Types of fibres,their classification,applications,properties, and structures
Further more polymers,their types and different type chemical bonds present in fibres,
1. Fiber Science
ďFiber Science is the study of the formation, structure, and
properties of fibers on micro to macroscopic levels.
ďThe study of fibrous materials and their use in a variety of
conventional and non-conventional applications.
2. Type of fibers
1- Manmade/Manufactured
a)- Synthetic ( Nylon, polyester, acrylic)
b)- Regenerated ( Rayon)
2- Natural Fibers
a)- Cellulosic origin
b)- Protein origin
3. Fiber Length
Length of fiber Class
Unit of
measurement Appearance
Long Filament fibers Yards/meters
Short Short fibers Inches/centime
ters
Classification of fibers on the basis of length
28. Manufactured fibers
ďManufactured (MF) fibers (formerly termed âman-madeâ) are formed
from a suitable raw material as a thick, sticky liquid, which is âspunâ
or extruded through spinneret holes, forming streams that are
solidified into fibers
ďThe raw material for MF fibers may be itself a natural substance, or it
may be synthetic (synthesized from basic chemical units), but it is
converted into textile fibers by a manufacturing process
ďWhile there are MF fibers made of natural rubber (as well as of
synthetic rubber), there is no such thing as a natural rubber fiber.
Similarly, Tencel lyocell is not a natural fiber; it is an MF fiber made of
a natural material, cellulose
29. ďTextile fibers are made up of molecules, these fiber molecules
are called polymers.
ď The Unit of polymer is called monomer ( mono-one: mer-part)
ďAt molecular level, polymer is extremely long and linear
whereas monomer is very small
ďMonomers are usually reactive whereas polymers tend to be
unreactive
ďThis causes the monomers to join end to end to form a polymer
called polymerization
31. ďLength of polymer is most important. All fibers, both natural and man
made have long to extremely long polymer lengths
ďMeasuring length of polymer is complicated yet not impossible
ďDegree of polymerization (DP) is therefore calculated
Degree of Polymerization=
Average molecular weight of polymer
Molecular weight of the repeating unit in the polymer
32. ⢠5000 DP for cotton means 5000 repeating units (cellobiose)
⢠Polymerization of natural polymers are not known
⢠Polymerization of synthetic polymer is categorized into
a. Addition Polymerization
a. Condensation Polymerization
33. a)- Addition Polymerization
Monomers add or join end to end without liberating any by product on
polymerization.
Some fibers which consist of addition polymerization are acrylic,
modacrylic, polyethylene, polypropylene etc.
34. b) Condensation Polymerization
ďIn this process monomers join end to end and liberate a by
product
ďThis product is a simple compound, e-g water, ammonia,
hydrogen chloride
ď Some fibers consisting of condensation polymerization are
elastomeric, nylon and polymers.
35. ⢠Polymers of cotton, acetate, flax, silk, triacetate, viscose and
other regenerated fibers and wool donât fit into above
classification because not enough is yet known about their
polymers and synthesis
36. Types of polymers
1-Homopolymer ( Same or one kind of polymer)
2-Copolymer ( Two or more different polymers)
Copolymers are further divided into
i. Alternating copolymer
ii. Block Polymer
iii. Graft Polymer
iv. Random polymer
38. ď The lack of branches in its structure
allows the polymer chains to pack closely
together, resulting in a dense, highly
crystalline material of high strength and
moderate stiffness.
ď 500,000 atomic units for High Density
Polyethylene
39. Copolymer
ďPolymerized from two or more monomers
⢠Silk is composed of 16 different amino acids
⢠Wool is composed of 20 different amino acids
ď Copolymers are sub categorized into four groups
40. A thermoplastic resin produced by the
copolymerization of styrene and maleic
anhydride
A rigid, heat-resistant, and chemical-resistant
plastic, it is used in automobile parts, small
appliances, and food-service trays
most of the copolymers contain about 5 to 20
percent maleic anhydride, depending on the
application, and some grades also contain
small amounts of butadiene for better impact
resistance.
Alternating copolymer
41. 41
Copolymers can be used to tailor functionality or generate
new behaviors.
Block copolymer, example:
Poly(styrene)-block-poly(butadiene)
Random copolymer, example:
Poly(styrene-ran-butadiene)
Graft copolymer,
example:
Poly(styrene)-graft-
poly(butadiene)
43. 43
Rod like polymers are used for very high strength, liquid
crystals, efficient viscosification
S
N
S
N
* *n
Rodlike because of helix
Rodlike because of linear backbone
46. (a) Linear structure; thermoplastics such
as acrylics, nylons, polyethylene, and
polyvinyl chloride have linear structures.
(b) Branched structure, such as
polyethylene.
(c) Crosslinked structure; many rubbers
and elastomers have this structure.
(d) Network structure, is highly cross-
linked; examples include thermosetting
plastics such as epoxies and phenolics.
48. Chemical Bonds
ďThe basic nature and reactivity of the fiber can be derived by
the type of chemical bond that holds the polymers together
ďA chemical bond is an attraction between atoms that allows
the formation of chemical substances that contain two or more
atoms
ďThe bond is caused by the electromagnetic force attraction
between opposite charges, either between electrons and nuclei,
or as the result of a dipole attraction
50. Intra-polymer Bonding
⢠Bonds holding the atoms together to make up the fibre polymer is
called intra-polymer bonding.
⢠Textile fibre polymers are mainly organic compounds, expect some
natural mineral and man-made inorganic fibres.
⢠They are predominantly composed of carbon and hydrogen atoms,
with some oxygen, nitrogen, chlorine and/or fluorine atoms.
⢠In general, single covalent bonds join the atoms forming the polymer
51.
52. Intra-polymer Bonds
The major bonds that are used for intermolecular bonding are as
follow
⢠Covalent bonds
⢠Amide or peptide group
⢠Benzene ring
⢠Ether linkages
⢠Ester groups
⢠Hydroxyl group
⢠Nitrile group
53. Covalent bonds
ďCovalent bonding is a common type of bonding, in which the
electro negativity difference between the bonded atoms is small
or nonexistent.
ďTheir bond energy or bond strength is between 330 and 420
kilojoules
54. The amide or peptide group:
ďIn chemistry, an amide is an organic compound that contains
the functional group consisting of a carbonyl group (R-C=O)
linked to a nitrogen atom (N).
ďWhen present in nylon polymers it is called the amide group.
ďIt is also present in silk, wool, mohair and all other animal or
protein fibres and then it is called peptide group
55. Benzene rings
ďThey are sometimes referred to as the aromatic radical.
ď It is a hexagon shaped molecule composed of mainly carbon
and hydrogen
56. Ether linkages
⢠The ether linkages may be found in polymers such as cellulose,
elastomeric, ester-cellulose and polyesters.
⢠It exists between carbon and oxygen atoms.
⢠Ethers are chemically unreactive. One reason for this is the
great chemical stability of the carbon-oxygen linkages found in
every ether molecule.
57. Ester groups
⢠They are formed by replacing the hydrogen of an acid with an
organic radical.
⢠In fibre polymers they are usually the reactions between:
a. A carboxyl group (-COOH), also called carboxylic acid
b. A hydroxyl group (-OH)
58. Inter polymer bonds
⢠In basic senses these bonds are responsible for holding the
polymers together for the formation of a fibre.
⢠The major bonds used for interpolymer bonding are as follows,
ďVan der Waals forces
ďHydrogen bonds
ďSalt linkages
59. Van der Waals forces:
ďThey are weak forces which exist in the interpolymer forces of
attraction when the atoms come close to one another.
ďThey are formed between atoms along the length of adjacent
polymers when these are less than 0.3 nm apart but no closer
than about 0.2 nm.
ďThey occur between all fibre polymer system and their bond
energy in 8.4 KJ.
60. Hydrogen bonds
ďThey are formed between hydrogen and oxygen atoms, and
hydrogen and nitrogen atoms on adjacent polymers when these are
less than 0.5 nm apart.
ďThey occur within the natural polymers, regenerated cellulose
polymers, nylon polymers, polyvinyl alcohol, polyester polymers,
protein and secondary cellulose acetate fibres.
ďTheir bond energy is 20.9 KJ
ďThe hydrogen bonds are mainly responsible for the tenacity and the
elastic-plastic nature of the natural, regenerated cellulose, nylon,
PVA and protein fibres
61. Salt linkages
⢠They are formed between the carboxyl radical on one polymer
and the positively charged amino group on an adjacent
polymer.
⢠They exist mainly in the protein and nylon fibre polymers.
⢠Their bond energy is 54.4 KJ.
⢠They are responsible for the attraction of the water molecules
and they too contribute to the strength of the fibre.
⢠The presence of salt linkages is necessary for dye absorption