PMMA

1. Acrylic Family

2. Chemical structure

3. History
•The first acrylic acid was created in 1843. Methacrylic acid,
derived from acrylic acid, was formulated in 1865. The
reaction between methacrylic acid and methanol results in
the ester methyl methacrylate.
•The German chemists Fittig and Paul discovered in 1877
the polymerization process that turns methyl methacrylate
into polymethyl methacrylate.
• In 1933 the German chemist Otto Röhm patented and
registered the brand name PLEXIGLAS. In 1936 the first
commercially viable production of acrylic safety glass
began.
•During World War II acrylic glass was used for submarine
periscopes, and windshields, canopies, and gun turrets for
airplanes.

4. Preparation
•PMMA is routinely produced by emulsion
polymerization, solution polymerization and bulk
polymerization.
•Generally radical initiation is used (including living
polymerization methods), but anionic polymerization of
PMMA can also be performed.
•PMMA produced by radical polymerization (all
commercial PMMA) is atactic and completely
amorphous.
•To produce 1 kg (2.2 lb) of PMMA, about 2 kg (4.4 lb)
of petroleum is needed.

5. Processing:
•The glass transition temperature (T
g
) of atactic PMMA is
105 °C. The T
g
values of commercial grades of PMMA
range from 85 to 165 °C (185 to 329 °F)
•All common molding processes may be used, including
injection molding, compression molding, and extrusion.
•The highest quality PMMA sheets are produced by
cell casting, but in this case, the polymerization and
molding steps occur concurrently.

6. Preparation of monomer
C
C
H
3C
O
H
3C
O
CH
2
Methylmethacrylate
H
2SO
4
125
O
C
C
C
H
3C
NH
2.H
2SO
4
O
CH
2 CH
3OH
H
2O
C
H
3C
CH3
HO
CN
Acetone
cyanohydrin
Methacrylamide
sulphate

7. Preparation
C
C
CH
3
O
CH
3
O
H
2C C
C
CH
3
O
CH
3
O
H
2
C
n
Methylmethacrylate Poly(methylmethacrylate)
polymerisation

8. Synthesis of PMMA via new
techniques
•PMMA can be obtained by conventional
methods of polymerization in emulsion
resulting in particles in the range of 1 to 20
μm.
•Recently, other methods has been used for
the synthesis of this polymer,among them
sonochemistry using ultrasound waves as
the source of energy.

9. Synthesis of PMMA…….
•Polymerization was carried out via free radicals
from an aqueous solution of different
concentrations of a cationic surfactant
cetyltrimethylammonium bromide (CTAB)
and different concentrations of the insoluble
monomer Methyl Methacrylate (MMA) as the
disperse phase.
•The reaction was carried out at a frequency of
20 kHz for 1 h under N2 atmosphere.

10. New method of preparation
H
3C CH
3
OH
CHO
2-hydroxy-2-methylpropanal
O
KMnO
4
H
3C CH
3
OH
COOH
H
2SO
4
H
2C CH
3
COOH
2-hydroxy-2-methylpropanoicacid methacrylicacid
CH
3
OH
H
2
SO
4
H
3C
O
O CH
3
methyl
methacrylate
polymerisation
H
3C
CH2
O
O CH
3
n
polymethylmethacrylate

11. Chemical properties
•PMMA is a linear thermoplastic about 70-75%
syndiotactic. Because of its lack of complete
stereoregularity and bulky side groups, it is
amorphous.
•Both isotactic and syndiotactic PMMA have been
prepared but have not been offered commercially.
H
3C
O
H
3C
H
3C
O
H
3C
H
3C
O
H
3C
H
3C
O
H
3C
O O O O
TheIsotacticPMMAchain

12. Chemical………
•PMMA swells and dissolves in many organic solvents; it
also has poor resistance to many other chemicals on
account of its easily hydrolyzed ester groups.
•It undergoes pyrolysis almost completely to monomer by
a chain reaction because of the active radical and the α-
methyl group that blocks the possibility of chain transfer
reaction.

13. Physical properties
•PMMA is strong and lightweight.
•Outstanding properties include weatherability and
scratch resistance.
•It has a density of 1.150–1.190 g/cm3 about less than
half that of glass and similar other plastics.
•It also has good impact strength, higher than both glass
and polystyrene; however, PMMA's impact strength is
still significantly lower than polycarbonate and some
engineered polymers.
•PMMA ignites at 460 °C (860 °F) and burns, forming
carbon dioxide, water, carbon monoxide and low
molecular weight compounds, including formaldehyde.

14. •Comonomers such as butyl acrylate are often added to
improve impact strength.
•Dyes may be added to give color for decorative applications,
or to protect against (or filter) UV light.
•Fillers may be added to improve cost-effectiveness.
•Comonomers such as methacrylic acid can be added to
increase the glass transition temperature of the polymer for
higher temperature use such as in lighting applications.
:Modification of properties

15. •Transparent glass substitute
•Daylight redirection
•Medical technologies and implants
•Artistic and aesthetic uses
Applications:

16. Applica……..
•William Feinbloom introduced lenses made from PMMA,
contacts became much more convenient. These PMMA
lenses are commonly referred to as "hard" lenses.
•PMMA is used as a shield to stop beta radiation emitted
from radioisotopes.
•PMMA was used in laserdisc optical media and in 3D
optical data storage
•PMMA, in a purified form, is used as the matrix in dye-
doped solid-state gain media for solid state dye lasers.
•Artificial fingernails are made of acrylic.
•Small strips of PMMA are used as dosimeter devices
during the Gamma Irradiation process.

17. •For many years, PMMA has been successfully depolymerised
by contact with molten lead at about 500° C.; the monomer
MMA can be obtained in a purity of more than 98%.
•Although this process gives MMA of high purity, the use of
lead is undesirable, from an environmental viewpoint.
:PMMA Recycling

18. •It can be synthesized as a simple linear-chain structure or
cross-linked. Polyacrylamide is not toxic. However,
unpolymerized acrylamide, which is a neurotoxin, can be
present in very small amounts in the polymerized acrylamide
:Polyacrylamide

19. Stability:
•Chemical degradation occurs when the labile amine moiety
hydrolyzes at elevated temperature or pH, resulting in the
evolution of ammonia and a remaining carboxyl group.Thus,
the degree of anionicity of the molecule increases.
•Thermal degradation of the vinyl backbone can occur through
several possible radical mechanisms, including the
autooxidation of small amounts of iron and reactions between
oxygen and residual impurities from polymerization at
elevated temperature
•Mechanical degradation can also be an issue at the high
shear rates experienced in the near-wellbore region.

20. Uses of polyacrylamide:
•One of the largest uses for polyacrylamide is to flocculate
solids in a liquid.
•Another common use of polyacrylamide and its derivatives is
in subsurface applications such as Enhanced Oil Recovery.

21. •It has also been advertised as a soil conditioner called Krilium
by Monsanto Company in the 1950s.
•The ionic form of polyacrylamide has found an important role
in the potable water treatment industry.

22. Sodium polyacrylate:
•Sodium polyacrylate, also known as waterlock, is a polymer
with the chemical formula [-CH
2
-CH(COONa)-]
n
widely used in
consumer products. It has the ability to absorb as much as
200 to 300 times its mass in water. Acrylate polymers
generally are considered to possess an anionic charge. While
sodium neutralized polyacrylates are the most common form
used in industry, there are also other salts available including
potassium, lithium and ammonium.

23. Mechanism:
•Sodium Polyacrylate polymer can retain excessive
amounts of water because of the osmotic pressure (i.e.
movement of water through a semipermeable
membrane).Osmotic pressure induced by the high water
concentration outside a sodium polyacrylate molecule
draws the water into the center of the molecule. Sodium
polyacrylate continues to absorb the water until there is
an equal pressure of water inside and outside the
sodium polyacrylate molecule.

24. Applications:
•Sequestering agents in detergents. (By binding
hard water elements such as calcium and magnesium)
•Thickening agents
•Coatings
•Fake snow
•Super absorbent polymers

26. References:
•From Wikipedia, the free encyclopedia
•http://www.ehow.com
•http://www.pslc.ws
•http://www.heathland.nl/index.html
•Microsc Microanal 11(Suppl 2), 2005 Copyright 2005
Microscopy Society of America
•Journal of Microencapsulation, 2012, 1–15, Early Online
2012 Informa UK Ltd.
•http://www.theinformedgardener.com