mostafa salehi - Institute of Polymeric Materials, Department of Polymer Engineering, Sahand University of Technology,
mostafa rezaei - Institute of Polymeric Materials, Department of Polymer Engineering, Sahand University of Technology,
Mahdi Salami hosseini - Institute of Polymeric Materials, Department of Polymer Engineering, Sahand University of Technology,

In foaming process, cellular structure is achieved by expansion of a blowing agent in polymer melt matrix. Upon sudden pressure drop of the system in the presence of physical blowing agent, bubble nucleation starts causing the bubble to grow as gas diffuses into the bubbles. The condition of a growing bubble especially number of neighborbubbles has dramatic effect of its growth behavior. In the present study, the bubble nucleation and expansionphenomena in Polystyrene/n-pentane batch foaming system was investigated for different bubble conditions. For thispurpose, a polystyrene sheet with thickness of 300μm was impregnated by n-pentane in certain saturation time and temperature and then by rapid pressure drop the foaming process was initiated and recorded using a stereo microscope equipped with a digital camera. It was observed that in the case of single growing bubble, the growth dynamics is only suppress by the diffusion of the blowing agent. But, in the presence of the neighbor bubbles, the growing adjacent bubble limited the growth of the bubble. The behavior of different bubbles with different neighboring condition were investigated and studied in details

Polystyrene, n-pentane, Visual Foaming, Foaming Dynamics, Solubility