Low-density polyethylene (LDPE) foams blown with CO₂ typically present severe shrinkage problems, which makes them have to be produced by using hydrocarbon as the blowing agent. In this work, we first clarified the characteristics in foaming LDPE with various pure gases (N₂, CO₂, and i-C₄H₁₀). The foaming behavior of the pure gases showed that i-C₄H₁₀ was weak in cell nucleation, N₂ in cell growth, and CO₂ in dimensional stability. Every gas type was very weak in one aspect (cell nucleation, cell growth or dimensional stability) but strong in the other two. To solve the problems of pure gas foaming, CO₂ - N₂ mixtures were proposed as the blowing agent to foam LDPE. The results showed that the CO₂ - N₂ mixture could not only produce a synergistic effect on cell nucleation, but also effectively solve the shrinkage problem of LDPE foams, which could completely eliminate the safety risks and time-consuming aging period.

用CO ₂吹制的低密度聚乙烯（LDPE）泡沫通常会出现严重的收缩问题，这使得它们必须通过使用烃作为发泡剂来生产。在这项工作中，我们首先阐明了使用各种纯净气体（N ₂，CO ₂和i -C ₄ H ₁₀）发泡LDPE的特性。纯气体的发泡行为表明，i -C ₄ H ₁₀在细胞核中弱，在细胞生长中N ₂和CO ₂弱。在尺寸稳定性方面。每种气体在一个方面（细胞成核，细胞生长或尺寸稳定性）都非常弱，而在另两个方面则很强。为了解决纯气体发泡问题，提出了将CO ₂ -N ₂混合物作为发泡LDPE的发泡剂。结果表明，CO ₂ -N ₂混合物不仅可以对泡孔形核产生协同作用，而且可以有效解决LDPE泡沫的收缩问题，可以完全消除安全隐患和费时的老化时间。