A direct method for evaluating polymer foamability

In this study, we proposed a direct method to rapidly evaluate polymer foamability by using a new self designed foaming apparatus with nitrogen (N2) as a blowing agent. Two parameters, the foaming temperature window and the correlation factor of the foam density with foaming temperature were used to characterize the foamability. Low density polyethylene (LDPE) and linear low density polyethylene (LLDPE) resins were selected as samples to compare their foamability. The results showed that LDPE had a foaming temperature window as wide as at least 52 °C, whereas that of LLDPE was only 8 °C. Moreover, the foam density and cell morphology were insensitive to foaming temperature for LDPE but sensitive for LLDPE. The inherent capability of LDPE for gas foaming was much better than that of LLDPE.