cm-1 - Prof. Yusuf Yagci

YALOVA UNIVERSITY
FACULTY OF ENGINEERING
DEPARTMENT OF ENGINEERING
TEST METHODS FOR POLYMERS I
PLM 305
Assoc. Prof. Dr. Mehmet Atilla TAŞDELEN
[email protected]
www.POLYMAT.org
COURSE OUTLINE
Week
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Topic
Introduction, Preliminary Identification Methods: Solubility, Density, Behaviour on Heating
(Atilla)
Determination of Water uptake and moisture, Determination of ash amount, Thermal
Expansion Coefficient (Hamit)
Electrical and Optical Properties and Their Measurement, Thermal Conductivity (Hamit)
Surface Tension, Surface Resistance, Refractometry, Refractive Index Measurement in
Transparent Plastics, Colour Determination (Hamit)
Fire Resistance, Aging: Thermal Aging, UV Aging, Aging under Atmospheric Conditions and
Ozone Effects (Hamit)
Determination of Structure of Polymers. Spectroscopic Methods: Ultraviolet-Visible
Spectroscopy (Atilla)
Infrared Spectroscopy (Atilla)
Infrared Spectroscopy (Atilla)
Nuclear Magnetic Resonance Spectroscopy (1H and 13C NMR) III (Hamit)
Midterm
Nuclear Magnetic Resonance Spectroscopy (1H and 13C NMR) III (Hamit)
Colligative Properties, Determination of Molecular Weight of Polymers : End-Group
Analysis, Viscosity Measurements (Atilla)
Gel Permeation Chromatography (GPC), Light Scattering (Atilla)
Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and Transmission
Electron Microscopy (TEM) (Hamit)
Where in the spectrum are these
transitions?
Where in the spectrum are these
transitions?
Basics of Light, E&M Spectrum, and
X-rays
Light can take on many forms. Radio waves, microwaves, infrared, visible, ultraviolet, X-ray and gamma
radiation are all different forms of light.
The energy of the photon tells what kind of light it is. Radio waves are composed of low energy
photons. Optical photons--the only photons perceived by the human eye--are a million times more
energetic than the typical radio photon. The energies of X-ray photons range from hundreds to
thousands of times higher than that of optical photons.
The speed of the particles when they collide or vibrate sets a limit on the energy of the photon. The
speed is also a measure of temperature. (On a hot day, the particles in the air are moving faster than on
a cold day.)
Very low temperatures (hundreds of degrees below zero Celsius) produce low energy radio and
microwave photons, whereas cool bodies like ours (about 30 degrees Celsius) produce infrared
radiation. Very high temperatures (millions of degrees Celsius) produce X-rays.
Techniques and information content
Molecular
Molecular
Libration
vibrations
(hindered rotations)
Electronic
Absorption
Infrared,
Raman,
EELS
Microwave,
THz
Valence band and
shallow electronic
levels (atoms)
Deep electronic
core levels (atoms)
UV absorption
UV photoemission
Electron loss
Visible
Fluorescence
Luminescence
X-ray photoemission
(XPS, ESCA)
Auger Electron (AES)
What is Infrared?
• Infrared radiation lies between the visible and microwave portions of
the electromagnetic spectrum.
• Infrared waves have wavelengths longer than visible and shorter than
microwaves, and have frequencies which are lower than visible and
higher than microwaves.
• The Infrared region is divided into: near, mid and far-infrared.
• Near-infrared refers to the part of the infrared spectrum that is closest
to visible light and far-infrared refers to the part that is closer to the
microwave region.
• Mid-infrared is the region between these two.
• The primary source of infrared radiation is thermal radiation. (heat)
• It is the radiation produced by the motion of atoms and molecules in an
object. The higher the temperature, the more the atoms and molecules
move and the more infrared radiation they produce.
What is Infrared? (Cont.)
Humans, at normal body temperature, radiate
most strongly in the infrared, at a wavelength
of about 10 microns (A micron is the term
commonly used in astronomy for a
micrometer or one millionth of a meter). In
the image to the left, the red areas are the
warmest, followed by yellow, green and blue
(coolest).
The image to the right shows a cat in
the infrared. The yellow-white areas
are the warmest and the purple areas
are the coldest. This image gives us a
different view of a familiar animal as
well as information that we could not
get from a visible light picture. Notice
the cold nose and the heat from the
cat's eyes, mouth and ears.
Vibrational Spectroscopy: Theory
In IR spectroscopy, IR photons is absorbed and
converted by a molecule into energy of molecular
vibration
m1
m2
r
A simple harmonic oscillator is a mechanical system
consisting of a point mass connected to a massless
spring. The mass is under the action of a restoring
force proportional to the displacement of the particle
from its equilibrium position and the force constant k
of the spring (under the classical Hooke’s law)
Infrared Spectroscopy
• The bonds between atoms in the molecule stretch and bend, absorbing
infrared energy and creating the infrared spectrum.
Symetric Streching
Simetrik Gerilme
Asymetric Streching
Asimetrik Gerilme
There are four bending vibrations
Scissoring
Twisting
Rocking
Düzlem içi eğilme Düzlem içi eğilme Düzlem dışı eğilme
(Makaslama)
(Sallanma)
(Yana sallanma)
Wagging
Düzlem dışı eğilme
(Bükülme)
IR Spectrum
• Plot IR energy vs. %transmittance (%T)
– Energy scale in wave numbers, wn (cm-1)
– %T scale
• Compares intensity of IR striking sample (Iin) with
intensity of IR leaving sample (Iout)
• 100%T no light absorbed by sample
• 0% all light absorbed by sample
IR Spectrum
The History of Infrared Spectroscopy
Infrared (IR) Spectroscopy:
–Herschel first recognized the existence of
IR and its relation to the heating of water
–First real IR spectra measured by Abney
and Festing in 1880’s
–IR spectroscopy became a routine
analytical method as spectra were
measured and instruments developed from
1903-1940 (especially by Coblentz at the
US NBS)
–IR spectroscopy through most of the 20th
century is done with dispersive (grating)
instruments, i.e. monochromators
–Fourier Transform (FT) IR instruments
become common in the 1980’s, led to a
great increase in sensitivity and resolution
J. F. W. Herschel
W. Coblentz
Infrared Spectroscopy
A molecule can be characterized (identified) by its molecular
vibrations, based on the absorption and intensity of specific
infrared wavelengths.
Infrared Spectroscopy
For isopropyl alcohol, the infrared absorption bands identify the
various functional groups of the molecule.
The Principles of FTIR Method
Sample Analysis Process
1. The Source: Infrared energy is emitted from a glowing black-body source. This
beam passes through an aperture which controls the amount of energy presented to
the sample (and, ultimately, to the detector).
2. The Interferometer: The beam enters the interferometer where the “spectral
encoding” takes place. The resulting interferogram signal then exits the
interferometer.
Sample Analysis Process
3. The Sample: The beam enters the sample compartment where it is transmitted through or reflected off
of the surface of the sample, depending on the type of analysis being accomplished. This is where specific
frequencies of energy, which are uniquely characteristic of the sample, are absorbed.
4. The Detector: The beam finally passes to the detector for final measurement. The detectors used are
specially designed to measure the special interferogram signal.
5. The Computer: The measured signal is digitized and sent to the computer where the Fourier
transformation takes place. The final infrared spectrum is then presented to the user for interpretation
and any further manipulation.
Sampling
Gases:
• high resolution is required to clarify the
detailed structure inherent to a gas sample.
• The cell internal pressure must be adjusted
for quantitative analysis of the gas sample
• Gas Cells with 5 cm or 10 cm Light Path.
Numune Hazırlama
Liquids
Using NaCl disks
Numune Hazırlama
Solids
Katı ise:
1-KBr peleti hazırlanması
2-Pasta hazırlanması
3-NaCl diski üzerinde katı film
oluşturulması
 Eğer örnek katı ise spektroskopik potasyum
bromür (KBr) yardımı ile birkaç tonluk basınç
altında ince şeffaf bir tablet oluşturularak
spektrum alınır.
 KBr’ün infrared bölgesinde absorpsiyonu
olmadığı için kullanılması uygundur.
 Kullanılan KBr nem içermemelidir.
 Çünkü içerdiği nemin IR spektrumunda hatalı
bantların gozlenmesine neden olur.
Numune Hazırlama
IR spektrumlarının alınması için yöntemler
Çözelti ise:
 Çözeltilerin spektrumunun alınması sırasında
dikkat edilmesi gereken en önemli şey, şeçilen
çözücünün IR bölgesinin her yerinde ışığı
geçirebilmesi gerekmektedir.
 Bu nedenle en fazla tercih edilen çözücüler
karbontetraklorür, kloroform, karbondisülfür,
siklohekzan, benzen, tetrakloroetilendir.
 Bu çözücülerden uygun olanı herhangi biri ile
örneğin %0.1-10 ‘lük bir çözeltisi hazırlanır.
 Hazırlanan bu çözelti infrared hücrelerine
koyulur. Ayrıca kullanılan çözücünün hücreninn
yapıldığı maddeyi çözmemesine de dikkat
edilmelidir.
Numune Hazırlama
IR spektrumlarının alınması için yöntemler
Transmisyon-FTIR tekniğinde örnek, IR ışının geçiş yolu üzerine konulmaktadır.
Buna karşılık ATR-FTIR (Hafifletilmiş Toplam Yansıtma, Attenuated Total
Reflectance) yönteminde örnek, IR’ye geçirgen olan özel bir kristalin yüzeyi ile
temas ettirilir.
Numune Hazırlama
IR spektrumlarının alınması için yöntemler
Sampling
IR spektrumlarının alınması için yöntemler
Frekans
Bağ Gerilme Frekans Tablosu
Frekans atomlar ağırlatıkça düşer.
Frekans bağ kuvveti veya bağ enerjisi arttıkça artar.
Example
Bağ Gerilme Frekans Tablosu
Simetrik
Gerilme
Düzlem içi eğilme
(Makaslama)
Düzlem içi eğilme
(Yana sallanma)
Example
Frekans
Example
Example
O-H Band at 3300 cm-1.
Example
3300 civarinda
Secondary amine (R2NH), broad and one spike.
Primary amine (RNH2), broad and two spike.
Tersiyer amine (R3N), not detected.
Example
Ketones, Aldehydes and Carboxylic acids, C=O bağları ~1710
cm-1.
Örnekler
Aldehydes has additionally two C-H signals: ~ 2700 ve 2800
cm-1.
Example
Carboxylic acid has additionally O-H band.
Example
 C=O bağlarının C=C bağlarıyla konjugasyonu gerilme frekansını ~1680
cm-1 ye düşürür.
 Bir amidin C=O grubu daha düşük frekansta absorblar: 1640-1680 cm-1.
 Bir esterin C=O grubu daha yüksek frekansta absorblar: ~1730-1740 cm1.
 Küçük halkalardaki karbonil grupları (5 C veya daha az C) daha da
yüksek frekansta absorblar.
Example




C - N ~ 1200 cm-1
C = N ~ 1660 cm-1 more stronger than C = C bands
C ≡ N ~ 2200 cm-1
Alkyne C ≡ C has a weak absorption at 2200 cm-1.
FT-IR Bands
Interpretation of infrared spectra
Applications of Infrared Analysis
•
•
•
•
•
•
•
Pharmaceutical research
Forensic investigations
Polymer analysis
Lubricant formulation and fuel additives
Foods research
Quality assurance and control
Environmental and water quality analysis
methods
• Biochemical and biomedical research
• Coatings and surfactants
• Etc.
Capabilities of Infrared Analysis

Identification and quantitation of organic solid, liquid
or gas samples.

Analysis of powders, solids, gels, emulsions, pastes,
pure liquids and solutions, polymers, pure and mixed
gases.

Infrared used for research, methods development,
quality control and quality assurance applications.

Samples range in size from single fibers only 20
microns in length to atmospheric pollution studies
involving large areas.
Polyethylene
Polyethylene
Low-density
polyethylene
(LDPE) % 50
cristallinity
High-density
polyethylene
(HDPE) % 70
cristallinity
Polypropylene
Polypropylene
(a) atactic
(b) syndiotactic
(c) isotactic
The absorbance values at 970 and 1460 cm-1 do not depend upon the tacticity, whereas the absorbances at 840, 1000
and 1170 cm-1 are characteristic of isotactic PP, and the absorbance at 870 cm-1 is characteristic of syndiotactic PP.
Polyisobutylene
Polytetrafluoroethylene
Poly(vinylidene fluoride)
Poly(vinyl chloride)
Polystyrene
Poly(para-xylene)
Poly(vinylidene chloride)
Poly(vinyl acetate)
Poly(vinyl alcohol)
Poly(cis-isoprene)
Poly(chloroprene)
Poly(methyl methacrylate)
Poly(butyl acrylate)
Poly(methacrylic acid)
Nylon 66 vs Nylon 610
nylon 6 6
nylon 6 10
Poly(dimethyl siloxane)
Poly(acrylamide)
Poly(ethylene oxide) Mn=8000
Poly(ethylene oxide) Mn=400
Poly(epichlorohydrin)
Polycarbonate
Poly(ethylene terephthalate)
Poly(caprolactam)
Copolymer Composition
The absorbance
values at 2250 and
1600 cm−1
in this spectrum were
0.205 and 0.121,
respectively.
Copolymer Composition
The absorbance values at 1020 and 720 cm−1 in this
spectrum were 0.301 and 0.197, respectively.
Estimate the composition of this sample.
Isocyanate Amount
The absorbance values at 1020 and 720 cm−1 in this
spectrum were 0.301 and 0.197, respectively.
Estimate the composition of this sample.