Homogeneous polyurethane foaming systems containing polyester diol, ethylene glycol, and alkylated polyethylenimine‐CO2 adducts

Abstract

AbstractCO2 adducts from alkylated polyethylenimines (PEIs) in powder form are newly developed blowing agents for polyurethanes (PUs) to replace the ozone‐depleting and/or global warming halogen‐containing blowing agents. However, they are difficult to disperse into the raw materials of PUs. Herein, we explored reactive solvents for alkyl‐grafted PEI‐based CO2 adducts (xCn‐PEI‐CO2s, whose alkyl carbon number n = 4, 8, or 12 and grafting rate x = 5%, 10%, or 15%) and found that the most effective solvent was ethylene glycol (EG), with solute mass concentrations exceeding 50%. According to this, we designed homogenous foaming systems for PUs, containing poly(ethylene‐co‐diethylene glycol adipate)diol, EG, and different xCn‐PEI‐CO2 blowing agents, with mass percentages of 85, 11.25, and 3.75, respectively. The xCn‐PEI‐CO2 blowing agents in the ternary mixture could effectively blow PUs, with densities ranging from 210 to 240 kg/m3. The addition of 0.1 g of water as an extra blowing agent reduced the densities down to 110 kg/m3, compared with the 140 kg/m3 density of the control foam blown solely by water. The liquid status of the ternary foaming mixtures and their cooperative performance with water to blow PUs could enhance the suitability of the climate‐friendly xCn‐PEI‐CO2 blowing agents in PU foam industry.