In situ formation and processing of ultra high molecular weight polyethylene blends into precursors for high strength and stiffness fibers

We present a novel process for the manufacture of ultra high molecular weight polyethylene precursors which can be subsequently made into high‐stiffness, high‐strength fibers or films. This process combines solid‐state extrusion and an in situ constrained solvent swelling process into a single stage for precursor preparation. The precursors produced by this process are shown to be highly ductile and porous. The inclusion of a small quantity of nontoxic solvent (10 wt% mineral oil) in the process has also been shown, using DSC and SEM characterization techniques, to provide the following process advantages: (i) better interfacial cohesion, because of the enhanced chain mobility at the particle surface due to the solvating effects; (ii) improved processability; and (iii) more uniform thermal properties and morphology across the extrudates due to enhanced heat transfer.