Blends of non-crystallizable components

In addition to the studies on blends of polyolefins described above, in which the two components are crystallizable, investigations have also been carried out on blends of non-crystallizable components. 

Amorphous films of PVF2/PMMA blends were prepared by initial precipitation from a solvent and rapid solidification at 15 °C from the molten state (Martfnez-Salazar et al., 1991). Moreover, these two constituents were considered as miscible (Noland et al., 1971). The PVF2/PMMA compositions studied were 25/75,45/55, 50/50, 55/45, 60/40 and 75/25 by weight. The presence of a single X-ray halo as well as a single Tg value for all the blends, in the above compositions range, favours the view that these materials are composed of homogeneous mixtures at molecular level. The parallel decrease of the microhardness, which obeys a simple expression  

2 Microhardness of coreactive blends the influence of chemical interactions 

This effect is called melt-induced sequential reordering. The driving force for this transformation is supposed to be the resultant entropy increase. More about the chemical interactions in blends of condensation homopolymers and copolymers can be found in Fakirov (1999), a book devoted to these problems. 

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