Model polymer synthesis for use in char forming heat shield

Pendleton, E. L.

English

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jNAS 7-344 Th_ Dow Ch_ical Company
SYNTHESIS AND CHAPACTERIZATION OF MODEL POL_4ERS FOR
USE IN THE INVESTIGATION OF CHAR FORMING HEAT SHIELDS
NLg£BER 1 STATUS REPORT JANUARY 1965
D_STRIBUTION
NASA/WOO (I) H. E. Hennis
NASA/Ames (4) B. Legler
W. L. Bressler E.L. Pe_dleton
R. L. Carlyle M.E. P1"uitt
R. D. Eddy L.F. Sonnabend
R. F. Helmreich R.Y. Wen
ELF24ENT ONE - EPOXY RESINS
Researchers: R. L. Carlyle Problem No. : 7504
E. Legler
R. D. Eddy
J__anuary Objectives :
Obtain all starting materials including epoxy novolac resin, Nadic
methyl anhydride and necessary catalysts. Begin chemical and
physica] characterization of the monomers and polymers. Fabricate
molds and have first lot of billets ready by the month's end.
Large lots of both D.E.N. 438 epoxy novolac resin and Nadic methyl
anhydride (NMA) were obtained. Sufficient amounts of DMP-30 and
benzyl dimethyl am.ine catalysts were obtained_ The greater part
of analytical results on the D.E.N. 438 and NMA have been obtained,
Molds were fabricated to mold 1-1/2" by 6" sample billets.
Phase 1 was completed with the molding of D.K.N. 438/NMA billets
in the three ratios 1/0.75, 1/O.85, and 1/O.95 equivalents D.E.N.
438 per equivalent NMA. The billets are ready for shipment. Work
is progressing on obtaining physical and chemical analytical
results to aid in _haractelizlng the cured polymer. General pb,,qj
properties were obtained on the Phase 1 billet formulations. _-
'-
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1965011709
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Discussion:
I. Analytical results were obtained on the monomers as follows:
Analytical Results
Lot No. 12094 Nadic Methyl
, __D_E:N. 438 _Anhydride
Percent Epoxide 24.2 --
Gardner Color 1 --
Brookfield Viscosity, 125°F 53,400 cps --
Ostwald tube Viscosity 50°C - 35,980 cps 15.6°C - 423 cps
Ostwald Tube Viscosity 65°C - 4,570 cps 25°C - 172 cps
Ostwald Tube Viscosity 75°C - 1.630 cps 50°C - 32 cps
PeRcent Lights 0.2 --
Molecular Weight 680 182 (178 Theor.)
Water, ppm 155 --
Specific Gravity 1.231 --
Durran Softening Point 31°C --
MetaLs
Iron, ppm 0.3 0.2
Aluminum, ppm 2.0 2.5
Calcium, ppm ii.O 4.0
CHOH
Carbon, % 73.34 66.54 (Theor. 67.45)
Hydrogen, % 6.30 5.57 ( " 5.62)
Oxygen, _ 20.34 26.92 ( " 26.96)
Nitrogen, _ - - -
i Hydrol_yzable Chloride,% 0.06 -
Refractive Index 1.5952 1.5045
2. Preparation of Billets and C1_red Resin Samples
The following mixing and molding procedure was used:
i. Heat resin to 60°C under nitrogen purge.
2. Add Nadic methyl anhydride and mix 15 minutes.
3. Add Catalyst and mim 30-40 minutes.
4. Deaerate with vacuum for 5 minutes.
5. Pour into mold preheated to I05°C ) .
6. Cure 4 hgurs at IO5°C ) under nitrogen seal
7. Cure i_5 hours at 200°C )
8. Cool to room temperature )
9. Remove from molds and store in nitrogen purged triple
tight metal cans.
3. Recipes chosen for the first sample series are:
Samm!eNo. IA IB IC
D.E.N. 438 parts by wt. I00 i00 i00
Nadic methyl anhydride parts
by wt. 75 85 95
DMP-30 parts by wt. 1.5 i_5 1.5
1965011709-002
- 3 -
4. A paztial list of the physical properties measured on
these recipes follows:
IA ]J IC
Heat distortion temp.,°F 360 403 352
Flexural strength, psi 11,5OO 13,000 15,280
Compressive yield strength,psi 19,630 20,640 20,510
Tensile Strength, psi 3,410 3,960 4,440
Izod impact-ft.-!b./_nch of notch 0.19 0.22 0.19
Rockwell "M" hardness 117 122 123
5. Chemical and physical testing will continue. A more complete
list of properties for the three recipes will be forwarded
as soon as possible. The anhydride and D.E.N. 438 epoxy
resin should be completely characterized by about March i.
Accelerator or catalyst materials will be characterized as
tL, e permits.
6. Synthesis studies for the para tertiary butyl adduct of
D.E.N. 438 are not yet completed. This work will continue
through February.
7. In response to the request for a resume' of the analytical
and physical propertie_ tests that will be used for character"
zation work on this project, the following list is provided:
Analytical results requested on D.E.N. 438
Viscosity curve
Durran softening point
Total _ OH
Phenolic OH
J
Total chloride
! Inorganic chloride
'i _ C, H, O, N.
Quantitative on metals
l Infrared scan
Analytical results requested on Nadic Methyl Anhydride (NMA)
Molecular weight Free acid _otal chloride
Viscosity curve Unsaturation Purity by hydzolysis
Sp. Gr. 25°C _ C, H,O, N Quantitative on meta
Water Inorganic chloride Infrared scan
Analytical results requested on catalyst
DMP-30 Infrared scan
BDMA Infrared scan
Analytical results to be requested on catalysts
Water
Percent lights
! Prima_ and secondary amines
Phenol content
1965011709-003
Analytical results to be requested on cured resins
Reflectance infrared
Nujol Mull infrared
Infrared on resin cured between salt plates
Mold release penetration into sample
Method: Remove outer 5 mils
Remove 2nd 5 mils
Obtain material from interior of sample
Mold sample without mold release
Compare for fluoride by
Nujoi Mull I.R.
Mass spec on pyrolyzed sample
Chemical analysis (probably too
insensitive for low concentrations)
Sol-gel ratio
Peak exotherm during cure
Physical properties op cured resins at room temperature
Tensile strength
Compressive yield strength
Flexural strength
Izod impact
Rockwell hardness
8. The following list shows specific techniques or methods
used for some of these tests:
Chemical and Physical Methods
Percent Epoxide HBr titration method or Pyridine HCl reflux
method
Percent Lights 150°C at iO mm Hg for one hour
Molecular Weight Ebullioscopic (boiling point in dioxane)
Water Fischer water titration
Metals
Iron Emission spectroscopy
Aluminum " "
Calcium " "
CHON
Carbon Pregl method
Hydrogen " "
Oxygen Modified Unterzaucher Method
Nitrogen Kjeldahl Method
Hydrolyzable
Chloride Caustic-solvent reflux-AgNOs potentiometric
titration
1965011709-004
- 5 -
_'s ical Properties
Heat distortion temperature ASTM D-648-56 (264 psi)
Flexural Strength ASTM D-790-58T
Compressive Yield Strength ASTM D-695-54
Tensile Strength ASTM D-638-60
Izod Impac_ ASTM D-256-56
Rockwell _== Hardness ASTM D-785-60
Recipe used for Heat Distortion Measurement (Standard)
Mixture D.E.N. 438 - IOO parts
MDA - 28 parts
CAlre 2 Hours - 93°C
4-1/2 Hrs. - 204°C
MDA = Methylene Dianiline
Heat Distortion Temperature for Lot No. 12094 D.E.N. 438 =
429.8°F
9. As agreed the outer surface of the three samples (six billet
were machined away.
• Febr:aary Objectives :
i. ?reparation of Jv'_tD _vA_pou._/_.____.__._ density, foams from
]).E.N. 438/Nadic methyl anhydride will be examined to determ
::'easibil ity.
2. Techniques will be established for conducting sol/gel studie
cf the cured epoxy systems.
ELEMEhT THREE - PHENOLICS
Resear,:hers: L. F. Sonnabend Problem No.: 0299069107
K. Y. Wen
_Tanuary Objectives:
i. Preparation of Bisphenol I, a mixture cf 2,2'-2,4'- and
4,4'-isomers.
1965011709-005
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2. Preparation of 2,2'-isomer of Bisphenol I.
Bisphenol I _CH2_12
Summary:
i. Mixture of isomeric Bisphenol I was prepared from excess
phenol and diC_DPO. Work has begun in isolation of the
three isomers by thin-layer chromatography.
2. ?_ starting material, ethyl p-hydroxybenzoate, for the
synthesis of the 2,2'-isomer of bisphenol I was prepared.
Discussion:
Oda, et al. CA. 60, 11926 c (1964) reported the synthesis of the
4,4°-isomer of Bisphenol I. Attempts will be made to prepare
sufficient quantity of this isomer for the synthesis of polymer.
The preparation of finished billets is not scheduled for this
phase of the program. As shown in the time schedule contained
in the contract proposal, preparation of billets begins after the
fourth month, or about the end of April.
Feb____ruaryObjectives:
i. Synthesis of 4,4'-isomer of Bisphenol I.
2. N.M.R. study on isomers isolated by TLC.
3. Synthesis of methy!ol derivatives from the 4,4'-isomer and
the mixture of Bisphenol I.
Schedule:
In response to ARTICLE II - REPORTS, page 3 of Contract NAS7-344.
i which requires that a schedule of man hours versus time be
provided, a revised copy of the man time estimated for the Epoxy
Element is attached (see following page).
1965011709-006
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The original man time schedule for the Phenoiics Element is
correct as it was origanally submitted when the cross-hatched
areas are not counted (see original proposal.)
Respectfully s,_bmitted,
Elmer L. Pendleton
ib Program Manager
attach
1965011709-008


Synthesis and characterization of model polymers for use in the investigation of char forming heat shields status report no. 1

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