Alkalin Polymers

1. POLYMERS
Presented By: Özlem Akalın
MSc.Chemical Engineer

2. WHAT IS POLYMER ?
Polymers are substances whose
molecules have high molar
masses and are composed of a
large number of repeating units.
1) NATURAL POLYMERS
(Proteins, starches, cellulose, latex)
2) SYNTHETIC POLYMERS (
commercially produced large scale plastics
and others)

3. How does it obtained?
Polymers are formed by chemical reactions
Main small components are joined
sequentially and formed chain.
In many polymers, only one monomer is used.
This kind is called as ‘homopolymer’
In others, two or three different monomers
may be combined.
This kind of polymers are called as
‘co-polymer’

4. Classification of Polymers
Polymers are classified by the characteristics of the
reactions by which they are formed.
1. Addition Polymerization: If all atoms in the
monomers are incorporated into the polymer.
(example; Polyolefins)
2. Condensation Polymerization: Two different
groups of atoms join together and some of the
monomers are released into small molecules, such
as water.(Polyester,polyamides (nylon)

5. POLYETHYLENE TEREPHTHALATE
Polyethylene terephthalate (PET), or polyethylene terephthalic
ester (PETE), is a condensation polymer produced from the monomers
ethylene glycol, HOCH2CH2OH, a dialcohol, and dimethyl terephthalate,
CH3O2C–C6H4–CO2CH3, a diester. By the process of transesterification,
these monomers form ester linkages between them, yielding a polyester.
PETE fibers are manufactured under the trade names of Dacron and
Fortrel. Pleats and creases can be permanently heat set in fabrics
containing polyester fibers, so-called permanent press fabrics. PETE can
also be formed into transparent sheets and castings. Mylar is a trade name
for a PETE film. Transparent 2-liter carbonated beverage bottles are made
from PETE. (The opaque base on some bottles is generally made of
HDPE.) One form of PETE is the hardest known polymer and is used in
eyeglass lenses.

6. POLYETHYLENE
Polyethylene is perhaps the simplest polymer, composed of chains of
repeating –CH2– units. It is produced by the addition polymerization of ethylene,
CH2=CH2 (ethene). The properties of polyethylene depend on the manner in
which ethylene is polymerized. When catalyzed by organometallic compounds at
moderate pressure
(15 to 30 atm), the product is high density polyethylene, HDPE. Under these
conditions, the polymer chains grow to very great length, and molar masses
average many hundred thousands. HDPE is hard, tough, and resilient. Most
HDPE is used in the manufacture of containers, such as milk bottles and laundry
detergent jugs. When ethylene is polymerized at high pressure (1000–2000 atm),
elevated temperatures (190–210°C), and catalyzed by peroxides, the product is
low density polyethylene, LDPE. This form of polyethylene has molar masses of
20,000 to 40,000 grams. LDPE is relatively soft, and most of it is used in the
production of plastic films, such as those used in sandwich bags.

7. POLYVINYL CHLORIDE
Polymerization of vinyl chloride, CH2=CHCl (chloroethene),
produces a polymer similar to polyethylene, but having chlorine atoms at
alternate carbon atoms on the chain. Polyvinyl chloride (PVC) is rigid and
somewhat brittle. About two-thirds of the PVC produced annually is used
in the manufacture of pipe. It is also used in the production of “vinyl”
siding for houses and clear plastic bottles. When it is blended with a
plasticizer such as a phthalate ester, PVC becomes pliable and is used to
form flexible articles such as raincoats and shower curtains.

8. POLYPROPYLENE
This polymer is produced by the addition polymerization of
propylene, CH2=CHCH3 (propene). Its molecular structure is similar to
that of polyethylene, but has a methyl group (–CH3) on alternate carbon
atoms of the chain. Its molar masses falls in the range 50,000 to 200,000
grams. Polypropylene (PP) is slightly more brittle than polyethylene, but
softens at a temperature about 40°C higher. Polypropylene is used
extensively in the automotive industry for interior trim, such as instrument
panels, and in food packaging, such as yogurt containers. It is formed into
fibers of very low absorbance and high stain resistance, used in clothing
and home furnishings, especially carpeting.

9. POLYSTYRENE
Styrene, CH2=CH–C6H5, polymerizes readily to form
polystyrene (PS), a hard, highly transparent polymer. The molecular
structure is similar to that of polypropylene, but with the methyl groups of
polypropylene replaced by phenyl groups (–C6H5). A large portion of
production goes into packaging. The thin, rigid, transparent containers in
which fresh foods, such as salads, are packaged are made from polystyrene.
Polystyrene is readily foamed or formed into beads. These foams and beads
are excellent thermal insulators and are used to produce home insulation and
containers for hot foods. Styrofoam is a trade name for foamed polystyrene.
When rubber is dissolved in styrene before it is polymerized, the polystyrene
produced is much more impact resistant. This type of polystyrene is used
extensively in home appliances, such as the interior of refrigerators and air
conditioner housing. [For more information about this polymer, see
Chemical Demonstrations: A Handbook for Teachers of Chemistry, by
Bassam Z. Shakhashiri, Volume 1 (1983), page 241.]

10. Major Grouping Methods
Major industrial plastics groups include:
• THERMOPLASTICS: one part, re-softenable w/ heat alone, crystalline or
amorphous.
• THERMOSETS: two or more parts react, amorphous.
• ELASTOMERS: Soft, pliable polymers such as rubber and neoprene.
• THERMOPLASTIC ELASTOMERS (e.g. Santoprene): injection-
moldable so applicable to mass-production.
• POLYMER BLENDS: Also known as alloys, polymer blends are "mixtures"
of various polymer chains to form a distinct polymer substance. Polymer
blends can also include additives, reinforcements, and fillers.
• SYNTHETIC POLYMER SUBSTANCES
• MODIFIED NATURAL POLYMER SUBSTANCES
• HOMOPOLYMER: All mers along a polymer chain are of the same type.
• COPOLYMER: Mers along a polymer chain are of two or more types.

11. PLASTICS vs. PLASTICS
AMORPHOUS POLYMERS: e.g., PVC, Polystyrene, Acrylic, ABS, PPO, PC,
Polyetherimide have
-a wide melting range,
-low shrinkage after molding,
-better impact and lower chemical resistance than crystalline polymers,
-moderate heat resistance,
-dimensional stability,
and superior cosmetics of outer surfaces.
CRYSTALLINE POLYMERS: e.g., PPS, PBT (Valox), Polypropylene (PP), have
-a sharply-defined melting point,
-high shrinkage after molding,
-low impact strength,
-high heat resistance,
-good fatigue endurance,
-good lubricity; wear resistance,
-good chemical resistance,
and the ability to flow in thin-walled sections.

12. Why Do We Care About Material?
Choice of material impacts the Manufacturing process
Product performance Cost
Environmental impact?
Three materials are the prime candidates for use
in automotive
bodies
Actually three groups of materials
Steel
The current dominant material
Aluminum
Polymer composites
Ester Resin with Glass Fiber Reinforcement

13. Plastics vs. Metals
From an engineering point of view, plastics differ from metallic materials in
the following ways:
-
Plastics tend to have pronounced non-linear time-dependent stress/strain
behavior. Below the yield point, metals typically have elastic behavior which
is nearly linear.
-
Instead of a single melting point, plastics typically have a
Glass Transition Temperature (TG).
Metals typically have a clearly-defined melting point.
-
Plastics in general exhibit pronounced creep. Metals undergo creep to a
certain extent, but for most engineering configurations their creep is
insignificant.
-
Plastics tend to degrade or denature (due to heat) rather than corrode within
a typical atmosphere. Of course, chemical degradation can occur when
reactive chemicals are present. Plastics impregnated with organic fillers can
be subject to bacterial infestation. Metals can corrode even in a benign
atmosphere from reaction with oxygen and water, but are not affected by
bacteria.

24. POLYMER USAGE & TYPES (1996 Australian Plastics)
Polymer Type Ton/yr Usage Area
Polyamide 13.700 Injection moulding, wire
and cable
Polypropylene 175.000 Injection moulding, fibres,
monofilament, film and
sheet extrusion
HDPE 193.100 Plastic materials, pipe
applications, film & bags
LDPE 72.500 Packaging applications
Polystyrene 59.000 Foam usage, injection
moulding
PVC 186.800 Pipe, conduit, profile
entrusion, film

25. POLYMER USAGE IN SECTORS (1996 Australian Plastics)
Usage Area Ton/yr
Packaging 350.400
Pipes, conduit 141.100
Houseware app. 33.000
Electrical & electronic demand 70.300
Marine applications 9.100
Coated fabric,footwear, textile 18.500
Electrical appliance 22.900
Transportation 41.300
Toys,sporting, leisure goods 19.700

26. World Polyolefins Market
LDPE, LLDPE, HDPE, POLYPROPYLENE are POLYOLEFINS
Represent the largest segment of the global thermoplastics app. 78.8
million metric tons, 63% of total market.
Golobal demand for them expected %7 avg.annual percent range
through 2005.Polymer production capacity for world scale plant
ranges from 250.000 to 450.000 metric tons/year.
Between 2000-2005 world wide polypropylene capacity forecast to
increase by over 9 million metric tons.

27. Forecast for the Future
Linear Polyethylene (LLDPE,HDPE) capacity in the Middle East will
double and polypropylene almost quadruple. This incremental capacity
exported from the Middle East to European and Asian markets.Korea will
continue to be a significant exporter into China.
Polyolefin prices are forecast to remain under downward pressure during
most of 2000 and 2001 and begin recover in 2002, topping out in 2004.
The unprecedented amount of industry consolidations by producers may
certainly have a long term effect on global price patterns.