Climate‐friendly polyurethane blowing agent based on a carbon dioxide adduct from palmitic acid grafted polyethyleneimine

Abstract

To explore a new blowing agent for polyurethanes (PUs), palmitic acid was grafted onto a branched polyethyleneimine (bPEI; weight-average molecular weight 5 25,000 Da) via N,N 0 -carbonyldiimidazole condensation to form a hydrophobically modified bPEI [palmitic acid grafted branched polyethyleneimine (C 16 -bPEI)] with a grafting rate of 12%. A CO 2 adduct of C 16 -bPEI, which trapped 16.8% CO 2 in it, was synthesized from C 16 -bPEI. The long alkyl chain grafting improved the dispersibility of the CO 2 adduct in the PU raw materials and favored a homogeneous release of CO 2 to blow PUs during the exothermic foaming process. The preliminary results show that the foams possessed a density of 72.0 kg/m 3 and a compressive strength of 246 kPa; this matched the required values of foams for the thermal insulation of underground steel pipes. This new blowing agent emitted nothing but CO 2 to the atmosphere, so it will not promote ozone depletion and will avoid global warming problems that are associated with traditional blowing agents such as chlorofluorocarbons and hydrochloroflourocarbons.

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

“…Grafting with alkyl or polyether chains onto PEI backbones can somewhat enhance the dispersibility of the consequent PEI-CO 2 adducts into PU raw materials. [14][15][16][17][18][19][20][21] Moreover, the side chain grafting can F I G U R E 7 Morphology of polyurethane (PU) foams blown using various blowing agents. The blowing agent type of the foams is indicated as in Figure 6.…”

“…10 In response to the concerns associated with traditional PU blowing agents, we have recently explored a series of CO 2 -releasing blowing agents based on the CO 2 adducts of hydrophobically modified polyethyleneimines (PEIs). [14][15][16][17][18][19][20][21] These CO 2 adducts are thermally instable and can absorb the polymerization heat of PUs to release CO 2 to blow the PUs. The hydrophobic modification facilitates the dispersion of the PEI-based CO 2 adducts into PU raw materials, which is a prerequisite for successful foaming.…”

“…Previously, solid CO 2 -adduct blowing agents were used to blow PUs. [14][15][16][17][18][19][20][21] This pioneering work could pave the way for the industrialization of environmentally friendly CO 2 adduct-based blowing agents.…”

In situ synthesis of CO2 adducts of modified polyethylenimines in polyether polyols for polyurethane foaming

“…Very recently, we developed a series of CO 2 adducts from polyethylenimines (PEIs) grafted with various hydrophobic side chains. [17][18][19][20][21][22][23] These adducts can release CO 2 to blow PUs by absorbing the polymerization heat of PUs, while almost not participating in the chemical reactions of PU formation. 23 The hydrophobic side chains can facilitate the dispersion of the CO 2 adduct blowing agents into the PU white component (i.e.…”

Carbon Dioxide Activation and Conversion by Hyperbranched Polyethylenimine/ZnI2 Catalysts

“…The most special property of the hyperbranched molecules is that they possess many functional groups which can multiply the numbers of adsorption and catalytic sites. , Moreover, hyperbranched molecules are attractive in their easy preparation owing to their absence of regular structure and high symmetry . Polyethyleneimine (PEI) which contained multiple amino groups (Scheme ) was widely used in gas adsorption, , gene delivery, self-healing flexible network hydrogel, and polyurethane foams. , Owing to the hyperbranched structure with multiple amino groups, PEI is possibly an ideal candidate for the reaction of epoxides and CO 2 .…”