FIRE RESISTANT POLYMERS BASED ON BISPHENOL-C
Richard E. Lyon
Fire Research ProgramFire Safety Section AAR-422
FEDERAL AVIATION ADMINISTRATIONW.J. Hughes Technical Center
Atlantic City International Airport, NJ 08405
OUTLINE OF TALK
FIRE RESISTANT BISPHENOL-C POLYMERS
• FAA Fire Resistant Materials Program
• Background of Bisphenol-C Polymers
• New Bisphenol-C Polymers
• Fire & Flammability Results
• Conclusions
FAA PROGRAM OBJECTIVE:
Eliminate burning cabinmaterials as a cause of
death in aircraft accidents by 2010.
A WIDE RANGE OF DELIVERABLES
Thermoset Resins
• Interior decorative panels • Secondary composites • Adhesives
Thermoplastics • Decorative facings • Telecommunications equipment • Molded seat parts • Passenger service units • Electrical wiring • Transparencies/glazing • Thermoacoustic insulation films
Textile Fibers • Upholstery • Carpets • Murals • Tapestries • Thermoacoustic insulation blankets
Elastomers (rubber)
• Seat cushions • Pillows • Sealants/gaskets
APPLICATIONS
Supporting Research
• New synthetic chemistries • Predict flammability from polymer chemical structure • Lab-scale method for measuring polymer fire hazard
PRODUCTS
A VERSATILE BUILDING BLOCK IS NEEDEDThermoplastics Thermosets
C l C ≡N
p h o s g e n e
O
O O n
Polycarbonate
O
O O
O
n Polyester
Epoxy e p i c h l o r o h y d r i n
Epoxy-Cyanate Ester
BlendsO O
ClCl
H H(BPC = R)
phthaloyl chlorides
C l C l
O
– H2O
Polyarylether
O C NOCN
Cyanate Ester R
OO
OO
R R
R
n
GAPS IN MATERIALS FIRE SAFETY TECHNOLOGY
A. Affordable routes to ultra fire resistant polymers
B. Ultra fire resistant polymers with:• low/moderate processing temperature
• good strength & toughness• colorability and colorfastness
C. Relationship between material properties and fire performance.
D. Relationship between chemical composition and fire performance.
E. Scaling Relationships: micro-, bench-, quarter-, full-scale
F. Fundamental understanding of fire resistance mechanisms
(Attributes of Bisphenol-C Based Polymers)
BACKGROUND: Bisphenol-C Polymers
1874: Chloral-phenol condensation reaction product (I)first reported.
2 HO +
Phenol Chloral
CCl
Cl
ClHC
O
– H2OHO OH
CC
Cl ClCl
HI
H+
1874: Dehydrochlorination to 1,1-dichloro, 2,2-bis(4-hydroxyphenyl) ethylene (bisphenol-C, BPC) first reported.
— HCl
Bisphenol C (BPC)
Cl ClC
CHO OHHO OHCC
Cl ClCl
HI
BACKGROUND: Bisphenol-C Polymers
1964: Polycarbonate from BPC first reported.
— HCl
Bisphenol-C (BPC)
Cl ClC
CHO OHCl Cl
OC+
Phosgene
CCl Cl
CO OOC
Bisphenol-C Polycarbonate
1965: “Self-Extinguishing Epoxies” from BPC first reported in Poland.
CH2 CH–CH2–ClO
2Epichlorhydrin
— 2 HCl+ CH2—CH–CH2–O
OO–CH2–CH—CH2
O
Diglycidylether of Bisphenol C (DGEBC) III
Cl ClC
CBisphenol C (BPC)
Cl ClC
CHO OH
BACKGROUND: Bisphenol-C Polymers
1970’s: GE begins research to obtain non-burning (XB) plastics. Investigates bisphenol-C, etherimide, and acetylenicpolymers.
C.B. Quinn, 1967—R—(-C≡C—C≡C-)—
Char Yield
Oxygen Index
% Diacetylene
0 20 40 60 80 100
—R—(-C≡C-)—
% Acetylene
0 20 40 60 80 100
Char Yield
Oxygen Index
• 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).
O
n
CO
Cl Cl
O XB-1
O
O
n
CH3
O
O
N N
CH3
O O 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
Char Yield (%)
25
54
L.O.I. [%O2]
26
56
UL 94
V-0
V-2
Polymer
CCl2
C O C
O
n
OO C
OCH3
C
CH3 n
O
BPA
BPC
FAR25.853(a-1) Peak/Total*
(kW/m2) (kW-min/m2)
*1/16-inch (0.063 in) sample
thickness
153 / 58
55 / 33
1997: FAA measures flaming heat release rate ofBPC polycarbonate in OSU fire calorimeter.
BACKGROUND: New Flammability Screening Test
1998: FAA develops milligram-scale heat release rate testto accelerate search for new polymers
Forced Non-flamingCombustion
TEST METHOD REPRODUCES FLAMING COMBUSTION
Flaming Combustion
Pyrolysis-Combustion Flow Calorimetry
Sample
Exhaust
N2
DAQO2
Polymer Solid
Flame
Flow-meter
O2 Analyzer
Pyrolyzer
Combustor
Gas Scrubbers
Pyrolysis Zone
MOLECULAR FIRE PARAMETER IDENTIFIED
Dividing the peak kinetic heat release rate by β gives a material property, the Heat Release Capacity
(J/g-K)ηc h c 0 ( 1 – µ ) E a
eR T p 2 ≡
max •
β = Qc
h c 0 = Heat of Combustion of Fuel Gases
E a = Global Activation Energy for Pyrolysis µ = Char Fraction
e = The natural number 2.7183…
T p = Temperature at Peak Mass Loss Rate
= Gas Constant R
HEAT RELEASE CAPACITY PREDICTS FIRE RESPONSE
0
200
400
600
800
1000
1200
1400
Ave
rage
Fla
min
g H
RR
(kW
/m2 )
Heat Release Capacity (J/g-K)
250 15000 500 750 1000 1250
POM
PEPS
ABS
PBTPMMA
PESF
PEI
Nylon 66
Epoxy
PAI
PC
PEEK
PTPET
PPqext = 50 kW/m• 2
slope = 1 kg-K/m2-s(as per 1-D burning model)
Provides new capability for rapid screening of research polymersfor fire resistance.
BACKGROUND: Flammability Screening Yields Results
1998: FAA collaborates with Ciba Specialty ChemicalsPerformance Polymers Division, Brewster, NY to develop ultrafire resistant cyanate ester thermoset resins for aircraft interiors
BPC cyanate ester identified as having lowest heat releasecapacity of any thermoset tested to date
BPC cyanate ester patents filed by Ciba
BPC cyanate ester scaled-up and prepregged for bench scalefire calorimetry testing
1999-present:
University (UMASS, Rice) research continues onBPC copolymers and blends.
BACKGROUND: Thermal Degradation Mechanism Identified2000: “Thermal Decomposition Mechanism of…”, M. Ramirez,
DOT/FAA/AR-00/42, and A. Factor, GE Plastics
CCl2
CR∆
CCl
CR
Cl• •
electron transfer
CCl
CR
Cl–+CCl
C
R
Cl +–
phenyl migration
C CRCl
Cl – 2 HCl (↑)
char– R (↑)
– ∆ (exothermic)
C CR••
350-450°C– 80 kJ/mole
BPC THERMOPLASTICS
Polycarbonate
Polyetherketone
Polyarylates
POLYCARBONATE: BPA vs BPC
LEXAN™ Chloral
Polycarbonate
Tg (°C) 168152Flex Modulus (ksi) 376336Flex Strength (psi) 16,300 16,200
NBS Smoke (Dm) 165 75Oxygen Index (%) 5626
Tensile Yield Strain (%) 10 11
Heat Release Capacity (J/g-K)
390 29
Morphology Amorphous Amorphous
OO C
OCH3
C
CH3 n
CCl2
C OO C
O
n
FAR 25.853(a-1) Heat Release Peak/Total* (kW/m2) / (kW-min/m2)
*0.063 in153 / 58 55 / 33
POLYETHERKETONE: Carboxyl vs. DCE
O C
O
n
ULTRAPEK™ ChloralPolarylether
CCl2
CO
n
Tg (°C) 161 166
Flex Modulus (ksi) 426530Flex Strength (psi) 18,900 18,000
NBS Smoke (Dm) 17N/AOxygen Index (%) 5234
Tensile Yield Strain (%) 7 10
124 20
Morphology Semicrystalline Amorphous
Tm (°C) 381 N/A
Heat Release Capacity (J/g-K)
POLYARYLATES: BPA vs. BPC
HDT (°C) 160-174Flex Modulus (ksi) 391325Flex Strength (psi) 11,000 11,700
NBS Smoke (Dm) N/A109Oxygen Index (%) 4736
Tensile Failure Strain (%) 50 50
460 18
Morphology Amorphous
Heat Release Capacity (J/g-K)
n
RC
O
C
O
OO
CH3
CCH3
R = R =
Amorphous160
C
C
Cl Cl
POLYARYLATE: BPA-BPC Copolymers & Blends
Flammability does notfollow simplerules of mixtures.
0
100
200
300
400
500
0 20 40 60 80 100
Hea
t Rel
ease
Cap
acity
, J/g
-K
Mole Percent BPC
BlendsCopolymers
020406080100
Mole Percent BPA
UpperBound
LowerBound
Rules of Mixtures
—C—O—
O
O—C
O
50/50 iso/para
—R—
BPA or BPC
C
CCl Cl
R =(BPC) (BPA)
CCH3H3C
J.R. Stewart, 2000
BPC THERMOSET POLYMERS
Epoxy
Cyanate Ester
Epoxy-Cyanate Ester Blends
EPOXIES: Synthesis as per DGEBA
2
— HCl
HO +
Phenol Chloral
CCl
Cl
ClHC
O
– H2O
CH2 CH–CH2–ClO
2
Epichlorhydrin Bisphenol C (BPC)— 2 HCl
II
+
HO OHCC
Cl ClCl
HI
Cl ClC
CHO OH
CH2—CH–CH2–OO
O–CH2–CH—CH2O
Diglycidylether of Bisphenol C (DGEBC) III
Cl ClC
C
H+
EPOXY FORMULATIONS: Hardeners Examined
N
N
H
H3C
CH2CH3
EMI-24(2 phr)
NH2
H2N MDA(58 phr)
H2NN
H
NNH2
HTETA(14 phr)
OCN
Cl
Cl
NCO Cyanate esterof BPC
(53 phr DBEBC)
OH
Cl
Cl
HOBPC
(78 phrDGEBC)
OHC
CH3
CH3
HO
BPA(66 phr DGEBA)
FIRE RESISTANCE OF BPC EPOXY LIMITEDBY HIGH FUEL VALUE OF GLYCIDYL ETHER
–O–CH2–CH–CH2–O—CC
Cl ClOH
a) DGEBC-BPC
CC
Cl Cl
–O–CH2–CHO
CH2
b) DGEBC-EMI
Dichloroethylidene (DCE) grouphas zero fuel value, but…
“R” Heat of combustion,hc = 7 kJ/g-polymer (theoretical)
“R” group for epoxy has relatively high
fuel value.
= 11 kJ/g-polymer (measured)
EPOXY HEAT RELEASE CAPACITIES
DGEBA DGEBC
EMI-24 TETA MDA BPA BPC CEBPC
Hardener
0
200
400
600
800
1000
Hea
t Rel
ease
Cap
acity
, J/g
-K
UL 94 V-0(typically)
EPOXY FIRE CALORIMETRY: Peak HRR
DGEBCDGEBA
0
50
100
150
Peak
Rat
e of
Hea
t Rel
ease
, kW
/m2
EMI-24 TETA MDA BPA BPC CEBPC
Hardener
Glass fabric laminaFAR 25.853 (a-1)
FAA Maximum
EPOXY FIRE CALORIMETRY: Total Heat ReleaseGlass fabric lamina
FAR 25.853 (a-1)DGEBA DGEBC
0
10
20
30
40
50
60
70
Tota
l Hea
t Rel
ease
, kW
-min
/m2
EMI-24 TETA MDA BPA BPC CEBPC
Hardener
FAA Maximum
(2-min, flaming)
MECHANICALS: BPA ( ) vs. BPC ( ) Epoxy
0
20
40
60
80
100
120
140
Yiel
d St
ress
, MPa
EMI-24 TETA MDA
Hardener
STRENGTH
0
0.5
1.0
1.5
2.0
2.5
3.0
Youn
g’s
Mod
ulus
, GPa
EMI-24 TETA MDA
Hardener
STIFFNESS
0
20
40
60
80
100
120
140
²Hpo
lym
, kJ/
mol
e
EMI-24 TETA MDA BPA BPC CEBPC
Hardener
HEAT OFPOLYMERIZATION
Gla
ss T
rans
ition
Tem
pera
ture
, °C
EMI-24 TETA MDA BPA BPC CEBPC
Hardener
0
50
100
150
200
250
No
data
GLASS TRANSITIONTEMPERATURE
FLAMMABILITY: BPA ( ) vs. BPC ( ) Epoxy
Oxygen Index UL 94
EMI-24 TETA MDA BPA BPC CEBPC
Hardener
0
5
10
15
20
25
30
35
40
Lim
iting
Oxy
gen
Inde
x, %
O2
(v/v
)
No
data
No
data
No
data V-0
V-1
V-2
HB
UL
94 R
anki
ngEMI-24 TETA MDA BPA BPC CEBPC
Hardener
5V No
data
No
data
COMBUSTABILITY: BPA ( ) vs. BPC ( ) Epoxy
DecompositionTemperature Heat of Combustion
0
5
10
15
20
25
30
Hea
t of C
ombu
stio
n, k
J/g-
poly
mer
EMI-24 TETA MDA BPA BPC CEBPC
Hardener
0
100
200
300
400
500
Peak
Mas
s Lo
ss R
ate
Tem
pera
ture
, °C
EMI-24 TETA MDA BPA BPC CEBPC
Hardener
< DGEBA >
< DGEBC >
0
10
20
30
Cha
r Yie
ld, %
(w/w
)
EMI-24 TETA MDA BPA BPC CEBPC
Hardener
Char Yield50
40
CYANATE ESTER: Polymerization Reaction
OCNC
Cl Cl
NCO
N
NN
CCl Cl
CCl
Cl
CClCl
200°C
BPC triazine thermoset polymer
BPC cyanate ester monomer
EFFECT OF BISPHENOL ON HEAT RELEASE RATEOF CYANATE ESTERSASTM 1354, cone calorimeter at 50 kW/m2 heat flux, neat resin, 1/4-inch thick
CNCO
CH 3
CH 3
OCN
CNCO
CH 3
H
OCN
NCO CH 2 OCN
CH 3
CH 3H3C
H3C
CCCH 3
CH 3
CH3
CH3
NCO OCN
NCO OCN
CClCl
C
0 200 400 600 800 1000 1200
Hea
t Rel
ease
Rat
e, k
W/m
2
Time, seconds
200 kW/m2
BPC CYANATE ESTER: FAA Heat Release Rate Test
-10
0
10
20
30
40
50
60
Hea
t Rel
ease
Rat
e, k
W/m
2
0 50 100 150 200 250 300 350Time, sec
2current AC phenolic panel
BPC cyanate ester panel
FAR 25.853(a-1)
glass fabric lamina1/8-in NOMEX honeycomb
glass fabric lamina
STRUCTURAL COMPOSITES FOR NAVY SUBMARINESOnly 3 resins pass fire performance requirements as glass composites:
Fire Test/Characteristic Requirement(MIL-STD-2031)
Composite Resin Phthalo-
nitrile SiliconeBPC-CETime to ignition (s) at irradiance:
passpass25 kW/m2 > 300 passpasspass> 15050 kW/m2 passpasspasspass> 9075 kW/m2
passpass> 60 pass100 kW/m2
Peak/Average Heat Release Rate (kW/m2) at irradiance:passpass< 50/50 pass25 kW/m2
passpass< 65/50 pass50 kW/m2
passpasspass< 100/10075 kW/m2
passpassSmoke Obscuration, Dmax/Ds (avg):
100 kW/m2 < 150/120 pass< 200/100 passN/Apass
Combustion Gas Toxicity (CO/CO2/HCN/HCl): passN/ApasspoorgoodgoodMechanical Properties
Cure Temperature < 200°C > 375°C N/A
J. Koo, et. al., SAMPE 2001
CYANATE ESTER-EPOXY REACTIVE BLENDSBPC Cyanate Ester (Ciba RD 98-228)
C16H8O2Cl2
MW: 331.16 g/molEW: 165.58 g/eqMP: 75 ± 2 °CCl: 21.41 wt%
CNCO
CCl Cl
OCN
BPC Epoxy (Pacific Epoxy XPR-1015)
C OO CH2CH2 CH CH2CHO
H2CO C
Cl ClMW: 393.27 g/molEW: 209.39 g/eqMP: 91 ± 4 °CCl: 16.93 wt%
C20H18O4Cl2
BPC Blends Cyanate:Epoxy %Cl1:08:26:44:62:80:1
21.420.519.618.717.816.9
Blend ratios prepared from the reported equivalent weights
CYANATE ESTER-EPOXY REACTION
Cyclotrimerization reaction of the cyanate ester (A) and the subsequent reaction with the glycidylether (B) to form the oxazoline
Cyanate Ester OxazolineTriazine
3 33(A) (B)
N
O CH2O
OR'
RCHH2C
O
CH2
OR'
²+
NN
NO
O
O
RR
R
OC N
R²
Glycidylether
Glycidylether OxazolidoneIsocyanurate
N
N
N
O
OO
R
R
R CHH2CO
CH2
OR'
O N
O
R
OR'
+ 3 3²
(D)(C)
Rearrangement of the triazine (C) to form isocyanurate and the subsequent reaction with the glycidylether (D) to form the oxazolidone
FTIR MONITORING OF CE-EP CURE CHEMISTRY
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
100 150 200 250 300
Nor
mal
ized
Pea
k H
eigh
t
Temperature (°C)
Cyanate Ester Epoxy Triazine Oxazoline
FIRE PERFORMANCE OF BPC CYANATE ESTER-EPOXY BLENDS
0
100
200
300
400
500
0
5
10
15
20
25
30
35
0 0.2 0.4 0.6 0.8 1
Hea
t Rel
ease
Cap
acity
of B
lend
, J/g
-K(B
aseline Corrected)
OSU
Peak HR
R, kW
/m2
Mole Fraction BPC-Epoxy in Blend
40600
CONCLUSIONS: Comparing Properties
Average Change (5-7 polymers)
BPC / BPA
– 90 %Fire Hazard Potential (ηc):
Fire Hazard (HRR): – 60 %
Glass Transition Temperature, K: + 3 %
Modulus: + 10 %
+ 10 % Yield Strength:
Yield Strain: + 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