Jaeryeong Jeong  Jongho Choi  DaeSung Jung  Aye Aye Myint  Jaehoon Kim

Vol. 32,  No. 1, pp. 50-60, Mar.  2026
10.7464/ksct.2026.32.1.50

Airbag sheet Dissolution-precipitation Hansen solubility parameter High-quality polymer recycling

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A dissolution-precipitation recycling process was developed to recover high-quality polyamide, particularly PA66, from silicone-coated automotive airbag waste. Solvent screening based on Hansen solubility parameters (HSP) identified formic acid as an effective solvent and methanol as a suitable antisolvent. Optimal processing conditions were established by adjusting key variables including solution concentration, solvent concentration, dissolution temperature, and dissolution time. The process achieved a recovery yield exceeding 90% under mild conditions (≤ 20 w/v%, room temperature, 1 h). Thermal characterization using TGA and DSC confirmed that no silicone residues remained in the recovered polymer and that the thermal decomposition and melting behavior exhibited minimal changes compared to the virgin material. XPS analysis demonstrated the complete removal of Si-based coatings and the retention of nitrogen-containing amide bonds, indicating preservation of the polymer’s chemical purity. ATR-FTIR spectra revealed no shifts in characteristic polyamide functional groups, confirming that the polymer backbone was not degraded during solvent exposure. Furthermore, GPC analysis showed that the recovered polymer maintained or slightly increased its Mw values and exhibited stable retention times, indicating negligible chain scission and a molecular weight distribution compatible with practical reuse. These results collectively verify that the proposed dissolution-precipitation process enables the high-purity recovery of PA66 without compromising its structural integrity, even from complex silicone-coated composite waste streams. The process demonstrates strong industrial potential for the upcycling of end-of-life automotive polymer components toward resource-circulating manufacturing.