Introduction of carboxylic acid group to polypropylene fabric for battery separator

Carboxylic acid group was introduced by radiation-induced grafting of acryl ic acid (AAc) onto a polypropylene (RP) nonwoven fabric for a battery separ ator. The AAc-grafted PP nonwoven fabric was characterized by IR, SEM, and TGA. The wetting speed, electrolyte retention, electrical resistance, and t ensile strength were evaluated after grafting of AAc. It was found that the wetting speed, electrolyte retention, thickness, and ion-exchange capacity increased, whereas the electrical resistance decreased with increasing gra fting yield. The elongation of AAc-grafted PP nonwoven fabric decreased wit h increasing grafting yield in dry state, whereas the elongation increased in wetting state.