The synthesis of three novel aromatic polyimides (PIs) containing spiro units is described. These PIs are soluble at room temperature in most common organic solvents, facilitating their processability. Additionally, they are highly thermally stable, with thermal decomposition temperatures (T_d10%) over 500 °C, and had moderately high T_g values between 230 and 265 °C. Robust self-standing thin films were prepared from these polyimides, via the solution casting method, which were suitable for gas transport measurements. The relatively low permeability and selectivity of these PIs, as compared to Polymers of Intrinsic Microporosity (PIMs) that also contain spirocyclic structures, demonstrate the importance of restricting rotation within the polymer chain, which is a key structural feature of the PIMs.

描述了三种含有螺环单元的新型芳香族聚酰亚胺（PI）的合成。这些PI在室温下可溶于大多数常见的有机溶剂，从而提高了它们的可加工性。此外，它们具有极高的热稳定性，热分解温度（T _d10％）超过500°C，并且具有中等较高的T _g温度介于230至265°C之间。通过溶液浇铸法，由这些聚酰亚胺制备出坚固的自支撑薄膜，适用于气体传输测量。与还包含螺环结构的本征微孔聚合物（PIM）相比，这些PI的相对较低的渗透性和选择性证明了限制聚合物链内旋转的重要性，这是PIM的关键结构特征。