الفهرس 
Effect of Type, Concentration, and order of Addition of Nano-Sized Carbon Black on some Physical Properties of Natural Rubber Composites
AbstractOnly 14 pages are availabe for public view
 |  | from | 137 |  |  |
| | | from | 137 | | |
Abstract
Different composites of natural rubber (NR) which are loaded with 60 phr (around the critical concentration) of three types of carbon blacks (CBs) namely; N220, N326, and N774 have been prepared according to the standard technique. The temperature dependence of the electrical conductivity of 60 phr- loaded CB/NR composites show different conduction mechanisms (hopping or tunneling) compared to that of the pure NR sample which exhibits the normal thermally activated behavior. The results of mechanical tests show that, sample N220/NR exhibits the higher tensile strength, modulus of elasticity, abrasion resistance, and hardness than the other samples. After that we focus on the effect of the order of addition of three types of CBs on the conduction mechanisms and mechanical properties. For this, the 60 phr of CB was divided into three equal parts, each of which represents one type of CBs. The results of this order of addition do not show remarkable changes which lead us to reduce the total concentration to 30 phr (around the percolation threshold). A theoretical model has been suggested to explain the obvious changes of electrical conductivity upon the order of addition of these types of CBs