Structure and properties of melt-spun fibers of polyethylene blended with cellulose fibers

Melt spinning of high-density polyethylene (HOPE) blended with cellulose nano-fibers was carried out to estimate the maximum attainable mechanical properties of the compound. HOPE was also chemically modified to improve its interaction with cellulose fibers. When the fibers prepared at the same take-up velocities were compared, polyethylene fibers blended with only 1 wt% of cellulose fibers showed higher tensile modulus and strength than those of neat polyethylene fibers. Structure analysis of the fibers through wide-angle X-ray diffraction and birefringence measurements revealed that the mechanical properties improved because of enhanced molecular orientation of HOPE molecules rather than through the reinforcement by the cellulose fibers. Single fiber pull-out test was also performed to determine the interfacial shear strength between the matrix resin and the fiber. The results showed that the interfacial shear strength between the HOPE and the cellulose fiber was 6.5 MPa, which indicates poor adhesion, while that between the modified HOPE and the cellulose fiber increased to 30.6 MPa.