Hierarchical constraint distribution of ultra-high molecular weight polyethylene fibers with different preparation methods
The hierarchical constraint characteristics of ultra-high molecular weight polyethylene (UHMW-PE) fibers with different structures were evaluated by in situ wide-angle X-ray diffraction (WAXD) measurement during heating. Two UHMW-PE fibers were used in this study, an original gel-spun fiber and a processed fiber that was tensile-drawn from the original fiber above the static equilibrium melting temperature of PE. A difference in fiber processing induced change in constraint distribution attributed to morphological heterogeneity. The original gel-spun fiber, which had a heterogeneous structure, induced the constraint distribution because of the obvious existence of skin and core. In contrast, the tensile-drawn fiber, which had a homogeneous structure formed by the fusion adhesion between twisted single yarn surfaces, depressed the constraint distribution. These results demonstrate that a difference in fiber processing induces change in hierarchical characteristics with different structural dimensions.
KeywordsConstraint State WAXD Hexagonal Phase Orthorhombic Phase Phase Transition Behavior
Synchrotron WAXD measurements were performed under the approval of the Photon Factory Program Advisory Committee (Proposal 2004G265). This work was partly supported by a Grant-in-Aid for the Japan Society for the Promotion of Science (JSPS) Fellows and the Industrial Technology Research Grant Program from the New Energy and Industrial Technology Development Organization (NEDO) of Japan. M. Kakiage expresses his gratitude for the JSPS Research Fellowships for Young Scientists.