الفهرس 
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Abstract
his thesis includes four chapters:
1- Chapter 1, includes introduction and aim of work.
2- Chapter 2, includes materials and methods.
3- Chapter 3, includes results and discussion.
4- Chapter 4, includes the references.
Among the various polymeric additives employed to formulate
modern engines and industrial lubricants, are the types which act as
viscosity index improvers and pour point depressants.
This work is aimed at synthesing of some high homopolymers and
copolymers which can be used to improve viscosity index and depress
pour point for lubricants.
It can be a merit if these polymers acquired high shear stability
under engines operation conditions.
Accordingly, the thesis is divided in the following parts:-
1. Introduction, which includes:
- Properties of crude oils and their refining methods to produce
lubricating base oils.
- Classification of finished lubricating oils, either as engine or
industrial lubricants.
- Types of additives for lubricating oils, which in use to improve
their properties or even enhance new properties.
- Types, properties and effects of polymeric additives in use with
different lubricants.
- Polymerization techniques to synthesis different types of the
polymeric additives.
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2. Aim of the work is concentrated on synthesis of high polymers
and copolymers, which can be used with base oils as viscosity
index improvers and pour point depressants.
3. Experimental part, which includes the following:-
- Methods to synthesis homopolymers and copolymers.
- Properties of used materials and chemicals.
- Specifications for used analytical and experimental instruments.
- Measurements of properties for synthesized polymers which
include the following:
• Solubility in different base oils.
• Molecular weight determination.
• Structure characterizations via IH NMR and IR
spectroscopy.
- Measurements of performance properties for blends of
synthesized polymers with neutral base oils, which include:
• Measurements of viscosities at different temperatures.
• Calculation of viscosity index for different blends.
- Measurements of performance under different mechanical shear
forces.
- Measurements of pour point for different lubricant - polymeric
blends at low temperatures.
4. Results and discussion, which includes:
- Characterization properties for synthesized polymers.
- Properties of synthesized polymers with neutral base oils.
- Evaluations for polymers blends functions on properties of
lubricant.
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~ Change in polymers chemical and their addition ratios are also
considered.
- Relation between performance properties for synthesised
polymers as additives with their monomers ratios, chain length
of alkyl groups and final chemical compositions.
5. Summary
6. Sources and references for datas proposed techniques and
evaluations methods, which are used allover the thesis.
In the experimental part the following reactions are carried out.-
a- Homopolymerization reactions to synthesis polyalkylmethacrylates
and polystyrenes.
b~ Copolymerization reactions to synthesis styrene with the
following monomers:
1- Octyl methacrylate (OCMA)
2- Dodecyl methacrylate (DDMA)
3- Octadecyl methacrylate (ODMA)
c- Quaternary copolymerization reactions between styrene and
different monomers of alkylmethacrylates.
In all these reactions, dimethyl formamide (DMF) is used as a solvent,
benzoyl peroxide is used as a free radical initiator.
Reaction temperature is 75°C for a time of 4 - 7 hour.
Copolymers composition are evaluated and confirmed VIa IH
NMR and IR spectroscopy.
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To study rate of change in properties of polymer blends with base
oils under different temperatures, copolymer of styrenealkylmethacrylates
is used at concentration 5% wt. Reaction temperature
is withen the range from 30 to 90°C.
Results are compared with homopolymers of polyalkyl
methacrylates and polystyrenes under same conditions. whereas styrenealkylmethacrylates
copolymer viscosity values were intermediate”among
those of homopolymers, which improve the aim to prepare this
copolymers.
Results are showed that styrene-alkylmethacrylate copolymers
have viscosity values in between those of the other two homopolymers,
such results support the thesis aim, i.e. to synthesis styrenealkylmethacrylate
copolymers with a good balance 10 their
characteristics.
To detect the optimum percentage of monomers in the composition
of copolymer which act as viscosity index improvers or pour point
depressants, different ratios of styrene and alkylmethacrylate are used,
from 0.1 mol to 0.9 mol styrene with vice verse 0.9 mol to 0.1 mol
alkylmetbacrylates. The best ratio is found at styrene 0.4 mol, with
alkylmethacrylate 0.6 mol.
Molecular weight of synthesised copolymers are found within the
range from 94509 to 385618, which is in accordance with what require to
- used as lubricant polymeric additives.
Influences of different parameters (chain length of different
alkylmethacrylates and their incorporation” ratios) on properties of
synthesized copolymers are measured and discussed.
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Viscosities and pour points for copolymers dissolved at different
.concentrations (0.5 - 2% wt) in a mixture of base oils (80% neutral base
oil 260/290 and 18-19.5% bright stock oil) at temperatures 40°C
& 100°C, are measured, then their viscosity indices are calculated.
Obtained results are according to the following:
Change in ,-
Synthesised copolymers and
quaternary copolymers at cone. Viscosity, eSt
Viscosity Pour
2wt.% at at index point
40°C 100°C
Blank lubricant mixture 69.7 6.8 92 -3
Sty-octyl methacrylate (I) 86.76 10.88 111 -18
Sty-dodecyL methacrylate (II) 100.23 12.59 120 -3
S-ty-octadeeyl methacrylate (III) 124.71 21.09 196 -15
Sty-OCMA-DDMA-ODMA (IV) 94.65 11.65 112 -6
Sty-OCMA-DDMA-ODMA (V) 105.55 13.09 120 -18
Sty-OCMA-DDMA-ODMA (VI) 93.89 11.48 110 -3
These results indicate that synthesised copolymers and quaternary
copolymers ean be used as viscosity index improvers and/or pour point
depressants.
As these types of copolymers are not yet available commercially,
therfore their performance efficiencies are comparatively evaluated with
available commercial typed, e.g, styrene - isoprene copolymer and
polyalkyl methacrylate.
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Synthesised copolymers are found with performance properties
better than commercial ones.
Shear stability index (SSI) IS 16.9 @100 °C for synthesised
copolymers found better in comparison to 25, for styrene-isoprene
copolymer and 55 for polyalkylmethacrylates .
On the other hand, it has been found that synthesized [Sty-OCMADDMA-
ODMA (V)] quaternary copolymer is the most efficient pour
point. depressant. It acquires more depression in pour, point than
polyalkylmethacrylate commercial additive, wheras it decrease from
-3°C to -18°C at concentration of 0.5 % wt, while depression with the
commercial additives is stopped at -12°C
Achieved results can greatly help ill synthesis of polymeric
additives with high efficiency for multigrade motor oils over prolonged
performance periods.