IR Spectroscopy use to identify fiber using vibrations of chemical bonds. Spectra of samples are compared with spectra of pure reference materials.

1. IR SPECTROSCOPY IN
TEXTILE

2. WHAT IS INFRA RED ?
• INRARED IS A LATIN WORD THAT MEANS UNDER. IN 1800
ASTRONOMER WILLIAM HERSCHEL DISCOVERED A TYPE OF
INVISIBLE REDIATION IN THE LIGHT SPECTRUM BEYOUND RED
LIGHT. THAT IS CALLED INFRARED LIGHT.
• INFRA RED LIGHT IS ELETROMAGNETIC RADIATION WHICH
LONGER THAN VISIBLE LIGHT
• EXTENDS IN SPECTRUM 700nm TO 1mm & 430THz & 300GHZ
• THE INFRA RED REGION HAS DIFFERENT PORTION,IN
CHEMISTRY WE NEED THE VIBRATIONAL PORTION OF THE
INFRA RED REGION THAT IS 2.5µm TO 15µm

3. Application of IR Spectroscopy in textile
• Textiles have been made of various fibres using
independent fibres and mixtures. Due to the
abundance and similarity of textiles, identifying them
is difficult, but an important procedure. IR
Spectroscopy use to identify fiber using vibrations of
chemical bonds. Spectra of samples are compared
with spectra of pure reference materials.

4. ELECTROMAGNETIC SPECTRUM
• A portion of the electromagnetic spectrum showing
the relationship of the vibrational infrared to other
types of radiation.
• Ref: Introduction of Spectroscopy by Donald L. Pavia
INFRARED

5. INFRA RED SPECTROSCOPY
• IR SPECTRUM IS ONE OF THE IMPORTANT PHYSICAL
PROCEDURE TO IDENTIFY THE STRUCTURE OF ANY CHEMICAL
COMPOUND.
• THE MLOLECULES ARE VIBRATED CORRESPONDING TO EACH
OTHER
• THIS VIBRATION IS HAPPENED IN ANY SPECIFIC ENERGY STATE.
• IR SPECTROSCOPY MAINLY DEPEND ON THIS VIBRATION.
• SO, IT IS CALLED VIBRATIONAL SPECTRUM

6. RELATION BETWEEN MOLECULAR VIBRATION & IR SPECTROSCOPY
• ALL BONDED ATOMS MOLECULARLY VIBRATE. SOME
TYPES OF MOLECULAR VIBRATIONS ARE SHOWN
BELOW.

7. • EVERY BOND HAS DIFFERENT FREQUENCY OF VIBRATION
• SAME BOND IN DIFFERENT MOLECULAR STRUCTURE ABSORB
DIFFERENT INFRARED.
• SO INFRARED SPECTRUM CAN BE USED FOR A MOLECULE AS
A FINGER PRINT USED IN HUMAN.

8. PRINCIPLE OF INFRA RED SPECTROSCOPY
• INFRARED SPECTROMETRY WORKS BY ANALYZING THE NUMBER
OF INFRARED PHOTONS AND THE AMOUNT OF ENERGY FOUND IN
INFRARED PHOTONS ABSORBED BY THE MOLECULE.

10. • VIBRATIONAL ENERGY BOND LENGTH
• THIS ENERGY MEASURED BY

11. • A DIATOMIC MOLECULE CAN BE CONSIDERED AS TWO VIBRATING
MASSES CONNECTED BY A SPRING.
• THE BOND DISTANCE CONTINUALLY CHANGES, BUT AN
EQUILIBRIUM OR AVERAGE BOND DISTANCE CAN BE DEFINED.
• WHENEVER THE SPRING IS STRETCHED OR COMPRESSED BEYOND
THIS EQUILIBRIUM DISTANCE, THE POTENTIAL ENERGY OF THE
SYSTEM INCREASES.
• AS FOR ANY HARMONIC OSCILLATOR, WHEN A BOND VIBRATES, ITS
ENERGY OF VIBRATION IS CONTINUALLY AND PERIODICALLY
CHANGING FROM KINETIC TO POTENTIAL ENERGY AND BACK
AGAIN.
• THE TOTAL AMOUNT OF ENERGY IS PROPORTIONAL TO THE
FREQUENCY OF THE VIBRATION,

12. • THE STRETCHING FREQUENCY IS EXPLAIN THROUGH HOOK’S
LAW
• THE VIBRATIONAL FREQUENCY(FROM HARMONIC
OSCILLATION)
[ ]
BOND
ATOM

13. HERE,
K=FORCE CONSTANT DEPEND ON THE STRENGTH OF CHEMICAL BOND
µ=REDUCED MASS
k, µ DIFFERENT FOR DIFFERENT MOLECULE
BY PLACING THIS TWO VALUE FOR DIFFERENT MOLECULE WE GET
DIFFERENT v (WAVE NUMBER) 600cm∙‫י‬ - 4000cm∙‫י‬
THAT MEANS THE VIBRATIONAL SPECTRUM IS PRODUCED IN THE REGION
IR,THE VIBRATIONAL REGION FREQUENCY RANGE 600cm∙‫0004-י‬cm.
FOR THIS REASON IR SPECTRA GIVES ELECTROMAGNETIC RADIATION FOR
THE CHEMICAL MOLECULE

14. CONDITION FOR MOLECULE IN IR ACTIVE
• THE MOLECULE MUST BE ASYMETRIC
• TO ABSORB THE ELECTROMAGNETIC ENERGY, THE
MOLECULE MUST HAVE PARMANENT OR VARIBLE
DIPOLE

15. PEAK RESOLUTION
• THE HIGHER THE ELECTRO
NEGETIVITY DIFFERENCE BETWEEN
THE ATOM THE STRONGER THE
BOND DIPOLE
• THE STRONGER THE BOND DIPLE
THE MORE INTENSE THE PEAK
• IN C-O,C-N,C-C THE µ STRENGTH IS
DIFFERENT µco>µcN>µc-C
• BOND STRENGTH DIFF
FREQUENCY DIFF
• FREQUENCY DIFF PEAK DIFF

16. THE INFRARED SPECTROMETER
• THE INSTRUMENT THAT DETERMINES THE ABSORBTION
SPECTRUM FOR A COMPOUND IS CALLED INFRARED
SPECTROMETER
• THERE ARE TWO TYPES OF SPECTROMETER
- DISPERSIVE SPECTROMETER
- FOURIER TRANSFORM (IT GIVES MUCH MORE RAPIDLY
SPECTRUM THAN DISPERSIVE)

17. SIMPLIFIED IR SPECTROMETER

18. MODERN IR SPECTRUM

19. WORKING PROCEDURE OF SPECTROMETER
• HERE THE SPECTROMETER MAINLY WORK WITH TRANSMITTANCE
• PERCENT TRANSMITTANCE = IS/IR X 100
• WHERE
IS = THE INTENSITY OF THE SAMPLE BEAM,
AND IR = THE INTENSITY OF THE REFERENCE BEAM.
• IN MANY PARTS OF THE SPECTRUM, THE TRANSMITTANCE IS
NEARLY 100%, MEANING THAT THE SAMPLE IS NEARLY
TRANSPARENT
• TO RADIATION OF THAT FREQUENCY (DOES NOT ABSORB IT).
MAXIMUM ABSORPTION IS THUS REPRESENTED BY A
• MINIMUM ON THE CHART. EVEN SO, THE ABSORPTION IS
TRADITIONALLY CALLED A PEAK.

20. WHAT TO LOOK FOR WHEN EXAMINING INFRARED SPECTRA
• AN INFRARED SPECTROMETER DETERMINES THE POSITIONS
AND RELATIVE SIZES OF ALL THE ABSORPTIONS, OR PEAKS, IN
THE INFRARED REGION AND PLOTS THEM ON A PIECE OF
PAPER. THIS PLOT OF ABSORPTION INTENSITY VERSUS
WAVENUMBER (OR SOMETIMES WAVELENGTH) IS REFERRED
TO AS THE INFRARED SPECTRUM OF THE COMPOUND.

21. • FIGURE 2.4 SHOWS A TYPICAL INFRARED SPECTRUM, THAT OF
3-METHYL-2-BUTANONE. THE SPECTRUM EXHIBITS AT LEAST
TWO STRONGLY ABSORBING PEAKS AT
C=O 1715
C-H 3000

22. USE OF IR SPECTRUM IN TEXTILE
• INFRA RED SPECTROSCOPY IS A VALUABLE TOOL IN
DETERMINATION OF FUNCTIONAL GROUPS WITHIN A FIBER
• IN CONTINUOUS PAD DYING M/C,THERE IS A INFRA RED SENSOR
CHAMBER,THAT GIVES RAY &SCAN THE FABRIC WHICH SHOW THE
SIDE CENTER SHADE VARIATION IN COMPUTER.
• BY THIS SYSTEM WE KNOW THE SIDE CENTER SHADE
VARIATION&BY CONTROLLING THE PADDER PRESSURE WE CAN
MINIMIZE THE VARITION.
• IN LAB,THERE IS A IR DYEING M/C,THAT HEAT THE CHAMBER BY
INFRA RED HEATING SYSTEM.HERE WE DONOT NEED STEAM TO
GENERATE HEAT WHICH IS REQUIRED IN BULK DYEING M/C.

23. • ONCE DETACHED FROM SEEDS, COTTON FIBERS CONTINUE
THROUGH PROCESSING AND OFTEN CONTAIN ADDITIONAL
FOREIGN MATTER, PARTICULARLY BOTANICAL TRASH (LEAVES,
HULLS, SHALE, STEMS, SEED COAT FRAGMENTS, ETC.), WHICH
BECOMES ENTANGLED WITHIN THE FIBERS.
• A FOURIER TRANSFORM INFRARED (FTIR) SPECTROMETER IS USED
TO CHARACTERIZE THE CHEMICAL COMPOSITION OF COTTON
TRASH. INFRA RED SPECTROSCOPY HAS THE POTENTIAL TO
DETERMINE DISTINCT CHEMICAL COMPONENTS ASSOCIATED WITH
VARIOUS TYPES OF TRASH.
• SIMILAR SIGNATURE PEAKS ARE OBSERVED IN THE SPECTRA OF
LEAF, STEM, HULL, AND SEED COAT FRAGMENTS

25. CONCLUSION
• AT LAST WE CAN SAY THAT THE IR SPECTRUM IS VERY IMPORTANT
TO INDENTIFY THE FUNCTIONAL GROUP OF AN ORGANIC
COMPOUND.FOR THIS REASON IT IS COMPARED WITH FINGER
PRINT OF MOLECULE.NOW A DAYS IR SPECTRUM IS ALSO USED IN
TEXTILE SECTOR IN VARIOUS PURPOSE