Morphology evolution of miscible blends between crystalline PA6 and amorphous PA6IcoT

摘要

The morphology evolution of miscible blends of a semicrystalline polyamide 6 (PA6) and an amorphous polyamide 6Ico6T (PA6IcoT) was investigated using an internal Brabender mixer at a temperature range 220-260°C. Morphology of the blends was characterized by scanning electron microscopy (SEM) and laser particle analysis. Temperature rising dissolution was used to separate the different phases of the blends and the phase compositions were determined by Fourier transform infrared (FTIR) spectroscopy. The particle size evolution of the dispersed phase (PA6) was calculated and agreed well with experimental observation. It was found that the particle size was quickly reduced to nanometer scale after several minutes of processing. A convection-diffusion model was adopted to study the phase evolution during melt-melt mixing stage and compute the dimension of each phase. The results strongly support the notion of existence of distinct phases during blending, whose development can be well described by the model. The dispersed phase is reduced mainly by stretching of flow, while the broadening of the blending phase can be primarily attributed to molecular diffusion. The study also suggests the possibility to prepare novel polymer blends with nanometer sized domain of high uniformity.