The invention is a crystalline fiber comprising syndiotactic polystyrene, or a mixture. Preferably the fiber is a high strength fiber isotactic polystyrene and syndiotactic polystyrene wherein the fiber is monoaxially oriented, has a tensile strength of 10,000 psi or greater, and a modulus of 1,000,000 psi or greater.

In another aspect the invention is a process for the preparation of fibers of syndiotactic polystyrene, or a mixture of isotactic polystyrene and syndiotactic polystyrene which comprises:

• A. contacting syndiotactic polystyrene, or a mixture of isotactic polystyrene and syndiotactic polystyrene with a solvent for the polystyrene at elevated temperatures under conditions such that a homogeneous solution is formed which has sufficient viscosity to be extruded;
• B. extruding the solution through an orifice to form a fiber at elevated temperatures;
• C. quenching the fiber by passing the fiber through one or more zones under conditions such that the fiber solidifies;
• D. removing the solvent for the polystyrene from the fiber; and
• E. cooling the fiber to ambient temperature.

In the embodiment where it is desirable to prepare high strength fibers, the fibers are further exposed to the following process steps:

• F. heating the fiber to a temperature above the glass transition temperature of the polystyrene;
• G. redrawing the fiber to elongate the fiber, maximize crystallinity, and induce monoaxial orientation of the polystyrene in the fiber.