Properties of Rigid Polyurethane Foams Blown by HFC-365mfc and Distilled Water

Properties of Rigid Polyurethane Foams Blown by HFC-365mfc and Distilled Water

Rigid polyurethane foams (PUFs) were prepared from polymeric 4,4-diphenylmethane diisocyanate (PMDI), polyether polyol, silicone surfactant, amine catalysts, and hydrofluorocarbon (HFC-365mfc) and distilled water as blowing agents. The density and compressive strength of the PUF samples were decreased with the increase of the blowing agent. This is mainly due to that the cell size of the PUF samples is increased with the increase of blowing agent. From the result of the effect of blowing agents on the thermal conductivity of the PUF samples, it was observed that, when the amount of the distilled water was fixed, the thermal conductivity of the PUF samples decreased with the increase of the amount of HFC-365mfc. Also, when the amount of HFC-365mfc was fixed, the thermal conductivity of the PUF samples decreased with the increase of the amount of distilled water. From the results of thermal conductivity of PUF samples, it is suggest that the thermal conductivity of the PUF samples depends on the thermal conductivity of blowing agent as well as the total amount of the entrapped blowing gas inside the closed cell of the PU foams. Also, PU foams blown by mixed blowing agent such as HFC-365mfc and distilled water may increase in the structural stability of the PU foams by matching of the rates of gelling and foaming reactions for the formation of desired foams compared the PU foams blown by HFC-365mfc or distilled water alone.

Rigid polyurethane foams (PUFs) were prepared from polymeric 4,4-diphenylmethane diisocyanate (PMDI), polyether polyol, silicone surfactant, amine catalysts, and hydrofluorocarbon (HFC-365mfc) and distilled water as blowing agents. The density and compressive strength of the PUF samples were decreased with the increase of the blowing agent. This is mainly due to that the cell size of the PUF samples is increased with the increase of blowing agent. From the result of the effect of blowing agents on the thermal conductivity of the PUF samples, it was observed that, when the amount of the distilled water was fixed, the thermal conductivity of the PUF samples decreased with the increase of the amount of HFC-365mfc. Also, when the amount of HFC-365mfc was fixed, the thermal conductivity of the PUF samples decreased with the increase of the amount of distilled water. From the results of thermal conductivity of PUF samples, it is suggest that the thermal conductivity of the PUF samples depends on the thermal conductivity of blowing agent as well as the total amount of the entrapped blowing gas inside the closed cell of the PU foams. Also, PU foams blown by mixed blowing agent such as HFC-365mfc and distilled water may increase in the structural stability of the PU foams by matching of the rates of gelling and foaming reactions for the formation of desired foams compared the PU foams blown by HFC-365mfc or distilled water alone.