Trifluoromethylated <i>N,S</i>-Acetal as\na Chemical Platform for Covalent Adaptable Networks: Fast Thiol Exchange\nand Strong Hydrostability for a Highly Transparent Material

This work presents the synthesis and characterization\nof a highly\ntransparent and colorless covalent adaptable network (CAN) exhibiting\nshort relaxation times (30 s at 150 °C) and limited creep at\n100 °C. Based on <i>N,S</i>-acetal functions, strongly\nstabilized by a trifluoromethyl group, this network, however, retains\nthe ability to undergo fast thiol exchanges. The present article describes\na detailed monitoring of the cross-linking via ATR-FTIR and <sup>19</sup>F HRMAS NMR (high-resolution magic angle spinning NMR), the complete\nstructural characterization of the material via <sup>13</sup>C HRMAS\nNMR, and the comprehensive study of the rheological properties of\nthis novel <i>N,S</i>-acetal network. This CAN shows hydrolytic\nstability and higher activation energies (>90 kJ mol<sup>–1</sup>) than its nonfluorinated counterparts. Its reprocessing occurs under\nrelatively mild conditions without the need for a catalyst, and depolymerization\ncan be achieved either with an amine (benzylamine), under acidic\nconditions (1 M HCl) at room temperature, or with a thiol (1-dodecanethiol)\nat 100 °C.