The controlled preparation of secondary cells realizes the bimodal structure through two different pressure drop methods

The formation conditions of secondary cells are elaborated systematically for the first time by in-situ dynamic visualization with the LDPE/CO2 system, using through two different pressure drop methods (core-back and cooling contraction). Notably, a novel formation mechanism of secondary cells is proposed. Subsequently, experiments with different core-back distances are designed to realize pressure relief in two stages. The results show that the control of secondary cells realizes the bimodal structure through the control of pressure relief. The number of cells increases from 139 to 252 cells, and the size of cells decreases from 256.48 to 106.24 mu m, as well the core-back distance changes from 0.6 to 0.1 mm. These fundamental understandings will provide valuable guidance for the preparation of bimodal cells in microcellular injection molding.