Visualization observation of cells growth in low-density polyethylene foaming processes

Low-density polyethylene (LDPE)/p, p-oxybis (benzenesulfonylhydrazide) (OBSH) system was carried out to investigate the cell growth during foaming process with a visualization apparatus at a constant temperature. The results showed that the cells growth of LDPE foams follows the Logistic function with a higher correlation coefficient of 0.96738. Here, a method was adopted to establish the relationships between cell growth and foaming process with first and second derivatives of cell mean diameter vs. time, which reflected the cells growth rate and driving force during cell growth, respectively. Moreover, we elucidated the interactions of cells growth at less-foamed, better-foamed and over-foamed stages were asymmetric during foaming process, which resulted from the greater cells deformation. This revealed the method in describing cells growth provided a visual comprehension of the mechanisms for foaming process.