AMA (Poly-Methyl-Methyl-Acrylate) are the most preferred polymer types. When these polymers are to be used in engine oils, attention is paid to the property known as SSI (Shear Stability Index). The SSI index is the degradation and loss of polymer structure after processing or operation. The lower the SSI, the more synthetic the polymer becomes and the less it degrades. Currently, the most preferred polymer in engine oils is OCP polymer,