Preparation of Polymer Blends from the Melt

Safety precautions Before this experiment is carried out, Sect. 2.2.5 must be read as well as the material safety data sheets (MSDS) for all chemicals and products used. 

In practice, blends are often prepared by mechanical mixing in the melt. As a rule the products are demixed, but dispersed so finely that the phase structure can only be detected with a transmission electron microscope (TEM). 

In the laboratory simple tests for the miscibility of polymer melts can be carried out, in which the turbidity of the system is an indicator for the immiscibility. 

Two polymer solutions (5 wt%) are successively dripped into a common precipitation bath under vigorous stirring.The precipitate is a powder blend that consists of small grains of the components. 

If such a powder blend is fused on a hot plate after suction and drying, a turbid two-phase melt is formed with incompatible components (e.g., PS/PMMA), whereas a clear mixed melt is formed from compatible components (PS/PPE or SAN/PMMA). 

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Example 5.22 Preparation of Polymer Blends from the Melt... 

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