Reversibly Cross‐Linked Polyamide 6 Using 1‐(5‐(Aminoethyl)‐2‐nitrophenyl)Ethanol as Photolabile Cross‐Linker

ABSTRACT Reversible cross‐linking of thermoplastic materials allows thermoplastic processing before and after cross‐linking, while improving the mechanical and thermal properties after cross‐linking during the use phase. Hence, reversible cross‐linking can play an important role in establishing circularity by enabling mechanical recycling of a cross‐linked material after de‐linking. This exploratory study investigates 1‐(5‐(Aminoethyl)‐2‐nitrophenyl)ethanol as a photolabile cross‐linker (PXL) for polyamide 6 (PA6). The PXL is melt‐mixed with PA6 in two concentrations and processed into samples, which are investigated by Dynamic Mechanical Analysis (DMA) and Differential Scanning Calorimetry (DSC) before and after UV‐exposure. The addition of the PXL increases the storage modulus from 1.585 MPa for neat PA6 to 2.550 MPa for PA6 with 3 wt.% PXL and 3.470 MPa for PA6 with 6 wt.% PXL, respectively. Exposure to UV radiation decreases the storage modulus with increasing exposure time. The crystallinity decreases from 33,32% for neat PA6 to 30,71% for PA6 with 3 wt.% PXL and to 29,71% for PA6 with 6 wt.% PXL When the samples with PXL are exposed to UV‐radiation, an increase in the crystallinity is observed. The results of this exploratory study indicate that PA6 can be cross‐linked with 1‐(5‐(Aminoethyl)‐2‐nitrophenyl)ethanol and that de‐linking through UV‐exposure is possible.