Thermal Rearrangement Polymers have a strong potential regarding to gas separation membrane materials, especially for the purification of methane containing gas streams, due to their inter-connected bottleneck-type pores. However, most TR polymers reveal high permeabilities and high conversions only at high temperatures of 450 °C. Our study demonstrates a method to enhance the permeability at lower annealing temperatures by tailoring the thermally triggered decomposition and reaction cascade via modification and temperature protocol. In this study a set of seven carbonate ester modifications was prepared and thermo-analytically studied by means of DSC and TGA-FTIR on-line analysis combined with structure determination methods and quantum mechanical simulations. Two decarboxylative alkyl-transfer reaction mechanisms were formulated for the decomposition reaction of the carbonate ester group. A correlation of the size and branching of the carbonate ester connected alkyl group and its effect on the film properties and gas separation performance was studied. High polyimide to polybenzoxazole conversions were determined for the modified polymers and a 2008 upper bound performance was obtained for all materials, after annealing at 400 °C. Furthermore, the ethyl carbonate ester (ECO₃PI-1) polymer entered the target zone above an ideal selectivity of CO₂/CH₄ of 30 after aging, making it an attractive membrane material.

热重排聚合物在气体分离膜材料方面具有很强的潜力，特别是用于净化含甲烷的气流，因为它们具有相互连接的瓶颈型孔。然而，大多数 TR 聚合物仅在 450 °C 的高温下才显示出高渗透率和高转化率。我们的研究展示了一种通过修改和温度协议调整热触发分解和反应级联来提高较低退火温度下渗透率的方法。在这项研究中，通过DSC和TGA-FTIR在线分析结合结构确定方法和量子力学模拟，制备了一组七种碳酸酯改性并进行了热分析研究。为碳酸酯基团的分解反应制定了两种脱羧烷基转移反应机制。研究了碳酸酯连接的烷基的大小和支化的相关性及其对薄膜性能和气体分离性能的影响。测定了改性聚合物的高聚酰亚胺到聚苯并恶唑的转化率，并且在 400°C 退火后，所有材料都获得了 2008 年的上限性能。此外，碳酸乙酯（ECO 测定了改性聚合物的高聚酰亚胺到聚苯并恶唑的转化率，并且在 400°C 退火后，所有材料都获得了 2008 年的上限性能。此外，碳酸乙酯（ECO 测定了改性聚合物的高聚酰亚胺到聚苯并恶唑的转化率，并且在 400°C 退火后，所有材料都获得了 2008 年的上限性能。此外，碳酸乙酯（ECO₃ PI-1) 聚合物在老化后进入目标区域，超过理想的 CO ₂ /CH ₄选择性30，使其成为一种有吸引力的膜材料。