Hyphenated Spectroscopy Techniques - TA Instruments · 2000-08-31 · Hyphenated Spectroscopy...

Basic Theory and Instrument Design of FT-IR

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Thermal Analysis and Rheology Short CourseConcord, NHApril 10, 2018

Hyphenated Spectroscopy Techniques

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Analytical Instruments Overview

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Revenue ending in Q1 2017


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The widest range of analytical methods to drive deeper materials insights

EDS

Elemental imaging at high spatial resolution

Raman

Chemical compound

identification

Identification of both

organic and inorganicmaterials

FTIR

Chemical compound

identification

Identification of organic

materials in bulk state

XRF

Bulk state elemental

composition

XRD

Structural crystallinity

and composition

XPS

Surface analysis

quantitative chemical

state

We deliver a full spectrum of analytical tools that enable customers to advance their research, product development, and quality control capabilities

UV-Vis

Quantitative measurement of reflection

or transmission properties of

a material

Electron Microscopy

Multiscaleimaging & analysis of

various materials

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Wavenumbers(cm-1)

Wavelength (µµµµm)

The Electromagnetic Spectrum

107 106 105 104 103 102

x-rays

ultraviolet

visible

near-IR

mid - IR

far-IR

XRF UV-Vis Infrared

10-3 0.01 0.1 1 10 100

radio

Technique

Range


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• Work fast…

• Little or no sample prep, rapid screening

• …on a range of samples…

• Organics, inorganics, films, coatings, paper, fibers, more

• …and answer fundamental questions

• What is this stuff? How much is in there? In what form?

• Analyze samples from ‘cradle to grave’

• R & D, process control, QA/QC, failure analysis, waste

The Power of Molecular Spectroscopy

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Core Molecular Spectroscopy Techniques

FTIR• Chemical fingerprint • Fast analysis

picoSpin NMR• Benchtop NMR• No cryogens

Raman Spectroscopy• Chemical fingerprint • Fast analysis• Greater sampling options –microscopy options


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• Energy varies along the x-axis

• Wavelength in nanometers or microns, Wavenumber (cm-1)

• Response is along the y-axis

• Absorbance, transmittance, reflectance

• Different molecules absorb light differently (“Peaks”)

• This is what enables spectroscopy to tell us something!

General ‘Rules’ for Molecular Spectroscopy

Energy

Re

sp

on

se

“Peaks”


Polymer Deformulation Studies using FT-IR Coupled to TGA

Breaking it Down


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Overview

• Deformulation

• What is it?

• Why do it?

• Common materials

• FT-IR as a deformulation tool

• Classical technique

• TGA coupled with FT-IR

• Physical property correlation with chemical data

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Deformulation

• Reverse Engineering

• Unknown material composition

• Failure Analysis

• Known material gone wrong

• Polymers

• Plastics

• Fillers

• Formulation

• Rubber

• Carbon Black: O-Rings, Tires

• Epoxies, Resins, Adhesives

• Entrained solvents, Breakdown products

• Fabrics, Paper products


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TGA-IR: The Basics

Vapor

IRBalance

Pan

Heated TransferLine

Temperature Ramp

Weight Loss Curve

Derivative Weight Loss Curve

Infrared Series File

Quantitative: How much is coming off?T “G” A – Gravimetric Analysis

Qualitative: What is coming off?FT-IR – Chemical information

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TG

A F

urn

ac

e

TransferGas In

Sample

Heated Transfer Line

IR BeamIR Beam

FT-IR Spectrometer

Exhaust

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Absorb

ance

500 1000 1500 2000 2500 3000 3500 4000

Wavenumbers (cm-1)

Infrared Spectrum

H2O

H2OH2O

H2O 0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Ab

so

rba

nce

1000 1500 2000 2500 3000 3500

Wavenumbers (cm-1)

CH4CH4

CH4

CH4 0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

0.55

0.60

0.65

0.70

0.75

0.80

0.85

0.90

Ab

so

rba

nce

500 1000 1500 2000 2500 3000 3500 4000

Wavenumbers (cm-1)

CH4

CH4

TGA-FTIR: Experiment

TGA Gas Cell

TGA Gas Cell


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Experimental Set-up

Low Volume

IR Gas CellTGA Conditions

• Sample size: 10 – 15mg

• TGA program: N2 Purge Isothermal

• Temperature : Ambient up to 650 C

FT-IR Conditions• Transfer line temp: 300 C

• TGA-IR Module temp: 300 C

• Data Collection: 8 cm-1, 5 scans/spectrum

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Simple Situation – Calcium Oxalate

• Three weight-loss peaks

• H2O ; CO + CO2 ; CO2

• H2O


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• Polymers

• Textiles

• Coatings

• Residual solvent

• Product stability

• Additive analysis

Example Applications

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Good

Bad

Subtraction

Good

Bad

Search result

Gasket analysis

Classic Root Cause AnalysisClassic Root Cause Analysis


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• These nanoparticles are stabilized by ligands

• Heating breaks down the complexes, releasing ligand

Deformulating Nanoparticles

TOPO

ODPA

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• A critical electronic component, in a sealed chamber, was degrading

• Concern was for outgassing of other materials in the chamber

• The insulation of a wire was found to be the cause

Outgassing of Electronic Component

Formaldehyde

Water


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Complete Analysis: Mercury TGA

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Polycarbonate Poly(acrylonitrile:butadiene:styrene)

Polycarbonate/Poly(acrylonitrile:butadiene:styrene)(PC+ABS)

Blended Polymer – Complex Matrix

PC+ABS Characterization


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PC+ABS Characterization: Preliminary Evaluation

• OMNIC Mercury TGA software analyzes the complete data set

� Principle component analysis followed by multi-component search

� Guides the interpretation and additional searching

Two Wt Loss Areas

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PC+ABS Characterization – Early Weight Loss

• Extract data from first weight loss region

� 420 – 440 C range �Mixture search using OMNIC Specta software

�Primarily Styrene and related materials


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PC+ABS Characterization: Major weight loss

• Extract data from 2nd weight loss region

� 510 - 540 C range

� Direct search in OMNIC provides enough information

� Bisphenol A is the major component

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PC+ABS Characterization – Something’s missing

• Nitrile component predicted by structure

� Not readily pulled out of this complex mixture

� OMNIC Specta - Peak Search comes in handy

� Isocyanic acid – based on nitrile peaks between 2300 & 2200 cm-1


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Environmental Stress Cracking is…the premature embrittlement and subsequent cracking of a plastic

due to the simultaneous and synergistic action of stress and

contact with a chemical agent

Environmental Stress Cracking (ESC) Investigation

Jeffrey A. Jansen

[email protected]

Chemical

Plastic

Stress

• Chemical agent permeates into molecular structure →

lower ductility

• Mechanism includes interference with inter-molecular

forces bonding polymer chains

• Reduces energy required for disentanglement/slippage

to occur producing a shift in the preferred mechanism

from yielding

ESC Failure Mechanism:

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• Scrape samples with Diamond ATR:

� Fracture Zone & Intact Area

� Subtract the two spectra followed by Multi-Component Search

�Some clues, but overall unsatisfactory result

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• TGA-IR Analysis:

� Early weight loss area 300 – 360 C

� Extracted spectrum subjected to OMNIC Specta Multi-Component Search

� Identified acetic acid and medium-chain length methyl ester


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• TGA-IR Analysis:

� Main weight loss area 390 – 440 C

� Extracted spectrum subjected to OMNIC Specta Multi-Component Search

� Identified an aromatic alcohol, longer-chain length methyl ester

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Poly(ethylene:propylene:diene) (EPDM)

EPDM Characterization


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EPDM Characterization

• Paraffinic:

• Naphthenic:

• Aromatic:

EPDM Compounding - Hydrocarbon Plasticizers

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10.88% Plasticizer(1.38mg)

41.26% EPDM(5.25mg)

486°C

189°C

393°C

0.0

0.2

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1.0

1.2

De

riv. W

eig

ht

(%/°

C)

0

20

40

60

80

100

Weig

ht (%

)

0 100 200 300 400 500 600 700

Temperature (°C)

Sample: EPDM RubberSize: 12.7140 mgMethod: Isothermal for

TGARun Date: 10-Oct-2014 15:40Instrument: TGA Q5000 V3.15 Build 263

Universal V4.7A TA Instruments

EPDM Characterization: TGA Analysis - Quantitative


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• Plasticizer:

� Paraffinic hydrocarbon

• EPDM Breakdown:

� Unsaturated hydrocarbon

EPDM Characterization: TGA-IR Results – Qualitative


Textile Example


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Diamond ATR Of Fabrics (Pre-TGA)

• Diamond ATR shows difference between fabrics

• Many unique peaks seen below 1000cm-1

NYCO

FR

Ab

so

rba

nce

1000 1500 2000 2500 3000 3500 Wavenumbers (cm-1)

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NYCO TGA-IR Data

Temperature (°C) vs. Time (min)

200

400

600

Te

mp

(C

)

Weight loss (mg) vs. Time (min)

0

2

4

6

Wt.

Lo

ss (

mg

)

Gram-Schmidt (GS)

0.02

0.04

0.06

0.08

IR I

nte

nsity

5 10 15 20 25 30

Time (minutes)

Temp ramp profile (imported from TGA software)

Weight loss profile (imported from TGA software)

GS shows total IR response as function of time-Peaks in GS correlate to sample weight loss and significant off-gassing detectedFor NYCO, 1 major thermal event was observed at ~26min- Next slide will show IR spectra in that time region


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NYCO Evolved Gas Spectra

Linked spectrum at 26.122 min.Linked spectrum at 25.782 min.

Linked spectrum at 26.377 min.Linked spectrum at 26.632 min.

0.02

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0.12

0.14

0.16

0.18

0.20A

bso

rba

nce

500 1000 1500 2000 2500 3000 3500 Wavenumbers (cm-1)

Linked spectrum at 26.377 min.

0.0085

0.0090

0.0095

0.0100

0.0105

0.0110

0.0115

0.0120

0.0125

0.0130

0.0135

Ab

so

rba

nce

2900 2950 3000 3050 3100

Wavenumbers (cm-1)


0.0114

0.0116

0.0118

0.0120

0.0122

0.0124

0.0126

0.0128

0.0130

0.0132

0.0134

0.0136

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0.0140

0.0142

0.0144

0.0146

0.0148

0.0150

Ab

so

rba

nce

850 900 950 1000 1050

Wavenumbers (cm-1)

• Major evolved gas is CO2 at 26min

• Just before CO2 evolution, small signal observed

at ~3000 and ~900cm-1

• See next slide for ID of these peaks

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NYCO – 26.37min Detailed Spectral Analysis9

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96

4

30

16

23

57

211

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Ammonia


Methane

Carbon dioxide

Carbon monoxide

Ab

so

rba

nce

500 1000 1500 2000 2500 3000 3500

Wavenumbers (cm-1)

• 4 components observed including CO2, CO, methane and ammonia

• Spectral overlay shows peaks that match to each species


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FR Fabric TGA-IR Data

Temperature (°C) vs. Time (min)

200

400

600Te

mp

(C

)

Weight loss (mg) vs. Time (min)

2

4

6

Wt L

oss (

mg

)

Gram-Schmidt

0.002

0.004

0.006

0.008

0.010

IR I

nte

nsity

5 10 15 20 25 30

Time (minutes)

For FR Fabric, 3 major thermal event was observed at ~16, 26, 31mins- Next slide will show IR spectra in that time region

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FR Fabric Evolved Gas Spectra

Absorbance (Abs)

-0.005

0.000

0.005

Wavenumbers (cm-1)

3800 3600 3400 3200 3000 2800 2600 2400 2200 2000 1800 1600 1400 1200 1000 800 600

Time (minutes)=15.8 min, point #186

Absorbance (Abs)

-0.005

0.000

0.005

Wavenumbers (cm-1)

3800 3600 3400 3200 3000 2800 2600 2400 2200 2000 1800 1600 1400 1200 1000 800 600


Absorbance (Abs)

0.000

0.005

0.010

0.015

0.020

Wavenumbers (cm-1)

3800 3600 3400 3200 3000 2800 2600 2400 2200 2000 1800 1600 1400 1200 1000 800 600


Absorbance (Abs)

0.000

0.005

0.010

0.015

0.020

Wavenumbers (cm-1)

3800 3600 3400 3200 3000 2800 2600 2400 2200 2000 1800 1600 1400 1200 1000 800 600


650°CSpectrum matches to CO2 and CO evolution

345°CSee next slide for library search

Absorbance (Abs)

0.000

0.005

0.010

Wavenumbers (cm-1)

3800 3600 3400 3200 3000 2800 2600 2400 2200 2000 1800 1600 1400 1200 1000 800 600


Absorbance (Abs)

0.000

0.005

0.010

Wavenumbers (cm-1)

3800 3600 3400 3200 3000 2800 2600 2400 2200 2000 1800 1600 1400 1200 1000 800 600


542°CSpectrum matches to CO2 evolution


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345°C Linked Spectrum Library Search

• Best match is brominated species

• Species was not seen in NYCO sample

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Conclusions - Deformulation using FT-IR & TGA

• TGA coupled to FT-IR advances capabilities to break materials down

• OMNIC Series, Mercury TGA and OMNIC Specta software provide tools for

analysis of complex mixtures

• Understanding the chemistry of the materials being analyzed is important


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Other Applications for Spectroscopy

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•Transmission

• Preferred method for quantitative analysis

• Sample mixed and pressed; good sensitivity

• Attenuated total reflectance (ATR)

• The sample must contact the crystal

• Simple and fast, generally non-destructive

• Diffuse reflectance (DRIFTS)

• Dilute sample in a matrix (like KBr)

• Simple, but requires mixing

• Specular reflectance

• Sample must be reflective or on a mirror

• Signals can be very weak

Add the Right Tools


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ATR of Heat Shrink Tubing: Inner Wall

• ATR and OMNIC Specta reveal two components: Polymer and Mg(OH)2

• Mg(OH)2 is used as a flame retardant

Poly(ethylene-co-vinyl acetate) 14 wt. % vinyl acetate

Magnesium Hydroxide

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ATR of Heat Shrink Tubing: Outer Wall

• Outer wall shows something

else

• Subtract outer – inner

• Tyzor 131® is found

• This is a cross-linker

• Causes tubing to shrink!


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• Run on Ge ATR

• Multiple

components

• Base polymer

• Silane slip-aid

Black Rubber Gasket

Hyphenated Spectroscopy Techniques - TA Instruments · 2000-08-31 · Hyphenated Spectroscopy...

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Transcript of Hyphenated Spectroscopy Techniques - TA Instruments · 2000-08-31 · Hyphenated Spectroscopy...