Synthesis Of Poly α-oleifn Drag Reducing Agents By Solution Polymerization With Ziegler-natta Catalyst

Poly α-olefin Drag Reducing Agent (DRA) is a kind of olefin polymer withsuper-high molecular weight, and little Drag Reducing Agent added into the crudeoil or product oil can increase transmission capacity. Drag reduction rate can beimproved through control polymerization condition.DRA was synthesized with TiCl4/AlR3as catalyst and α-olefin as monomers bysolution polymerization in this article, including α-hexylene/α-dodecene copolymerwas synthesized with TiCl4/Al(Et)3, α-hexylene/α-dodecene copolymer wassynthesized with TiCl4/Al(i-Bu)3as catalyst, α-hexylene/α-octylene/α-dodeceneterpolymer was synthesized with TiCl4/Al(i-Bu)3as catalyst. Effects of thepolymerization conditions on drag reduction rate were investigated. The bestpolymerization conditions were obtained when drag reduction rate up to the max.The best polymerization conditions with Al(Et)3as catalyst forα-hexylene/α-dodecene copolymer were: volume ratio ofV(α-dodecene):V(α-hexylene)2:3, main catalyst TiCl4dosage0.08g, co-catalystdosage0.4mL, the volume of solution12mL, polymerization temperature0℃. Theresuslts showed that the drag reduction rate could be up to54.46%.The best polymerization conditions with Al(i-Bu)3as catalyst forα-hexylene/α-dodecene copolymer were: volume ratio ofV(α-dodecene):V(α-hexylene)1:1, main catalyst TiCl4dosage0.06g, co-catalystdosage Al(i-Bu)30.4mL, the volume of solution18mL, polymerization temperature-10℃. The resuslts showed that the drag reduction rate could up to58.98%.The best polymerization conditions of the α-hexylene/α-octylene/α-dodeceneterpolymer were: volume ratio of V(α-dodecene): V(α-octylene):V(α-hexylene)3:2:1,main catalyst TiCl4dosage0.06g, co-catalyst Al(i-Bu)3dosage0.2mL,polymerization temperature-10℃, the volume of solution10mL. The resusltsshowed that the drag reduction rate could up to54.11%. Through curve fitting method we found that the linear relation between theintrinsic viscosity, viscosity-average molecular weight and drag reduction rate of thepolymer that synthesized with Al(Et)3was better than the polymer that synthesizedwith Al(i-Bu)3.The choices of catalysts have influence on intrinsic viscosity.The IR, XRD and1HNMR results showed the DRA was α-olefin polymer withlow isotacticity and it was the target.Finally, in the same polymerization conditions, α-hexylene/α-dodecenecopolymer and α-hexylene/α-octylene/α-dodecene terpolymer synthesized withAl(Et)3as catalyst has not difference in IR and1HNMR results. XRD results showthat α-hexylene/α-dodecene copolymer has high isotacticity thanα-hexylene/α-octylene/α-dodecene terpolymer. It can be seen that when increasemonomer types, the isotacticity of drag reducing agents will be reduced.