Remarkable Promotion Effect of Sulfation over the SiO₂‐Supported Vanadium‐Oxide‐Based Catalysts for UHMWPE

Abstract

The effects of sulfation on VOx/SiO2–MOy (M = Al, Zr, or Ti) are systemically studied for the synthesis of ultrahigh molecular weight polyethylene (UHMWPE), showing that the activity remains stable under the investigated polymerization temperature (Tp) from 70 to 90 °C, and is almost doubled after sulfation. According to the results of NH3–TPD, pyridine‐adsorption‐fourier transform infrared spectroscopy (FTIR) and X‐ray photoelectron spectroscopy (XPS), the enhancement effect in activity is likely related to the promoted acidity of the catalysts and the increased electron deficiency of the V center. Remarkable cocatalyst dependence is found and has the priority of diethylaluminum chloride (DEAC) > ethylaluminum sesquichloride > triisobutylaluminum > triethylaluminum, and the highest activity of 5200 kg PE mol−1 V could be obtained with DEAC as cocatalyst. The viscosity average molecular weight (Mv) of the PEs can be regulated from 3 to 5 × 106 g mol−1 by decreasing Tp from 90 to 70 °C. Based on the results of differential scanning calorimetry (DSC) annealing experiments, highly entangled UHMWPE is produced.

Shish‐kebab structure evolution of HDPE/UHMWPE during hot drawing

“…In our prior research, we successfully synthesized an array of high-performance bimodal PE in reactor alloys using custom-designed catalysts. [43][44][45][46][47][48] Subsequently, we created a series of HDPE/UHMWPE blends through solution blending, characterizing their exceptional mechanical properties. 49 Our findings revealed that incorporating UHMWPE increased the blend's crystallization rate, while elevating the ultrasonic intensity led to more stable crystal nucleus structures and thicker crystal layers.…”

“…In our prior research, we successfully synthesized an array of high‐performance bimodal PE in reactor alloys using custom‐designed catalysts 43–48 . Subsequently, we created a series of HDPE/UHMWPE blends through solution blending, characterizing their exceptional mechanical properties 49 .…”