Effect of blowing agent on mechanical and thermal properties of natural rubber for sponge ball applications

The present work aims to examine the effects of azodicarbonamide (ADC) blowing agent on mechanical and thermal properties of natural rubber (NR) sponges by minimizing ADC loading that can be added. This was aimed to clean the slag originating in the condenser tube of the power plant factories by using the flexible sponge ball. The NR sponge with maximal loading of 15 phr of ADC was incorporated and the crosslinking propagation, the mechanical properties in terms of tensile strength, elongation at break and modulus together with the thermal characteristics were elucidated. It was found that the ADC accelerates effectively the vulcanization of the sponges, resulting in a decrease of cure and scorch times. The addition of ADC not only decreased the density of NR, but also decreased hardness, tensile strength, elongation at break and tensile modulus correlating to the increase of porous inside the NR matrix. The obtained properties were compared to the original ball tube received from the power plant. It was observed that the produced-NR sponge has better properties by means of tensile properties and also the dynamic properties during temperature ranges of -20 to 100 °C. The lower Tan δ is shown, while the Tg is increased. This refers to superior elasticity of NR sponge that is proper for cleaning condenser tube in power plant together with suitable pore size and shape designing.