)3. But there are also organic additives which improve hardness like Rhenosin A from RheinChemie, a mixture of novolak and hardener. Rhenosin A can be used alone or in combination with carbon black or silica. Perhaps a combination of silica, Si 69 and Rhenosin A is the optimum.