Cellulose/Polypropylene Composites: The Use of AKD and ASA Sizes as Compatibilizers

Alkyl ketene dimer (AKD) and alkenyl succinic anhydride (ASA) were used in both solution and emulsion forms to treat 100% cellulose and 70/30 wt.% cellulose/polypropylene composite sheets made by both an air-formation technique and traditional wet handsheet formation. In all cases, the air-formed sheets had poorer mechanical properties than did the handsheets. While the treatments appeared to have a visible affect on the spreading of polypropylene over cellulose, the effects of the treatments on mechanical properties were almost always negative. Annealing the wet-formed handsheets for five minutes at 130°C before pressing gave control sheets with improved modulus, strain-to-break, and burst strength, but had a slight negative effect on air-formed sheet properties. The effect of treatments on the water durability of the air-formed sheets was minimal or adverse, while for the wet-laid handsheets, the treatments were slightly beneficial if the sheets had been annealed, but detrimental if they had not.