Synthesis of Cationic Waterborne Polyurethanes from Waste Frying Oil as Antibacterial Film Coatings

Table 6

Water, acid, and alkaline resistance of cationic waterborne polyurethane (CWPU) films with various internal emulsifier contents.

Formula	Water	Acid	Alkaline^b
CWPU-1	Excellent^a	Excellent^a	3 : 15
CWPU-2	Excellent^a	Excellent^a	3 : 28
CWPU-3	Excellent^a	Excellent^a	3 : 35

^aFilms did not change after immersion in distilled water or 5% H₂SO₄ for 24 h at room temperature. ^bTime (h : min) detected when films exhibited blistering after immersion in 5% () NaOH at room temperature.