Study On The Structure And Crystalline Transformation Of Phenolphthalein Poly(Ether Sulfone)/Nylon 6 In-Situ Composite

In this paper, phenolphthalein poly(ether sulfone)/nylon 6 composites were prepared in situ polycondensation by acide opening caprolactam. The structure of composites, interaction between PES-C&caprolactam and PES-C&nylon6 matrix, crystalline transformation was characterized. Non-isothermal crystallization behaviors of the composites were also investigated.The molecular weight of nylon 6 was measured by viscosimetry. The result indicated that nylon 6 in the composites had a lower molecular weight than pure nylon 6. The result of FTIR showed that the hydrogen-bonds were found in the caprolactam/PES-C and PES-C/nylon 6, there was a strong interaction between them. SEM photograph showed that PES-C dispersed well in nylon 6 matrix when there was a small PES-C content. With the content of PES-C increased, the stronger aggregation effect caused inhomogenous phase section.The results of WAXD indicated that the addition of PES-C did not change the basalαcrystal form of the original composites, and all quenched composites had theγcrystal form. Theαandγcrystal forms both existed when quenched composites were annealed at lower temperature, and the crystalline transformation ofγtoαform was hindered because of the hydrogen bonds between PES-C and nylon 6. Theαcrystal form uniquely existed in pure nylon 6 and the composites when they were annealed at 200℃.The results of FTIR spectra and DSC indicated that the crystalline transformation degree ofαtoγform became bigger when the composites were treated in aqueous iodine and potassium iodide solution with longer time and higher concentration, and at lastαform totally transformed toγform. And the crystalline transformation ofαtoγform was hindered by PES-C in the composites.The studies of crystallization kinetics of the composites indicated that non-isothermal crystallization behaviors could be described by Jeziorny and Liu methods, and the mode of nucleation and crystallization growth were changed. Crystallization of nylon 6 in the composites was hindered by PES-C, and the semi-crystallization time became longer. In the DSC curves of the composites, there were two melted peaks because the composites have a different perfect crystalline.