A Comparative Study of AlCl₃ and FeCl₂-Modified TiCl₄/MgCl₂/THF Catalytic System in the Presence of Hydrogen for Ethylene Polymerization

Table 4

Influences of Lewis acids and hydrogen on polyethylene.

Catalyst	H2/C2H4 molar ratio	Melting temperature; () in °C	Crystallinity; () in %	Mw; (g/mol)	Mn; (g/mol)	Mw/Mn
None-THF	0	132.9	55.4	—	—	—
	0.08	131.2	58.0	452,127	74,155	6.1
	0.20	129.8	59.7	249,214	40,292	6.2
	0.30	129.0	56.2	178,786	31,277	5.7
Al-THF	0	133.8	54.7	—	—	—
	0.08	131.2	60.7	335,552	53810	6.2
	0.20	130.0	60.1	204,614	35,852	5.7
	0.30	130.1	68.5	189,568	33,557	5.7
Fe-THF	0	134.2	52.8	—	—	—
	0.08	131.9	55.7	370,021	56,998	6.5
	0.20	130.0	66.8	230,272	35,756	6.4
	0.30	130.0	62.8	201,312	29,107	6.9

Determined by DSC.
Determined by GPC.
Condition: polymerization was performed in 2 L autoclave, [Ti] = 0.008 mmol for all catalysts, Al/Ti molar ratio = 140, cocatalyst = TEA, polymerization time = 1 h, reaction temperature = 80°C, total pressure = 8 bars under 1 bar of nitrogen, and desired amount of H₂/C₂H₄ molar ratio = 0, 0.08, 0.20, and 0.30.