Abstract: A new ultra-fine full-vulcanized powdered acrylic rubber was used to modify phenolic resin in this paper. The interface reaction and heat resistance of the modified resin were studied with FTIR and DTA-TG. Experiment results showed that many active groups exist in the surface of ultra-fine powdered acrylic rubber, so it can joint with phenolic resin by chemical bond. Therefore modified resin with higher toughness and improved heat resistance can be obtained. As a result, the strength and toughness of modifi...