In this thesis, two kinds of polymeric blends mainly consisting of Nylon6(N6) and polypropylene(PP) were prepared and their mechanical properties were investigated as a function of the content of campatibilizer, maleic anhydride grafted polypropylene(PP-g-MAH). The two kinds of blends were composed of PP matrix phase and Nylon dispersion phase. One kind of the PP matrix used in these blends was the isotactic-polypropylene(i-PP) and the other was the ethylene propylene block copolymer(Block-PP). In the case of the blend containing i-PP, the toughening agent, EPR, was physically added into the blend, whereas the EPR was included in the Block-PP when it was polymerized. The two kinds of the blends differed in the domain size of the dispersed EPR phase, which contributes to enhancing the impact strength of the blends. While the EPR phase in the mixture of i-PP and EPR resulted in the relatively larger domain size, the EPR phase in the Block-PP showed relatively smaller EPR domain size. The size of EPR domain in N6/i-PP/EPR blends seemed to be controlled by the viscosity matching between the EPR and N6/i-PP during the mechanical blend. However, in the case of N6/Block-PP blends, the domain size of EPR is small enough to be independent of the viscosity matching effect. PP-g-MAH added into these PP/N6 blends as a compatibilizer is well to react with the amine groups at the chain end of Nylon to form N6 grafted PP (PP-g-N6) molecules. Those are expected to be at the interface between Nylon and PP phases to reduce the interfacial tension of two phases. The reduction in the interfacial tension by addition of the compatibilizer is believed to reduce the size of Nylon domain. The effect of compatibilizer on the size of Nylon domain was found to be independent of the PP based matrix phase. It is because the size of the dispersed Nylon domain is expected to be governed only by the amount of the in situ formed PP-N6. The mechanical properties of the blends investigated in this study were Izod impact strength and flexural modulus. It is generally understood that the impact strength of the blends is closely related to the morphological feature of the blends, especially the size of the dispersed phase. With decreasing the size of dispersed phase, the impact strength of the blend is generally increased. Since the size of the dispersed Nylon domain in both of the two blends are nearly same, the main factor affecting the impact strength of the blends will be the size of EPR domain. Since the EPR domain of the Block-PP was smaller than that of i-PP/EPR, the blends containing Block-PP showed a superior impact strength to the blends containing i-PP/EPR. The flexural moduli of the two kinds of the blends showed the similar values, which is due to the fact that the two blends have the nearly same Nylon domain size. The use of Block-PP in the Nylon blends is more preferable than the i-PP/EPR because it shows appreciable toughness enhancement with less significant loss of stiffness.
