Synthesis And Properties Of Poly-?-olefin Drag Reducer

In order to meet the increasing consumption of refined oil,drag reducing agents can be charged into refined oil to reduce fluid drag within pipelines and increase throughput of refined oil,without increasing the power consumption of the transfer pump or laying new pipelines.Meanwhile,the cost of oil transport can be decreased to a large extent.Therefore,it is of great significance to develop product oil drag reducers with excellent drag reduction properties and good dissolving properties.In this paper,high-carbon alpha olefins were used as polymerization monomers.The effects of polymerization conditions on the relative molecular weights of the polymers and the polymers'drag reduction rate were investigated.The effects of polymer side chain length on the crystalline properties and drag reduction rate were also discussed.The molecular structures and drag reduction performance of commercial industrial drag reducers were analyzed as well.In the Chapter 2,?-olefin octene was selected as the monomer in the homopolymerization catalyzed by TiCl₄/Al?i-Bu?₃ to prepare polyolefin with ultra high relative molecular weight.The effects of polymerization conditions on the relative molecular weights of the polymers and the effect of polymerization time on polymers'drag reduction rate were investigated.The optimum polymerization conditions were obtained as follows:the polymerization temperature 0?,molar concentration of TiCl₄ as main catalyst 5.2×10^-4mol/L,volume ratio of monomer to cyclohexane 1?1,and reaction time at least 1440 min.Under these conditions,the relative molecular weight of the polymers was higher than3.50×10⁶.The rotating disk system was used to test the polymer drag reduction rate.The drag reduction rate of polyoctene gradually increased,and stabilized at about 14%with the increase of reaction time.In the Chapter 3,under the optimum polymerization conditions,four kinds of long-chain?-olefins,including hexene,octene,decene,and dodecene,were polymerized.The effects of the side chain length of the monomers on the crystallinity and drag reduction performance of the polymer were discussed.The ¹³CNMR results indicated that the polymerization was completed and the resultant homopolymers were consistent with the designed ones.The DSC and XRD measurements showed that when the side chain length of the monomers were four carbon atoms or more,the crystallinity of polymer increased with the increase of side chain length of polyolefin,which affected the solubility of polymer drag reducers.At room temperature,the solubility of polyhexene,polyoctene and polydecene were better than polydodecene and polypentene.The results revealed that the drag reduction rate tended to increase with the increase of the side chain lengths of the drag reduction agents when their relative molecular weights were the same.The drag reduction performance and molecular structure of several commercial drag reducers were compared and analyzed.The results showed that the drag reduction rate ranked as imported BH drag reducer,imported IS drag reducer,and domestic HG drag reducer in order from high to low.The domestic HG drag reducer might be a copolymer of decene and other high-carbon olefins,the imported BH drag reducing agent a hexene-octene copolymer,and the imported IS drag reducing agent a decene homopolymer to our best knowledge.