presance of various particle and its affect of the polymer

1. RUBBER
TECHNOLOGY
(3132602)
AIM: To study about importance of
elements in polymer chemistry.
L.D COLLAGE OF ENGINEERING
L.D COLLAGE OF ENGINEERING

2. Index
1. CARBON
2. OXYGEN
3. HYDROGEN
4. NITROGEN
5. HALOGEN
6. SULFUR
7. SILICON
8. PHOSPHORUS
9. METALS

3. CARBON
 The most common oxidation state of carbon in inorganic
compounds is +4, while +2 is found in carbon monoxide
and transition metal carbonyl complexes.
 The most important element in organic chemistry and
polymer chemistry, and forms all or most of the main
chain in most polymer molecules.
 Carbon can form very long chains of interconnecting
carbon–carbon bonds, a property that is called
catenation
 Neither electropositive nor electronegative, and the C-C
bond by itself is completely neutral and very stable, as we
see in diamond and graphite.
 Carbon electronagetivity - 2.5

4.  Electron configuration: [He] 2s2
2p2
 The energy and strength of the C-C bond are quite
sufficient for thermal stability and for ultraviolet light
stability.
 Attachment of other elements to the carbon atom
introduces polarity into the C-C bond and thus lowers its
stability.
 Most of the effects upon polymer properties are due to
the attachment of these other elements to the carbon.
 In the C=C double bond the two pairs of electrons
between two carbon atom can be accommodated
electrically with good stability.
 This make the C=C double bond very reactive with
oxygen, halogens, ozone and hydrogen halides, reactions
which are important in the utilization of rubber.
 When the C=C double bond is in the alpha position at the
end of the molecule, it is very often polymerizable by free
radical or ionic mechanisms, particularly with application
of appropriate initiators. This is important in monomer
casting.

5.  Thealpha carbon (Cα) in organic molecules refers to the
first carbonatom that attaches to a functional group,
such as a carbonyl. The secondcarbon atom is called the
beta carbon(Cβ), and the system continues naming in
alphabetical order with Greek letters.
 In aromatic structure, the unsaturation of the C=C
double bond is completely stabilized by resonance, and
these aromatic structure provides high thermal stability
in polymer molecules

6. OXYGEN
 Dioxygen provides the energy released in combustion and
aerobic cellular respiration, and many major classes of
organic molecules in living organisms contain oxygen
atoms, such as proteins, nucleic acids, carbohydrates, and
fats, as do the major constituent inorganic compounds of
animal shells, teeth, and bone.
 Electronegativity is 3.44
Most of the mass of living organisms is oxygen as a
component of water, the major constituent of lifeforms.
 Oxygen is the most common element in organic chemistry
and in polymer structure.
 It is much more electronegative than carbon and
hydrogen.
 The presence of oxygen atom in polymer structure also
frequently produces high surface energy and surface
tension.
 The stability of the C-O-C bonds depends very much upon
the groups to which it is attached in aromatics.
 The C=O carbonyl bond is resonating structure which effect
the polarity and reactivity of adjacent groups.

7.  The -CO2- group in polymers and in the side chain o
f polymers made from ester type monomers is quiet s
ensitive to hydrolysis.
 The O-O bond of peroxides is very unstable.
 The presence of such weak O-O peroxide bond in the
polymer structure makes it particularly sensitive to t
hermal degradation.
It absorbs ultraviolet light strongly in the range of 2800 –
3200 angstrom and this can cause instability of the
polymer towards ultraviolet light aging.
The -CO2- group in polymers and in the side chain of
polymers made from ester type monomers is quiet
sensitive to hydrolysis.
The O-O bond of peroxides is very unstable.
The presence of such weak O-O peroxide bond in the
polymer structure makes it particularly sensitive to
thermal degradation.

8. HYDROGEN

9.  it undergoes substitution reaction which forms
chlorinated polymer by halogenation reaction.
 The aliphatic C-H bond has low surface energy, low
surface tension, low adhesion and low friction.
 The aromatic C-H bond is quite stable, but still permits
reactions and has moderate surface tension , producing
less lubricity and higher adhesion.
 When the aromatic ring is activated by some groups
such as phenolic hydroxyl or amine, these greatly
activate C-H bonds in the para and ortho position.
 When H is attached to elements other than carbon , it
becomes much more reactive but when H attached
with O in hydroxyl groups may be highly reactive.
 This is important in formation of cellulose ester,
polyesters, and polyvinyl.

10. NITROGEN
 Nitrogen in third most common element in organic
chemistry.
 Most of the known varieties may be regarded as derived
from ammonia, hydrogen cyanide, cyanogen, and
nitrous or nitric acid. The amines, amino acids, and
amides, for example, are derived from or closely related
to ammonia.
 It is intermediate between carbon and oxygen in periodic
table, so it is electronegative in nature.
 Nitrogen Electronegativity
 Bonds between carbon and Nitrogen are fairly strong but
also provide fairy polar, providing strong adhesion to
polar substance.
 About bond,- C N = Nitrile bonds, which is presence in
ABS and SAN resins, acrylic fiber.
 Nitrile rubber is strongly polar and unshared pair of
electrons on the Nitrogen highly exposed and available
for very strong Hydrogen bonding.

11. Nitrile rubber is strongly polar and unshared pair of
electrons on the Nitrogen highly exposed and
available for very strong Hydrogen bonding.
When acrylonitrile polymers are burned it is possible
that HCN has may be released, forming very toxic
conditions N H bond It is fairly reactive, while is
important in polymerization of polyamides and in the
cure of urethane, urea and melamine resins.
Modification of the properties of nylon.
O=C-N-H in polyamides introduced polarity and
powerful Hydrogen bond.
This responsible for water absorption and moderately
moist absorption.
It is also responsible for very high surface energy and
surface tension which are useful in adhesives.

12. HALOGENS
 The halogen elements in group VII of the periodic
table are the most negative elements known, and
also have the smallest atomic radius.
Element Electronegativity
Florine (F) 4.0
Chlorine (Cl) 3.0
Bromine (Br) 2.8
Iodine (I) 2.5
Fluorine :
 Fluorine is the most negative and smallest of the
halogens almost as small as hydrogen.
 The C-F bond has very low surface energy giving low
surface tension, high lubricity and nonwetting
properties to a high degree. These properties are useful
in stain-proofing fabrics, nonstick cooking utensils.
Mold lubricants and self-lubricating bearing surface

13.  The C-F bond is chemically very stable and it has high
thermal and ultraviolet light stability this stability is
useful in gasket and in high temperature plastics and
elastomers.
 Chlorine :
Chlorine is slightly less negative and larges than fluorine,
but still forms quite strong covalent bonds with carbon.
Chlorine provides flame resistance. The high polarity and
surface energy of the C-Cl bond also produce high
surface tension and adhesion.
Chlorine creates strong polarity and perhaps some
hydrogen bonding, thus provides both strength and
plasticizer compatibility in PVC.
Higher atomic weight produces polymer of higher
specific gravity.
High polarity and surface energy of C-Cl bond produces
high surface tension and adhesion.

14.  Bromine :
 Bromine is considerably larger and less electronegative than
chlorine.
 It forms fairly stable bonds with carbon, but splits out easily
under the influence of heat or ultraviolet light, usually
causing discoloration.
 Only by adding small amounts of bromine in polymer gives
high degree of flame resistance.
 Iodine :
 Iodine is the largest and least electronegative of the halogens,
and the bonds it forms with carbon are quite unstable, so that
it is hardly ever found in polymer molecules.
 If it could be firmly bound, it would probably provide high
density, high flame-resistance.
According to size : F < Cl < Br < I
According to electronegativity : F > Cl > Br > I

15.  Organosulfur compounds are organic compounds that
contain sulfur.
 Sulfur is fairly similar to oxygen in its chemical properties,
but less electronegative and larger in size.
 The sulfide link aliphatic polymers is quite sensitive to
atmospheric or chemical oxidation.
 Vulcanization is a chemical process that converts natural
rubber and other polydiene elastomers into cross-linked
polymers.
 The most common vulcanization agent is sulfur. It forms
bridges between individual polymer molecules when
heated with rubber
SULFER

16.  Sulfur electronegativity is 2.58 .
 Steric hindrance of the benzen rings are more than
sufficient to protect the sulfide group against oxidation
in aromatic polymers.
 The -Sx- group of polysulfide rubbers is fairly weakly
bonded and fluid, providing the chemical reactivity
which is useful in equilibration and vulcanization.
 The -SO2- group in polymeric sulfones is itself quite
stable, and the oxygens projecting from it each have
two pairs of unshared electrons to donate for the strong
hydrogen bonding to adjacent molecules.

17.  More than 90% of the Earth's crust is composed of silicate
minerals, making silicon the second most abundant
element in the Earth's crust (about 28% by mass) after
oxygen.
 Silicon is more electropositive and larger than carbon.
 Organosilicon compounds are organometallic compounds
containing carbon–silicon bonds.
 Most organosilicon compounds are similar to the ordinary
organic compounds, being colourless, flammable,
hydrophobic, and stable to air.
 Si-Si bonds and Si-H bonds are unstable and reactive.
 Silicon electronegativity is a 1.9
 The Si-C bond in organosilane is very stable, due to this
silicon polymers are useful as high temperature
elastomers.
 The Si-OH silanol bond is very reactive and polymerizes
rapidly to form silicones.
SILICON

18.  The Si-O-R organosilixane bond is also quite reactive and
polymerizes or reacts with substrates readily.
 The Si-O-Si bond in both glass and silicon polymers is very
stable to heat. Its is useful in the preparation of silicone
polymers.
 Silicone rubber is an elastomer (rubber-like material)
composed of silicone itself a polymer containing silicon
together with carbon, hydrogen, and oxygen. Silicone
rubbers are often one- or two-part polymers, and may
contain fillers to improve properties or reduce cost.

19. PHOSPHORUS
 It has a concentration in the Earth's crust of about one
gram per kilogram (compare copper at about 0.06
grams). In minerals, phosphorus generally occurs as
phosphate.
 Phosphorus electronagtivity is a 2.19 .
 Slightly more electropositive than nitrogen.
 Produces the greatest flame retardant effect.
 The P-O-C bond provides useful structures for
incorporation into polyether, polyesters and
polyurethane.
 The P-C bond accompanied by high toxicity and it is not
commonly used in production of polymers.
 Two widely used compounds in this class are parathion
and malathion; others are Diazinon, naled, methyl
parathion, and dichlorvos. They are especially effective
against sucking insects such as aphids and mites.

20. METALS
 The mass of the Earth is approximately 5.98×1024 kg. In
bulk, by mass, it is composed mostly of iron (32.1%), oxygen
(30.1%), silicon (15.1%), magnesium (13.9%), sulfur (2.9%),
nickel (1.8%), calcium (1.5%), and aluminium (1.4%); with
the remaining 1.2% consisting of trace amounts of other
elements.
 A variety of metallic elements are occasionally useful in
polymer structure.
 Metal-organic compounds (metalorganics, metallo-
organics) are a class of chemical compounds that contain
metals and organic ligands, which confer solubility in
organic solvents or volatility.
 Compounds with these properties find applications in
materials science for metal organic vapor deposition
(MOCVD) or sol-gel processing.
 Metals have very less electronagtivity than other
compund. Ex [Na-0.93, Ni-1.91, Fe-1.83, Al-1.61, Ca-
1.00, Cu-1.90]
 Sodium ions commonly used in ionomers to provide fairly
strong thermoplastic cross-link which combiner
processability and toughness in the final polymer.

21.  Polymer containing high concentration of sodium carboxylate
side groups are soluble in water and used for thickening food
latex paints.
 Several group-II metal are frequently used in vulcanization of
elastomer particularly magnesium, calcium and zinc.
 Calcium also proving cross-links when calcium acrylate is
polymerization for soil stabilization.
 Addition at metals in polymer well increases the price of
polymer.