Phase Morphology, Crystalline Structure and Properties of Binary and Ternary Polyamide Based Blends
Hans-Joachim Radusch, Daniela Tomova
University Halle-Wittenberg
Germany
Keywords: blends, polyamide, morphology
Polyamide (PA) based blends become more and more important and have already got commercial relevance. Generally, the phase morphology as well as the physical and application properties of multi-component polymer systems prepared via melt mixing processes are dependent on the properties of the components, the thermo-dynamic miscibility of the different polymers, the ratio of the components and the quality of the mixture resulting from the mixing intensity of the melt mixing device, and the degree of homogeneity, respectively. In polymer blends based on polymer components with semi-crystalline structure, e.g. PA based blends, also the crystallization behavior is playing an important role concerning formation of the crystalline structure and property level. Furthermore, chemical reactions during mixing, e.g. realized in reactive blends, will influence the morphology and properties of the final polymer system essentially.
The mechanisms of phase morphology formation are discussed, especially for PA based blends with reactive components. Results of morphology formation investigation are presented from PA based binary dynamic vulcanizates, and ternary PA6/PA66/rubber systems with functionalized and non-functionalized rubber components. The use of functionalized rubber components results in an essential refinement of the dispersed phase. By the Hobbs spreading coefficients is was possible to predict the type of phase morphology in the ternary systems. Encapsulation of PA in the dispersed rubber particles could be shown experimentally by AFM.
For the understanding of property changes also the knowledge of crystalline structural alterations is necessary. The crystalline structure in binary PA6/PA66 blends is strongly influenced by the high miscibility in the melt but the tendency for separated crystallization. The blend micrographs, DSC and X-ray measurements exhibit the structural changes caused by the interactions between the components