Question

In a semi-crystalline polymer processed from solution, the presence of residual solvent will both decrease and broaden the melting range of the crystals. Why? First, consider both the spherulites and the surrounding amorphous components. Next, consider only the structure found on the interior of the spherulites.

Answer 1

Explanation:

The presence of residual solvent is a factor that affects the glass temperature of the polymer. This is because a residual solvent decreases the free volume in a polymer. All types of polymers have total occupied volume, which is composed of an occupied volume and a free volume. The free volume is the volume needed for the polymer chains to move around. Thus, if there is a big free volume in the polymer it will decrease the glass transition temperature and will both decrease and broaden the melting range of the crystals.

In a polymer with crystalline spherulites and the surrounding amorphous, will have a bigger surrounding amorphous with the presence of residual solvent. Which will decrease the melting range of the crystals. The structure found on the interior of the spherulites is pure crystalline polymer, so probably the residual solvent will not be inside them.