Micro ftir my-labforhire1

Chemical Microanalysis for
Industry
State-of-the-Art Analysis for hire
Medical Device Problem Solving
Polymer Problem Solving
Industrial Problem Solving
Asbestos Analyses
etc., etc., etc.
by
John Donohue
201-294-2581
John Donohue - donohuejjp@gmail.com

Hello. I’m John Donohue and this is the best Infrared Microscope ever made by
any manufacturer:
Nicolet’s IR-Plan Research Microscope
mounted on a Magna 560 Mainbench
This amazing instrument allows my Lab
to obtain the Chemical Identity, via the
Infrared Spectrum, of an area as small
as 10 microns by 10 microns
(10μX10μ). That’s as small as 9 red
blood cells placed in a 3X3 square.
When you can chemically identify
objects that small you can perform such
amazing investigations that they
can often depart completely from the
expected and traditional uses of Infrared
Spectroscopy, as you will see.
These documents will describe the type
of analyses I perform for Industry and
Publication using this instrument and
the other equipment in my Laboratory.
Part 1: Introduction to the Technology and Method

Mirrored “Lampshade”
Mirrored “Flying Saucer”
Hard Silicon Surface for ATR “Contact” Spectra
My IR-Plan is usually set up with Two Reflachromats:
One For Reflection And Transmission, The Other Dedicated To ATR
More “Specialized Reflachromats” and Visible Light Objectives are available, if needed
… and Visible Light Objectives for
Visible and Polarized Light MicroscopyJohn Donohue - donohuejjp@gmail.com

Microscope Reflection Mode
Lightpath
The Upper Reflachromat objective
projects a conical surface of IR radiation
through the sample. It reflects off the
shiny metal beneath the sample and
follows the same conical surface up
through the sample, back to the
objective, and from there to the detector.
This mode is very fast and easy to
perform. The shiny metal substrate is
usually 0.005 inch aluminum sheet
taped onto a microscope slide. It is cut
from 5 inch by 5 inch sheet that is
cheap and disposable. It can also be
performed on any flat or curved metal
surface such as injection molding tool
surfaces, medical steel cannulas, engine
valves, gun metal, you name it.
To Detector
From Source
Sample
on metal
Shiny Metal Substrate
Shiny Metal Substrate

>The FTIR Microscope increases greatly the utility of FTIR and allows the successful
use of IR in analyses that simply could not be done by a Mainbench alone.
>The Micro - ATR Objective obtains surface spectra (of the top ~micron of material)
with almost no sample prep. This is excellent for thin coatings or surface analysis.
>The FTIR Microscope can obtain useful spectra from extremely thin samples as
small as a 10μ X 10μ Square. The amount of mass providing such a signal can
approach the Detection Limits of GC/MS
>Example - FTIR Microscope’s Limit of Detection is about a 10μ X 10μ Square :
If sample is 1μ thick, 10μ X 10μ X 1μ sample of Polyethylene = how many grams?
1cc of PE = 1g = 10mm X 10mm X 10mm = 1000 cubic mm = 103 mm =>
10mm X 10mm X 10mm = 104 μ X 104 μ X 104 μ = 1012 cubic microns =>
So: 1012 cubic microns = 1g
10μ X 10μ X 1μ =100 cubic microns = 102 cubic microns
102 / 1012 = 10-10 g
So: 10μ X 10μ X 1μ sample of Polyethylene = 0.0000000001 grams of PE
So, the FTIR Microscope can ID 100 trillionths of a gram of PE
UNIQUE ADVANTAGES OF THE FTIR MICROSCOPE
How sensitive is it? See arithmetic below.

Microscope ATR Mode and Lightpath
The ATR Reflachromat objective
projects a conical surface of IR
radiation onto the inside of the ATR
Crystal’s Sample Contact Point. A
small part of the IR radiation
“tunnels” into the sample touching
this Contact Point. Some of it is
absorbed and the rest continues on
to the detector.
This mode is particularly well-suited
to surface analysis (surfaces that are
bioactive, drug eluting, bioresorbable,
coated, “blooming” additives,
lubricious, non-thrombogenic, etc.).
It is also a good choice for highly
absorbing materials that are difficult
to get an IR beam in and out of such as
Black Rubber.
From Source
To Detector
SampleSample

How Small Can Samples Be?
How small IS the 10μ X 10μ Limit of Detection?

Back of USA Penny
Lincoln
Memorial

Lincoln seated on Penny’s back
This image is 11.2mm X 8.5mm.

Lincoln seated on Penny’s back; mm scale to left
This image is 3.0mm X 2.3mm.

IR-Plan Visible Light 10X Objective view (Glass)
Lincoln’s Head and Shoulders
This image is 550μ X 420μ

IR-Plan IR Objective 15X Reflachromat view: Lincoln’s Head
This is the magnification at which
Knife-edge apertures are used to frame
the area to be analyzed
and FTIR Spectra are obtained.
10μ X 10μ
This image is 390μ x 300μ
Limit of
Detection:
“Lincoln’s “Eye”

Lincoln’s Face on the previous slide is about 140μ X 120μ.
The IR-Plan can obtain good spectra from much smaller
samples than this (see asbestos ribbon, below). The thin
polymer coating on Lincoln’s Face is easily IDd
as Polycarbonate by a Spectral Library Search.

Asbestos Identification
by IR Microscopy and/or
Polarized Light Microscopy
Part 2: Asbestos Testing

Friable Asbestos Identification by IR Microscopy of broken cementitious tile:

Zooming in on the Friable Asbestos

Microscopic amount of Asbestos squashed onto aluminum sheet

NOTE: Often Spectra are corrected for humidity in the Laboratory air

The Asbestos sample is Chrysotile

The IR Microscope is so very sensitive that even a 20μ X 65μ area
of a Single “ribbon” of Asbestos is enough for Identification

Asbestos Identification and Quantification
is routinely performed as per
EPA-600-R-93-116 using
Polarized Light Microscopy (PLM)
Examples of PLM in my Labs
Materials Analyses follow

>These barrels were for “Epinephrine
Pens” needed to counter the threat of
Nerve Gas and thus keep Saudi Arabia
from backing down to Iraq in the Gulf
War. This allowed the USA to Stage
the invasion of Kuwait.
>The barrels were breaking 100% upon
ejection from mold with undercut.
>Defect invisible until Crossed Polarizers
revealed “Knit Line” pointing to
Crack Initiation Point.
>The molten plastic was too cool when
It came squeezing around the Core Pin
for the two advancing Melt Fronts to
melt together adequately.
>I told Manufacturer to increase
Zone Temperatures by 30 degrees C
and Ejection Breakage ceased.
... and that’s how I won the war.
Device Production
Restarted and Defect
Determined and Eliminated
Via Stress Birefringence
Analysis
Crack
Initiation
Point

Polypropylene Syringe Wall Cross Section
Control of Cooling Rate is a major parameter
in Determining Morphology and Properties
This type of work was very important in the
implementation of Clear Polypropylene Devices
using Milliken Clarifying Agents that have the
undesirable effect of increasing the brittleness
of Polypropylene.
Polypropylene Syringe Gate Cross Section
Control of Rheology is a major parameter
in Determining Morphology and Properties
This type of work was also very important in
the implementation of Radiation Sterilization
which also has the undesirable effect of
increasing the brittleness of Polypropylene.
Injection Molding Morphology and Physical Properties

Solving Medical Device problems using
IR Microscopy
Visible Microscopy
Part 3: Application to Medical Device issues

-0.30
-0.25
-0.20
-0.15
-0.10
-0.05
0.00
0.05
0.10
0.15
Absorbance
100015002000250030003500
Wavenumbers (cm-1)
Silicone Lubricated Gasket
Less Silicone After Surface Scraped
No Silicone After Acetone Wash:
Silicate-filled rubber polymer
ATR Spectra of Surface of IR-Opaque Rubber

2.3mm x 3.0mm Photos of an Insulin Needle Point
The Technology of a Needle Point
What can we learn with a fast analysis?

420μ x 550μ Photos of Needle’s three cut planes
The “subtle” cut

IR-PLAN 550μ X 420μ FOV of Point and Enhanced Image
Raw Image Obtained
Digital Enhanced Image
A “Metal Burr” is visible
on this needle point.

-0.000
0.001
0.002
0.003
0.004
0.005
0.006
0.007
0.008
0.009
0.010
0.011
0.012
Absorbance
100015002000250030003500
Wavenumbers (cm-1)
Infrared Microscopy Provides Chemical Identification that shows
Gelled Lubricant is used on Hypodermic Needles
3.0mm x 2.3mm
550μ X 420μ
390μ x 300μ
Gel is Silicone

8.5mm X 11.2mm
Hoop Stress cracking
Polyetherimide (PEI) Stopcock Outerbody resists splitting caused by fatty Feeding
Liquids but costs more than Polycarbonate (PC) (which is cracked by combination of
fats and stress). Stopcock InnerBody is pressed into Outerbody and this strong PEI
polymer can still crack if it can’t stretch enough under this “Hoop Stress”
tensile load (vs PC which is very stiff but also very TOUGH/RUBBERY).
Engineering Resins: ESCR vs “Hoop Stress Failures”

PET Barrels That Failed At Gate
A “Cold Slug” in an Injection Molding “Gate”
can initiate breakage at unacceptably low force

Gate A Gate BRidge/Valley
Cold Slugs
Blade Striations
Devices broke due to “Cold Slug” in Injection Molding Gate

Identification of PET Barrel Skirt
Contaminant by Micro-FTIR

Smudges on PET at Tip Insert of Barrels
Parting Line

Pre-Extracted Cellulose on PET Skirt Same Area of PET Skirt After Wiping
Streaks where Grease
was removed
Cellulose
Grease about
to be removed
PET Barrel Skirt Bloom removed for analysis

Silicone
Cellulose
Grease Found Previously
Grease Found Recently
PET Barrel Skirt Contaminant is Same as Found previously
The Difference Seen below is Cellulose from the Kimwipe.
The Grease is both an Acid (1712 cm-1) and an Ester (1737 cm-1).

An unusually profitable Bioresorbable Implant with a brilliant Market-dominating future had its
Market Launch endangered by the occurrence of foreign matter inside the tiny molded
PolyLactide:Glycolide implant. A CERTAIN fix was required immediately: the cause had to be
IDd with certainty and eliminated.
Many Hypotheses were proposed:
>The Resin Supplier suggested that Residual Monomer was boiling
during molding. Extensive testing of residual monomer levels in
retained lot samples vs amount of bubbles found from molding those
lots was proposed.
>Molding Engineers suggested that the bubbles were: Shrink Voids,
Entrapped Air, Entrapped Condensation, Etc. Humidity archives were
to be examined and production areas were to be desiccated.
>”Shotgun Experiments” were about to be fired in every direction.
Instead a “RIFLE BULLET” EXPERIMENT was aimed right at the bubbles themselves.
>Contaminant was Bubbles Inflated while Flowing  “COMET”.
>Cut thin Cross-sections of the polymer through the Bubbles.
>Micro-FTIR repeatedly found a single deposit of Secondary Amide
localized in a small area on each Bubble’s inner surface.
Part 4: Nailing the Answer and Preventing a Recall
Flow
Direction

Hazy Translucent
Area on border of
Bubble
When a thin slice of the Part, containing the Bubble, was shaved off,
the Hole in the shaving had a tiny region on its circumference
that was Hazy Translucent while the rest of the circumference and
of the part’s shaving was Clear Translucent
Cross-section of Bubble
Clear translucent polymer slice

1534
1648
3060
3288
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
Absorbance
1000150020002500300035004000
Wavenumbers (cm-1)
“Zooming in” on Hazy deposit on Bubble’s circumference
Increases the Secondary Amide Absorbance Peaks relative to the PLG’S...
PLG
PLG
...therefore the hazy area is a Secondary Amide
FTIR Microscopy
Zooming in

-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
Absorbance
1000150020002500300035004000
Wavenumbers (cm-1)
Three Amide deposits on Aluminum with PLG dissolved away.
Two Amide deposits squashed onto Aluminum.
Methylene Chloride removed
most of the PLG
Squashed onto Aluminum
Squashed onto Aluminum
Amide
Amide
... so what is this Secondary Amide and what is it doing?

Synergistic Use of
FTIR Microscope
and
Gas Chromatograph / Mass Spectrometer
The two most powerful instruments
In Analytical Chemistry
... so what is this Secondary Amide
and what did it do?

The SIS Thermal Desorber
A Heated Inlet for GC/MS
sold by Scientific Instrument Services

Carrier Gas Flowpath to Mass Spec Detector
Pure He flowing through
glass lined steel tube
that contains sample.
Tube is injected into
GC Inlet and heated.
Volatiles separate on
column and are analyzed
by the MS.

Excised tiny intact Bubbles melted in THDSB
pop and release CO2 (and NOT O2 or N2)
PLG Hydrolysis in heated tube releases Lactide and Glycolide

Hydrolysis of PLG: The Chemistry Occurring
The moisture in the amide flakes
forms steam during injection
molding, inflating the bubbles.
The steam is consumed as it
hydrolyzes the PLG, filling the
bubbles with CO2.
as per Dr. C. C. Chu of CornellJohn Donohue - donohuejjp@gmail.com

Spectral changes of PLG hydrolyzed on Hotplate
Carbonyl and Hydroxyl orbitals
are formed as the controls
hydrolyze on the hotplate.

Spectral changes of PLG vs proximity to amide deposit
The concentration of the same Carbonyl
and Hydroxyl orbitals is seen to increase
with increasing proximity to the bubbles
formed by the amide flakes. This large
gradient in concentration occurs across
a microscopic range of distance from the
bubbles’ walls.
It is in analyses like this one that the
FTIR Microscope is the very best tool
there is. No other instrument could
do this work: easy and exact spatial
localization of a chemical identification.

Preventing Recall - Conclusion
>Skin Flakes boiled off their water, inflating the “comets”
>As this steam inflated the PLG, it was immediately consumed by the PLG’s
Hydrolysis Reaction
>Hydrolyzing PLG emits CO2, the gas remaining inside the “comets” that was
detected by GC/MS as the “comets” melted and popped
>Hydrolyzing PLG on a hot plate using drops of water  Darkened spots ranging
from light brown to nearly black
>FTIR spectra of these darkened regions  peaks appearing near 1730 cm-1 and
1620 cm-1
>FTIR spectra obtained from microscopic regions as the area examined approached
the hydrolyzed circumference of the “comet” slices  peaks appearing near 1730
cm-1 and 1620 cm-1
>The polymer pellets were protected against any further contamination by skin
flakes, there was no further problem with “comets”, the product launch was
continued, and the implant dominated its market  One Billion $ in $ales per year

Ending $100MM/yr Device Factory Shutdown
caused by “wrinkled” Injection Molded Parts
A $100MM per year device factory was shutdown because Injection
Molded parts were slightly wrinkled. No one was going to make any
money until the problem was fixed.
Possible causes that were proposed for investigation:
>Electrical supply fluctuations
>Cooling Water Heat Transfer fluctuations
>Press Horsepower fluctuations
Many “Shotgun Experiments” were about to begin with no expense to be spared
--- BUT ---
>The Polypropylene (PP) Resin was supposed to contain Sodium Benzoate (NaBZT), an
additive that makes the Polymer solidify at a higher temperature (faster) than normal.
>This fact suggested that the best place to look for the cause was in the PP pellets
themselves.
>I developed an Infrared analytical method that measured very quickly the NaBZT
concentrations of large numbers of individual pellet.

Plant Shutdown Ended
“Wrinkled” Injection Molded Parts caused by Resin Supplier’s Error
FREQ
NaBZT Concentration
This is one example of when to use the FTIR Mainbench instead of the Microscope:
When you want to analyze as large of an area as possible per each scan.
>The Resin Supplier by mistake had added
different pellets to the Finished Material:
pellets that contained a significantly higher
concentration of NaBZT than the correct
pellets. These wrong pellets were dumped
into the Railcar on top of the correct Resin.
>The resulting mixed resins received only the
little bit of blending that occurred during
transport from the Railcar to the Silo and
then to the Hoppers.
>The Parts wrinkled because the varying NaBZT
concentrations caused varying degrees of
Shrinking and Packing during molding.
...but some had too much
Analytical Method developed
to measure RAPIDLY the
Concentration of individual pellets
proving Bimodal Distribution
Most Pellets had
Right NaBZT amount

FTIR Microscopy can do a lot more
than the simple chemical
identification of contaminants.
> It can determine the physical morphology of polymers.
> It can measure the oxidative degradation caused by
radiation sterilization (dosimetry).
> It can measure the hardness of PVCs, Polyurethanes,
and numerous other Thermoplastic Elastomers
> It can measure the Butadiene or Styrene content of Styrenics
Part 5: Special Applications

Measuring Changes in Crystallinity:
PET Tube Turned Opaque White
Customer complained that PET catheter was opaque white instead of clear
BUT
Had the customer accidently left this catheter in a hot Autoclave overnight?

Polyethylene Terephthalate Crystal Structure

The Mettler Hotstage
Remove the glass window and insert a strip of aluminum sheet or a thin, “homemade” KBr “poker chip”.
Then you can obtain spectra while heating the sample.

Spectral Differences Between Clear And Hazy PET Tubes
Crystallinity Peaks marked in Hazy Return
Full
Spectrum
zoom in
The hazy (opaque white)
catheter had spectral
differences when
compared to the clear
catheter (crystallinity peaks
are shown at right)

When the clear tube was quenched
from the melt by Boiling it in Water,
it crystallized, turning white like the
Customer’s Hazy returned tube.
Proof that Spectral Differences Between Clear and Hazy Tubes
are due to Crystallinity
Crystallized in Boiling Water
Crystallized in Boiling Water
The Spectra of the clear tube when
it is molten at 260C is the same as
when it is quenched from the melt
by Liquid Nitrogen.
BUT when it is quenched from the
melt by Boiling it in Water, it
anneals and grows crystals.
Crystallized by Customer’s
Unknown Method

Proof that White catheter has hydrolyzed to Lower Molecular Weight
When the Clear tube, a PET control
sample, and the Hazy PET were
melted and then instantly quenched
from the melt in Liquid Nitrogen, the
Hazy sample has already Crystallized.
and the Clear tube sample has not.
The Hazy PET crystallizes much more
readily because it has Hydrolyzed to
a Lower Molecular Weight.
When the clear tube is melted and
kept (quenched) in ambient air for
4 seconds or 10 seconds before being
quenched in Liquid Nitrogen,
NO crystallization begins after the 4
seconds in air and only a tiny amount
after the 10 seconds in air.
The Hazy PET crystallizes much more readily because it has Hydrolyzed to a Lower Molecular Weight.
The Customer probably left the catheter in a hot Autoclave overnight.

Effects of Radiation
and Accelerated Aging
Part 6: Radiation Sterilization Issues

ATR Spectrum
Reflection from smear
on aluminum sheet
The bloom visible on this catheter
was analyzed both by contacting
its surface with the ATR Objective
and by smearing the bloom onto
aluminum sheet and analyzing
the smear by Reflectance.
The smear shows only the DEHP
while the ATR sees both the
DEHP and the PVC catheter.
Radiation Increases PVC Blooming
Of Cytotoxic DEHP Plasticizer

Radiation Generates Free Radicals in Polypropylene

Free Radicals Generate Carbonyl Groups in Polymers

Test Method Development
Decreased Ductility Can Cause Devices To Break During Use.
Radiation may increase the force to strain the device, but the strain
at break decreases. Devices seldom fail because they’re too stiff.
They fail because they break.
A Syringe barrel wall may be unbreakable
during use despite receiving the highest
radiation dose allowed. Syringe tips may
be much more fragile. Customer complaint
history and product history may indicate
what areas of a product are areas of concern;
what are the products’ weakest links. It is
these modes of failure that must be tested.
Testing must mimic the mode of failure
expected during customer use. Breakage
tests must be performed at a speed of
deformation similar to that experienced
by the product during customer use.
Testing samples subjected to Accelerated
Aging will provide data quickly that predicts
the future behavior of products. The Test
Protocols will define the Accelerated Aging
to be used.

Measuring Radiation Damage using Micro-FTIR
Mounting Aluminum Sheet On 3X2 Glass Slide

Shavings off Polypropylene Barrel’s Surface Analyzed Herein:
Shavings Obtained with Razor Blade

Close-ups of Polypropylene Shavings Analyzed Herein

0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
Absorbance
1000150020002500300035004000
Wavenumbers (cm-1)
Same Polypropylene Film Before and After 40 kGYs of Cobalt Radiation
Blue is after

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
Absorbance
20002500300035004000
Wavenumbers (cm-1)
Blue is after
Hydroperoxides Carbonyls

0.08
0.10
0.12
0.14
0.16
0.18
0.20
0.22
0.24
0.26
Absorbance
16001700180019002000
Wavenumbers (cm-1)
Blue is after
Scissioned Polymer Chains Oxidize

IR Spectrum Shows Radiation Induced Oxidation of Polypropylene
as per J. Donohue MDDIJohn Donohue - donohuejjp@gmail.com

Polypropylene Oxidation from 20 and 40 kGYs of Cobalt Radiation

The “Dark Reaction” of Irradiated Polypropylene
Oxidative Degradation Continues Long After Irradiation Has Ceased
This is the Reaction that is Accelerated by Accelerated Aging

Dr. Apostolou and I “wrote the book” on Accelerated Aging Methods that work

Oxygen Can More Easily Penetrate and React
with the Polymer in a Thin Film

This Post Rad Oxidation is Not Just Peroxide Scissions.
Ambient Oxygen Continues to React with the Polymer.
This is Proven by this Vacuum Oven Aging.

Polyethylene Undergoes Similar Oxidation
when Irradiated with 20 and 40 kGYs

A Carbonyl Index Can be Defined to Measure this Oxidation

Statistical Results for Micro-FTIR Dosimetry of Gamma vs Control
The Micro-FTIR Method is Accurate, Precise, and Robust

0.10
0.20
0.30
0.10 0.20 0.30
0.00
0.00 0.40
X = Thickness of slice (area of 1304 cm-1 Absorbance)
Area of C=O
Absorbance
divided by X
(Carbonyl Index)
Radiation Damage (= Dose) Measured for Thin Surface
Shavings of Sterilized Polypropylene Medical Devices
Shavings of samples with 0 Mrads
Shavings of samples with 3.5 Mrads
Shavings of sterile product
Shavings of underdosed product
FTIR Microscopy can determine a competitor’s dose or detect underdosed non-sterile devices.

Stability of Fina Syndiotactic and Isotactic
Polypropylenes to Cobalt Radiation
and Accelerated Aging

Ziegler-Natta and Metallocene Catalysts
Controlled Orientation of Monomer Approach To Active Site
Yields Controlled Stereoregularity of Polymer Chain Formed.
For Z-Ns, Solid Catalysts Control Approach to Active Site.
For Metallocenes, Molecular Structure Controls Approach.

Stereostructure of
Isotactic Polypropylene
Hydroperoxide Formation
by “Backbiting” Oxidation
Strings of Close, Unstable,
Pendant Hydroperoxides
Free Radical Degradation of Isotactic Polypropylene

0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
Absorbance
1000150020002500300035004000
Wavenumbers (cm-1)
Isotactic Polypropylene Before and After 38 kGy & 17 Days @ 70 C
Hydroperoxides Carbonyls
The Isotactic Polymer is extensively Oxidized by Irradiation.
It sizzles like bacon when it is melted.

0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
Absorbance
1000150020002500300035004000
Wavenumbers (cm-1)
Syndiotactic Polypropylene Before and After 38 kGy & 17 Days @ 70 C
The Syndiotactic Polymer exhibits very little Rad-induced Oxidation

0.08
0.10
0.12
0.14
0.16
0.18
0.20
0.22
0.24
Absorbance
16001700180019002000
Wavenumbers (cm-1)
IPP & SPP: 38 kGy & 70 C Aging Study
Accelerated Aging Increases IPP Oxidation
but has Very Little Effect on SPP
IPP @ 70 C: 17 Days
88 Hrs
16 Hrs
0 Hrs
IPP 0 Dose
SPP 0 Dose
SPP @ 70 C:
0 to 17 Days

0.08
0.10
0.12
0.14
0.16
0.18
0.20
0.22
0.24
Absorbance
16001700180019002000
Wavenumbers (cm-1)
IPP & SPP: 38 kGy & 40 C Aging Study
IPP @ 40 C: 17 Days
88 Hrs
16 Hrs
0 Hrs
IPP 0 Dose
SPP 0 Dose
SPP @ 40 C:
0 to 17 Days
Accelerated Aging Increases IPP Oxidation
but has Very Little Effect on SPP

Radiation Sterilized
Syndiotactic Polypropylene
Generates an Order of
Magnitude Less Volatiles
than an Equal Mass of
Irradiated Isotactic Polypropylene
THDSB/GC/MS Analyses
of Post-Rad Volatiles

The Close, Unstable, Pendant Hydroperoxides Explode Like a String of Firecrackers
CO2
acetaldehyde
acetone
acetic acid
4-hydroxy4-methylpentanone
2,4-dimethylfuran
cyclopropylacetone
allylacetone
acetic anhydride
3,5,5-trimethylfuranone
acetoacetone
THDSB/GC/MS IDENTIFICATION
OF IPP POST-RAD VOLATILES
Heated Irradiated Isotactic Polypropylene Degrades
into Volatiles Based on C-C-O Units that Reveal the
Chemical Mechanisms of its Oxidation

Thermally Degraded Post Rad Isotactic Polypropylene
Emits Low Mass Scission Products Based on C-C-O Units …
Air & Water
Desorbed Out
Of Tube
Acetone
Acetic Acid
… Because Similar Oxidized Structures Degrade into Similar Volatiles
THDSB/GC/IR Analyses of Post-Rad Volatiles

Thermally Degraded Post Rad Syndiotactic Polypropylene
Emits a Far More Random Mix of Scission Products …
Air & Water
Desorbed Out
Of Tube
2-Hydroxy-Propionic Acid
3-Methyl-2,4-Pentanediol
4-Butyl-Gamma-Octanolactone
… Because a More Random Dispersion of Oxidized Structures Yields
a More Random Mix of Volatile Degradation Products
THDSB/GC/FTIR Analyses of Post-Rad Volatiles
John Donohue -
donohuejjp@gmail.com

Phenolic Antioxidants Protect Against Radiation Damage by
Scavenging the Free Radicals Formed in the Polymer by Radiation
Part 7: Additives; their Analysis and Issues

But Phenolic Antioxidants Turn Plastic Yellow When Irradiated

Hindered Amine Light Stabilizers Form Cytotoxic Hydroxylamines
as they Protect the Polymer from Radiation Damage
Without Discoloration

Millad 3988 Clarifies Polypropylene
Molding Heat Causes Hydrolysis, Releasing Benzaldehyde Derivatives
This Causes the Polymer to Emit a “Cherry Candy” Smell
Millad makes Polypropylene more brittle

Clarified Polypropylene Crystallized at 130 C from the Melt
Nucleation Determines Morphology
ClarifiedNot Clarified
Sublimation depletes Boundary of MilladPolypropylene Spherulites grow
Millad prevents
Spherulite growth

Millad Forms Thermally Unstable Precipitate if it is Overheated During
Injection Molding. Precipitate’s Sizzling Decomposition into Gaseous,
Superheated Aldehyde Strips Char out of Molding Press and Into Molded Parts.
Heated excised precipitate chunks undergoing thermal decomposition on Hotplate

Sizzling Decomposition into Aldehyde and Arylate
>Tiny orange spots were
scattered across the
Polypropylene matrix
>Any attempt to get the spectrum
of more than one orange spot at
a time yielded only a spectrum
of the Polypropylene matrix
>But the IR-Plan can can zoom in
on a single tiny orange spot to
yield the Arylate spectrum
shown …
… and Thermal Desorption of the
degrading material into the
GC/MS can show the formation
of the Aldehydes and Alcohol
Intermediates.

Thermal Decomposition of Precipitate Forms Aldehyde.
Cannizzaro Reaction of Aldehydes Forms Acid and Alcohol.
Condensation of Acid and Alcohol Forms Arylate.
Arylate Forms The Orange Spots

Thin Layer Chromatography (TLC) can Separate Chemical Mixtures that the
GC/MS can’t: Chemicals that are non-Volatile or Thermally Unstable
Liquid carries chemicals in spot of extract up the plate, separating themJohn Donohue - donohuejjp@gmail.com

>TLC is done on a Plate Covered with
Fluorescent Silica
>UV Light makes the Separated
Chemicals from the Mixture
Visible
>The Regions of Silica Containing
these Chemicals are scraped off
the plate, separated from the Silica,
and Identified using the Analytical
Instrumentation
Under Visible Light
Under UV Light
After Scraping

0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
Absorbance
1000150020002500300035004000
Wavenumbers (cm-1)
Measuring Durometer of FINISHED (competitive) Devices:
FTIR of DEHP Plasticized PVC Device vs Pure PVC
Pure PVC
Part 8: Tricks of the Trade

-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
Absorbance
1450150015501600
Wavenumbers (cm-1)
FINISHED Device: Measuring Plasticized PVC Durometer
Hard Endotracheal Tube
Soft Nasogastric Tube
DEHP
PVC
Spectra “normalized” for equal plasticizer (DEHP) content show
that the harder PVC has a higher PVC to Plasticizer Ratio
Such a test can tell the Durometer used by a Competitor
Higher
PVC
conc.

0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
Absorbance
1000150020002500300035004000
Wavenumbers (cm-1)
Reverse engineering competitive catheters
Micro-FTIR Spectrum of Pellethane
zoom in here next slide

0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
0.60
Absorbance
1360138014001420
Wavenumbers (cm-1)
Micro-FTIR ID: FINISHED Device Pellethane Durometer
80A
90A
75D
>Many catheters have tips made from a softer grade
material than the shaft.
>FTIR can measure the Durometer of finished
Polyurethane devices quickly and easily
>Multiple runs below show that the method is robust

0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
Absorbance
1000150020002500300035004000
Wavenumbers (cm-1)
Micro-FTIR Spectrum of Tecothane

0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
0.18
Absorbance
1360138014001420
Wavenumbers (cm-1)
Micro-FTIR ID: FINISHED Device Tecothane Durometer
74A
85A
55D
75D

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
Absorbance
1000150020002500300035004000
Wavenumbers (cm-1)
Micro-FTIR Spectrum of Tecoflex with 20% BaSO4

0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
Absorbance
130013201340136013801400
Wavenumbers (cm-1)
Micro-FTIR ID: FINISHED Device Tecoflex Durometer
80 A
85 A
100 A
65 D
60 D
NOTE:
This method is more accurate than the
manufacturer’s ability to control or measure
their Durometer. The Hardness Pucks that
were supplied by the manufacturer (after
measuring Durometer with a Hardness Tester)
and were supposed to be 60 D were instead
HARDER than the supposed 65 D pucks.

HIGH-GLOSS
ABS CRACKS
LOW-GLOSS ABS
RESISTS CRACKING
FTIR Shows Why High-Gloss ABS Has Less ESCR Than Low-Gloss ABS
More Styrene/Butadiene Rubber dispersed in the Acrylonitrile matrix
yields High Gloss ABS with less resistance to Environmental Stress Cracking

Packaging Materials
>There are a lot of “Tricks of the Trade” in Materials Analysis.
>For example, Most packaging films are laminates with outer
heat-sealable plies and an inner strength ply.
>The FTIR Microscope requires Liquid Nitrogen (LN2) to operate
and this LN2 can be used to cryo-fracture materials.
>Cryo-fractured laminated films can be separated easily into their
individual plies for material identification and also for accurate
thickness measurements free from thickness artifacts caused by
cutting techniques that can decrease the measured thicknesses.

The film contains K-Resin…
…and the stretched Heat Seal Ply is EVA
Device package bottom web was
cryo-fractured with liquid N2 and
the heat seal ply was stretched over
aluminum sheet.

cryo-fractured with liquid N2 and
the protruding and overhanging
plys show a Surlyn center ply
sandwiched in EVA heat seal plys.
Surlyn center ply
protruding from
fractured laminated
film
Surlyn ply and EVA heat
seal ply together
John Donohue -

cryofractured with liquid N2 and
this two ply film separated into
a K Resin ply and a more flexible
EVA heat seal ply.
K Resin ply is stiffer
EVA heat seal ply

Chemical Degradation of Polycarbonate
by Dymax Adhesive
Analysis of White Stain inside Cured Part
Part 9: UV Adhesives and the Chemical Fragility of Polycarbonate

ABSTRACT
>Polycarbonate (PC) has poor resistance to attack by a large number of chemicals.
>Chemicals that “plasticize” PC cause problems that include clouding, warping,
crazing, cracking, breaking, falling apart, etc. For example, Formula 409 contains
about 10% “grease cutter” and will quickly destroy PC; especially when the PC has
a relatively low Molecular Weight and/or lots of molded-in-stress pulling it apart.
>Chemicals that are “Bases” (electron donators) catalyze the polymerization of PC
and therefore can also catalyze the reverse reaction, depolymerizing PC into
oligomers of Bisphenol A (BPA) monomer or the BPA monomer itself. For
example, Amines famously do this to PC.
>A major ingredient of the Dymax adhesive is N,N-Dimethylacrylamide (a base). It
is well-known that many adhesives will attack PC if they are in contact with it too
long prior to being cured. This chemical is one of the reasons for this. When the
adhesive is completely cured, this chemical is completely consumed (this fact is
demonstrated using the spectra herein).
>The white stain on the PC in contact with the “cone” of adhesive is partially
depolymerized PC. Its FTIR spectra show the presence of both PC and the
endgroups (that appear as BPA and its oligomers) are formed from the scissioning
of PC. The adhesive must be quickly and fully cured to prevent this.
>The side of the adhesive cone that was peeled free from the PC is coated with
a thin shattered film of PC. The side that was in contact with the Polyurethane
(PUR) is coated with the PUR. Thus, the adhesive is tougher and more tenacious
than either polymer.

What Happened to the Polycarbonate?

White Stain Seen Through the PC Wall Prior to Dissection
White Stain is Connected to the PC

White Stain Remains on PC After Adhesive is Peeled Back
Polycarbonate
Peeled-back
Dymax Adhesive
Polycarbonate

White Stain Remains on PC Higher Magnification
Polycarbonate Polycarbonate

White Stain Remains on PC

The White Stain is Partially Depolymerized Polycarbonate so FTIR shows that
it contains Absorptions for PC, Oligomers, and BPA Monomer
Polycarbonate
White Stain
Bisphenol A
John Donohue -

The Surface of the Adhesive that was against the PC is encased
in a thin shattered PC Film that again contains Oligomers and BPA

Thin Shattered Film on Adhesive that was against the
PC contains Polycarbonate, BPA, and Oligomers
Polycarbonate
BPA
John Donohue -

The other side of the adhesive was against the
Polyurethane and it is encased in that Polyurethane
Polyurethane Tube
John Donohue -

What Chemical(s) Attacked
the Polycarbonate?

O
O
N
O
OH
O
OH
O
DYMAX Disclosed 5 Components of this Adhesive
N,N-DimethylacrylamideIsobornyl Acrylate
Irgacure 184 Darocur 1173
Reactive Diluents
Photoinitiators
Ketone
Amide
These 4 are All Ketones and one is also an Amide. Ketones can Craze and Crack
Polycarbonate and Amides can Depolymerize it to Bisphenol A. John Donohue -

Pre-UV Adhesive
Post-UV Adhesive
Adhesive Taken Off Device
Adhesive’s Spectrum Pre and Post Polymerization by UV
Double Bond at 1612 cm-1 Completely Consumed by Polymerization
Double Bond
John Donohue -

Double Bond @ 1614 cm-1
N, N, Dimethylacrylamide’s Double Bond is Consumed during the Polymerization
The Two Carbons Become Part of the Cured Adhesive’s “Backbone”
The Absorption Disappears as the Adhesive Cures
This Chemical Attacks the Polycarbonate

The Isobornyl Acrylate’s Double Bond is also Consumed by the Polymerization
Double Bond

Drug Eluting Coronary Stent Coatings
Part 10: Drug Eluting Heart Stent Coatings

Copyright ©1996 American Heart Association
Edelman, E. R. et al. Circulation 1996;94:1199-1202
Angioplasty and Stenting are Competitive Procedures
Divergent processes of vascular repair after balloon angioplasty
and stenting of an atherosclerotic vessel

Divergent processes of vascular repair after balloon angioplasty and
stenting of an atherosclerotic vessel. Balloon angioplasty (top) compresses
and fractures the atherosclerotic plaque (light gray) and tunica media
(black), slightly enlarging the artery. After a few days, a thin layer of
platelet-rich thrombus (dark gray) lines the lumen and fills the dissection
plane. The lumen shrinks from combined effects of early elastic recoil and
later formation of a fibrocellular neointima (speckled area). Stent
deployment after angioplasty (bottom) compresses the dissection plane
and enlarges the lumen while stretching the artery with minimal elastic
recoil. Within hours to days after stenting, caps of thrombus infiltrated with
inflammatory cells (dark gray) form over stent struts (black rectangles),
particularly abundant at sites of deep injury. Over ensuing weeks, a
neointima forms (speckled area), thicker where injury is more severe.
Although intimal growth after stenting is greater than after balloon
angioplasty, the residual lumen is also larger, as the scaffolding of the stent
maintains luminal dimensions. Late changes in arterial size are not depicted
because the contribution of remodeling to restenosis after angioplasty or
stenting remains incompletely characterized.
(Figure prepared by James Squire.)
Edelman, E. R. et al. Circulation 1996;94:1199-1202

Stents scrape blood vessel walls. This injury causes reblockage.
Edelman and Squire

Stents scrape blood vessel walls
Edelman and Squire

Drug Eluting Coated Stent
3.0mm X 2.3mm

420μ X 550μ 300μ X 390μ

A Different Manufacturer’s
3.0mm X 2.3mm

420μ X 550μ 300μ X 390μ
A Different Manufacturer’s

IR Spectrum of PC 1036 from Biomaterials 21 (2000) 1847-1859
Phosphatidyl Choline (PC)
coating, invented by
Biocompatibles, Ltd., used
on some Medtronic and
Abbott Drug Eluting
Coronary Stents.
Spectra of coatings obtained
off the actual stent surfaces
show the PC coating and the
anti-restenosis drug it elutes.
All drug was extracted from
the Abbott stent but PC
coating remains.
John Donohue -

IR Spectra of pure PC, PC 1036, Medtronic Stent Coating, and
Abbott Stent Coating
 The Pure PC’s IR shows most of the vibrations present in the PC 1036 coating.
 The PC 1036 IR was published back when Biocompatibles, Ltd. was trying to
“drum up” big company interest in their materials. [This particular spectrum is
slightly distorted (an “enlarged” 1090 vibration) because it is a surface spectrum
(obtained via ATR) of a PC polymer in which the hydrophilic PC moieties have
been rotated preferentially to the surface by contact with water. The 1090 is the
C-O-P stretching vibration.]
 The Medtronic (Endeavor™) and Abbott (BiodivYsio™) stent coating spectra
were obtained by reflection off the stents’ surfaces.
 The stent coatings are excellent matches to the spectrum of PC 1036. Since this
is the coating Biocompatibles, Ltd. developed for the BiodivYsio stent, I believe
it is the PC coating on the Medtronic and Abbott stents. EDAX can be run using
the SEM to see if silicon is detected from the PC 1036 TSMA component. The
literature published by Biocompatibles, Ltd. suggests a TSMA content of 3 to 5%.
At this loading EDAX should detect the silicon.

Biocompatibles, Ltd. developed the PC-coated
BiodivYsio™ stent and marketed a number of PC
polymers. One of these polymers, PC1036, appears
to be the PC coating on the BiodivYsio stent,
now a product of Abbott. It also appears to be
the coating Abbott has licensed to Medtronic for
the Endeavor stent.
PC 1036 is made using the four acrylic monomers
shown here.
>2-methacryloyloxyethyl phosphorylcholine (MPC)
>lauryl methacrylate (LMA)
>hydroxypropyl methacrylate (HPMA)
>3-trimethoxysilylpropyl methacrylate (TSMA)
MPC supplies the PC functionality to the polymer.
LMA helps the polymer adhere to metal surfaces.
TSMA makes the polymer crosslinkable, which
improves its adhesion and cohesion and helps control
its rate of drug elution.
HPMA is a co-crosslinker that, used with TSMA at 25%
loading, gave good mechanical properties.
AIBN (azoisobutyronitrile) initiates polymerization.
PC 1036 Biocompatibles, Ltd.
Biocompatibles, Ltd. paperJohn Donohue - donohuejjp@gmail.com

TSMA Hydrolysis initiates the Crosslinking of the Coating
The Drug Elution Rate is determined mainly by the extent of crosslinking.
The hydroxy groups of the HPMA moiety will crosslink with TSMA also.
Biocompatibles, Ltd. paper

Part 11: Particulate Identification

Cardboard-Colored Cellulose
Organic Coating on one side

Biodegradation of an Insect
This insect
died of
natural causes
in the spring
of 2006.
(No insect’s
were harmed
in the
making of
this document)
After storage in an airtight container for more
than one year, webbing is growing on it.
All 8.5mm X 11.2mm
Part 12: Fish Hooks, “Bait”, and Electronics

8.5mm X 11.2mm 2.3mm X 3.0mm
Webbing at Eye

Views of Webbing
8.5mm X 11.2mm

… yields a better protein Spectrum after
it is Squashed
-0.2
-0.1
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
1.3
Absorbance
100015002000250030003500
Wavenumbers (cm-1)
550u X 420u FOVs
Spectra of Webbing on Aluminum Sheet …
Webbing placed on sheet
Webbing squashed on sheet

-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
Absorbance
1000150020002500300035004000
Wavenumbers (cm-1)
Polyimide
White Epoxy
Green Ink
Blue Ink
8.5mm X 11.2mm
2.3mm X 3.0mm
Epoxy
Polyimide
Metal
Inkjet Cartridge Printhead
Laser Cut Metal “Window”

11.2mm X 8.5mm
3.0mm X 2.3mm
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Absorbance
1000200030004000
Wavenumbers (cm-1)
PET + Butylacrylate Adhesive
Butylacrylate Glue
Cu & Glue is between PET & Polyimide
Ceramic beneath slotted Metal
Micaceous Cleavage of Ceramic
Printhead Dismantled – Piezoelectric Ceramic Under Metal

Who made the Chip that’s encased in hard black epoxy?
Original Photo Flipped Image
Toshiba

Fish Hook Manufacturing Processes:
Cutting, Bending, Welding, Coating
8.5mm X 11.2mm FOVs

Fish Hook’s Point and Scratched Inorganic Coating:
420u X 550u FOVs

Micro ftir my-labforhire1

Recommended

Recommended

More Related Content

What's hot

What's hot (7)

Viewers also liked

Viewers also liked (6)

Similar to Micro ftir my-labforhire1

Similar to Micro ftir my-labforhire1 (20)

More from John Donohue

More from John Donohue (10)

Recently uploaded

Recently uploaded (20)

Micro ftir my-labforhire1