Infrared Microscopy and Microanalyses for hire: Analytical Lab for small companies

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Infrared Microscopy and Micro Analyses for hire, …

Infrared Microscopy and Micro Analyses for hire,
Exact answers and interpretations for lowest prices,
Expert chemical analyses and interpretations,
I don't just tell you what it is, I tell you why it happened.

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  • 1. 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
  • 2. Part 1: Introduction to the Technology and Method 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. John Donohue - These documents will describe the type of analyses I perform for Industry and Publication using this instrument and the other equipment in my Laboratory. donohuejjp@gmail.com
  • 3. 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 Mirrored “Flying Saucer” Mirrored “Lampshade” … and Visible Light Objectives for Visible and Polarized Light Microscopy John Donohue Hard Silicon Surface for ATR “Contact” Spectra - donohuejjp@gmail.com
  • 4. Microscope Reflection Mode Lightpath From Source To Detector 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. Sample on metal Shiny Metal Substrate Shiny Metal Substrate John Donohue - donohuejjp@gmail.com
  • 5. UNIQUE ADVANTAGES OF THE FTIR MICROSCOPE How sensitive is it? See arithmetic below. >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 John Donohue - donohuejjp@gmail.com
  • 6. 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. From Source To 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. John Donohue - donohuejjp@gmail.com Sample
  • 7. How Small Can Samples Be? How small IS the 10μ X 10μ Limit of Detection? John Donohue - donohuejjp@gmail.com
  • 8. Back of USA Penny Lincoln Memorial John Donohue - donohuejjp@gmail.com
  • 9. Lincoln seated on Penny’s back This image is 11.2mm X 8.5mm. John Donohue - donohuejjp@gmail.com
  • 10. Lincoln seated on Penny’s back; mm scale to left This image is 3.0mm X 2.3mm. John Donohue - donohuejjp@gmail.com
  • 11. IR-Plan Visible Light 10X Objective view (Glass) Lincoln’s Head and Shoulders This image is 550μ X 420μ John Donohue - donohuejjp@gmail.com
  • 12. 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. This image is 390μ x 300μ Limit of Detection: “Lincoln’s “Eye” 10μ X 10μ John Donohue - donohuejjp@gmail.com
  • 13. 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. John Donohue - donohuejjp@gmail.com
  • 14. Part 2: Asbestos Testing Asbestos Identification by IR Microscopy and/or Polarized Light Microscopy John Donohue - donohuejjp@gmail.com
  • 15. Friable Asbestos Identification by IR Microscopy of broken cementitious tile: John Donohue - donohuejjp@gmail.com
  • 16. Zooming in on the Friable Asbestos John Donohue - donohuejjp@gmail.com
  • 17. John Donohue - donohuejjp@gmail.com
  • 18. Microscopic amount of Asbestos squashed onto aluminum sheet John Donohue - donohuejjp@gmail.com
  • 19. NOTE: Often Spectra are corrected for humidity in the Laboratory air John Donohue - donohuejjp@gmail.com
  • 20. The Asbestos sample is Chrysotile John Donohue - donohuejjp@gmail.com
  • 21. The IR Microscope is so very sensitive that even a 20μ X 65μ area of a Single “ribbon” of Asbestos is enough for Identification John Donohue - donohuejjp@gmail.com
  • 22. John Donohue - donohuejjp@gmail.com
  • 23. 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 John Donohue - donohuejjp@gmail.com
  • 24. Device Production Restarted and Defect Determined and Eliminated Via Stress Birefringence Analysis Crack Initiation Point >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. John Donohue - donohuejjp@gmail.com
  • 25. Injection Molding Morphology and Physical Properties 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. John Donohue - donohuejjp@gmail.com
  • 26. Part 3: Application to Medical Device issues Solving Medical Device problems using IR Microscopy Visible Microscopy John Donohue - donohuejjp@gmail.com
  • 27. ATR Spectra of Surface of IR-Opaque Rubber 0.15 0.10 0.05 Silicone Lubricated Gasket Abs orbanc e 0.00 -0.05 -0.10 Less Silicone After Surface Scraped -0.15 -0.20 -0.25 No Silicone After Acetone Wash: Silicate-filled rubber polymer -0.30 3500 3000 John Donohue - donohuejjp@gmail.com 2500 2000 Wavenumbers (cm-1) 1500 1000
  • 28. The Technology of a Needle Point 2.3mm x 3.0mm Photos of an Insulin Needle Point What can we learn with a fast analysis? John Donohue - donohuejjp@gmail.com
  • 29. 420μ x 550μ Photos of Needle’s three cut planes The “subtle” cut John Donohue - donohuejjp@gmail.com
  • 30. 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. John Donohue - donohuejjp@gmail.com
  • 31. Infrared Microscopy Provides Chemical Identification that shows Gelled Lubricant is used on Hypodermic Needles 3.0mm x 2.3mm 390μ x 300μ 0.012 0.011 0.010 0.009 0.008 Absorbance 0.007 0.006 0.005 Gel is Silicone 0.004 0.003 0.002 0.001 -0.000 3500 550μ X 420μ 3000 John Donohue - donohuejjp@gmail.com 2500 2000 Wavenumbers (cm-1) 1500 1000
  • 32. Engineering Resins: ESCR vs “Hoop Stress Failures” 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). Hoop Stress cracking 8.5mm X 11.2mm John Donohue - donohuejjp@gmail.com
  • 33. PET Barrels That Failed At Gate A “Cold Slug” in an Injection Molding “Gate” can initiate breakage at unacceptably low force John Donohue - donohuejjp@gmail.com
  • 34. Devices broke due to “Cold Slug” in Injection Molding Gate Gate A Ridge/Valley Cold Slugs Blade Striations John Donohue - donohuejjp@gmail.com Gate B
  • 35. Identification of PET Barrel Skirt Contaminant by Micro-FTIR John Donohue - donohuejjp@gmail.com
  • 36. Smudges on PET at Tip Insert of Barrels Parting Line John Donohue - donohuejjp@gmail.com
  • 37. PET Barrel Skirt Bloom removed for analysis Pre-Extracted Cellulose on PET Skirt Same Area of PET Skirt After Wiping Cellulose Grease about to be removed Streaks where Grease was removed John Donohue - donohuejjp@gmail.com
  • 38. PET Barrel Skirt Contaminant is Same as Found previously The Difference Seen below is Cellulose from the Kimwipe. The Grease is an Acid (1712 cm-1) and an Ester (1737 cm-1). 0.45 5.S il icone B B L Lube A TR,B radmons K i mw iped B loom in P E T B B L skirt,G ri ffith,RE FL32 0.40 P E T B B L ski rt grease,K imWi ped& MC d,Castro,RE FL32,2/27/09 120a2209,MICR,CE LLU LOS E ,A CCU W IP E /A L,2/244 0.35 0.30 0.25 0.20 0.15 Log(1/ R) 0.10 0.05 Grease Found Recently 0.00 -0.05 -0.10 -0.15 Grease Found Previously -0.20 -0.25 Cellulose -0.30 -0.35 Silicone -0.40 4000 3500 3000 2500 2000 Wavenumbers (c m-1) John Donohue - donohuejjp@gmail.com 1500 1000
  • 39. Part 4: Nailing the Answer and Preventing a Recall 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. Flow Direction >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. John Donohue - donohuejjp@gmail.com
  • 40. 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 Clear translucent polymer slice Hazy Translucent Area on border of Bubble Cross-section of Bubble John Donohue - donohuejjp@gmail.com
  • 41. “Zooming in” on Hazy deposit on Bubble’s circumference Increases the Secondary Amide Absorbance Peaks relative to the PLG’S... 3.4 3.2 PLG FTIR Microscopy 3.0 2.8 PLG 2.6 2.4 Absorbance 2.2 1648 2.0 3288 1.8 1534 3060 1.6 1.4 1.2 1.0 0.8 Zooming in 0.6 0.4 0.2 4000 3500 3000 2500 2000 Wavenumbers (cm-1) 1500 1000 ...therefore the hazy area is a Secondary Amide John Donohue - donohuejjp@gmail.com
  • 42. Three Amide deposits on Aluminum with PLG dissolved away. Two Amide deposits squashed onto Aluminum. Amide Amide Methylene Chloride removed most of the PLG 4.0 3.5 3.0 Absorbance 2.5 2.0 1.5 1.0 Squashed onto Aluminum 0.5 0.0 Squashed onto Aluminum -0.5 -1.0 4000 3500 3000 2500 2000 Wavenumbers (cm-1) 1500 1000 ... so what is this Secondary Amide and what is it doing? John Donohue - donohuejjp@gmail.com
  • 43. ... so what is this Secondary Amide and what did it do? Synergistic Use of FTIR Microscope and Gas Chromatograph / Mass Spectrometer The two most powerful instruments In Analytical Chemistry John Donohue - donohuejjp@gmail.com
  • 44. The SIS Thermal Desorber A Heated Inlet for GC/MS sold by Scientific Instrument Services John Donohue - donohuejjp@gmail.com
  • 45. 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. John Donohue - donohuejjp@gmail.com
  • 46. 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 John Donohue - donohuejjp@gmail.com
  • 47. 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. John Donohue - donohuejjp@gmail.com as per Dr. C. C. Chu of Cornell
  • 48. Spectral changes of PLG hydrolyzed on Hotplate Carbonyl and Hydroxyl orbitals are formed as the controls hydrolyze on the hotplate. John Donohue - donohuejjp@gmail.com
  • 49. 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. John Donohue - donohuejjp@gmail.com
  • 50. 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 John Donohue - donohuejjp@gmail.com
  • 51. 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. John Donohue - donohuejjp@gmail.com
  • 52. Plant Shutdown Ended “Wrinkled” Injection Molded Parts caused by Resin Supplier’s Error Analytical Method developed to measure RAPIDLY the Concentration of individual pellets proving Bimodal Distribution >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. FREQ Most Pellets had Right NaBZT amount ...but some had too much >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. 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. John Donohue - donohuejjp@gmail.com
  • 53. Part 5: Special Applications 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 John Donohue - donohuejjp@gmail.com
  • 54. 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? John Donohue - donohuejjp@gmail.com
  • 55. Polyethylene Terephthalate Crystal Structure John Donohue - donohuejjp@gmail.com
  • 56. 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. John Donohue - donohuejjp@gmail.com
  • 57. 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) John Donohue - donohuejjp@gmail.com
  • 58. Proof that Spectral Differences Between Clear and Hazy Tubes are due to Crystallinity 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 in Boiling Water 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. Crystallized in Boiling Water Crystallized by Customer’s Unknown Method John Donohue - donohuejjp@gmail.com
  • 59. 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. John Donohue - donohuejjp@gmail.com
  • 60. Part 6: Radiation Sterilization Issues Effects of Radiation and Accelerated Aging John Donohue - donohuejjp@gmail.com
  • 61. Radiation Increases PVC Blooming Of Cytotoxic DEHP Plasticizer 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. ATR Spectrum Reflection from smear on aluminum sheet John Donohue - donohuejjp@gmail.com
  • 62. Radiation Generates Free Radicals in Polypropylene John Donohue - donohuejjp@gmail.com
  • 63. Free Radicals Generate Carbonyl Groups in Polymers John Donohue - donohuejjp@gmail.com
  • 64. 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. John Donohue - donohuejjp@gmail.com
  • 65. Measuring Radiation Damage using Micro-FTIR Mounting Aluminum Sheet On 3X2 Glass Slide John Donohue - donohuejjp@gmail.com
  • 66. Shavings off Polypropylene Barrel’s Surface Analyzed Herein: Shavings Obtained with Razor Blade John Donohue - donohuejjp@gmail.com
  • 67. Close-ups of Polypropylene Shavings Analyzed Herein John Donohue - donohuejjp@gmail.com
  • 68. Same Polypropylene Film Before and After 40 kGYs of Cobalt Radiation Blue is after 2.0 1.8 1.6 Absorbance 1.4 1.2 1.0 0.8 0.6 0.4 0.2 4000 3500 3000 2500 2000 Wavenumbers (cm-1) John Donohue - donohuejjp@gmail.com 1500 1000
  • 69. Same Polypropylene Film Before and After 40 kGYs of Cobalt Radiation Blue is after 0.70 0.65 0.60 0.55 Absorbance 0.50 0.45 Hydroperoxides Carbonyls 0.40 0.35 0.30 0.25 0.20 0.15 0.10 4000 3500 3000 2500 Wavenumbers (cm-1) John Donohue - donohuejjp@gmail.com 2000
  • 70. Same Polypropylene Film Before and After 40 kGYs of Cobalt Radiation Blue is after 0.26 Scissioned Polymer Chains Oxidize 0.24 0.22 Absorbance 0.20 0.18 0.16 0.14 0.12 0.10 0.08 2000 1900 1800 1700 Wavenumbers (cm-1) John Donohue - donohuejjp@gmail.com 1600
  • 71. IR Spectrum Shows Radiation Induced Oxidation of Polypropylene as per J. Donohue MDDI John Donohue - donohuejjp@gmail.com
  • 72. Polypropylene Oxidation from 20 and 40 kGYs of Cobalt Radiation John Donohue - donohuejjp@gmail.com
  • 73. The “Dark Reaction” of Irradiated Polypropylene Oxidative Degradation Continues Long After Irradiation Has Ceased This is the Reaction that is Accelerated by Accelerated Aging John Donohue - donohuejjp@gmail.com
  • 74. Dr. Apostolou and I “wrote the book” on Accelerated Aging Methods that work John Donohue - donohuejjp@gmail.com
  • 75. Oxygen Can More Easily Penetrate and React with the Polymer in a Thin Film John Donohue - donohuejjp@gmail.com
  • 76. 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. John Donohue - donohuejjp@gmail.com
  • 77. Polyethylene Undergoes Similar Oxidation when Irradiated with 20 and 40 kGYs John Donohue - donohuejjp@gmail.com
  • 78. A Carbonyl Index Can be Defined to Measure this Oxidation John Donohue - donohuejjp@gmail.com
  • 79. Statistical Results for Micro-FTIR Dosimetry of Gamma vs Control The Micro-FTIR Method is Accurate, Precise, and Robust John Donohue - donohuejjp@gmail.com
  • 80. Radiation Damage (= Dose) Measured for Thin Surface Shavings of Sterilized Polypropylene Medical Devices Shavings of samples with 3.5 Mrads 0.30 Shavings of sterile product Area of C=O Absorbance 0.20 divided by X (Carbonyl Index) Shavings of underdosed product Shavings of samples with 0 Mrads 0.10 0.00 0.00 0.10 0.20 0.30 0.40 X = Thickness of slice (area of 1304 cm-1 Absorbance) FTIR Microscopy can determine a competitor’s dose or detect underdosed non-sterile devices. John Donohue - donohuejjp@gmail.com
  • 81. Stability of Fina Syndiotactic and Isotactic Polypropylenes to Cobalt Radiation and Accelerated Aging John Donohue - donohuejjp@gmail.com
  • 82. 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. John Donohue - donohuejjp@gmail.com
  • 83. Free Radical Degradation of Isotactic Polypropylene Stereostructure of Isotactic Polypropylene Hydroperoxide Formation by “Backbiting” Oxidation Strings of Close, Unstable, Pendant Hydroperoxides John Donohue - donohuejjp@gmail.com
  • 84. Isotactic Polypropylene Before and After 38 kGy & 17 Days @ 70 C The Isotactic Polymer is extensively Oxidized by Irradiation. It sizzles like bacon when it is melted. 1.8 1.6 Absorbance 1.4 1.2 1.0 Hydroperoxides Carbonyls 0.8 0.6 0.4 0.2 4000 3500 3000 2500 2000 Wavenumbers (cm-1) John Donohue - donohuejjp@gmail.com 1500 1000
  • 85. Syndiotactic Polypropylene Before and After 38 kGy & 17 Days @ 70 C The Syndiotactic Polymer exhibits very little Rad-induced Oxidation 2.0 1.8 1.6 Absorbance 1.4 1.2 1.0 0.8 0.6 0.4 0.2 4000 3500 3000 2500 2000 Wavenumbers (cm-1) John Donohue - donohuejjp@gmail.com 1500 1000
  • 86. IPP & SPP: 38 kGy & 70 C Aging Study Accelerated Aging Increases IPP Oxidation but has Very Little Effect on SPP 0.24 0.22 IPP @ 70 C: 17 Days 88 Hrs 16 Hrs 0 Hrs 0.20 Absorbance 0.18 SPP @ 70 C: 0 to 17 Days 0.16 0.14 0.12 IPP 0 Dose SPP 0 Dose 0.10 0.08 2000 1900 1800 1700 Wavenumbers (cm-1) John Donohue - donohuejjp@gmail.com 1600
  • 87. IPP & SPP: 38 kGy & 40 C Aging Study Accelerated Aging Increases IPP Oxidation but has Very Little Effect on SPP 0.24 0.22 IPP @ 40 C: 17 Days 88 Hrs 16 Hrs 0 Hrs 0.20 Absorbance 0.18 SPP @ 40 C: 0 to 17 Days 0.16 0.14 IPP 0 Dose 0.12 SPP 0 Dose 0.10 0.08 2000 1900 1800 Wavenumbers (cm-1) John Donohue - donohuejjp@gmail.com 1700 1600
  • 88. 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. John Donohue - donohuejjp@gmail.com
  • 89. THDSB/GC/MS Analyses of Post-Rad Volatiles Radiation Sterilized Syndiotactic Polypropylene Generates an Order of Magnitude Less Volatiles than an Equal Mass of Irradiated Isotactic Polypropylene John Donohue - donohuejjp@gmail.com
  • 90. CO2 acetaldehyde THDSB/GC/MS IDENTIFICATION OF IPP POST-RAD VOLATILES acetone acetic acid Heated Irradiated Isotactic Polypropylene Degrades into Volatiles Based on C-C-O Units that Reveal the Chemical Mechanisms of its Oxidation 2,4-dimethylfuran acetoacetone cyclopropylacetone 4-hydroxy4-methylpentanone allylacetone acetic anhydride 3,5,5-trimethylfuranone The Close, Unstable, Pendant Hydroperoxides Explode Like a String of Firecrackers John Donohue - donohuejjp@gmail.com
  • 91. THDSB/GC/IR Analyses of Post-Rad Volatiles 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 John Donohue - donohuejjp@gmail.com
  • 92. THDSB/GC/FTIR 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 John Donohue donohuejjp@gmail.com
  • 93. Part 7: Additives; their Analysis and Issues Phenolic Antioxidants Protect Against Radiation Damage by Scavenging the Free Radicals Formed in the Polymer by Radiation John Donohue - donohuejjp@gmail.com
  • 94. But Phenolic Antioxidants Turn Plastic Yellow When Irradiated John Donohue - donohuejjp@gmail.com
  • 95. Hindered Amine Light Stabilizers Form Cytotoxic Hydroxylamines as they Protect the Polymer from Radiation Damage Without Discoloration John Donohue - donohuejjp@gmail.com
  • 96. 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 John Donohue - donohuejjp@gmail.com
  • 97. Clarified Polypropylene Crystallized at 130 C from the Melt Nucleation Determines Morphology Not Clarified Clarified Millad prevents Spherulite growth Polypropylene Spherulites grow Sublimation depletes Boundary of Millad John Donohue - donohuejjp@gmail.com
  • 98. 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 John Donohue - donohuejjp@gmail.com
  • 99. 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. John Donohue - donohuejjp@gmail.com
  • 100. 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 John Donohue - donohuejjp@gmail.com
  • 101. 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 Johnspot of donohuejjp@gmail.com plate, separating them in Donohue - extract up the
  • 102. Under Visible Light >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 After Scraping Under UV Light John Donohue - donohuejjp@gmail.com
  • 103. Part 8: Tricks of the Trade Measuring Durometer of FINISHED (competitive) Devices: FTIR of DEHP Plasticized PVC Device vs Pure PVC 4.5 4.0 3.5 Absorbance 3.0 2.5 2.0 1.5 1.0 0.5 0.0 4000 Pure PVC 3500 3000 2500 2000 Wavenumbers (cm-1) 1500 1000 John Donohue - donohuejjp@gmail.com
  • 104. FINISHED Device: Measuring Plasticized PVC Durometer 2.2 Higher PVC conc. 2.0 1.8 Hard Endotracheal Tube 1.6 1.4 Absorbance 1.2 1.0 Soft Nasogastric Tube 0.8 0.6 0.4 DEHP 0.2 0.0 -0.2 PVC -0.4 1600 1550 1500 Wavenumbers (cm-1) 1450 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 John Donohue - donohuejjp@gmail.com
  • 105. Reverse engineering competitive catheters Micro-FTIR Spectrum of Pellethane 1.1 1.0 0.9 0.8 Absorbance 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 4000 3500 3000 2500 2000 Wavenumbers (cm-1) 1500 1000 zoom in here next slide John Donohue - donohuejjp@gmail.com
  • 106. Micro-FTIR ID: FINISHED Device Pellethane Durometer 0.60 >Many catheters have tips made from a softer grade material than the shaft. 0.55 0.50 >FTIR can measure the Durometer of finished Polyurethane devices quickly and easily Absorbance 0.45 >Multiple runs below show that the method is robust 0.40 80A 0.35 0.30 90A 0.25 0.20 75D 0.15 1420 1400 1380 Wavenumbers (cm-1) John Donohue - donohuejjp@gmail.com 1360
  • 107. Micro-FTIR Spectrum of Tecothane 1.6 1.4 Absorbance 1.2 1.0 0.8 0.6 0.4 0.2 4000 3500 3000 2500 2000 Wavenumbers (cm-1) 1500 1000 zoom in here next slide John Donohue - donohuejjp@gmail.com
  • 108. Micro-FTIR ID: FINISHED Device Tecothane Durometer 0.18 0.16 74A Absorbance 0.14 0.12 85A 0.10 0.08 0.06 55D 0.04 75D 0.02 1420 1400 1380 Wavenumbers (cm-1) John Donohue - donohuejjp@gmail.com 1360
  • 109. Micro-FTIR Spectrum of Tecoflex with 20% BaSO4 0.80 0.75 0.70 0.65 0.60 Absorbance 0.55 0.50 0.45 0.40 0.35 0.30 0.25 0.20 0.15 0.10 0.05 4000 3500 3000 2500 2000 Wavenumbers (cm-1) 1500 1000 zoom in here next slide John Donohue - donohuejjp@gmail.com
  • 110. Micro-FTIR ID: FINISHED Device Tecoflex Durometer 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. 1.2 80 A 1.1 1.0 0.9 85 A Absorbance 0.8 0.7 0.6 100 A 0.5 0.4 60 D 65 D 0.3 0.2 0.1 1400 1380 1360 1340 Wavenumbers (cm-1) John Donohue - donohuejjp@gmail.com 1320 1300
  • 111. FTIR Shows Why High-Gloss ABS Has Less ESCR Than Low-Gloss ABS LOW-GLOSS ABS RESISTS CRACKING HIGH-GLOSS ABS CRACKS More Styrene/Butadiene Rubber dispersed in the Acrylonitrile matrix yields High Gloss ABS with less resistance to Environmental Stress Cracking John Donohue - donohuejjp@gmail.com
  • 112. 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. John Donohue - donohuejjp@gmail.com
  • 113. Device package bottom web was cryo-fractured with liquid N2 and the heat seal ply was stretched over aluminum sheet. The film contains K-Resin… …and the stretched Heat Seal Ply is EVA John Donohue - donohuejjp@gmail.com
  • 114. Device package bottom web was 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 donohuejjp@gmail.com
  • 115. Device package bottom web was 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 John Donohue - donohuejjp@gmail.com
  • 116. Part 9: UV Adhesives and the Chemical Fragility of Polycarbonate Chemical Degradation of Polycarbonate by Dymax Adhesive Analysis of White Stain inside Cured Part John Donohue - donohuejjp@gmail.com
  • 117. 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. John Donohue - donohuejjp@gmail.com
  • 118. What Happened to the Polycarbonate? John Donohue - donohuejjp@gmail.com
  • 119. White Stain Seen Through the PC Wall Prior to Dissection White Stain is Connected to the PC John Donohue - donohuejjp@gmail.com
  • 120. White Stain Remains on PC After Adhesive is Peeled Back Polycarbonate Polycarbonate Peeled-back Dymax Adhesive John Donohue - donohuejjp@gmail.com
  • 121. White Stain Remains on PC Higher Magnification Polycarbonate John Donohue - donohuejjp@gmail.com Polycarbonate
  • 122. White Stain Remains on PC John Donohue - donohuejjp@gmail.com
  • 123. 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 donohuejjp@gmail.com
  • 124. The Surface of the Adhesive that was against the PC is encased in a thin shattered PC Film that again contains Oligomers and BPA John Donohue - donohuejjp@gmail.com
  • 125. Polycarbonate Thin Shattered Film on Adhesive that was against the PC contains Polycarbonate, BPA, and Oligomers BPA John Donohue donohuejjp@gmail.com
  • 126. The other side of the adhesive was against the Polyurethane and it is encased in that Polyurethane Polyurethane Tube John Donohue donohuejjp@gmail.com
  • 127. What Chemical(s) Attacked the Polycarbonate? John Donohue - donohuejjp@gmail.com
  • 128. DYMAX Disclosed 5 Components of this Adhesive N O Reactive Diluents O Amide O Isobornyl Acrylate N,N-Dimethylacrylamide Ketone Photoinitiators HO O Irgacure 184 HO O Darocur 1173 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 donohuejjp@gmail.com
  • 129. Adhesive’s Spectrum Pre and Post Polymerization by UV Double Bond at 1612 cm-1 Completely Consumed by Polymerization Double Bond Pre-UV Adhesive Post-UV Adhesive Adhesive Taken Off Device John Donohue donohuejjp@gmail.com
  • 130. 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 Double Bond @ 1614 cm-1 John Donohue - donohuejjp@gmail.com
  • 131. The Isobornyl Acrylate’s Double Bond is also Consumed by the Polymerization Double Bond John Donohue - donohuejjp@gmail.com
  • 132. Part 10: Drug Eluting Heart Stent Coatings Drug Eluting Coronary Stent Coatings John Donohue - donohuejjp@gmail.com
  • 133. Angioplasty and Stenting are Competitive Procedures Divergent processes of vascular repair after balloon angioplasty and stenting of an atherosclerotic vessel Edelman, E. R. et al. Circulation 1996;94:1199-1202 Copyright ©1996 American Heart Association John Donohue - donohuejjp@gmail.com
  • 134. Edelman, E. R. et al. Circulation 1996;94:1199-1202 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.) John Donohue - donohuejjp@gmail.com
  • 135. Stents scrape blood vessel walls. This injury causes reblockage. Edelman and Squire John Donohue - donohuejjp@gmail.com
  • 136. Stents scrape blood vessel walls Edelman and Squire John Donohue - donohuejjp@gmail.com
  • 137. Drug Eluting Coated Stent 3.0mm X 2.3mm John Donohue - donohuejjp@gmail.com
  • 138. Drug Eluting Coated Stent 420μ X 550μ 300μ X 390μ John Donohue - donohuejjp@gmail.com
  • 139. Drug Eluting Coated Stent 420μ X 550μ 300μ X 390μ John Donohue - donohuejjp@gmail.com
  • 140. A Different Manufacturer’s Drug Eluting Coated Stent 3.0mm X 2.3mm John Donohue - donohuejjp@gmail.com
  • 141. A Different Manufacturer’s Drug Eluting Coated Stent 420μ X 550μ 300μ X 390μ John Donohue - donohuejjp@gmail.com
  • 142. 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. IR Spectrum of PC 1036 from Biomaterials 21 (2000) 1847-1859 John Donohue donohuejjp@gmail.com
  • 143. 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. John Donohue - donohuejjp@gmail.com
  • 144. PC 1036 Biocompatibles, Ltd. 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. John Donohue - donohuejjp@gmail.comBiocompatibles, Ltd. paper
  • 145. 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 John Donohue - donohuejjp@gmail.com
  • 146. Part 11: Particulate Identification John Donohue - donohuejjp@gmail.com
  • 147. Cardboard-Colored Cellulose Organic Coating on one side John Donohue - donohuejjp@gmail.com
  • 148. John Donohue - donohuejjp@gmail.com
  • 149. John Donohue - donohuejjp@gmail.com
  • 150. John Donohue - donohuejjp@gmail.com
  • 151. Part 12: Fish Hooks, “Bait”, and Electronics After storage in an airtight container for more Biodegradation of an Insect This insect died of natural causes in the spring of 2006. than one year, webbing is growing on it. (No insect’s were harmed in the making of this document) All 8.5mm X 11.2mm John Donohue - donohuejjp@gmail.com
  • 152. Webbing at Eye 8.5mm X 11.2mm 2.3mm X 3.0mm John Donohue - donohuejjp@gmail.com
  • 153. Views of Webbing 8.5mm X 11.2mm John Donohue - donohuejjp@gmail.com
  • 154. 550u X 420u FOVs Spectra of Webbing on Aluminum Sheet … 1.3 Webbing placed on sheet 1.2 1.1 1.0 0.9 Abs orbanc e 0.8 0.7 0.6 0.5 0.4 0.3 0.2 Webbing squashed on sheet 0.1 0.0 -0.1 -0.2 3500 3000 2500 2000 Wavenumbers (cm-1) 1500 1000 … yields a better protein Spectrum after it is Squashed John Donohue - donohuejjp@gmail.com
  • 155. Inkjet Cartridge Printhead 8.5mm X 11.2mm 2.0 1.5 Epoxy Polyimide Polyimide 1.0 Metal Abs orbanc e 0.5 0.0 White Epoxy -0.5 -1.0 -1.5 Green Ink -2.0 -2.5 -3.0 4000 Laser Cut Metal “Window” Blue Ink 3500 3000 2.3mm X 3.0mm John Donohue - donohuejjp@gmail.com 2500 2000 Wavenumbers (cm-1) 1500 1000
  • 156. Printhead Dismantled – Piezoelectric Ceramic Under Metal 11.2mm X 8.5mm Cu & Glue is between PET & Polyimide Ceramic beneath slotted Metal 3.0 PET + Butylacrylate Adhesive 2.5 2.0 1.5 Absorbance 1.0 0.5 0.0 -0.5 Butylacrylate Glue -1.0 -1.5 -2.0 -2.5 4000 3000 2000 Wavenumbers (cm-1) 1000 Micaceous Cleavage of Ceramic 3.0mm X 2.3mm John Donohue - donohuejjp@gmail.com
  • 157. Who made the Chip that’s encased in hard black epoxy? Toshiba Original Photo Flipped Image John Donohue - donohuejjp@gmail.com
  • 158. Fish Hook Manufacturing Processes: Cutting, Bending, Welding, Coating 8.5mm X 11.2mm FOVs John Donohue - donohuejjp@gmail.com
  • 159. Fish Hook’s Point and Scratched Inorganic Coating: 420u X 550u FOVs John Donohue - donohuejjp@gmail.com