Film formation

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FILM FORMATION IN COATINGS PROVIDED BY : EMAD BEHDAD

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This powerpoint is presented by Emad Behdad

Transcript of Film formation

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FILM FORMATIONIN COATINGS

PROVIDED BY :

EMAD BEHDAD

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INTRODUCTION

THE MOST IMPOTRANT STEP IN ANY COATING PROCESS

THIS IS THE CONVERSION OF THE COATING FROM LIQUID TO SOLID

FILM FORMATION BEHAVIOUR AND POLYMER GLASS TRANSITION TEMP

PLAY A SIGNIFICANT CHANGE IN THE PROPERTIES OF A POLYMER

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THERMOPLASTIC COATINGS

What are the thermoplastics? • Commonly referred to as “plastics”.

• Melt on heating and re-solidify on cooling.

• Common plastics are polyethylene, polypropylene, nylon, PVC etc.

• Used mostly for moulding into articles such as bottles, caps and components or by extrusion into packaging, carrier bags, pipes and fibers etc.

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PolymersCross-Linking Polymers

Bonds formed between

polymer chains make the

polymer stiffer.

Natural rubber is too soft and

chemically reactive to

make a useful material.

By vulcanizing the rubber

(cross-linking the polymer

chains) useful materials are

made.

Rubber is usually cross-

linked with sulfur.

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Cross-Linking Polymers

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Thermal Behavior of Polymers

Glass Transition Temperature (Tg)

At low temperatures, all amorphous polymers are stiff and glassy, sometimes

called as the Vitreous State, especially for inorganic polymers.

• On Warming, polymers soften in a characteristic temperature range known as the

glass-rubber transition region.

• The glass transition temperature (Tg), is the temperature at which the amorphous

phase of the polymer is converted between rubbery and glassy states.

• Tg constitutes the most important mechanical property for all polymers. In fact,

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Glass transition

The temperature above which the glass becomes soft and viscous

enough to work is related to the glass transition temperature, Tg.

Below the glass transition temperature, the material is

relatively hard and stiff; above it, it becomes more viscous.

This shows up in the volume/temperature curve.

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Effects of tg on volume and modulus

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Sol-Gel Processing

• larger variety of precursors

• many processing options

preparation of inorganic-organic hybrid materials possible

low thermal stress of the substrate

simple coating techniques

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SOL GEL PREPARATION

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Sol-gel processing scheme

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Sol-gel facilities

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Coating techniques

Dipping

Spraying

Doctor bladingPainting

Rolling

Flow coating

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spin coating

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DIP COATING

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REFERENCES

Journal of Sol-Gel Science and Technology

WWW.ANAVILLAFRANCA.COM

Handbook of Sol-Gel Science and Technology

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THANKS FOR YOUR ATTENTION