Drawing of nylon 6,6 and ultrahigh molecular weight polyethylene fibers in supercritical CO2

The drawing of nylon 6,6 and ultrahigh molecular weight polyethylene (UHMWPE) fibers has been studied at elevated temperatures in a CO2 environment in the supercritical phase regime, With nylon, the CO2 increases the crystallinity and orientation of the fiber significantly resulting in 30% higher strength values, With UHMWPE fibers, the ultimate strength is only increased slightly. However, the modulus can be improved by 50% in comparison to air drawn fibers at the same temperature. For both polymer fibers, temperature has a large effect on the final structure and the engineering properties of the fiber.