VATIS UPDATE Article

Researchers at School of Chemical and Biological Engineering, Seoul National University and Korea University, Republic of Korea, investigated the effects of liquid-type additives on the morphology, thermal conductivity, and mechanical strength of polyurethane (PUR) foams. The PUR foams synthesized with perfluoroalkane showed a smaller average cell diameter and a lower thermal conductivity than PUR foams prepared with propylenecarbonate or acetone.

The average cell diameter of the PUR foams decreased from 228 to 155 μm and the thermal conductivity decreased from 0.0227 to 0.0196 kcal/mh °C when the perfluoroalkane content was 0.0 to 2.0 php (parts per hundred polyol by weight). The perfluoroalkane likely acted as a nucleating agent during the formation of the PUR foams. The addition of perfluoroalkane induced the smaller cells size of the PUR foams probably due to lower surface tension of the polyol and perfluoroalkane mixture, resulting in high nucleation rate.

The smaller cell size appears to be the main reason for the improvement in the thermal insulating and the mechanical properties of these PUR foams. The compressive strength of the PUR foams prepared with perfluoroalkane was higher than the PUR foams prepared with the propylenecarbonate and acetone. Based on the morphology, thermal conductivity, and compressive strength, researchers suggested that the perfluoroalkane is an efficient liquid-type additive for the improving the thermal insulation of PUR foams.