Transcript ULTRA FIRE RESISTANT THERMOSET POLYMERS Richard E. Lyon
ULTRA FIRE RESISTANT THERMOSET POLYMERS
Richard E. Lyon
Fire Research Program Fire Safety Section AAR-440 FEDERAL AVIATION ADMINISTRATION W.J. Hughes Technical Center Atlantic City International Airport, NJ 08405
OUTLINE OF TALK
ULTRA FIRE RESISTANT THERMOSET POLYMERS
•
FAA Fire Resistant Materials Program
•
Background of Bisphenol-C Polymers
•
New Bisphenol-C Polymers
•
Fire & Flammability Results
•
Conclusions
FAA PROGRAM OBJECTIVE:
Eliminate burning cabin materials as a cause of death in aircraft accidents by 2010.
PROGRAM DELIVERABLES
PRODUCTS
Supporting Research Thermoset Resins Thermoplastics Textile Fibers Elastomers (rubber)
APPLICATIONS
• New synthetic chemistries • Predict flammability from polymer chemical structure • Lab-scale method for measuring polymer fire hazard • Interior decorative panels • Secondary composites • Adhesives • Decorative facings • Molded seat parts • Telecommunications equipment • Passenger service units • Electrical wiring • Transparencies/glazing • Thermoacoustic insulation films • Upholstery • Murals • Carpets • Tapestries • Thermoacoustic insulation blankets • Seat cushions • Pillows • Sealants/gaskets
A VERSATILE BUILDING BLOCK IS NEEDED
Thermoplastics Thermosets
BACKGROUND: Bisphenol-C Polymers 1874
: Chloral-phenol condensation reaction product (I) first reported.
O Cl H+ Cl Cl Cl C 2 HO + HC C Cl HO C Cl – H 2 O
I
H Phenol Chloral OH
1874
: Dehydrochlorination to 1,1-dichloro, 2,2-bis(4-hydroxyphenyl) ethylene (bisphenol-C, BPC) first reported.
HO
I
Cl Cl Cl C C H OH — HCl HO Cl C Cl C Bisphenol C (BPC) OH
BACKGROUND: Bisphenol-C Polymers 1964
: Polycarbonate from BPC first reported.
HO Cl C C Cl Bisphenol-C (BPC) OH
+
Cl O C Cl Phosgene — HCl O Cl C C Cl O Bisphenol-C Polycarbonate O C
1965
: “Self-Extinguishing Epoxies” from BPC first reported in Poland.
BACKGROUND: Bisphenol-C Polymers 1970’s:
GE begins research to obtain non-burning (XB) plastics. Investigates bisphenol-C, etherimide, and acetylenic polymers.
C.B. Quinn, 1967
• Acetylenic groups increase char yield in flame.
• Too many acetylenes
increase
flammability (decrease LOI)
BACKGROUND: Bisphenol-C Polymers 1970’s:
GE develops and patents industrial process chemistry to make BPC-polycarbonate (XB-1) and polyetherimide (XB-2).
XB-1 XB-2 GE downselects to XB 2 (ULTEM™) because of fire (UL)
and
high temperature (TEM) capability.
BACKGROUND: Bisphenol-C Polymers 1980’s – 1990’s:
Research in chloral condensation polymers continues in Poland and Russia but not in U.S.A.
• Fire testing limited to flame tests (flammability).
• High LOI (50-60) and “self-extinguishing” behavior attributed to chlorine content.
• No commercial activity.
1994:
Comprehensive review:
Condensation Polymers Based on Chloral And Its Derivatives
, A.L. Rusanov, Progress In Polymer Science, Vol. 19, pp. 589 662 (1994)
BACKGROUND: Flaming Heat Release Rate Measured 1997: O
FAA measures flaming heat release rate of BPC polycarbonate in OSU fire calorimeter .
Polymer Char Yield (%) L.O.I. [%O 2 ] UL 94 FAR 25.853(a-1) Peak/Total* (kW/m 2 ) (kW-min/m 2 )
BPA
CH 3 C CH 3 O O C n 25 26 V-2 153 / 58 O
BPC
CCl 2 C O O C n 54 56 V-0 55 / 33
*1/16-inch (0.063 in) sample thickness
BACKGROUND: New Flammability Screening Test 1998: FAA develops milligram-scale heat release rate test to accelerate search for new polymers
Forced Nonflaming Combustion
TEST METHOD REPRODUCES FLAMING COMBUSTION
HEAT RELEASE CAPACITY PREDICTS FIRE RESPONSE
slope = 1 kg-K/m 2 -s (as per 1-D burning model)
Provides new capability for rapid screening of research polymers for fire resistance.
BACKGROUND: Flammability Screening Yields Results 1998: FAA collaborates with Ciba Specialty Chemicals/Vantico Performance Polymers Division, Brewster, NY to develop ultra fire resistant cyanate ester thermoset resins for aircraft interiors BPC cyanate ester identified as having lowest heat release capacity of any thermoset tested to date BPC cyanate ester patent filed by Ciba/Vanitco BPC cyanate ester scaled-up and prepregged for bench scale fire calorimetry testing 1999-present: University (UMASS, Rice) research continues on BPC copolymers and blends.
BACKGROUND: Thermal Degradation Mechanism Identified 2000:
“Thermal Decomposition Mechanism of…”, M. Ramirez, DOT/FAA/AR-00/42, and A. Factor, GE Plastics 350-450 °C
– 80 kJ/mole
BACKGROUND: Technology Transfer 2001: FAA Scales up BPC polycarbonate chemistry with Dow Chemical, Freeport TX 2002: U.S. Navy tests and approves BPC cyanate ester composites for use in submarines.
2003: VANTICO obtains composition of matter patent for BPC cyanate ester .
2004: NAVY awards SBIR programs to develop BPC thermoset process chemistry for large shipboard structures
BPC THERMOSET POLYMERS
Epoxy Cyanate Ester Epoxy-Cyanate Ester Blends
EPOXY
EPOXIES: Synthesis as per DGEBA
2 HO Phenol + O HC Cl C Cl Cl Chloral H+ – H 2 O HO
I
Cl Cl Cl C C H — HCl OH 2 CH 2 O CH–CH 2 –Cl Epichlorhydrin + — 2 HCl HO Cl C Cl C Bisphenol C (BPC)
II
OH Cl C C Cl CH 2 —CH–CH O 2 –O O–CH 2 –CH—CH 2 O Diglycidylether of Bisphenol C (DGEBC)
III
EPOXY FORMULATIONS: Hardeners Examined EMI-24
(2 phr) H N H 2 N
TETA
(14 phr) N H NH 2
MDA
(58 phr)
BPC
(78 phr DGEBC) HO CH 3 C CH 3
BPA
(66 phr DGEBA) OH
Cyanate ester of BPC
(53 phr DBEBC)
FIRE RESISTANCE OF BPC EPOXY LIMITED BY HIGH FUEL VALUE OF GLYCIDYL ETHER
Dichloroethylidene (DCE) group has zero fuel value, but… “R” group for epoxy has relatively high fuel value.
“R” Heat of combustion, h c = 7 kJ/g-polymer (theoretical)
= 11 kJ/g-polymer (measured)
EPOXY HEAT RELEASE CAPACITIES DGEBA DGEBC
UL 94 V-0 (typically)
EPOXY FIRE CALORIMETRY: Peak HRR DGEBA DGEBC Glass fabric lamina FAR 25.853 (a-1)
150 100 50
FAA Maximum
0 EMI-24 TETA MDA
Hardener BPA BPC
CEBPC
EPOXY FIRE CALORIMETRY: Total Heat Release DGEBA
70 60 50 40 30 20 10 0 EMI-24
DGEBC
TETA MDA
Hardener Glass fabric lamina FAR 25.853 (a-1) FAA Maximum (2-min, flaming) BPA BPC
CEBPC
MECHANICALS: BPA ( STIFFNESS HEAT OF POLYMERIZATION ) vs. BPC ( ) Epoxy
140 120 100 80 60 40 20 0
STRENGTH
EMI-24 TETA
Hardener
MDA 250 200 150
GLASS TRANSITION
100 50 0 EMI-24
TEMPERATURE
TETA MDA
Hardener BPA BPC
CEBPC
CYANATE ESTERS
CYANATE ESTER: Polymerization Reaction
BPC cyanate ester monomer
200 °C
BPC triazine thermoset polymer
EFFECT OF BISPHENOL ON HEAT RELEASE RATE OF CYANATE ESTERS
ASTM 1354, cone calorimeter at 50 kW/m 2 heat flux, neat resin, 1/4-inch thick
BPC CYANATE ESTER: FAA Heat Release Rate Test
glass fabric lamina 1/8-in NOMEX honeycomb glass fabric lamina
STRUCTURAL COMPOSITES FOR NAVY SUBMARINES
Only 3 resins pass fire performance requirements as glass composites:
Fire Test/Characteristic
Time to ignition (s) at irradiance:
Requirement (MIL-STD-2031) Composite Resin BPC-CE Phthalo nitrile Silicone 25 kW/m 2 50 kW/m 2 75 kW/m 100 kW/m 2 2 > 300 > 150 > 90 > 60
Peak/Average Heat Release Rate (kW/m 2 ) at irradiance:
pass pass pass pass 25 kW/m 2 50 kW/m 2 75 kW/m 2 < 50/50 < 65/50 < 100/100 pass pass pass pass pass pass pass pass pass pass pass pass pass pass pass pass pass 100 kW/m 2
Smoke Obscuration, D max /D s (avg):
< 150/120 < 200/100 pass pass pass N/A pass pass
Combustion Gas Toxicity (CO/CO 2 /HCN/HCl): Mechanical Properties
pass good N/A good pass poor
Cure Temperature
< 200 °C > 375 °C N/A J. Koo, et. al., SAMPE 2001
CYANATE ESTER-EPOXY BLENDS
FIRE PERFORMANCE OF BPC(CE-EP) BLENDS
600 500 400 300 200 100 0 0 0.2
0.4
0.6
0.8
Mole Fraction BPC-Epoxy in Blend
10 5 1 0 40 35 30 25 20 15
CONCLUSIONS: Comparing Properties
Average Change (5-7 polymers)
Fire Hazard Potential (
h
c ): Fire Hazard (HRR): Glass Transition Temperature, K: Modulus: Yield Strength: Yield Strain: BPC / BPA – 90 % – 60 % + 3 % + 10 % + 10 % + 10 %
ACKNOWLEDGEMENTS
Jennifer Stewart, Huiquing Zhang,
UMASS
Lauren Castelli, Mike Ramirez,
FAA
Arnie Factor, Mike MacLaury,
GE Plastics
Borsheng Lin, Mike Amone,
Ciba Specialty Chemicals
Richard Walters,
Galaxy Scientific
Gary Green,
Pacific Epoxy