Molecular Dynamics Simulations for Resolving Scaling Laws of Polyethylene Melts

Long-timescale molecular dynamics simulations were performed to estimate the actual physical nature of a united-atom model of polyethylene (PE). Several scaling laws for representative polymer properties are compared to theoretical predictions. Internal structure results indicate a clear departure from theoretical predictions that assume ideal chain statics. Chain motion deviates from predictions that assume ideal motion of short chains. With regard to linear viscoelasticity, the presence or absence of entanglements strongly affects the duration of the theoretical behavior. Overall, the results indicate that Gaussian statics and dynamics are not necessarily established for real atomistic models of PE. Moreover, the actual physical nature should be carefully considered when using atomistic models for applications that expect typical polymer behaviors

Supramolecular sulfur-containing polymers with hydrogen bonding

Although sulfur-containing polymers have been realized by various methods such as copolymerization and reverse vulcanization, there are few reports on the synthesis of supramolecular sulfur-containing polymers in which a supramolecular polymer is fused with a sulfur-containing polymer. Herein, we prepare a supramolecular sulfur-containig polymer by introducing a 2-ureido-4[1H]pyrimidinone (UPy) unit at both ends of linear sulfur and connecting between the UPys via hydrogen bonding.This is an Accepted Manuscript of an article published by Taylor & Francis in Journal of Sulfur Chemistry on 03 Mar 2023, available at 10.1080/17415993.2023.2183773

Study of Gamow-Teller transitions from132Sn via the (p,n) reaction at 220 MeV/u in inverse kinematics

International Conference on Nuclear Structure and Related Topics (NSRT15)The charge-exchange (p, n) reaction at 220 MeV has been measured to extract the strength distribution of Gamow-Teller transitions from the doubly magic unstable nucleus 132Sn. A recently developed experimental technique of measuring the (p, n) reaction in inverse kinematics has been applied to the study of unstable nuclei in the mass region around A∼100 for the first time. We have combined the low-energy neutron detector WINDS and the SAMURAI spectrometer at the RIKEN radioactive isotope beam factory (RIBF). The particle identification plot for the reaction residues obtained by the spectrometer provides the clear separation of the CE reaction channel from other background events, enabling us to identify kinematic curves corresponding the (p, n) reaction. Further analysis to reconstruct the excitation energy spectrum is ongoing