Polyacrylonitrile rotating

Dipolefdipole Interactions (Freely Rotating) ShortRange Varies as -Hr6 0.5-2 kcalhnole, Polyacrylonitrile Poly(vinyl chloride)... 

In polyacrylonitrile appreciable electrostatic forces occur between the dipoles of adjacent nitrile groups on the same polymer molecule. This restricts the bond rotation and leads to a stiff, rodKke structme of the polymer chain. As a result, polyacrylonitrile has a very high crystalline melting point (317°C) and is soluble in only a few solvents, such as dimethylformamide and dimethylacetamide, and in concentrated aqueous solutions of inorganic salts, such as calcium thiocyanate, sodium perchlorate, and zinc chloride. Polyacrylonitrile cannot be melt processed because its decomposition temperature is close to the melting point. Fibers are therefore spun from solution by either wet or dry spinning (see Chapter 2). 

Liao C-C, Wang C-C, Chen C-Y and Lai W-J (2011) Stretching-induced orientation of polyacrylonitrile nanofibers by an electrically rotating viscoelastic jet for improving the mechanical properties, Polymer 52 2263-2275. 

In polyacrylonitrile appreciable electrostatic forces occur between the dipoles of adjacent nitrile groups on the same polymer molecule. This intramolecular interaction restricts bond rotation and leads to a stiff chain. As a result, polyacrylonitrile has a very high crystalline melting point (317 C) and is soluble... 

Fennessey and Farris collected tows of aligned polyacrylonitrile (PAN) fibers using a rotating drum set-up. The tows, measuring ca. 32 cm x 2 cm, were then linked together and twisted using a Roberta-type electric twister. 

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