Mechanically tunable dual-component polyolefin fiber mats via two-dimensional multilayer coextrusion

Recently developed two-dimensional multilayer coextrusion and post-process drawing were combined to fabricate polyolefin composites with independently tunable size (9 μm width × 3 μm thickness to 5 μm width × 0.9 μm thickness) and mechanics (e.g. modulus from 1340 to 2010 MPa). Post-process drawing of the composite studied via in situ synchrotron WAXS and SAXS imparted higher crystallinity and more uniform and aligned crystallites (f_H,PP = 0.93 and f_H,HDPE = 0.90) resulting in an improved modulus, while also increasing and narrowing the melting temperature. After drawing, the composites were simultaneously delaminated and consolidated using a high pressure water jet to produce dual-component fiber mats with high specific surface area, which was related to the fiber size and rectangular cross-section unique to this process. The tunability of the HDPE and PP fibers produced via this process hold distinct advantages over solvent-based techniques, such as electrospinning, for many high performance applications.