Table 1.

Recipe for the preparation of the polyurethane (PU) prepolymer. MHHNA—4-methoxyl-N-(2-hydroxy-1-hydroxymethylethyl)-1,8-naphthalimide; TMP—trimethylol propane; CO—castor oil; DHHNA—4-diethylamino-N-(2-hydroxy-1-hydroxymethylethyl)-1,8-naphthalimide; IPDI—isophorone diisocyanate; HDO—1,2-hexadecanediol; BDO—1,4-butanediol; THF—tetrahydrofuran.

Prepolymer	IPDI/g	CO/g	TMP/g	HDO/g	BDO/g	Fluorescent dye/g	THF/g
PU-TMP	2.22	0	0.158	0	0.534	0	10
PU-CO	2.22	0.75	0	0	0.592	0	10
PU-MHHNA	2.22	0.4	0	0.2	0.572	0.016 a	10
PU-DHHNA	2.22	0.4	0	0.2	0.572	0.018 b	10

^a MHHNA, 5.3 × 10⁻² mmol. ^b DHHNA, 5.3 × 10⁻² mmol.