Multi-grade lubricating oils

To provide a mechanism of gellation for petroleum-based greases and encapsulants. Related to this, block copolymers provide viscosity index improvement in multi-grade lubricating oils. Tri-block copolymers... 

Viscosity Index Improver Viscosity index improvers, which can be present in multi-grade lubricating oils, can bias measurements. However, the biases can be reduced to negligible proportion by using the specified solvent-to-sample dilution and an internal standard. 

Lubricant additive, usually a high molecular-weight polymer, that reduces the tendency of an oil to change viscosity with temperature. Multi-grade oils, which provide effective lubrication over a broad temperature range, usually contain V.I. improvers. 

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