Synthesis of Laboratory\nNylon: A Scale-Up Method for\nHigh Molecular Weight Polyamides

Here, we report a benchtop scale two-stage polyamidation\nprocess\nfor the synthesis of diacid/diamine (AA-BB) type polyamides (PAs)\nin quantities sufficient (30 g+) to obtain ASTM dogbones, IZOD bars,\nand rheology specimens with molecular weights ranging from 15 to 35\nkDa and minimal to no discoloration. Despite the extensive body of\nresearch in recent years reporting biobased AA-BB type PAs, the scale\nand molecular weights reported by many researchers are often inadequate\nfor meaningful comparisons with industrial resins. Commercially produced\nPAs usually use an initially high-pressure, moderate-temperature oligomerization\nreaction to prevent the diacid’s decarboxylation and the diamine’s\nevaporation. Subsequently, a second stage employs a higher temperature\nat reduced pressure and inert sweep gas for molecular weight enrichment\nwithout significant oxidative degradation. We have sourced commercial\nhardware and made simple modifications, such as a robust agitator\ncapable of wall-sweeping, to ensure uniform heat and mass transfer.\nThe resulting PAs exhibit mechanical properties on par with industrially\nsourced controls, demonstrating the effectiveness of our approach\nin bridging the gap between academic and industrial PAs. This eliminates\none of the significant roadblocks associated with developing new industrially\nrelevant polyamides and should be broadly applicable to researchers\nstruggling with the challenges of polyamidation.