Effect of blending sequence and elastomer content on the morphology and thermal behavior of a PET/PC/reactive elastomer blend

Since poly(ethylene terephthalate)/polycarbonate (PET/PC) blend was patented three decades ago, the blend has been used in numerous commercial products. Meanwhile, the study of the PET/PC blend has attracted great attention. Some of the research interests are, for example, how to improve the toughness of the blend; what the toughening mechanisms in the toughened system are; how reactive elastomer would affect the morphological structure of the blend and what the relationships between the processing condition and the property of the blend are. To answer these questions, a great deal of experimental work is necessary and new characterization techniques that may be employed to reveal the microstructure of the blend with no artifact and more convenience must be developed. In the present study, a new sample preparation technique for scanning electron microscopy (SEM) has been developed. Compared with TEM technique, the newly developed SEM sample preparation technique requires less expensive equipment and sample preparation time. It is possible to obtain an entire picture of the microstructure of the sample by this technique. With the help of this newly developed technique, together with thermal analysis, the blending sequence and elastomer content on the morphology, compatibility and crystallization behavior of the blends were characterized. It was found that blending sequence and elastomer content have strong influence on the size and final location of elastomer particles, as well as the phase distribution and degree of dispersion of PET and PC. It was also discovered that the incorporation of the reactive elastomer alters the compatibility between the PET and PC. In addition, use of elastomer would change the crystallization behavior of PET in the polymer blends, which, in turn, will affect its mechanical and chemical properties