Modelling of single bubble growth in carbon nanofibre filled mesophase pitch during carbonization

A single bubble growth model is presented for bubble growth in mesophase pitch during carbonization. This model is distinguished from typical polymer foaming models in its design to be used over a wider temperature range, its accounting for mass transfer from the liquid to the bubble, and the incorporation of reaction sites in the melt which produce volatile gases. The effect of nanofibre loading on growth is investigated in terms of viscosity, density and volatile concentration. It is found that the viscosity change is the controlling factor in altering the bubble growth rate in this system. Comparison with experimental data shows that a single bubble growth model is a reasonable assumption for carbon nanofibre loading of 1 wt% or below.