الفهرس 
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Abstract
In the present study,
1- A different types of surfactants were synthesized
A. Cationic thiol surfactants were synthesized:
1- Thiol surfactants (1-decane,1-dodeane and 1- hexadecane) -2-mercapto pyridine bromide (I,II and III) were synthesized via reaction of 2-mercaptopyridine and a mixture of alkyl halides with different alkyl chain lengths (1-bromo decane, 1- bromo dodecane and 1- bromo hexadecane) respectively .
2- Thiol surfactants (1-ocane,1-decane and1-dodecane) -4-mercapto pyridine bromide (IV,VandVI) were synthesized via reaction of 4-mercaptopyridine and a mixture of alkyl halides with different alkyl chain lengths (1-bromo octane,1- bromo decane and 1- bromo dodecane) respectively.
B. Amphoteric surfactant 4-(((1-dodecylpyridine bromide)-4-yl) methylene) amino) sodium benzoate (VII) and di-cationic surfactant 1-dodecyl-4-(((1-dodecylpyridine-4-yl)imino)methyl)pyridine bromide (VIII) were synthesized in two steps:
- The first step, a mixture of 4-nicotine aldehyde and sodium 4-amino benzoate was refluxed with 4-amino pyridine.
- The second step, the products prepared in the first step were refluxed with (1-bromododecane).
Then the structures of the prepared surfactants were inferred from spectral data (FTIR,1HNMR and Mass spectrum).
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2- Preparation of nanobentonite
Nanobentonite was prepared by crushing bentonite with the aid of a planetary Ball Mill PM 400.
Then characterized it by using : X-Ray Fluorescence , X-Ray Diffraction, FTIR and Transmission Electron Microscopy
3- Fabrication of nanocomposites
Fabrication of all nanocomposites by hand-lay-up method and cured at room temperature and atmospheric pressure.
I- Using nanobentonite/polyester
Adding different weight of nanobentonite to polyester, which showed increased in all the thermal and mechanical properties of nanocomposites by increasing the loading % weight of nanobentonite and showed maximum thermal and mechanical properties at 5% weight, but these properties decreased with increasing more than 5% weight lead to increasing the viscosity of nanocomposites which act as stress concentrators on the nanocomposite surface.
II- Using the prepared surfactants as additives to 5% nanobentonite/polyester, nanocomposites were fabricated as follow:
(A): Polyester / nanobentonite,
(B): Polyester / nanobentonite/ surfactant I,
(C): Polyester / nanobentonite / surfactant II,
(D): Polyester / nanobentonite / surfactant III,
(E): Polyester / nanobentonite / surfactant IV,
(F): Polyester / nanobentonite / surfactant V,
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(G): Polyester / nanobentonite / surfactant VI,
(H): Polyester/ nanobentonite/ surfactant VII,
(Y): Polyester/ nanobentonite / surfactant VIII.
4- Investigated the properties of all fabricated nanocomposites
• Thermal properties: Thermal gravimetric analysis (TGA) and Differential Scanning Calorimeter (DSC).
• Mechanical properties: tensile, flexural, compression and hardness.
• Morphological structure: Scanning Electron Microscopy (SEM) .
5-Addition different types of prepared surfactants to nanobentonite powders increased the mechanical and thermal properties of fabricated nanocomposites (B, C…, Y) than nanocomposite (A) which containing nanobentonite only.
6- But addition prepared surfactants (VI) to 5% weight of nanobentonite and polyester give nanocomposite (G) which had the following properties:
- Thermal properties of nanocomposite (G) , TGA analysis showed weight loss constant up to 400 ᵒC which the same temperature of decomposition 50 % of original weight of pure polyester and DSC analysis showed that Tg value increased from 358.1 °C (value of pure polyester) to 374.5°C (value of nanocomposite G) .
So nanocomposite (G) showed the best thermal stability due to surfactant (VI) act as a heat sink to accelerate the heat absorption of polyester.
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- Mechanical properties of nanocomposite (G), nano composite (G) showed improved the tensile strength about 17.5 %, improved flexural strength about 14.9% while improved the compressive strength about 22.8 % and improved hardness about 24.4% compared polyester.
So nanocomposite (G) showed the best mechanical properties compared other nanocomposites.
- Morphological structure, SEM showed nanocomposite (G) with uniform appearance and homogenous structure .
7- from the above results it can be concluded that nanocomposite (G) showed the optimum thermal and mechanical properties so it can be recommended to be used in the manufacture of drinking water pipes.