This powerpoint is presented by Emad Behdad

1. FILM FORMATION
IN COATINGS
PROVIDED BY :
EMAD BEHDAD

2. 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

3. 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.

4. Polymers
Cross-Linking Polymers
Natural rubber is
Bonds formed
too soft and
between
chemically
polymer chains
reactive to make
make the
a useful
polymer stiffer.
material.
By vulcanizing
the rubber
Rubber is
(cross-linking
usually cross-
the polymer
linked with
chains) useful
sulfur.
materials are
made.

6. 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,

7. 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.

8. Effects of tg on volume and modulus

9.  • larger variety of precursors
 • many processing options
 preparation of inorganic-organic hybrid materials
possible
 low thermal stress of the substrate
 simple coating techniques

10. SOL GEL PREPARATION

11. Sol-gel processing scheme

12. Sol-gel facilities

13. Coating
techniques
Flow
Dipping
coating
Rolling Spraying
Doctor
Painting
blading

14. spin coating

15. 
DIP COATING

16. REFERENCES
 Journal of Sol-Gel Science and Technology
 WWW.ANAVILLAFRANCA.COM
 Handbook of Sol-Gel Science and Technology