Polymers in Wire Coating (Kapton ? )

Document Sample
Polymers in Wire Coating (Kapton ? ) Powered By Docstoc
					      Polymers in Wire
      Coating (Kapton)
 Kapton is a registered trademark of E.I. Du Pont de
               Nemours and Company



 CE 435 Into to Polymers
 Group Members
   • Jason Womer
   • Tom Hanselman
   • Dan Boek
     Table of Contents

 Wire Coating Specs
 Swiss Air Flight 111
 Fire Prevention
 Crash Statistics
 Improving Insulation
 Conduction of Polymers
 Uses of Kapton
 Degradation of Polymers
Insulation
Requirements for Wires


Requirements for Machine-
tool Wires and Cables
Who Sets the
Standards?


 Requirements specified in the
  National Electrical Code
  (ANSI/NFPA 70)
 Also used in the National Fir
  Protection Association
  Electrical Standard for
  Industrial Machinery
  (ANSI/NFPA 79)
  How Are the Standards
  Set?

 The polymer insulation and the
  finished wires must comply
  with a flame test and are for use
  at temperatures of 90 °C (194
  °F) or lower in dry locations
 Must comply at 60 °C (140 °F) or
  lower where exposed to
  moisture, oil, or coolants
Electrical Problems May
Have Sparked Swiss Air
    Flight 111 Crash
       * Pictures Taken from Web Site (http://www3.ns.sympatico.ca/mr.187/photos.html)




 Urs
  Zimmermann
  (Pilot) and the
  planes flight
  recorder.
 The exact
  cause of the
  crash is
  unknown,
  however,
  evidence
  points towards
  a rapid and
  deadly
  electrical fire
                              Rapid Fire
                 * Pictures Taken from Web Site (http://www3.ns.sympatico.ca/mr.187/photos.html)




   According to record Zimmerman noticed
    smoke at approximately 10,000m and 16
    minutes later, the plane slammed into the
    Atlantic Ocean off Peggys Cove, N.S.
    Canada.
    • According to Susan Bradley, a spokeswoman
      for Boeing, Kapton was the primary coating
      on the wiring in Swissair Flight 111 (Maclean’s Sept 21, 1998 v111 n38
       p20(1))
       How Safe is Kapton 

                                         Wiring
                          Picture taken from web site (www.ece.msstate.edu/hvl/research.html)




   Patrick Price (Expert with the former Boeing Co. in
    Seattle) on Kapton wiring
      • “It’s like taking an incendiary bomb on board” (Maclean’s,
            Sept 21, 1998 v111 n38 p20(1))


   In 1982 the U.S. navy stopped using Kapton
    wiring in jet fighters when cracks in wires coated
    with Kapton were linked to on-board fires. (Maclean’s,
    Sept 21, 1998 v111n38 p20(1))


   Scientists have found Kapton is prone to rare but
    catastrophic “arc tracking” when the wire is
    subjected to chafing, vibration, and moisture. U.S. News
    and World Report, Sept 28, 1998 v125 n12 p44(1))

   If a wire cracks, electricity can arc to nearby
    material, setting it on fire. This is known as a flash
    over which burns at a searing 1,000 C.
                Deadly Games

   Swiss Air Flight 111 had approximately 240 km of
    wires running through it to bring passengers a
    premium video and gambling system in today’s
    intensely competitive market for business and
    first-class flyers.
   Each seat aboard Swiss Air Flight 111 had a video
    screen that pops out of the armrest like a tray
    table. Passengers could play video games, music,
    or even gamble.
      • It was this luxury which could have lead to the
         crash.
   The system costs about 2 million or more dollars
    per plane and was developed by Interactive Flight
    TechnologiesTM. A struggling company which said
    it wants out of the in-flight-entertainment
    business.
      • This web of wires from each seat to central
         computers aboard the plane generates a
         greater possibility for an electrical disaster. (Time,
        Nov 9, 1998 p58(1))
  Advanced Kapton
 Material is Being Used
         Today

 Since 1993 Kapton has been
  improved by wrapping it in a
  tough Teflon coating.
 In an article I found from 1998
  FAA officials said that old forms
  of Kapton may soon be removed
  from hundreds of planes.
 Boeing company spokesman
  John Thom said that “Kapton
  was and is certified for use on
  commercial airplanes”
  p20(1))
                          (Maclean’s, Sept 21, 1998 v111 n38
 Some Pictures from the
       aftermath
       Picture taken from web site (http://www3.ns.sympatico.ca/mr.187/photos.html)




 At left is one of the most
  recognizable photos from the
  tragedy as rescuers try in vain
  to find survivors. Pictured at
  right is the Emergency Service
  Paying tribute to Flight 111
Fire Prevention in Planes
              Picture taken from web page (http://www.airliners.net/open.file?id=13250)




   The Federal Aviation Administration or FAA
    announced in October of 1998 that Mylar
    insulation used in nearly 12,000
    passenger jets must be replaced to
    reduced the chance of fire.                                        (U.S. News and World Report, Oct 26, 1998
    p17(1))


      • It is believed that this type of insulation was
        set ablaze by a short circuit in the electrical
        equipment aboard the Swiss Air Flight 111
Luxury is
not always
better                          Picture from web site

(http://www.tsb.gc.ca/ENG/TSB_Investigations/Swissair/)




      The high tech video system aboard Flight
       111 used Microsoft Windows NT software,
       with wires connected to a central
       computer.                      (Time, Nov 9,1998 p58(1))


          • Investigators found that the wires had been
            connected to the same electrical pathways
            that powered vital parts of the aircraft.
                    – Therefore, if there is a problem with the video
                      system, then there is a problem with the whole
                      plane.
      In the future this type of video system
       should be connected to a separate area of
       the plane where vital networks in the
       plane will not be affected thus buying time
       for an emergency landing.
    Firefighting Training for
     Pilots and Prevention
       Web site (http.www.tsb.gc.ca/EN/TSB_Investigations/Swissair/site_pages/saf…/FireRecs_2000dec4.ht)




   The investigation into Swiss Air Flight 111
    revealed safety deficiencies in crew
    training and awareness, and procedures
    related to in-flight firefighting.
    • The TBS safety board issued the following
      recommendations to address safety
      deficiencies
         – A lack of a coordinated and comprehensive
           approach to in-flight firefighting.
         – Smoke/fire detection and suppression systems
           are insufficient
                   – There are no smoke/fire detection and
                     suppression systems in the cockpit or cabin or
                     any area not considered a fire zone.
         – The importance of making prompt preparations
           for a possible emergency landing is currently
           not recognized.
                   – This is due to company policy and the feeling
                     that it is an inconvenience.
         – Access to critical areas within the aircraft are
           inadequate.
                   – There has been little or no training provided to
                     aircraft crew on how to access areas behind
                     electrical or other panels
         Material For Fire
           Prevention

   Halon   (Washington Monthly, Sep 1997 v29 n9 p44(2))



    • Pressurized bottles of Halon – a highly
      effective fire fighting agent – have long been
      used in the cargo holds of larger jets but is not
      used in smaller planes
        – Brings us to the fact that in general the
          larger the vehicle the safer it usually is due
          to greater regulations.
   A Plastic Called PHA                                     (Discover, August 1999 v20 i8 p11)


    • PHA is a plastic which only emits water vapor when it
      burns, and it brakes down into a flame-resistant
      compound.
   There is also the possibility of Flame
    Retardant Material                                     (Class Notes)


    • Chlorine and Fluorine when added to material
      help in fire resistance.
        – Trade off would be the hazardous smoke this
          type of compound produces when it does burn.
        – Flash overs due to electricity arcing burn at a
          searing 1,000 C.
     Crash Statistics
  Larger The Vehicle the
          Safer
 Some airline safety facts                                  (Web Site (http://www.air-
  transport.org/public/speeches/view1997.asp?UniqueID=38))



    • You are more likely to die by being
      kicked to death by a donkey than
      in a plane crash
    • You are more likely to be crushed
      by a falling object
    • You are much more likely to be
      killed by your spouse
 You have one chance in about 7
  million from dying in an plane
  crash
Average Time
To React
To A Fire
(http://www.nifc.gov/gallery/manter.html)




        The average time between when an
         in-flight fire is detected and when
         the aircraft either ditches, conducts
         a forced landing, or crashes is about
         17 minutes.
         (http://www.tsb.gc.ca/ENG/TSB_Investigations/Swissair/site_pages/saf…/FireRecs_2000dec4.ht)


           • Some examples



          Type                              Date                            Minutes
          AN-12                             1967                            <10
          B-707                             1973                            ~7
          B-747                             1987                            19
          MD-11                             1998                            20
 Increase Your Chances

 Handy Hints For The Nervous
 Traveler   (http://www.amigoingdown.com)




  • 70% of incidences in recent year
    occur on take-off or landing
     – Try to book non-stop flights
  • Take note of where the nearest
    emergency exit is
  • Choose a large aircraft
     – The larger the vehicle the better
       your chances
    Does Fate Alone Decide
        Who Survives
 Most Likely No
 71% of the people who die in crashes
  die after the plane comes to a
  compete stop.     (People Weekly, Oct 20, 1997 v48 n16 p125(3))




 You can increase your chances by
  knowing your surroundings
    • How many isles to the exit
    • In case of fire if you can hold your
      breath for 30 seconds that’s how long it
      takes to exit the aircraft normally.
    • Don’t try and get your duffel bag in case
      of a crash
    • Pay attention to the safety procedures
      (life vests)
Where
To Sit
(http://www.aircrash.org/burnelli/)




  If you’re worried about impact
         (People Weekly, Oct 20, 1997 v48 n16 p125(3))



            • Sit in the back
  If you’re worried about a fuel
         fire
            • Sit forward of the leading edge of
              the wing
  If your worried about the plane
         breaking up
            • Sit by the over-wing exits
                       – This is the strongest part of the
                         aircraft due to the fuel being
                         carried in the wings
      Improved Electrical
     Apparatus Insulation
           Material

   One way to improve Wiring in planes is to
    use an improved insulation material
     • Currently many electrical wires use
       porcelain and glass insulators
     • An ethylene and vinyl acetate
       copolymer (EVA) tested better in the
       lab these forms of insulation                                                     (Polymer Engineering and
       Science:Jul. 1996, V.S. Ivanov, I.I. Migunova, N.A. Kalinina, G.N. Aleksandrov)


           – As discussed in class copolymers usually
             increase a materials ability to withstand
             an impact
           – Copolymers would help in wires that would
             be subjected to rough conditions
                       – Kapton currently has problems under
                         rough conditions
  Radiation-Induced
Current        (ChemAbsStudent, “Studies on radiation-induced current in polymeric insulating materials

         and their fine sturcture”, J. Master. Sci 17 no 10 (1982):3052-6)




 Degradation in crystalline
  materials such as Polyethylene
 Degradation in non-crystalline
  materials such as ethylene-
  propylene rubber used for wire
  insulation
  • For radiation-induced current
    degradation is affected more by
    the degree of crystallinity than its
    perfection.
  Method For Improving The
 Environmental Stress-Crack
Resistance or (ESCR)                (J. Appl. Poym. Sci. 16, no 9 (1972): 2375-86)




   (ESCR) is a critical factor in wire
    insulation
    • In studying the effect of rubber on
      (ESCR) the choice of a base resin is
      important
        – Depending on the resin and rubber
          combination you choose the (ESCR) can
          double or increase by 50-fold.
            – Kapton could be improved with slight
              variations in its production and perhaps
              different types of resins should be looked
              at
    • For example
        – The higher the molecular weight of
          Polyisobutylenes the more effective its
          performance as a stress crack additive
Polymers – Good
Insulators

 Polymers are good insulators
 because they are covalently
 bonded and their electrons are
 all tightly bound.
Polymers –
Conductors!?

 Doping of polymers with strong
  electron acceptors such as iodine
  can cause polymers to conduct
  nearly as well as metals.
 Doping to polyacetylene causes it’s
  conductivity to be 1010 times higher
  than pure polyacetalylene.
 This flexible electronic circuit
  functions even when it’s bent.
 http://focus.aps.org/v6/st18.html
Uses of KAPTON -
Properties

 Maintains its mechanical stability at
  very high and very low temperatures
 resists high mechanical stress
  during assembly operations
 has excellent electrical insulation
  and thermal properties
 has outstanding resistance to most
  chemicals, lubricants and fuels
 allows space and weight savings
Uses of KAPTON -
Electronics

 In electronic equipment, KAPTON is
  used as substrate material for
  Flexible Printed Circuits and
  punched, bonded or formed high
  performance part in small miniature
  switches. It can be etched in
  alkaline solns.
 Bar Code Labels
 Heat Sinks, to ensure optimal heat
  transfer between film and power
  transistors
 Masking tapes
Uses of KAPTON -
Bondable Application

 Can be bonded, coated or
 laminated to allow the
 following requirements
  •   Belts
  •   Thermal insulator in irons
  •   Fuel sensors
  •   Smoke hoods
  •   Blood bags
Uses of KAPTON -
Electronic Insulation

 Wire and cable insulation
 formed coil insulation of
  traction motors
 Magnet wire insulation
 transformer and capacitor
  insulation
Uses of KAPTON -
Automotive

 Alternator heat sink insulator
  pads
 Air bag (diaphragm)
 Flexible circuits
 Spark plug boot
Uses of KAPTON -
Aerospace

 Cockpit sun shade
 Speakers
 Flexible Curcuitry
 Acoustic insulation
 Thermal blankets
Uses of KAPTON -
Thermal Management

 Heat sink
 Power supplies
 Heater circuits
 Copier belts
 Carrier belts
 Coil insulation
Thermal Degradation –
Experimental Methods

 Thermogravimetry (TG)-
  measures loss in weight
 Differential scanning
  calorimetry (DSC)
 Differential thermal analysis-
  heat absorption or evolution
  due to either physical or
  chemical changes occurring
  within the polymer is measured
Thermal Degradation
Reactions

 Depolymerisation Reactions
  • Characterized by the breaking of
    the main polymer chain
    backbone so that at any
    intermediate stage the products
    are similar to the parent material
    in the sense that the monomer
    units are still distinguishable.
    The ultimate product may be
    monomer.
Thermal Degradation
Reactions

 Substituent Reactions
  • It is the substituents attached to
    the backbone of the polymer
    molecules which are involved so
    that the chemical nature of the
    repeat unit is changed although
    the chain structure may remain
    intact.
Oxidation of Polymers

 Degradation of polymers
  usually increases in the
  presence of oxygen
 R· + O2  ROO·
 ROO· + RH  ROOH + R·
 Termination
  • 2R·  R-R
  • R· + ROO·  ROOR
  • 2ROO·  ROOR + O2
Photo-degradation

 Wavelengths of light from sun range
  from infrared (>700nm) to the
  visible spectrum (400-700nm) to
  ultra-violet (<400nm).
 Energy of 700nm photon is 170
  kJ/mol and energy of 300nm photon
  is 390 kJ/mol
 Strength of C-C and C-H bond are 420
  and 340 kJ/mol respectively
 It is clear that the energies of the UV
  and possibly the visible
  components of sunlight are
  sufficient to break chemical bonds
Aircraft Crashes Due to
Failure in Wires


Short examples of Kapton
related crashed in aircraft
and what is being done to
prevent any further
mishaps
August 19,1980 Saudi
Arabian Airlines Tri-star

 After take off from Riyadh Airport a
  fire broke out in the rear cargo
  compartment.
 Plane returned to Riyadh as flames
  broke through the cabin floor and
  filled the cabin with smoke
 Upon investigation Kapton wires
  were found burnt out, and the
  insulation destroyed
 Also the wires had fractured ends , a
  sign of arcing, no other source for
  ignition could be found
January 14, 1985 British
Monarch Airline Boeing
757

 On a flight from the Canary
  Islands to Luton the aircraft has
  a serious wire bundle explosion
 As smoke begins to enter the
  cabin the pilot is able to make a
  forced landing in Portugal
 An investigation showed that
  moisture dripped onto the
  wiring below the lavatory and
  wet arc tracking occurred
  causing the bundle explosion
November 5, 1990
Philippine Airlines
Boeing 737

 Plane is being delayed for take
  off when explosion occurs
 The explosion was in the fuel
  tank
 After investigation the most
  probable cause was
  determined to be a spark from a
  faulty wire creating an
  explosion
March 17, 1991 Delta
Airlines Lockheed Tri-
star

 Plane is on way to Atlanta from
  Frankfurt when a fire breaks out
 Aircraft makes an emergency
  landing in Goose Bay
 Upon an investigation the most
  probable cause of the fire was
  electrical arcing in the wire
  bundle
Some Action Being
Taken

 Following a Valujet crash in
  Florida in 1998 Al Gore has
  headed a special commissin to
  determine the ageing effects
  on airplane wiring
 Other countries plan on doing a
  similar thing
 However, the tests will be non-
  intrusive

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:24
posted:11/16/2011
language:English
pages:44