A novel scCO2 dyeing strategy for superior coloration of UHMWPE fiber

Ultra-high-molecular-weight-polyethylene (UHMWPE) fibers have the highest stiffness-to-weight ratio of any available material, including metals. However, their applicability in consumer products is surprisingly limited. One reason for this is the inability to readily dye UHMWPE fibers, i.e. the fibers are only available in clear or black (carbon particle filled). Attempts to color UHMWPE fibers have only achieved limited dye uptake due to the high crystalline content of drawn UHMWPE fibers. In this study, we demonstrate that high dye uptake and high color intensity are possible in drawn UHMWPE via scCO2 dyeing of the as-spun fibers prior to drawing. The as-spun fibers are demonstrated to be drawn via standard methods into dyed high-performance fibers. Comparison of color intensity is made with UHMWPE fibers dyed after drawing and standard PET fibers. Mechanical properties are measured during the drawing process to demonstrate that the presence of dye does not reduce the drawability or the mechanical properties of the fibers.