Bis(trimethylsilyl)acetamide (BSA) was used to trimethylsilylate the hydrobromide salt of the synthetic polyamide poly-L-lysine (PLL-HBr) to improve its 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 formation of an interpenetrating polymer network (IPN) with ultrahigh molecular weight polyethylene via xylenes. Elemental analysis, FTIR, and NMR spectroscopic evidence supported highly efficient (81.7%) silylation for the BSA-treated PLL-SiMe3 product. Spectral data also showed complete silylation at the carboxyl, N-terminal alpha -amine, and the epsilon -amine groups. This chemistry provides solvent processing accessibility for PLL blends or grafting reactions not possible for the commercial hydrobromide salt of PLL.