Silylation of poly-L-lysine hydrobromide to improve dissolution in apolar organic solvents

Bis(trimethylsilyl)acetamide (BSA) was used to trimethylsilylate the hydrob romide salt of the synthetic polyamide poly-L-lysine (PLL-HBr) to improve i ts solubility in apolar organic solvents. The resulting trimethylsilylated derivative of PLL (PLL-SiMe3) was found to be soluble in methylene chloride , tetrahydrofuran, and xylenes. The PLL-SiMe3 was eventually used in the fo rmation of an interpenetrating polymer network (IPN) with ultrahigh molecul ar weight polyethylene via xylenes. Elemental analysis, FTIR, and NMR spect roscopic evidence supported highly efficient (81.7%) silylation for the BSA -treated PLL-SiMe3 product. Spectral data also showed complete silylation a t the carboxyl, N-terminal alpha -amine, and the epsilon -amine groups. Thi s chemistry provides solvent processing accessibility for PLL blends or gra fting reactions not possible for the commercial hydrobromide salt of PLL. ( C) 2001 John Wiley & Sons, Inc.