A triol-functional crosslinker combining the thermoreversible properties of Diels-Alder (DA) adducts in one molecule is designed, synthesized, and used as an ideal substitute of a traditional crosslinker to prepare thermal recyclable cross-linked polyurethanes with excellent mechanical properties and recyclability in a very simple and efficient way. The recycle property of these materials achieved by the DA/retro-DA reaction at a suitable temperature is verified by differential scanning calorimetry and in situ variable temperature solid-state NMR experiments during the cyclic heating and cooling processes. The thermal recyclability and remending ability of the bulk polyurethanes is demonstrated by three polymer processing methods, including hot-press molding, injection molding, and solution casting. It is notable that all the recycled cross-linked polymers display nearly invariable elongation/stress at break compared to the as-synthesized samples. Further end-group functionalization of this single molecular DA crosslinker provides the potential in preparing a wide range of recyclable cross-linked polymers.

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Herein, we developed a special strategy for the fast sensitization of red emitting copper nanoclusters with the assistance of green emitting copper nanoclusters.

We investigate the size dependence of geometric structure and elastic properties of phosphorene nanotubes (PNTs) with armchair and zigzag forms, by using ab initio periodic quantum chemical method combining with the linear combination of atomic orbitals. Nanotubes are constructed by rolling up the non‐planar honeycomb (010) two‐dimensional conventional monolayer. To explain the strength of bonding between P atoms, the bending stiffness and the amount of charge transfer have been calculated. We obtained different values of bending stiffness that for the PNTs rolled up along the two directions, which shows that the bending stiffness is changing with different chiralities. Our calculations also indicate that the distance between inner and outer atoms increases monotonically with increasing radius, while the charge transfer between the P atoms decreases. The Young's modulus and radial Poisson's ratio are insensitive to the tube radius. Furthermore, the zigzag nanotubes have higher values than armchair nanotubes. In addition, we find that both zigzag and armchair PNTs show semiconducting properties with different radius. It is expected that these properties have potential applications in nanometer‐sized devices design.

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The change in the infrared spectrum of polymer samples with temperature and their differential scanning calorimetry (DSC) experimental results are analyzed. According to the van't Hoff equation at constant pressure, the changes in the absorbance ratio corresponding to high and low vibrational states are calculated, and the apparent enthalpy differences of the vibration energy states transformation of the characteristic group can be obtained. From the experimental results, we can find that characteristic vibration modes of a chemical group in a polymer are under the influence of the glass transition process of the polymer with a different extent. The characteristic vibration modes of the same chemical group behave differently due to the influence of the polymer system at which the chemical moiety is situated.

In this work, solid-state 1 H NMR experiments were conducted to fully characterize the dynamic characteristics of a polystyrene/poly(vinyl methyl ether) blend with a mass ratio of 3 : 1 (PS/PVME 75/25). About 13% of whole PS was determined to locate in the mobile fraction of the PS/PVME 75/25 blend at room temperature. Increasing the temperature of this blend revealed three transitions. These results are expected to improve our understanding of the glass transition process in polymer systems.