In this work, recycled Poly(ethylene glycol-co-cyclohexane-1,4-dimethanol terephthalate) plastic (PETG) was used to enhance the properties and lower the cost of polypropylene(PP). In order to adjust the interfacial adhesion, three triblock copolymers having the same styrene block at two ends but different block in the middle, were used a the compatibilizers, namely, styrene-ethylene/butylene-styrene (SEBS), styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS). The ratio of PP to PETG was fixed at 70/30 and the relationship between interfacial adhesion and mechanical properties was investigated. The addition of SIS caused a considerable increase in Izod impact toughness, but only slightly improved toughness was observed for blends compatibilized with SEBS. The effect of SBS on improving the impact toughness lied in between that of SIS and SEBS. SEM micrographs showed that PETG forms a fibrillar-like structure for all the uncompatibilized and compatibilized blends, and the blends compatibilized with SBS have smallest domain size, the blends compatibilized with SEBS have largest domain size, while the ones compatibilized with SIS show a moderate domain size. Results from melt rheometry and SEM observation together with work of interfacial adhesion, indicated a strongest interfacial adhesion in blends compatibilized with SBS, poorest in blends compatibilized with SEBS, and moderate in blends compatibilized with SIS. It is very interesting to found that the much improved impact strength was not observed in the blends with the strongest interfacial adhesion but achieved in the blend with moderate interfacial adhesion. Investigation on the impact fractured surface revealed an easier debonding of fibril from matrix and consequently drawn out of matrix in blends compatibilized by SIS with moderate interfacial adhesion, which was considered as the main reason for the much improved impact toughness in this system. (C) 2009 Elsevier Ltd. All rights reserved.