The effect of the molecular architecture of a series of anionically synthesized linear and comb atactic polystyrenes (PS) on their foam properties including cell size, cell density, and volume expansion ratio (V.E.R.) was investigated. The comb-PS had the same molecular weight of the backbone, M_w,bb ≈ 290 kg/mol, Z_bb ≈ 20 entanglements, and branches, M_w,br ≈ 44 kg/mol, Z_br ≈ 3 entanglements, but different numbers of branches, 3 ≤ N_br ≤ 190. Batch foaming of well-purified linear and comb-PS using CO₂ resulted in cell densities about 10⁹ and 4 × 10⁹ cell/cm³, respectively, which shows that LCB has no distinct effect on the cell density, whereas a small amount of residual impurity in linear PS reduced the cell density to ∼10⁸ cell/cm³. For a comb-PS series with the same entangled backbone, M_w,bb ≈ 290 kg/mol, Z_bb ≈ 20 entanglements, and similar branches, M_w,br ≈ 44 kg/mol, Z_br ≈ 3 entanglements, but different numbers of branches, 3 ≤ N_br ≤ 190, an increase in the N_br to 120 with densely grafted comb conformation gradually increased the highest achievable V.E.R. close to a theoretical limit given by the CO₂ solubility. The further increase of N_br to 190 with a bottlebrush conformation reduced the V.E.R. of the foam. From a rheological point of view, this optimum N_br was related to a comb-PS which showed the maximum strain hardening factor (SHF ≈ 200) in uniaxial extension, and simultaneously the minimum in the zero shear viscosity, η₀. The optimum N_br = 120 for this comb-PS series corresponds to an average spacing distance between two neighbor branch points of about Z_s ≈ 0.2 entanglements.

研究了一系列阴离子合成的线性和梳状无规聚苯乙烯（PS）的分子结构对其泡沫性能（包括孔尺寸，孔密度和体积膨胀比（VER））的影响。梳PS有骨干，相同分子量中号_瓦特，BB  ≈290公斤/摩尔，ž _BB ≈20个缠结，和分支，中号_瓦特，BR  ≈44公斤/摩尔，ž _BR ≈3个缠结，但不同分支的数目，3≤ ñ _BR ≤190批次的纯化良好线性和梳-PS使用CO发泡₂导致细胞密度约10 ⁹和4×10 ⁹ 细胞/平方厘米^由图3可知，LCB对细胞密度没有明显影响，而线性PS中的少量残留杂质将细胞密度降低至约^{10 8}  cell / cm ³。对于梳-PS系列用相同的缠结骨干，中号_瓦特，BB  ≈290公斤/摩尔，ž _BB ≈20缠结，以及类似的分支，中号_瓦特，BR  ≈44公斤/摩尔，ž _BR ≈3个缠结，但不同分支的数目，3≤ ñ _BR ≤190，增加了ñ _BR紧密结合的梳状构型的120℃逐渐提高了可达到的最高VER，接近由CO ₂溶解度给出的理论极限。使用洗瓶刷将N _br进一步提高到190会降低泡沫的VER。从一个流变点，该最佳Ñ _BR是有关的梳PS其显示在单轴拉伸的最大应变硬化系数（SHF≈200），并同时在零剪切粘度的最小值，η ₀。该 梳状-PS系列的最佳N _br = 120对应于两个相邻分支点之间的平均间隔距离约为Z _s ≈0.2纠缠。