This document discusses various techniques used to investigate fiber structure, including X-ray diffraction, infrared spectroscopy, thermal analysis, electron microscopy, optical microscopy, nuclear magnetic resonance, scanning electron microscopy, and methods to determine glass transition temperature. X-ray diffraction and nuclear magnetic resonance are useful for analyzing fiber crystallinity and structure. Infrared spectroscopy provides information on chemical groups and molecular configuration. Thermal analysis measures properties as a function of temperature. Microscopy techniques examine fiber surfaces at different magnifications.

2. Tonmoy Kumar Bhoumik (172203)
Papon Kumar Singha (172204)
S. M. Zaki Muahid (172219)
Md. Al-Arafin Kaosad (172220)

3. The structure investigation of fiber means, measuring of fiber
structure manly introduce the fiber composition, length, weight,
thickness, fineness, flexibility, stability etc.
Its is also study of the structure and physical property of fibers.
Investigation of fiber structure help to acquire knowledge about
fiber an its composition for improving use of fiber in textile.
Investigation of fiber structure help to acquire knowledge about
fiber an its composition for improving use of fiber in textile.

4.  X-ray diffraction method
 Infra red rendition method
 Thermal analysis
 Electron microscopy
 Optical microscopy
 Nuclear magnetic resonance (NMR) Density
 Scanning electron microscope (SEM)
 Glass Transition Temperature, Tg

5. Diffraction is the study of the particular patterns that may be found
when waves pass through or round objects of particular shape. X-ray
diffraction is a most important tool for the study of fiber structure,
firstly because it gives information at the most important level of fine
structure and secondly because focusing of X-rays is not possible. So
that diffraction methods have to be used X- Ray diffraction is used to
measure the nature of polymer and extent of crystallite present in the
polymer sample.

6. Determination of chemical groups.
Determination of molecular spacing.
Determination of chemical bonding.
Determination of degree of crystallinity & orientation.
Determination of water absorption.

7. It gives information about only crystallinity of a fiber.
It gives information about internal structure of the fiber.
It gives information about the shape of scattering particles.
It gives information about the distribution of spacing between the
particles.

9. Infrared radiation (IR), sometimes referred to simply as
infrared, is a region of the electromagnetic radiation
spectrum where wavelength range from about
700 nanometers(nm) to 1 millimeter (mm). Infrared
waves are longer than those of visible light, but shorter
than those of radio waves. Correspondingly,
the frequency of IR are higher than those of microwaves,
but lower than those of visible light, ranging from about
300 GHz to 400 THz.

10. Infra-red (IR) spectroscopy is one of the most common and widely
used spectroscopic techniques. When electromagnetic waves
interact with matter, they are scattered and absorbed. Infrared
spectroscopy, radiation with wavelengths between 1 -15 μm
is absorbed at certain characteristic frequencies, which yield
structural information.
By using an infrared spectrometer, the variation in absorption can
be found and plotted against wavelength or the wavenumber.

12. It can be used for identification of the presence of certain groups in
the molecules
It can be used to investigate the degree of orientation of fiber.
It can be used to determine the amount of water in fibers.
It can be used to determine the α & β molecular configuration of
fiber.
It gives information of both crystallinity & non-crystallinity of
fibers.

13. Electron microscopy is a microscopy technique whereby a
beam of electron is transmitted through an ultra-thin
specimen, interacting with the specimen as it passes
through.

14.  Electron microscope method is better to examining the surface of the fiber.
 The main use of EM in fiber science has been in the range of medium to high
magnification, which is near or beyond the limit of the microscope.

15. The orientation of the polymer molecule can be
estimated.
A beam of light passing through the photographic
slide.
Recombine the information of picture by using lens

17. A diffraction grating of regularly spaced line, iluminated
by parallel light.With the mexima of the bride bands at
angle φ difined by the relation.
Nλ=a sinφ
[Where,n is an integer and λ is the wave length of the light.]

18. Thermal analysis is a collection of analytical techniques that
measure some properties of textile fibres as a function of
temperature. The properties measured by common thermal analysis
techniques are change of heat, mass. volume. dimension. strain.
stress etc.
Thermal analysis techniques are used in various ways in the fibre
and textiles industries. Fibre or polymer identification,
compositional analysis. stability, and mechanical properties are
typically determined using thermal analysis.

20.  Commonly use thermal analysis techniques used in the textile industry are follows:
1. Dilatometry (PVT) or Thermo-Mechanical Analysis (TMA): Measures
volume/dimension as a function of temperature and/or pressure.
2. Differential Scanning Calorimetry (DSC): Measures constant-pressure heat
capacity as a function of temperature.
3. Thermo-Gravimetric Analysis (TGA): Measures weight loss as a function of
temperature and time.
4. Dynamic Mechanical Analysis (DMA): Measures stiffness and energy losses as a
function of temperature. The use of thermal analysis techniques for various
measurements of textile materials are shown in fig.

21.  Nuclear magnetic resonance spectroscopy, mostly commonly known's as NMR
spectroscopy.
 NMR is a research technique that exploits the magnetic properties of certain
atomic nuclei to determine physical and chemical properties of atoms or the
molecules in which they are contained.
 In resonance phenomena the energy absorbed can be caused to varying two
way:
1. Either by scanning through a range of frequency, with maximum at the
resonant frequency.
2. By running through a change of magnetic field at constant frequency.

22.  Differentiation of the curve aids interpretation. The ratio of the intensity of the
broad band to the intensity of the narrow band gives a measure of the
crystalline/non-crystalline ratio in the material.

23.  What is even more interesting is the fact that the width of the broad band gives
a measure of the rigidity of the more highly ordered material. Statton has
shown that this decreases with temperature owing to the increasing thermal
oscillation in the crystal lattice, but it is also interesting that it increases on
drawing nylon and increases still more on hot stretching. Statton. as indicated
in the figure terms the parameter derived from the broadband width the matrix
rigidity. since the width depends on how firmly the resonating atom is held
within the surrounding matrix of highly ordered material. In a perfect crystal.
the width would be great; in a small or defective crystal. it would be less. In a
similar way. the width of the narrow band could indicate how firmly individual
atoms are held within their matrix of less ordered regions.

24.  A scanning electron microscope (SEM) is a type of electron microscope that
produces images of a sample by scanning the surface with a focused beam of
electron.
 The electrons interact with atoms in the sample, producing various signals that
contain information about the surface topography and composition of the
sample.
 SEM can achieve resolution better than 1 nanometer.

25. Nuclear magnetic resonance spectroscopy, most commonly known as NMR
spectroscopy. is a research technique that exploits the magnetic properties of
certain atomic nuclei to determine physical and chemical properties of atoms
or the molecules in which they are contained. It relies on the phenomenon of
nuclear magnetic resonance and can provide detailed information about the
structure, dynamics. reaction state, and chemical environment of molecules.
As usual in resonance phenomena, the energy absorbed can be caused to vary
in two ways: in this system, either by scanning through a range of frequencies,
with a maximum at the resonant frequency a change of magnetic field at
constant frequency. The latter procedure is usually adopted. and a typical
response for a solid polymer is shown in the figure. Differentiation of the curve
aids interpretation. The ratio of the intensity of the broad band to the intensity
of the narrow band gives a measure of the crystalline/non-crystalline ratio in
the material.

27.  Electron Source ("Gun")
 Electron Lenses
 Sample Stage
 Detectors for all signals of interest
 Display / Data output devices
 Infrastructure Requirements:
 Power Supply
 Vacuum System
 Cooling system
 Vibration-free floor
 Room free of ambient magnetic and electric fields

28. With a higher depth of field and greater image contrast,
scanning electron microscopy (SEM) is becoming the new
standard for characterizing filtration materials. An SEM
image affords a quick and high-resolution visualization of
filter media. Elemental analysis, via energy dispersive X-ray
spectroscopy (EDS) with SEM, allows for the identification
of elements in the fibers or particulates.

29.  When an amorphous polymer is heated, the temperature at which the polymer
structure turns “viscous liquid or rubbery" is called the Glass Transition
Temperature, Tg.
 This temperature (measured in °C or °F) depends on the chemical structure of
the polymer and can therefore be used to identify polymers.
 Amorphous polymers only exhibit a Tg.
 Crystalline polymers exhibit a Tm (melt temperature)

30.  Molecular Weight – In straight chain polymers, increase in MW leads to
decrease in chain end concentration resulting in decreases free volume at end
group region – and increase in Tg
 Molecular Structure - Insertion of bulky, inflexible side group increases Tg of
material due to decrease in mobility,
 Chemical cross-linking - Increase in cross-linking decreases mobility leads to
decrease in free volume and increase in Tg
 Polar groups - Presence of polar groups increases intermolecular forces; inter
chain attraction and cohesion leading to decrease in free volume resulting in
increase in Tg.

32. Identifying the Tg of polymers is often used for quality
control and research and development. Also, it is an
important tool used to modify physical properties of
polymer molecules.

33.  J.W.S. Hearle, W. E. Morton-Physical Properties of Textile Fibres - Woodhead
Publishing Ltd (2008)
 https://www.slideshare.net/hasanuzzamanhasan758/different-technique-
for-investigation-of-fiber-structure
 https://www.slideshare.net/parthrdx/methods-of-investigation-of-structure
 https://omnexus.specialchem.com/polymer-properties/properties/glass-
transition-temperature