Polyimides are commonly synthesized in a 2-step solution polymerization process. Such process requires long reaction times as well as specific care due to the use of potentially harmful solvents. In the present study, the total reaction time for producing polyimides has been lowered to less than 10 min by using a solvent-free continuous reactive extrusion process. The proof of concept was determined with the system based on 3,3′,4,4′-benzophenone-tetracarboxylic dianhydride (BTDA) and an aliphatic diamine, Jeffamine D-230 within a microextruder. Degrees of conversion to polyimide, determined with ¹³C NMR and DSC analysis, are over 90 mol % after 5 min of extrusion at 180 °C, 200 °C, and 225 °C, respectively. These syntheses were then transferred to a twin-screw extruder to form linear aliphatic-aromatic polyimides with two types of dianhydride: BTDA and pyromellitic dianhydride (PMDA). Comparison with a conventional solution polymerization process showed no significant differences in the polymers characteristics. The polyimides produced with this method presented glass transition temperatures ranging from 5 to 90 °C. The number-average molar masses measured were between 11 000 and 15 000 g·mol^–1.

中文翻译：

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无溶剂反应挤出是一种创新高效的聚酰亚胺合成方法

聚酰亚胺通常以两步溶液聚合法合成。由于使用了潜在有害的溶剂，这种方法需要较长的反应时间并需要特别注意。在本研究中，通过使用无溶剂连续反应挤出工艺，生产聚酰亚胺的总反应时间已降至10分钟以内。使用基于3,3'，4,4'-二苯甲酮-四羧酸二酐（BTDA）和脂肪族二胺Jeffamine D-230的系统在微型挤出机中确定概念验证。由¹³确定的转化为聚酰亚胺的程度分别在180°C，200°C和225°C挤出5分钟后，C NMR和DSC分析均超过90 mol％。然后将这些合成物转移到双螺杆挤出机中，以形成具有两种二酐类型的线性脂族-芳族聚酰亚胺：BTDA和均苯四甲酸二酐（PMDA）。与常规溶液聚合方法的比较表明，聚合物特性没有显着差异。用这种方法生产的聚酰亚胺的玻璃化转变温度为5-90℃。测得的数均摩尔质量为11000至15000 g·mol ^–1。