Tprinciple of wet spinning process-Part 8Affects solubility about supramolecular deconstruction

Effects of supramolecular deconstruction

1. Amorphous polymers are more solube than partly crystaline polymers.

 This is because the force between the former macromolecule is weak,and the latter due to the strong force between the molecules of the crystalline part,to make it completely dissolved,a higher temperature is needed.Crystalline polyene wick,for example,has limited swellin at 2 (RC) and can generally dissove at high temperature above 100 degree.Polyvingyl alcohol has a higher crystallinity.It usually needs to be dissoved under heating conditions. The higher the crystallinty,the lower the solubility.

2. Polarity is conductive to the dissolution of crystalline polymers.Poly crystalline polymers can also dissove at high temperatures,which is the amorohous part of the polymer mixed with the solvent.the strong interaction between the twocan release a lot of heat,resulting in partial melting of crystals,Polyparadimethy,for example ethyldester acid is soluble in o-chlorophenol and weight ratio is 1:1 phenol-tetrachloroethane in a mixed solvent.

Effects of solvent properties

The solubility of related to its chemical stucture,the strength of interaction between solvent and active  functional groups on mactomolecular chain and the degree of solvent association,Most of the hyperpolymers by concentrated solution spinning are generally dissoved in polar solvents.

The degree of solvation between polar sovent and polar polymer is related not only to the polar functional groups of the solvent, but also to the chain structure of the remaining parts,1.the larger the radical next to the polar group of the solvent molecule,the less soluble it is.2.The solubility of mixed solvent is better than that of single solvent.This is due to the existence of various characteristic functional groups in the polymer macromolecular chain,which can be solvated by various characteristic macromolecules,For example,cellulose diacetate with R=240~260 is more soluble in acerone-water(4%~5%)mixtues than in anhydrous acetone,