Waste silicone cross-linked polyethylene (Si-XLPE) recycling effectively by using solid-state shear mechanochemical (S 3 M) technology was investigated to make the better performance thermoplastic polyethylene. To make this thermoplastic material, the cross-linked structures of waste Si-XLPE that was consisted of the siloxane bonds must be de-cross-linked selectively instead of the destruction of the material main chains. The properties of recycled Si-XLPE materials were investigated by gel fraction measurements, gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter, torque rheological measurements, scanning electron microscope (SEM) and thermogravimetric analyzer (TG). From the results, it could be seen that the cross-linking bonds of the Si-XLPE were destroyed selectively by S 3 M technology and the mechanochemical milling also played a significant role in improving the materials process-ability and mechanical properties. Gel fraction measurements, GPC and FTIR showed that S 3 M technology could interrupt the cross-linked structures of Si-XLPE rather than the backbone chains by initiating the de-cross-linking reaction obviously; Torque rheological results further confirmed that the recycled Si-XLPE materials gained better plastic characteristics and process-ability after mechanochemical milling. Compared with the untreated Si-XLPE, the tensile strength and elongation at break of Si-XLPE samples after 10 cycles milling increased by 118.4% and 330.4%, respectively. J. VINYL ADDIT. TECH-NOL., 00:000-000,

Material recycling of silane cross-linked polyethylene (Si-XLPE) by the solid-state shear milling (S 3 M) technology could produce thermoplastic polyethylene. To take advantage of thermoplastic polyethylene from Si-XLPE, the de-cross-linked mechanism of Si-XLPE in S 3 M must be evaluated. The products prepared by the S 3 M technology were characterized using gel content, molecular weight measurement (GPC), Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance ( 29 Si-NMR), and re-cross-linking test to obtain insight into the selective de-cross-linking effect of the S 3 M technology. The results had confirmed that a cross-linking element consisting of Si−O−Si chemical bonds was destroyed during S 3 M, which was responsible for the destruction of cross-linked structures of Si-XLPE materials, and the molecular structures of the resulting products were close to that of silane-grafted polyethylene. The mechanical properties of Si-XLPE materials prepared by the S 3 M technology before and after water-cross-linking treatment were compared. It was found that the products obtained by the S 3 M technology could still undergo the cross-linking reaction and form more silane-grafted polyethylene with the increase of milling cycles. Based on the results of this study, we expected that practical applications of de-cross-linking of Si-XLPE materials could be successfully achieved. In this study, favorable conditions were established for the direct recovery of thermoplastic polyethylene from Si-XLPE by the selective de-crosslinking reaction in S 3 M and an idea about the recycling of Si-XLPE materials was developed.

In this study, the silicone cross-linked polyethylene (Si-XLPE) powder with better thermoplastic performance and abundant cross-linked network points was attained by using solid-state shear mechanochemical (S 3 M) technology and it was added into high-density polyethylene (HDPE) matrix to prepare Si-XLPE/HDPE tubes by a rotation extrusion rheometer. SEM and 2D-SAXS experiments showed that the presence of Si-XLPE and rotation extrusion facilitated the formation of stable shish-kebabs which deviated from the axial direction in polyethylene (PE) tubes. This result was interpreted that introduction of Si-XLPE in PE tubes provided abundant molecular cross-linked network structures, which suppressed the thermal movement and relaxation of oriented molecular chains owing to intermolecular interaction. Moreover, the axial and hoop flow field further promoted orientation of the permanent cross-linked network entanglement points and formation of more stable cluster-like shish structures in the off-axial direction during the rotation extrusion process. Besides, our experimental results had also ascertained that molecular orientation and shish-kebabs in off-axial direction should be the primary responsibility for the remarkable enhancement of hoop torsional strength in PE tubes. Hoop torsional strength of PE tubes adding Si-XLPE reached 19.58 MPa when the mandrel rotation rate was 30 r.p.m., while that of conventional extruded PE tubes was only 9.83 MPa. As a consequence, PE tubes with excellent performance were prepared under the combined effect of Si-XLPE and rotation extrusion.

Sodium-ion batteries (SiBs) are highly promising to substitute lithium-ion batteries (LiBs) in wide applications, such as energy storage. The metal sulfide or selenium are candidate anodes for high-energy density SiBs resulting from their theoretically higher initial coulombic efficiency, higher conductivity, and lower voltage polarization. Herein, we found that GeSe 2 is more favorable than GeS 2 for Na ion storage. The first-principle calculation revealed that the formation energy of GeSe 2 is 54.997 kJ mol −1 less than that of GeS 2 , Ge−Se bonds are easier to rebuild than Ge−S bonds, and Na 2 Se is easier to decompose than Na 2 S. The experimental investigation proved that all Na ions are reversible in a GeSe 2 /Na battery system when the operated voltage window was fixed in 0.01−3 V, which is not realized in a GeS 2 /Na battery. With galvanization discharge/charge voltage fixed in 0.01−2.5 V, the reversible capacity of GeSe 2 /C in the 1st,

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