Effects of Curing Agent and Carbon Black Filler Loading on Carbonization Behavior of Phenolic-Carbon Black Composites

The effects of curing agent (p-toluene sulfonic acid, PTSA) concentration, i.e., 1.0, 1.5, 2.0, 2.5, and 3.0 wt% on neat phenolic resin (in absence of carbon black) were investigated through the measurement of density, weight loss, linear shrinkage, and mechanical properties under compression mode to understand the carbonization behavior of carbon-carbon composite. The study was carried out after curing, postcuring, and carbonization. Also, thermogravimetric analysis was used to study the effects of curing agent concentration on thermal stability and kinetic parameters (i.e., activation energy, order of decomposition, pre-exponential term, etc). The kinetic parameters were evaluated by using four single heating rate techniques namely Friedman, Coats-Redfern, Freeman-Carroll, and Chang methods. Further, to study the effects of both carbon black filler loading and carbonization temperature, phenolic-carbon black composites were prepared at the loading of 10, 20, 30, 40 wt% using 1.5 wt% of PTSA. These were also investigated through density, weight loss, and shrinkage measurements after curing, postcuring, and carbonizing at the temperature of 600, 1000, and 1400 degrees C in nitrogen atmosphere. To analyze the evolution of carbon phase X-ray diffraction study was carried out for the carbonized samples. Finally, cured, postcured and carbonized composite samples were subjected to compression tests to study the compression strength and modulus. POLYM. COMPOS., 31:2069-2078, 2010. (C) 2010 Society of Plastics Engineers