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.

Self-foaming polymers: Opportunities for the next generation of personal protective equipment

“…Figure 9: Ionic carbamate salts for the preparation of (a) epoxy (Adapted with permission from [56]. Copyright (2015), American Chemical Society) and (b) PU foams (Adapted with permission from [146] Copyright (2019) Wiley Periodicals, Inc).…”

From gas release to foam synthesis, the second breath of blowing agents

“…127 However, Da et al presented the synthesis of a PU foam using both primary and secondary carbonated amines. 128 They notably discussed the effect of the steric hindrance on the secondary amine and reported that primary amine was more difficult to decarbonate at 100°C. The carbon dioxide is an interesting gas to produce since it is non-toxic and non-flammable.…”

Carbon dioxide adducts from DOPO‐grafted polyethylenimines as both blowing agents and flame retardants for polyurethanes

“…Previous undertakings have demonstrated that highly dispersible modified PEI-CO 2 blowing agents can facilitate the formation of PUFs with small cells. 26,28,34…”

“…We have successfully prepared hydrophobically modified polyethylenimines (PEIs), which can absorb CO 2 and then release CO 2 as a climate friendly blowing agent during the PU foaming process. [26][27][28] In this study, we adopted the Atherton-Todd reaction 29,30 to graft DOPO onto PEI backbones, and used the grafted PEIs to absorb CO 2 , obtaining a new kind of CO 2 adducts of PEIs that might serve as both blowing agents and flame retardants for PUs. The effects of the grafting rate on foaming process, mechanical properties and flame retardancy were investigated.…”