In:
Macromolecular Chemistry and Physics, Wiley, Vol. 218, No. 19 ( 2017-10)
Abstract:
The effects of sulfation on VO x /SiO 2 –MO y (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 ( T p ) from 70 to 90 °C, and is almost doubled after sulfation. According to the results of NH 3 –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 ( M v ) of the PEs can be regulated from 3 to 5 × 10 6 g mol −1 by decreasing T p from 90 to 70 °C. Based on the results of differential scanning calorimetry (DSC) annealing experiments, highly entangled UHMWPE is produced.
Type of Medium:
Online Resource
ISSN:
1022-1352
,
1521-3935
DOI:
10.1002/macp.v218.19
DOI:
10.1002/macp.201700236
Language:
English
Publisher:
Wiley
Publication Date:
2017
detail.hit.zdb_id:
1475026-0