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خدمات الطلاب المكتبية Students Library Services كتب - ملخصات - ملازم - نماذج اختبارات - اعداد للبحوث

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قديم 12-24-2008, 02:07 PM   #1
المبدع2006
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افتراضي طلب اذا سمحتم

السلام عليكم ورحمة الله وبركاته :
اخواني واحبائي عندي طلب ترجمة شريحتين اذا سمحتم لانني استخدمت جوجل وغيره ولم افهم المقصود منهم فياليت تساعدوني في الترجمة الدقيقة واكون شاكراً لكم .
الشريحة الأولى :
Do you know?
The first synthetic dye, picric acid, was prepared in the year 1771 from the natural pigment, indigo.
Have you ever wondered what gives the cloths your the jazzy colours, what gives the printer you use with your desktop the multicoloured printing. The answer to all this lies in the synthetic dyes. No doubt Synthetic dyes today has evolved into a multi billion dollar industry. Almost all the colours that you see today are Synthetic dyes. They are widely used for dyeing and printing in a broad range of industries. There are over 10,000 dyes, and the annual production globally, exceeds over 7 × 105 metric tones. They have become indispensable to the dyeing units specifically to textile units. It is a fact that fashion would not have so much vibrancy in terms of colours and generated so much hype and enthusiasm, were it not for the synthetic dyes. The synthetic dyes, can be named according to the chemical structure of their particular chromophoric group. For example, diphenylmethane derivatives, triphenylmethane compounds oxazine compounds, xanthene compounds, Azo dyes to name a few. Out of these Azo Dyes are one of the most popular varieties of synthetic dyes. Today it is being used up to 90% in the dyeing units, as they are versatile and simple to synthesize. Most of the synthetic dyes with a few exception are aromatic organic compounds which can be divided into groups like non-ionic (oil soluble), cationic, and anionic. A typical example of Cationic dye is Methyl violet, while Azo dyes are anionic dyes.
Synthetic dyes can be primarily made from aniline or chrome. Aniline dyes are obtained from chemical processes and is defined as a class of synthetic, organic dyes. Today the term dye is almost synonymous with any reference of synthetic organic dye or pigment. Aniline dyes are classified based on their degree of brightness or according to light fastness. They are also called coal tar dyes, because the synthetic aniline dyes were made up of coal tar initially, but they faded easily when exposed to sun light. While Chrome dyes were color fast and non-corrosive
الشريحة الثانية:
Mordant dyes can be defined as those dyes that requires a mordant for application as a dye. This upon combining with a mordant imparts insoluble colour on the substrates. The question now is what is a mordant? A mordant can be a substance of organic or inorganic nature that can combine with the coloring matter and is used for fixing in the production of the color.
Features of Mordant Dyes
Mostly mordant dyes have hydroxyl and carboxyl groups. To certain extent they can possess Amino groups.
They are negatively charged, i.e. Anionic.
Mordant dyes stain by ionic interaction like other ionisable dyes.
They ensure light-and-wash-fastness.
Prevents color bleeding.
Has the ability to brighten or changes some dye colors.
Methods of dyeing with Mordant Dye
The mordant dyes are generally applied to fibers by three distinct methods:
In the first method
Mordanting of the fiber is done with an appropriate metallic salt and then the dye is applied.
In the second method the fiber is dyed first and then it is treated with a suitable metallic salt to form an insoluble lake. This is called 'after-chrome' method and is used in fast dyeing of black and brown colour on the substrate wool.
The third method is the simultaneous application of the mordant and the dye. As the processes of 'metachrome' or 'monochrome' in wool dyeing.
About Mordants
The word MORDANT has its origin in the French language, meaning "to bite." Mordants are basically mineral salts which binds dyes into fiber. Over the years many amazing substances were applied as mordants. That includes arsenic and many other deadly chemicals.





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