Influence of Polyisoprene as Additiveson The Properties of Lubricating Oils

The object of this research is to study the influence of Polyisoprene as additive on the properties of base lubricating oils. Two types used of Polyisoprene which are (1502 &1320).The reason of polyisoprene used as additive because polyisoprene is the one types of viscosity improvers, cheap cost and available in Iraq.Measurements were made on three types of base lube oil stocks (40, 60&150) with a wide range of API gravities (34.97 for stock 40 , 29.29 for stock 60 and 20.65 for stock 150), first with (Polyisoprene 1502) and second with (Polyisoprene 1320) at different weight percent (concentration)of additives as follows: ( 0 , 0.5 , 1 , 2 , 4 , 6 & 8 %).The reason of used different weight percent of polyisoprene until 8% to showing the large influence of polyisoprene on base oil but in most industrial used additives from a few parts per million to 10 or 20 %.The properties of binary mixtures such as (Flash Point, Rust Test, Pour Point, Viscosity, Viscosity Index &Foam Test) were measured. It was Found that the two types of Polyisoprene have succeeded to raise (Viscosity, Pour Point,Viscosity Index and Rust test), the percent of rust decreases when weight percent of Polyisoprene increase, (Flash Point) decrease when weight percent of Polyisoprene increase because of benzene used as solvent to Polyisoprene, and no effect occurred when Polyisoprene was added on the (Foam test) of base oil.Comparison between the measured and calculated values of all the studied Iraqi-oil stock blends for different weight percent were found to be satisfactory, with an average absolute error of (3.9%) for (Flash Point), (8.4%) for (viscosity), (9.28%) for (Rust Test), (7.7%) for (Pour Point) and (6.56%) for (Viscosity Index) for the (498) data points used.