Fabrication of UV crosslinked polyethylene fiber for carbon fiber precursors

In this paper, linear low-density polyethylene (LLDPE) fibers were stabilized by ultraviolet ray (UV) irradiation, which provided a new treatment method for fabricating carbon fiber precursors. LLDPE chips were blended with a photo-initiator 4-chlorobenzophenone (4-CBP) and a crosslinker 1,2-polybutadiene (1,2-PB) to obtain spun particles, and then they were melt spun into the fibers. Then, UV irradiation of the as-spun fibers was performed to obtain precursors. An orthogonal experimental design investigated the effects of the ingredient ratio LLDPE:1,2-PB and UV irradiation time on the fiber gelation. The results show that the factor's order of influence was: ingredient ratio > UV irradiation time. The fiber gelation reaches a maximum of 67.51% at a dosage ratio of LLDPE:1, 2-PB of 97:2, and a UV irradiation time of 30 min. The UV irradiation introduced the crosslinking structure of LLDPE fibers, and the melting temperature of UV-XLPE fibers shifts toward lower temperatures, and the crystal size of the fibers decreased with increasing UV irradiation time. However, longer irradiation time does not beneficially affect the gelation degree. The low cost and feasible crosslinking method in this study offer the possibility of wide application of low-cost polyethylene-based carbon fibers.