Effect of temperature and molecular weight on the rate of spreading of polystyrene melts on plane soda lime glass surfaces

The effect of temperature T and weight-average molecular weight M?_w on the rate of spreading of polystyrene melts on plane solid surfaces has been examined. The activation energy E of spreading was estimated to be 25.2 ± 3 kcal/mole, which is of the same magnitude as the activation energy for flow of polystyrene melts. The rate of spreading was found to be inversely proportional to M?_w raised to the 1.5 power. This rate of spreading, measured as the time rate of increase in the liquid–solid contact area, dA/dt, could be expressed as where γ_1v is the melt surface tension and θ_d and θ_s are the dynamic and static contact angles, respectively. The numerical value of K has been calculated to be (6.025 ± 3.693) × 10^?14 in the temperature range of 110–260°C and for the values of M?_w from 2000 to 37000.