Poly-¦Á-olefin Dra Coated And Dispersed Research

Drag reducing agents in fluids can reduce fiction greatly in a fully developed turbulent channel flow. So it is very important that they can improve transport capacity of pipeline, save energy and reduce the cost of transportation. At present the most effective drag reducing agent is alpha-polyolefins. It must be prepared as suspension in order to be used more conveniently. The alpha-polyolefins usually need the surface treated because it can conglomerate easily for its high adhesive and elastic ability. In order to prevent conglutination, we often add dispersing agent to alpha-polyolefins suspension. However it usually has no good results because it dispersed by simple physical separating.In this paper the method of coating alpha-polyolefins via PVA modified urea-formaldehyde resin is reported for the first time. And we have got a good result in dispersion. Firstly we prepared PVA modified urea-formaldehyde prepolymer in alkalescent condition, and then the prepolymer solution polycondensed by citric acid activator in the mixture solution of 1-butanol and water. The indiscerptible urea-formaldehyde resin coated on the surface of alpha-polyolefins. Finally the alpha-polyolefins was dispersed in the solution steadily and equably by various accessory ingredients.In order to confirm the optimum condition of preparing urea-formaldehyde prepolymer, we have examined various conditions. And the optimum preparing condition was that 2.2% PVA, the ratio of urea to formaldehyde was 2:3, the catalyzer was TEA, the pH value was 8, and reacted 120min at 80℃. The prepolymer prepared in this condition was stable and had a good effect on coating alpha-polyolefins. We also confirmed the condition of polycondensation and coating. The optimum solvent was mixture of 1-butanol and water by the ratio of 4:1, the mixture's HLB value of S2 and T1 was 7, the pH value was 1.5 and reacted 120min at 30℃. The coating ratio of alpha-polyolefins can reach 95%.Furthermore, the following nonaqueous DRA and aqueous DRA were prepared. We also confirmed the formula of DRA suspensions each other. The formula of nonaqueous DRA suspension was 21.9% coated alpha-polyolefins, 65.4% 1-butanol, 2% CH-1A, 8.7% ethylene glycol monomethylether, 1% EBS and 1% 1-Octadecanol. The formula of aqueous DRA suspension was 21.9% coated alpha-polyolefins, 69.3% mixed solvent of ethanol and water by the ratio of 3:5, 1.2% PEG-2000, 0.8% TEA, 1.6% mixed S2 and T1 with the HLB value was 9, 0.03% HEC, 0.9% stearic acid, 3.9% liquid olefin and 0.4% Hexadecanol. The results indicated that the DRA suspensions prepared by coated alpha-polyolefins can disperse stably and have a good drag reducing capability. The drag reduction effectiveness can reach 40.36% and 39.43% by different suspensions.