Thermally rearranged polymers are a class of heterocyclic microporous polymers generated by in situ thermal rearrangement (TR) of ortho-hydroxy polyamides or polyimides at elevated temperatures to produce polybenzoxazole (PBO). Poly(hydroxyamide) (PHA) was selected as a model polymer to generate amide-derived PBO (APBO) owing to its lower TR temperature. A nano-size zeolitic imidazolate framework of ZIF-8 was synthesized and incorporated into the PHA matrix to form PHA-ZIF8 nanocomposites. Due to the presence of ZIF-8 inside the PHA matrix, interchain interactions in the PHA matrix may be inhibited that results in a reduced TR temperature for PHA conversion into APBO. Differential scanning calorimetry (DSC) confirmed that the TR temperature of PHA-ZIF8 nanocomposites decreases as a function of ZIF-8 loading. In addition, the conversion of PHA into APBO and the structural integrity of ZIF-8 before and after TR were visualized by Fourier-transform infra-red (FTIR) spectroscopy and X-ray diffractometer (XRD), respectively. Subsequent measurements of gas transport properties of both PHA-ZIF8 and APBO-ZIF8 nanocomposites revealed that the synergistic amalgamation of TR and formation of nanocomposites can boost hydrogen separation performance, particularly H₂/CH₄, of APBO-ZIF8-35% close to the 2008 upper-bound.

热重排聚合物是一类通过原位生成的杂环微孔聚合物在高温下对邻羟基聚酰胺或聚酰亚胺进行热重排（TR），以生产聚苯并恶唑（PBO）。由于其较低的TR温度，选择聚（羟酰胺）（PHA）作为模型聚合物以产生酰胺衍生的PBO（APBO）。合成了ZIF-8的纳米级沸石咪唑酸酯骨架，并将其掺入PHA基质中以形成PHA-ZIF8纳米复合材料。由于在PHA基质内部存在ZIF-8，因此PHA基质中的链间相互作用可能会受到抑制，从而导致TR温度降低，从而使PHA转化为APBO。差示扫描量热法（DSC）证实，PHA-ZIF8纳米复合材料的TR温度随ZIF-8负载的增加而降低。此外，分别通过傅里叶变换红外（FTIR）光谱和X射线衍射仪（XRD）观察了TR前后PHA向APBO的转化以及ZIF-8的结构完整性。随后对PHA-ZIF8和APBO-ZIF8纳米复合材料的气体输运性能的测量表明，TR的汞齐化和纳米复合材料的协同结合可以提高氢的分离性能，特别是HAPBO-ZIF8-35％的₂ / CH ₄接近2008年上限。