CO₂ adducts from hydrophobically-modified polyethylenimines (PEIs) in powder form are newly-developed environment-friendly blowing agents for polyurethanes (PUs). However, they are difficult to disperse into foaming systems that usually contain polyether polyols as the PU soft segments. Herein, we employ mixtures of di(propylene glycol) monomethyl ether-grafted polyethylenimines (DPG-PEIs) and poly(propylene glycol) (PPG) polyols to absorb CO₂, with in situ formation of the CO₂ adduct particles as PU blowing agents. Their CO₂ saturation degrees, revealed by thermogravimetry, scatter in the range of 93–98%. The DPG side chains tend to be exposed at the particle–matrix interface to stabilize the particles. In addition, some PPG oligomers in the matrix might entangle with the CO₂ adduct macromolecules during the in situ particle formation. The entangled PPG chains could further stabilize the suspending particles. The high grafting rate and high molecular weight of the PEI backbones could result in small particles, which largely thicken the foaming systems. The optimized blowing agents, with grafting rates between 5% and 8% and PEI backbone molecular weights not higher than 10k Da, show particle sizes from several hundreds of nanometers to ∼1 μm. The resultant foams demonstrate densities below 50 kg/m³ and compressive strengths over 200 kPa, comparable to the values from industrial foams. This in situ CO₂ adduction has potential as a universal method suitable for PU foaming at an industrial scale.

粉末形式的疏水改性聚乙烯亚胺（PEI）的CO ₂加合物是新开发的环保型聚氨酯（PU）发泡剂。然而，它们难以分散到通常包含聚醚多元醇作为PU软链段的发泡体系中。在这里，我们采用二丙二醇单甲醚接枝的聚乙烯亚胺（DPG-PEIs）和聚丙二醇（PPG）多元醇的混合物吸收CO ₂，并原位形成CO ₂加合物颗粒作为PU发泡剂。 。他们的CO ₂通过热重法显示的饱和度分散在93–98％的范围内。DPG侧链倾向于在颗粒-基质界面处暴露以稳定颗粒。另外，在原位颗粒形成期间，基质中的一些PPG低聚物可能与CO ₂加合物大分子缠结。缠绕的PPG链可以进一步稳定悬浮颗粒。PEI主链的高接枝率和高分子量可能会导致小颗粒，从而大大增加发泡系统的稠度。优化的发泡剂的接枝率在5％至8％之间，PEI主链分子量不超过10k Da，其粒径范围从几百纳米到约1μm。所得泡沫的密度低于50 kg / m ³和超过200 kPa的抗压强度，可与工业泡沫相比。这种原位CO ₂加成物有潜力作为适合工业规模PU发泡的通用方法。