1. REPORT DATE 2. REPORT TYPE Briefing Charts 4. TITLE AND … · 2012-02-16 · Georjon and Galy (Pol ym er 39, 343, 1998) ~~~-----~ showed that, for BADCy, the late stages of cun3

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1. REPORT DATE (DD-MM-YYYY) 19-08-2011

2. REPORT TYPEBriefing Charts

3. DATES COVERED (From - To)

4. TITLE AND SUBTITLE

5a. CONTRACT NUMBER

High Temperature Composite Resins: Re-Writing the Rules for Thermosetting 5b. GRANT NUMBER

Polymers 5c. PROGRAM ELEMENT NUMBER

6. AUTHOR(S) Andrew Guenthner, Kevin R. Lamison, Josiah T. Reams, Vandana Vij, Gregory R. Yandek,

5d. PROJECT NUMBER

Matthew C. Davis, Michael E. Wright, Lee R. Cambrea, and Joseph M..Mabry

5f. WORK UNIT NUMBER23030521

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

8. PERFORMING ORGANIZATION REPORT NUMBER

Air Force Research Laboratory (AFMC) AFRL/RZSM 9 Antares Road Edwards AFB CA 93524-7401

AFRL-RZ-ED-VG-2011-365

9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM(S)

Air Force Research Laboratory (AFMC) AFRL/RZS 11. SPONSOR/MONITOR’S

5 Pollux Drive NUMBER(S) Edwards AFB CA 93524-7048 AFRL-RZ-ED-VG-2011-365

12. DISTRIBUTION / AVAILABILITY STATEMENT Approved for public release; distribution unlimited (PA #11663).

13. SUPPLEMENTARY NOTES For presentation at the SAMPE High Desert Conference, Palmdale, CA, 20 Sep 2011

14. ABSTRACT This is a presentation for the the SAMPE High Desert Conference, about high temperature composite resins and re-writing the rules for thermosetting polymers.

15. SUBJECT TERMS

16. SECURITY CLASSIFICATION OF:

17. LIMITATION OF ABSTRACT

18. NUMBER OF PAGES

19a. NAME OF RESPONSIBLE PERSON Dr. Joseph M. Mabry

a. REPORT Unclassified

b. ABSTRACT Unclassified

c. THIS PAGE Unclassified

SAR

22 19b. TELEPHONE NUMBER (include area code) N/A

Standard Form 298 (Rev. 8-98)Prescribed by ANSI Std. 239.18

HIGH-TEMPERATURE COMPOSITE RI:SINS: RE-WRITING THE RULES FOR

THERMOSETTING POLYMERS 20 September 2011

~ •• • Outline

• Unusual Structure-Property Relationships in High-T 9 Thermosetting Polymers / "'

- Cause: expansion of the diBenedetto envelope (i ... -o ~

"'< ~0 - IEffects: .r,ON ottt~"

• T9 Significantly above cure temperature

• "Negative" shrinkage

• lm~>lications for Composite Resin Development

ON~ Acknovvledgements: Air Force Office of Scientific Research , j Ofhce of Nav<tl Research

Force Research Laboratory, Office of Naval Research -Pro~~ram Support; PWG team members (AFRL/RZSM)

DISTRIBUTION A: Approved for public release; distribution is unlimited I

AFRL Propulsion Directorate (AFRL/RZ)

• •

•

•

Model High-Temperature Thermosetting Polymers: Cyanate Esters

Catalyzed cure 1"'100 kJ/mol. cyanate ester eq.) c ... ..

Typical DSC Trace of CEs o© c~ " c 0 ..

'"'" ~ 0

C·· © ., . :© c ~ N

.. c c i-• • I~

c ,. ~ -

Tg:: 304"C '< e (after complete cure )

·(0) (Q) L A c

N © ~ " -c ~I"

0 so 100 150 200 250 300 350 400 BADCy ~ © N

.~

Temperature (0 C} :;

Glass transition temperatures at full cure of 200 - 400°C

.. c

Uncured resins exist as low-melting solid~, or low to moderate viscosity liquids, making thenn ideal for processes such as filament winding

Broad compatibility with co-monomers, thermoplastic tougheners, or nanoparticles for control of physical and mechanical characteristics

Sing1le species reaction chemistry is "cleaner" than epoxy resin and well-understood; enables development of superior predictive models for failure; readily catalyzed to cure at reasonable temperatures

DISTRIBUTION A: Approved for public release; distribution is unlimited

Examples of Cyanate Ester Resins

"BADCy"

"SiMCy"

.Name Density* (glee I)

Water Uptake*

OCN BADCy -38 304 1.195 2.3°/o

OCN

LECy -47 290 1.220 2.4o/o

SiMCy -46 260 1.175 1.8o/o

•

•

*after full cure w/ primary cure at 210 oc, systems include catalyst with 160 ppm Cu(ll) as Cu(II)AcAc with 2 phr nonylphenol

BADCy was the first-commercialized cyanate ester; it is least expensive and has the largest property database LECy is the most common room-temperature liquid dicyanate ester often used in filament winding formulations

OCN • SiMCy is a highly useful BADCy analog first synthesized by Wright eta/. (Polym. Prepr. 2004, 45 (2), 294) noted for its low water uptake


~ ~ •• ~ Cyanate Esters: Universe of Applications •

Q) a. 0 Q) > c Q)

0 = Q) "0 Q) c Q) co "0

J •• • Glass Transition as a Function of Extent

of Cure in a Thermosetting Polymer

>ou 0 i:-olhi:llll.d \.lll ~ .11 :!00 (

~.;n 0 "l•lh,•rm d <llr~ ll I "0 <

.::oo I 1 .. ~'

('\\) 0 u ... 100 orSP ,.....

~0 lt!ll 0 ')

()

1 <:P 0 .;n o-IY

lUll 110 II ~ 11-l lito II.X t.o

tl.

An exan1ple of how T0 values can be converte~d to conversiOn values based on the diBenedetto equation (from X. Sheng, rVI. Akinc, and M. R. Kessler, J. Therm. Anal. Calorim. 2008, 93, 77-85.) for EX-151 0 dicyanate ester resin, for which T~1 << T decamp

•

•

•

•

•

Note the steep dependence of T 9 on conversion as the system reaches full cure

The need for higher use temperatures pushes up T900 as better performing resins are developed

The need for ease of processing dictates that T 90 remain low, preferably below room temperature

As a result, composite resins are evolving to have an ever steeper diBenedetto curve, which results in a very strong dependence of T 9 on conversion.

Normally, T 9 depends on free volume in polymers, but as conversion dependence begins to dominate, the rules for structure-property relationships change

Ill Epoxy 0

Polyimide 200

Cyanate Ester -50

150

450

300

150

250

350

4.5

7.5

10.5


JWhen T9 Rises Fast Enoug_h wi~h -~on~ersion ,_ . ... It Exceeds T cure Despite VItrificatiOn ~

250 • 0

200 0 BADCy •

~ 150 )LECy

100 SiMCy

50 50 100 150 200 250

Cm e Tem,,eJ.ltlll e

•

T9 (°C) c>f Cyanate Esters Cured 12 h •

BADCy 134 168 246

LECy 142 183 21 3

SiMCy 152 186 •

100 300 90 • • 80 f., -- 250

Tg _,..- -- 70 0 0 0

Tou~ ~ - "-,:: 60 • 200 • .~ I ~ !2 50

I Size of "gap" scales ._!'

4> 40 150 ?: Q

I with diBenedetto ¢ 30 1-0> !.-' envelope 20 I 100 10 BADCy (Catalyzed) 0 50

0 2 4 6 8 10 12 14 16 18

T -ot;'ll Hou•s of Cut e

Vitrification slows down conversion, but does not stop it completely

Under isothermal conditions, the rate of conversion will fall as conversion increases, but the sensitivity of T

9 to conversion will

rise, resulting in a fairly constant rise in T 9

The greater the sensitivity, the further T 9 can rise above Tcure


•

•

J ••

' • J

"Vitreous Cure" Changes the Rules of Network Formation

Traditional Thermal Cure

r-1 r- r-

r • • • • • •

~

[ • • • ....... '- u

"Vitreous Cure"

r • J

• Cure results in: J

J

1

•

•

•

Net Shrinkage

Less permeability

Higher modulus

• Brittleness

• Cure results in:

• Net Expansion

• l-lirthar narrna!:lhil.if" 1 ll':;:jl lVI f'-'VI I I IVUVIII' LY

• Lower modulus

• Toughness

"Vitreous Cure" is promoted by rigid network segments with well-distributed extensibility, and by curH temperatures that are low in comparison to T 9 (though Tcure < T 9 may not be a criterion)

Both types of cure can happen sequentially, simultaneously, or in mixed form . -

~J _i_ _. DISTRIBUTION A: Approved for public release; distribution is unlimited

: 1:.

•S

" :I

":1 40 1 = ~ .. " :: 3 5· • ...

. "

Evidence for "Vitreous Cure" in Cyanate Esters

1.24

BADCyonly BADCyonly

1.23

;;-

! 1.22

~ ~ Gl '0

1.21 Georjon, 0 . and Galy, J. Polymer

~:eo C.90 C.S5 1.28+.80---0...,.85 __ ___;.,_0.,....90---0.,.....Q5 ___ 1 ...... ~tJ2 1998, 39, 343

FiJ:ttt'C' 2 Varialiun of the 18 1 Young's modulu-. and 1 1 ultrn~nntl muduJu., ·'"a functiom ofconver::,um 1 uncatalyzl·d Ol'lwork- - 1 \'anatlon of the Yuuni,., moduJu ... uf cnt.ll~ Zl'd Ol·twurk,.,.

Georjon 0 and Galy J. Journal of Applied Polymer Science 1997;65(12):2471-2479.

Tahl<' Y \'alu cc;; of Stt·<'c:<; lnt<'nc;ity Facto•· K1c and Fr;~ ct UJ'<' Tnu~hn<" c;;c: f:u fnt· Diff<'r<'nl Polycy:uuwat(' !'iC'IWOJ'k'l BADCy only

conversion

tl!!urt! J Dcn"t)' '~lu<'> ,,. J fufl('loun of CC'Il\o.'l'\lnn 1~1 room trmpcr"Ju"'l • . unctol~lv.ctl " "'""rh: l uo.:ot..~l}"'-4 n~t,.ur'-'

1.26

1.25

1.24 ... 1.23 ... .=:' 1.22 .~ 1.21 .. ----; 1.2 g )\l•lwork K11 t ~fPa 'm' GH (J nr1 :--......_......._ --

1.19 ------------

BAOCy

LEGy

1.18 100 0.8 170 g;, O.li 60

---""---......--. 90 0.:-1 55 1.17 p,;, 0.3 20 0.5 0.6 0.7 0.8 0.9

CIOO 0.9 220 (:ouvetslou C91 0.6 90 CR2 0.4 3;)

. .. as confirmed by recent AFRL data


•

Correlation Between Water Uptake, and Cyanurate Density

Cyan te Ester - mmol mmol c~anurate/ H20 I cc cc

BADCY 13.0 1. 7

LECY/3.0 1.6

SIMC'f I 2.7 1.1

THIOC~Y I 3.9 1.2

METHYLCY I 2.6 0.9 1\ ....... r". • ~ I l'l ~ /"\I U\.JY r I £.0

A C 1.~

REX-~~71 I 3.3 2.6

RTX3~36 I 1 . 9 0.4

In blend samples studied ... 1.8

1.6

I:! 1.4 -0 £ 1.2 0

~ 1

0.8

0.6

J.

r I

Error bars represent 1 a

2.5 2.6 2. 7 2.8 2.9 3 3.1 3.2

mmol cyan urate Icc

... and over all types of CE resins ... Blue = 1 bisphenyl 6

I:! 5 -0 4 £ 0 3 E E 2 • • . ·~

• •

• •

• = three-arm Purple= single-ring (meta) Orange=

.. •Based on data in Appendix a-3 of Hamerton, I (ed)., Chemistry and Technology of Cyanate Ester Resins (BiackieAcademic, 1994) (uses monomer d~ensity)

0 1.8 2 2.2 2.4 2.6 2.8 3 3.2 3.4 3.6 3.8 4 4.2 4.4 Triangle= lit

mmol cyanurate I cc value (x-axis uncertain)

Maintalining a low density of cyan urate groups appears to limit water uptake


•

•

•

Water Uptake and Free Volume Associated with Cyanurate Groups

~~~------------------~ Georjon and Galy (Polymer 39, 343, 1998) showed that, for BADCy, the late stages of cun3 led to an increase in free volume associated with the formation of cyan urate groiUps, and that the formation of free volume was directly connected to increased wat~er uptake.

Our resu Its to date show:

2000

17~80 0.80 o'lnval'llon • A similar correlation at high conversion

for other dicyanate monomers 3~--~~~·~----~~~

t oo o 0

• Th~t the effect is limited to very high conversions (otherwise both water uptake and free volume decrease with M {%)

increasing conversion), and

• Monomers with more free volume overall tend to absorb less water

2 0 0

• o •

1 • o0

0 •

o oo I

I

.... •••••• • •

o<> <><><> <> ~ i ~ <> ••••• • •

•

Thus, all free volume is not equally useful for wat~er uptake.

;~· 0+---~----~----~--~

0 200 400 600 800 t 112 I e (s112 mrri1

}

-- - -. . ... - . - ... OIS"f~I~.UT!ON A; Approved for public release; d!slfi~utio~~is unlimited ~ -~ - :.J... - L--· -- - . - --

Quantitative Prediction Tools for Wet T9

220

215

210

E 2o5

~ 200

~ 195

190

185

180 150

Slope = 0.55 ± 0.20 Intercept= 100 ± 45

rl !, '· T fl +t I 160 170 180

Dry Tg (0 C). 50 w (wt%)

190 200

• From studies of ternary blends

300 280 260

240 P' 220 ; 200

~ 180 3': 160

140 120 100 , .

100

Slope = 0.51 ± 0.07 Intercept = 91 ± 19

Uncatalyzed /

/

/ r / r

' r/ J. /

/

150

/ /

/ / ..

/; H ... /

Data shows wet T g is higher than dry T g in some cases!

200 250 300 350

Dry Tg (0 C)- 21 w (wt%)

•

• And from studies of molecular architecture

450 ...... -........-..... . ........-... - ... ~.., ....... -...........

4oo ~ I . ~

350 ~ •

u 300 ~ . 0

~ 250 ~ ~ • ..

• .

• 200 •

150 •

. .. . . .. ~

• • • • . . .. .. . 100 ...__....... ..... _ ... _ ... _ ................... _,__.....

-200 0 200 400 600 800 1000 1200 1400

Time (hours)

Marella (thesis, Drexel Univ., 2008) showed that uncatalyzed PT -30 cyanate ester exhibits only about 65°/o of the drop in Tg compared to a mildly catalyzed system; our measurement of the same effect yields a ratio of 40 ± 25o/o.


~ Comparison of Wet and Dry T 9 in Partially •• Cured Dicyanates

BP\DCy 125 147 171

BP\DCy 150 169 190

BP\DCy 200 248 220 I ' ' . ·' ··' f$mpr-r Hurt t f '

LIECy 125 147 170

LIECy 150 188 187

LECy 170 213 192

SiMCy 100 105 136

SiMCy 125 168 162 r SiMCy 150 203 179 "'.,, .. , ... th.u•f C\

• Hot/wet exposure can increase T 9 in common dicyanates too .


The Role of Flexible Junctions in Cyanate Ester Networks

GOAL: Replace cyanurate linkages with alternative network linkages to generate high Tg values via a high density of cross-linked network junctions without increasing water uptake, and while preserving toughness.

AF /Na~r Collaboration: Monome!r synthesized by Dr. Matthew Davis at NAWCWD China Lake

NAV~AIR

Publications: Guenthner, A. J.; Davis, M. C.; Lamison, K. R.; Yandek, G. R.; Cambrea, L. R.; Groshens, T. J.; Baldwin, L. C.; Mabry, J. M. "Synthesis, Cure Kinetics, and Physical Properties of a New Tricyanate· Ester with Enhanced Molecular Flexibility", Polymer, 2011' 52, :3933-3942 ; see also, same authors, "Cure Characteristics of Tricyanate Ester High-Temperature Composite Resins" in Proceedings of SAMPE '11.

"FiexCy"

DISTRIBUTION A: Approved for public release; distribution is unlimited 1 I

•

•

J •• .. Material

Flex.Cy-IPA

Flex:Cy-IPA

Flex:Cy-IPA

Flex:Cy-IPAc

Flex:Cy-EtOH

Flex:Cy-EtOH

Flex.Cy-EtOH

PT-30

~10 w ·We

Conversion Measurements for FlexCy and PT -30

Cure Cure Tgvia Tgvia Coover- Coover- Coover-Temp. Time OTMA OTMA sion via sion via sion via ec> (hrs) CTE Loss OTMA OTMA Ff-IR

ec> Peak CTE Loss Peak

f.9 210 24 310 i( 338 ) 0.91 0.92 0.83

250 2 307 >352o 0.90 >0.94 0.82

290 0.5 >34911 >34911 >0.95 >0.94 0.94

210 I 290 24 I 0.5 302 J1! 0.89 0.94 n/a

210 24 301 IC 317 1 0.89 0.88 nla

250 2 327 ~ > a 0.93 >0.94 nla

290 0.5 301 ~2a 0.89 >0.94 nla

210 24 274 IC 309 ) 0.82 0.85 0.80

250 2 309 >J'5"5a 0.88 >0.93 0.91

290 0.5 327 >35211 0.91 >0.92 0.80

210 I 290 24 I 0.5 314 >3898 0.89 >0.98 n/a

Coover-sion via

DSC

nla

n/a

<0.98

nla

n/a

nla

<0.98

n/a

n/a

<0.99

nla

a . Run terminated due to sample decomposition prior to measurement of loss peak

Unde~r some cure conditions, FlexCy exhibits a higher T 9

than PT -30, indicating a higher extent of cure was achieved

Although all samples show >80°/o conversion, quantitative comparisons are difficult


•

•

2500

FlexCy and Primaset® PT -30: FT-IR Cure Comparison

PT-30

FlexCy. cured 30 min at 290"'C 0.6 - - -- PT -30. cured 30 mi11 at 290''C 0.6

FlexCy. uncured

:: ~~ 0.5 - PT-30. uncUI'ed 0.5

It ,

! I I 1 I 0.4 41

0 0.4 ~

- ., .. 2000

II I I t II I I fl It 1 I It I I I I I I I I I I 1 rl 1111 I I I ~~I I 111 I \ ~ \ I I Ill I I 1\ I I II I I &I

II I ' ll • , . "'

0.3

0.2

0.1 .. .,.I

1500 0

1000 \AJ,..., """' ' . ...... k. ....... ,_....._ .. 1 \ VVaV~IIU III U~f \\..111 . ,

c ~ .0 ,_ 0 1./) .0 <{

~ ,\ " I I : \t \ 0. 3 I~ 'J

n. : ~ : \'' 0.2 I ••• , I 'v' I tl I •1\1 0 1

' "I . ,' ., I

0 2500 2000 1500 1000

'''-··-- ··- ~- -- , ____ .,\ VVdV~IIU III U~I \ C III ' 1

c (0 .0 ,_ 0 1./) .0 <{

FT-IR conversion estimates of 95°/o (FiexCy) and 80°/o (PT-30) are only approximate but show clearly that incorporation of the alternative linkage types facilitates full cure~ of the cyanate ester groups, improving dry T

9 and toughness.

Because of the high sensitivity ofT 9

to conversion that results from the large diBenE~detto envelope, the T

9 increase driven by higher conversion can outweigh the~

expected T 9

decrease due to incorporation of flexible chemical bonds.

DISTRIBUTION A: Approved for public release: distribution is unlimited 1

•

•

•

•

•

,J .... • Summary of Technical Content

The need for increased high-temperature performance while maintaining affordable processing for polymer matrix composite resins is driving the use of materials with a wider diBenedetto envelope (difference in cured and uncured T

9).

A wider diBenedetto envelope means that the resin T 9

can increase substantially with a very small increase in the extent of cure, which allows the resin T

9 to

significantly exceed the cure temperature, promoting "vitreous cure". Increased "vitreous cure" results in unusual structure-property relationships, including

- Decreased density with increasing cure

- Increased toughness with increasing cure ·- ------.-1 ···-"'-- ··-"--1 .... - . . . : .LL... :.----- - !.--... -·· --- 111\.;lt:Ct~t:U WC:tlt:l Uf.JlCIKt: Willi Hlt;rea~HIY t;Ure

Efforts to quantify the effect of cure on wet T 9

are underway. There appears to be a correlation between extent of cure and extent of "knockdown" but details (including the reason for unusual increases in T

9 on exposure) are not yet clear.

The high sensitivity ofT 9

to extent of cure also means that, in some cases, the judicious addition of flexible chemical linkages (that promote extent of cure) can result in a net increase in T 9 under some cure conditions.


Implications for Composite Resin Development

• Awareness of the Unusual Structure-Property Relationships Helps to ... - Minimize moisture uptake and improve hot I wet

pE~rformance in high temperature polymer matrix composites

- Take advantage of previously unrecognized means of irnproving resin toughness (near-complete cure and judicious use of flexible bonds) without sacrificing high use te·mperatures

- Stetter understand the impact of cure schedule on physical nr·nnortioc J-' I '-' J-' '-' I \. I '-' V

• Impact for USAF: More Reliable and Better-Performing Rocket I Airframe Propulsion - Hot I wet performance is often the limiting performance

factor

- Detection of mechanical damage is the major reliability concern


Atlas V

I

The Next $50 Billion

THE AIR FORCE LCAD

•,

\

Documents

1. REPORT DATE 2. REPORT TYPE Briefing Charts 4. TITLE AND … · 2012-02-16 · Georjon and Galy (Pol ym er 39, 343, 1998) ~~~-----~ showed that, for BADCy, the late stages of cun3