A new drag‐reducing polymer with improved shear stability for nonaqueous systems

摘要

AbstractTri‐n‐butylstannyl fluoride exhibited 75 drag reduction in a capillary rheometer at 25,000 Reynolds number in hexane at 0.1 concentration. There was no loss of drag reduction from shear degradation after 300 cycles at 17,000 Reynolds number. Tri‐n‐butylstannyl chloride showed no drag reduction under these same conditions. Polyisobutylene, similarly examined, gave 72 and 69 drag reduction at 0.01 and 0.1 concentrations, respectively; but after 300 cycles at 17,000 Reynolds number, the drag reduction fell to 45 for the 0.1 solution and to 40 after only 100 cycles for the 0.01 solution. The effectiveness of tri‐n‐butylstannyl fluoride is explained by the formation of a linear polymer SnF‐ ‐ ‐Sn—F‐ ‐ ‐ in which pentacoordinate tin is linked through fluorine bridges. The relative viscosity of tri‐n‐butylstannyl fluoride in hexane increased more rapidly with increased concentration and decreased more rapidly with increased temperature than similar solutions of polyisobutylene. This result is probably due to a shift in the average molecular weight