Interfacial elasticity of reactively compatibilized PP/PA6 blends

The aim of the present work was to evaluate the interfacial properties of compatibilized PP/PA6 blend by means of measuring the melt elasticity of the samples in conjunction with the Palierne model. The PP/PA blend samples varying in blend ratio and compatibilizer concentration were prepared in an internal mixer. The analysis of the relaxation time spectra of the compatibilized blends showed two distinct peaks which could be related to the elastic response of the droplets, tau s, and interface elasticity, tau beta. This was evidenced by decreasing the relaxation times with increasing the compatibilizer content. An attempt was also made to evaluate the interfacial tension and interfacial shear modulus of the blend samples by utilizing the expanded version of the Palierne model While the interfacial tension decreased with increasing compatibilizer concentration independent of PA content, the level of PP-g-MA was found to play a different role in determining the interface shear modulus of the samples depending upon PA dispersed phase content. This could be explained in terms of changing the morphology of the samples from emulsion type to emulsion in emulsion morphology. It was shown that in the reactively compatibilized polymer blends; similar to physically compatibilized systems, the interfacial shear modulus is proportional to the interfacial coverage, indicating that the same mechanism governs the compatibilization for two systems. It was demonstrated that the results of linear viscoelastic measurements can provide a great insight into understanding the correlation between the interfacial elasticity and the morphology of immiscible polymer blends.