Anti Oxidant for Rubber–PAO (Process Anti Oxidant) PAO is an inexpensive and highly potent staining type antioxidant. It is most widely used in the rubber compounds. It is in paste form, easy to handle & disperse well used alone at 0.50 – 2.0 phr levels. It provides long term excellent protection to rubber vulcanisates against oxidative ageing at ambient as well as elevated temperatures. It does not contribute to flex fatigue resistance and hence generally used in combination with anti ozonants / antidegradants. SPECIFICATION Colour Light brown to dark brown Specific Gravity 25.0Â