Polyvinyl Chloride

A.Vigneshwaran (14212003)

Department of Chemical EngineeringM.Tech Chemical Engineering

Petrochemical Technology [CH-551]

Introduction...

Polymer of Vinyl Chloride Monomer.

Third-most plastic polymer after PE & PP.

Transparent with a bluish tint.

Pure PVC is a white, brittle solid.

Insoluble in alcohol but slightly soluble in tetra-hydro furan.

Resistance to fire, water, oils and it has a low permeability to gases.

When PVC is burnt, it produces Chlorine which inhibits fire.

Not Suitable above 70°C.

History...

1872 - PVC was accidentally synthesized by German chemist Eugen

Baumann. The polymer appeared as a white solid inside a flask of vinyl

chloride that had been left exposed to sunlight.

1907 - The Russian chemist Ivan Ostromislensky and Fritz Klatte of the

German chemical company Griesheim-Elektron both attempted to use PVC

in commercial product.

1926 - Waldo Semon and the B.F. Goodrich Company developed a method

to plasticize PVC by blending it with various additives.

1950's - PVC volumes increased dramatically around the world. Purest

Refinery processes.

1960’s - A vinyl-based latex was formulated.

1980’s – Only Twenty companies were producing PVC.

Today - The third largest-selling commodity plastic in the world.

Production ...

PVC Production ...

80% - Suspension polymerization.

12% - Emulsion polymerization

8% - Bulk polymerization.

VCM and water are introduced into the reactor and a polymerizationinitiator, along with other additives. The reaction vessel is pressure tight tocontain the VCM. The contents of the reaction vessel are continually mixed tomaintain the suspension and ensure a uniform particle size of the PVC resin.The reaction is exothermic, and thus requires cooling. As the volume is reducedduring the reaction (PVC is denser than VCM), water is continually added tothe mixture to maintain the suspension. The polymerization of VCM is startedby compounds called initiators that are mixed into the droplets. Thesecompounds break down to start the radical chain reaction. Typical initiatorsinclude dioctanoyl peroxide and dicetyl peroxydicarbonate, both of which havefragile OO bonds. Some initiators start the reaction rapidly but decay quicklyand other initiators have the opposite effect. A combination of two differentinitiators is often used to give a uniform rate of polymerization.

PVC Production ...

After the polymer has grown by about

10x, the short polymer precipitates inside the

droplet of VCM, and polymerization

continues with the precipitated, solvent-

swollen particles. The weight average

molecular weights of commercial polymers

range from 100,000 to 200,000 and the

number average molecular weights range

from 45,000 to 64,000. Once the reaction has

run its course, the resulting PVC slurry is

degassed and stripped to remove excess

VCM, which is recycled. The polymer is then

passed through a centrifuge to remove water.

The slurry is further dried in a hot air bed, and

the resulting powder sieved before storage or

pelletization. Normally, the resulting PVC has

a VCM content of less than 1 part per million.

PVC Production…

A typical Formulation for an S-PVC Reaction ..

• De-ionized water 1000 kg

• VCM 725 kg

• Protective Colloid 0.725 kg

• (0.1wt% based on VC)

• Radical Initiator 3.6 kg

• (0.5wt% based on VC)

• Sodium Bicarbonate 0.19 kg

• (0.025wt% based on VC) (pH buffer)

PVC Production…

Animation Courtesy :

AGC Group- PT Asahimas Chemical, Indonesia.

(http://www.asc.co.id )

PVC Production ...

Mechanism of Polymerization ...

Mechanism of Polymerization ...

PVC Properties ...

PVC is a normal impact, high corrosion resistant polymer.

Because of its exceptional corrosion resistance, it is ideally suited for

applications where maximum chemical resistance is necessary.

Its high strength-to-weight ratio, cost efficiency, ease of fabrication and

economic balance make it the material of choice.

PVC conforms to ASTM D-1784-95 Class 12454-B (Formerly Type I

Grade 1) and is manufactured without the use of plasticizers or fillers.

It can be used in self-supporting construction up to 140º F (depending on

chemistry).

It exhibits excellent fire ratings (UL-94V-0) and has a flame spread under

20 per ASTM-E-84.

PVC Properties ...

Strength – PVC combines tensile strength and stiffness for the toughest

applications.

Chemical Resistance – PVC is resistant to most acids and alkali solutions.

Workability – PVC can be machined, cut, welded and glued for fabrication

versatility.

Low Cost – PVC is an economical choice for fabricating equipment, tanks,

pumps etc.

Consistency – PVC is extruded through most of the available gauges for

dimensional consistency.

Flammability – PVC is self-extinguishing.

References... http://guichonvalves.com

http://pslc.ws/macrog/pvc.htm

http://wiki.zeroemissions.at/index.php?title=Polyvinyl_chloride

http://www.asc.co.id

http://www.chemicalassociates.co.uk/chemicalassociatescasestudies/theelimination

offisheyesinsuspensionpvc/

http://www.dynalabcorp.com/technical_info_pvc.asp

http://www.elmhurst.edu/~chm/vchembook/401addpolymers.html

http://www.pvc.org/en/p/pvcsphysicalproperties

http://www.rusvinyl.ru/en/41/76

http://www.vec.gr.jp/english/library/fact/chapter1.html

Polymer Science, by V.R.Gowarikar.

www.aqualon.com

www.ausetute.com.aupvc.html

www.parsethylene-kish.com

A Polymer by

A.Vigneshwaran (14212003)

*gk Sprites