Lubricant Additives

Dispersants 155

The methods to make DVMs are shown in Figures 5.13 through 5.15. These are synthesized by

Grafting or reacting of a dispersancy-imparting monomer on an already-formed polymer,

as in the case of EPRs and SDRs [76–84].

Including such a monomer during the polymerization process, as in the case of polyacry-

lates and PMAs [85].

Introducing a reactive functional group in the polymer that can be reacted with a reagent to

impart dispersancy, as in the case of styrene–maleic anhydride copolymers [40,86–93].

Although most of the examples in Figures 5.13 through 5.15 pertain to the introduction of the basic
nitrogen-containing moieties, neutral DVMs are also known in the literature. These are made by
using nonbasic reactants, such as N-vinylpyrrolidinone, alcohols, or polyether-derived methacry-
late ester [79,94,95]. Recently, dispersant viscosity–improving additives with built-in oxidation

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Diamines

H 2 N

H 2 N

H 2 N

H 2 N

H 2 N

H 3 C

NH 2

NH 2

NH 2

NH 2

NH 2

Ethylenediamine

Triamines

Tetramines

Triethylenetetramine Aminoethylaminoethylpiperazine

N,N-dimethylaminopropylamine Primary amino group (1°)

Secondary amino group (2°)

Tertiary amino group (3°)

1 °

1 ° 1 °^3 °^2 °

2 °

2 °

3 °

2 ° 3 °

2 °

1 °

1 °

NH 2

1 °

1 °

3 °

CH 3

N

N N

H

N

NN

N

H

N

H

H

NH 2

NH

NH

N

Diethylenetriamine Aminoethylpiperazine

HN N

Bis(aminoethyl) piperazine

Alcohols

HO

HO

OH

OH

HO

HO

OH

Pentaerythritol

CH 3

HO

HO

OH

NH 2

Trimethylolpropane

Tris(hydroxymethyl)propane

Tris(hydroxymethyl)aminoethane

FIGURE 5.8 Amines and alcohols used to synthesize dispersants.