Preparing PAN films by expelling the solvent in polymer solution of different concentration with double diffusion and gathering PAN nascent fibers through various jet rate. The effect of entanglements between molecules on crystallization behavior of PAN molecules in solidification process was studied by rheometer

X-ray diffraction etc. The results show that the differences of polymer solution concentration affect the intensity of molecular chain in polymer solution which affects the entanglements between molecules and crystallization behavior. The stronger entanglement is

the lower crystallization is. Shearing could change the conformation of molecular chain

which promotes to weaken the entanglements so that it is benefit to elevate the activity of polymer chain and the crystallization of PAN nascent fiber.