Polyurethane foaming with CO2 adducts from C8 alkyl grafted polyethyleneimines: Optimization of the grafting rate and application of the blowing agents

ABSTRACT We previously explored a series of CO2 adducts from alkylated polyethylenimines with C4 to C16 alkyl side chains, serving as climate‐friendly blowing agents for polyurethanes (PUs). Among them, the polyethylenimine with C8 alkyl (2‐ethylhexyl) side chains demonstrated the highest foaming efficiency. In this study, we further changed the grafting rate of the C8 alkyl, from 7 to 16%, and investigated the effects of the resulting blowing agents on the foaming process. For both foaming systems containing a castor oil‐derived polyol (Polycin T‐400) or a poly(propylene glycol) polyol (Polyether 4110), the CO2 adducts with a grafting rate of 13% displayed the best foaming performance in terms of high dispersibility in the foaming systems, homogenous cellular morphology, and good mechanical properties. Moreover, the 13%‐C8‐alkylated blowing agent demonstrated high suitability for the foaming systems from biomass‐sourced polyols (like Polycin T‐400). Therefore, the optimized CO2‐adduct blowing agent could replace the currently used climate‐changing hydrochlorofluorocarbons and hydrofluorocarbons, as well as might contribute to the development of future renewable PU foams. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48752. The blowing agent with a grafting degree of 13% displays the best foaming performance and is suitable for foaming systems with biomass sourced polyols