Different types of base oils have a significant impact on the performance of poly(methyl methacrylate) additives, specifically manifested in aspects such as the improvement of thickening performance, viscosity index, pour point reduction effect, and shear stability. The following is a detailed introduction:
Thixotropic property
The polarity and refining degree of the base oil will affect the viscosity-increasing performance of the poly methyl methacrylate additive. The refined base oil with a lower refining degree and higher polarity can better dissolve the poly methyl methacrylate according to the principle of like dissolves like. The molecules of poly methyl methacrylate can extend more fully, resulting in the strongest viscosity-increasing effect. Hydrogenated base oil has a slightly smaller polarity, and the poly methyl methacrylate molecules in the oil are in a slightly curled state, with a smaller flow physical volume, and the viscosity-increasing effect is second. Synthetic hydrocarbons (such as PAO base oil and CTL base oil) have a high refining degree, high saturation, and weak polarity. They have poor solubility for poly methyl methacrylate and the viscosity-increasing effect is the weakest.
Improvement effect of viscosity index
In base oils with relatively low saturated hydrocarbon content, poly(methyl methacrylate) has a better effect in improving the viscosity index. For example, when poly(methyl methacrylate) is added to refined base oil, the improvement effect on the viscosity index is significant. However, in synthetic hydrocarbons with high saturated hydrocarbon content (saturated hydrocarbon content 100%), the effect is relatively poorer. Moreover, as the amount of poly(methyl methacrylate) added increases, the improvement effect on the viscosity index of the base oil gradually weakens.
The effect of reducing the pour point
Poly(methyl methacrylate) has significantly different effects on reducing the pour point of different base oils. In refined base oils and hydrogenated base oils, when the additive dosage increases to 6.0%, the pour point will significantly decrease. Beyond this dosage, the pour point hardly continues to decrease. In synthetic hydrocarbons, when the dosage of poly(methyl methacrylate) is 1.0%, the pour point of the oil will be significantly reduced. For example, the pour point of PAO base oil can be reduced from -36℃ to -66℃. However, when the dosage exceeds 1.0%, the pour point will instead increase.
Shear stability
The higher the content of saturated hydrocarbons in the base oil, the better the shear stability of poly methyl methacrylate.
