BPFC-DMS block copolymers were synthesized on a pre-pilot scale (i.e., to 5 Kg lots) and subsequently fabricated into clear, colorless films. Details of the synthesis procedures, property determinations, and film casting techniques are presented. Solubility, viscosity and molecular weight characteristics of the resulting product are reported

Futrell, J. H.

Hughes, B. M.

Owen, D. R.

English

NASA Technical Reports Server

FINAL REPORT
TO THE
NATIONAL AERONAUTICS SPACE ADMINISTRATION
Contract #NAS2-10064
MANUFACTURE OF DPFC-DMS -POLYMER IN THE 5KG RANGE
B. Mason Hughes
Principal Investigator
Flammability Res. Center
University of;Utah
Salt Lake City, Utah 84100
Donald R. Owen
Sub-contract - Tulane University
Principal Investigator
Jean. H. Jytitrelll - ''. - '•
•Director, \FJammabJ,Hiy Research Center"
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TABLE OF CONTENTS
Page
A. SUMMARY \ 1
B. SYNTHESIS OF BPFC-DMS BY INTERFACIAL CONDENSATION 2
C. FILM MANUFACTURE 6
D. PROPERTIES OF BPFC-DMS FILMS 8
E. BIBLIOGRAPHY 9
APPENDIX A 10
APPENDIX B 11
APPENDIX C 17
A. SUMMARY
'"BPFC-DMS block copolymers have been synthesized on a pre-pilot
scale (i.e., to 5 Kg lots) and subsequently fabricated into clear,
colorless films. Details of the synthesis procedures, property
determinations, and film casting techniques are presented. Solubility,
viscosity and molecular weight characteristics of the resulting
product are reported.
B. SYNTHESIS OF BPFC-DMS BY INTERFACIAL CONDENSATION
Approximately 10 Kgs of the dried polymer .has been produced by a
j
procedure involving the following three stages of batch processing:
• 1. Raw material synthesis
2. Oligomer synthesis
3. Block copolymerization
These steps will be discussed in sequence.
1. Raw Material Synthesis
Purification of Chloroform and Di'chloromethane
Because of availability and storage convenience, chloroform was
substituted for dichloroethane by this laboratory because of avail-
ability and storage for the endcapping procedure. Reagent grade CHCK
was purified by passing 4 liters of solvent under a slight N? pressure
through a 4 ft., 1 in. diameter glass column packed with #20 active
alumina. The filtrate was discharged directly into a fired, N~ blanket-
ted, oven dried, dark glass (or foil covered) container and stored in a
cool place. Dichloromethane, later used to replace CHC1., in the final
oligomer solution, was purified in a similar manner. The solvents were
stored for 1 week or less under these conditions. Solvents not used
within a week were repurified by the above procedure before they were
used.
BPF Storage and Usage
To minimize skin irritation and handling complications, BPF was
kept in solution (or slurry) form. Freshly recrystalized BPF was
placed in a vacuum oven at 90°C overnight then placed in a N^-filled
oven at 110°C for 24 hours. 315 g of BPF was then added to a fired, N2-
dried 1 gallon dark glass container containing 2700 ml of the
purified CHC1.,. This procedure was carried out in a solvent hood with
N2 flowing over the bottle neck at approximately 2 liters/min. The
bottle was purged by placing the teflon N~ delivery tubing into the
container and bubbling N? through the solution for a minimum of 2 minutes.
The container was then tightly capped and stored in a dark, cool area.
Similarly, 300 g of BPF per 2700 ml of CH-Cl,, was charged to a 1 gallon
brown glass container. Approximately 40 ml of acetone was added to
dissolve all the BPF. The latter solution was retained for use in the
copolymerization step.
Silicone Fluid Synthesis
D-4 silicone fluid was synthesized according to the procedure
outlined in Sorenson [1]. After the distillation and pyrolysis steps,
a mixture of approximately 50/50, D3/D4 siloxane fluid was obtained.
Under a slow stream of N?, 1426.4 g of the D3/4 solution was added to a
1 gallon, fired, N,, oven-dried, dark glass container. Then 80 g Si-
(CH-JpClp and 0.329 g FeCK (anhydrous) were added to the mixture.
After loosely capping the container, it was placed in an N~ drying oven
for 24 hours at 48°C. 1500 ml of the purified CHC1., was then added
under a slow stream of N?, and the bottle was tightly capped and stored
in the refrigerator. Shelf lives appear to be in excess of 1 year
without any loss in reactivity for solution prepared to this stage.
2. Oligomer Synthesis j
A 10 liter three-neck flask was assembled with thermometer, vented
dropping funnel, and a gas inlet tube and vent for N?/NH_. The inlet
tube was made from a long-stem dropping pipette which reached nearly to
the bottom of the flask. During assembly, a 2 liter/minute flow of N^
was directed through the flask and was left on for several minutes after
charging with reactant, in order to purge the system. 4500 ml of the
CHC1--BPF slurry was then charged to the vessel. The N? stream was
switched to ML, which was bubbled through the slurry at a rate of 1.84
liters/minute for 30 minutes. At the 20 minute mark a white precipitate
begins to appear. At 25 minutes reaction time stirring of the mixture
is facilitated by the addition of another 800 mis of purified CHCK.
The NhL is then switched off and the N? purge (0.2 £/min.) is started.
Equilibriated silicone "fluid is slowly charged to the dropping funnel
until 1140 ml have been added (two additions are necessary). Then the
silicone fluid is added to the reaction mixture at a rate of 30 ml/min
and an exotherm is observed. The resulting purple suspension was
stirred for 1 hour and then refluxed for 2 hours at 60-61°C.
The resulting fluid is an off-white suspension with pH - 7.0. Two
liters of distilled H?0 were then added and the mixture was acidified
with 2.4 N HCL to a pH of 3.0. Reagent grade acetone is added to clear
the solution (approximately 150-200 ml is required). The solution was
then transferred to a 4 1 flask and the aqueous phase discarded. The
organic phase was washed with 1000 ml increments of 2.4 N HC1, FLO, 0.5
M Na HCO~, HpO and H?0. MgSO. was then added to dry this organic phase.
The volume of the resulting clear, golden 'solution was halved by vacuum
1
 evaporation and then, with the aid of a steam bath, taken to dryness.
Average yeild at this point was 1050 g.
The residue was redissolved in CHpCl- (184 g in 1 J,), and sufficient
acetone was added to clear the solution. The solution was stored in a
dark glass, fired, N? oven dried bottle. Tightly sealed bottles of this
solution have also been demonstrated to have shelf lives of at least one
year, unrefrigerated, with no loss in reactivity or lowered molecular
weight in the resulting block copolymer.
3. Block Copolymerization
As described previously, all solutions were prepared and stored in
dark glass under N?. Further, as recommended by Schnell, Bottenbruch,
and Matzner [2, 3, 4], chloroform was replaced by methylenechloride in
all polymerization reactions to avoid coloration in the product. All
glass containers were washed thoroughly and rinsed with acetone, then
dried at 110°C. A 12 liter three-neck flask WLS fitted with thermometer,
dropping funnel, hL/phosgene vent and supply (e.g., capillary tube to
bottom of flask), and a paddle stirrer. This apparatus was flushed
continually with N? for the duration of the process.
3800 ml of the CH2C12 solution of BPF (110.8 g/fc) was added to the
flask. 3175 ml of the endcapped silicone solution was then added under
a slow stream of N?. The endcapped solution provides a theoretical
stoichiometric ratio of 11.6 percent by weight of elemental silicon.
7.0 ml of triethylamine was then pipetted into the organic phase and the
paddle stirrer was set at a moderate rate to mix the components into a
clear, slightly yellow, homogenous liquid.
A aqueous phase solution was prepared by adding 0.9 g sodium
gluconate per 1000 ml distilled H^O, and 3175 ml of the solution was
added to the flask. The N?/phosgene vent/supply was switched to phos-
gene and vented to a NaOII/MeOII trap. The dropping funnel was charged
with 950 ml of 16.55 M NaOH.
Phosgene was then bubbled through the mixture at a rate of 2.9
g/min (0.68 Jl/min STP) and the NaOH solution added at a rate of 5.5
ml/min to maintain the pH at 10 ± 0.5. (Variation in pH was not found
to be critical as long as the solution was kept at a pH > 9.7 to main-
tain alkaline phenoxides which hydrolyze phosgene at a greater rate than
water [2, 3, 5, 6].) After 125 minutes the phosgene rate was cut back
to 0.15 2,/min and the NaOH addition modified to maintain pH at 10 ± 0.5.
The solution at this time was a milky-white, two-phase suspension which
seemed to clear slightly with time.
After five hours at the lower phosgene addition rate and after
approximately 950 ml of NaOH had been added, thin filaments of polymer
were observed to form at the tip of the capillary gas tube. At this
point the phosgene addition was terminated and N? was bubbled through
the suspension to purge excess phosgene. The mixture was allowed to
settle and the aqueous phase discarded. The organic layer was washed as
described in the preliminary Statement of Work (dated April 3, 1978),
dried over MgSO. and precipitated in acetone/methanol solution. The
precipitate was filtered and vacuum dried at 80°C for 24 hours. Batches
processed in this manner had an average yield of 89 percent.
Chloroform cast films exhibited a tendency to shrink after one or
two days of storage in a v/arm, dry area. Average shrinkage along the
side of any sheet was approximately 3-4 cm. As drying continues after
release of the film from the plate, curling towards the glass side is
also prevalent.
C. FILM MANUFACTURE
Films have been cast giving clear colorless sheets 0.05 to 0.12 mm
thickness. Five percent solutions were made up by dissolving the
thourougly dried polymer in chloroform and stirring the solution over
MgSO.. The solutions were then filtered through coarse glass and
stored until ready to use. If cloudiness persisted after filtering, it
was cleared by heating to a low boil (with high agitation). If cloudi-
ness and difficulty in filtering occur, unacceptably high amounts of
unpolymerized silicone segments are present and the solution must be
reprecipitated in a 50:50 heptane acetone mixture, filtered and dried as
previously described.
The casting apparatus is similar to that described in the prelimin-
p
ary report, consisting of a 63.5 X 63.5 cm glJss sheet (1/8" glazing)
bounded on the sides by a wooden frame 6 cm high. A 500-550 ml portion
of the casting solution was slowly poured on the center of the casting
plate and a glass cover slid over to shield the solution from convective
currents. After 1-1 1/2 hours the films were noted to undergo unassisted
release from the glass. This release, complicated by static buildup and
inhomogeneity in drying, caused splitting in the films. This problem is
aggravated for films of increased thickness.
Accordingly the procedure was modified to include surface treatment
of the casting plate. 400 ml of a 1 percent solution of Si (CH-J^Cl-
in acetone was poured onto the plate and evaporated dry. The plate was
then flushed with water. This treatment proved to be effective in
minimizing the splitting and produced a more even distribution of the
casting fluid.
D. PROPERTIES OF BPFC-DMS FILMS
Samples of four groups were selected and designated as samples MB1-
4. Molecular weight determination by gel permeation chromatography
(GPC) show a range of Rw from 32,000 to 36,000 with dispersities from
1.65 to 1.9. Figure 1-4 in Appendix A give G.P.C. charts and computer
analysis of molecular weights and dispersities.
Intrinsic viscosities for the four groups and for the NASA-furnished
sample appear in Appendix B. The viscosities vary from 0.13 to 0.29
dl/g with the NASA sample at 0.27 dl/g. These values were obtained
employing chloroform as the solvent and a standard size 50 Cannon-Fenske
viscometer. o
Solubilities were determined by immersion of 1 g of both the film
and the dried granular powder in 20 ml of test solvent. The polymer and
film were found to be soluble up to at least 60 percent (by weight) in
CHC1.. and Chlorobenzene. The product is soluble up to 10-20 percent (by
weight) in dichloromethane, THF and ethylenedichloride. The film clouds
and swells considerably when placed in these solvents. The film forms a
cloudy surface layer in diethylether, hexane and heptum but does not
swell appreciably. Water and aliphatic alcohols have no short term
effect. Long term effects in the later solvents has not been tested.
IR data for the four films are reported in Appendix C.
APPENDIX A
GPC DATA FOR FILMS MB-1, MB-2, MB-3 AND MB-4
Instrument:
Solvent:
Sample Pressure:
Oven Temp.;
Refract. Temp.:
Flowrate:
Calibration:
Polymer:
Columns:
Waters Model
Toluene
85 K P sig
35°C
37°C
5.2 ml/count
Polyscience - Styrene polymer series
100 k - 2,900 Mw
1. TI 6040 50. 80A X 450 PFT
2. TI 6197 700-2000A X 700 PFT
3. TI 6600 5 X 10/3 1.5 X 10/4 X 750 PFT
4. TI 6488 100-350 A X 750 PFT
10
APPENDIX B
INTRINSIC VISCOSITIES OF NASA SUPPLIED BPC-DMS COPOLYMER
AND POLYMER FILM SAMPLES MB-1, MB-2, MB-3 and MB-4.
B.I. INTRINSIC VISCOSITY OF NASA SUPPLIED SAMPLE BPC-DMS BLOCK COPOLYMER.
Cannon-fenske Size 50 Normal Viscometer
Serial No. B677
Constant = 0.000389 at 100°F
Temp. = 26.8°C CHC13 Solvent
entration
C
0.0 g/dl
0.125
0.063
0.249
0.496
Efflux Time
t (sec . )
107.4 (.3)
111. 6 ( .2 )
109.5 ( .3 )
115.9 ( .3)
127.3 ( .6 )
N t
' *s
-
1 .0382
1.01738
1.07850
1.1846
N a(N r- l )
SP " Q
-
0.03816
0.01738
0.07850
0.1846
(In Nr)
C (dl /g)
-
0.299
0.273
0.304
0.342
From graphical extrapolation of above data [n] = 0.27 dl/g.
B. 2. INTRINSIC VISCOSITY OF SAMPLE MB-1
Cannon-Fenske Size 50 Viscometer
Serial No. B677
Constant - 0.000389 at 100°F
Temp. = 26°C CHC13 Solvent
nt
C
0.
0.
0.
0.
ration
0 g/dl
10
20
40
Effl
t (
97.
98.
103.
109.
ux
sec
4
7
0
0
(
(
(
(
Time
- )
.4)
.3)
.1)
.6)
N - *'•Mr +•
^s
-
1.0137
1.0575
1.1208
Nsp
0.
0.
0.
_(Nr - ] )
C
-
1370
2875
3020
(In Nr)
C (d l /g)
0.
0.
0.
-
1361
2795
2851
From graphical extrapolation of above data [n] = 0.13 ± .04 dl/g.
13

B.3. INTRINSIC-VISCOSITY OF SAMPLE MB-2.
Cannon-Fenske Size 50 Normal Viscometer
Serial No. B677
Constant = 0.000389 at 100°F
Temp. = 26°C Solvent CHC13
Concentration Efflux Time
 M _t_ M _(Nr" ) (In Nr)
C t (sec.) Nr~ts Nsp-
 c C (dl/g)
0.
0.
0.
0.
0 dl/g
10
20
40
96.
99.
101.
108.
4
5
3
5
(-2)
(.5)
(.2)
(-2)
1
1
1
-
.0329
.0512
.1263
0
0
0
-
.3290
.2560
.3158
0.
0.
0.
-
3237
2497
2973
From graphical extrapolation of above data [n] - 0.29 ± .03 dl/g.
14
ORIGINAL PAGE W
OF POOR QUALITY
B.4. INTRINSIC VISCOSITY OF SAMPLE MB-3.
Cannon-Fenske Size 50 Normal Viscometer
Serial No. B677
Constant = 0.000389 at 100°F
Temp. = 26°F Solvent CHC13
Concentration Efflux Time ...
 =_t_ w jNr" ) (In Nr)
C t (sec.) Nr~ts Nsp-
 C C (dl/gj"
0.0 (g/dl)
0.10
0.20
0.40
95.7 (.1)
97.5 ( .3)
101.2 ( .3)
105.2 ( .3 )
-
1.0200
1.0575
1.0997
-
0.200
0.2875
0.2491
-
0.1980
0.2795
0.2376
From graphical extrapolation of above data [n] = 0.21 ± .03 dl/g.
15
B.5. INTRINSIC VISCOSITY OF SAMPLE MB-4.
ORIGINAL PAGE 88
OF POOR QUALITY
Cannon-Fenske Size 50 Normal Viscometer
Serial No. B677
Constant = 0.000389 at 100°F
Temp. = 26°F Solvent CHC1.
Concentration
C
Efflux Time
t
(In Nr)
C (dl/g)'
0
0.
0.
0.
(g/di)
10
20
40
i 96.
97.
99.
103.
1
9
5
7
(.1)
(.1)
(.2)
(.4)
1
1
1
-
.0181
.0347
.0785
0.
0.
0.
-
1810
1735
1963
0.
0.
0.
-
1794
1706
1889
16
E. BIBLIOGRAPHY
1. Sorenson, W. R. and Campbell, T. W., "Preparative Methods of
Polymer Chemistry", 2nd Ed., Interscience Publ. N. Y. (1968).
2. Schnell, H., Chemistry and Physics of Polycarbonates, Inter-
science, John Wiley & Sons, N.Y. (1964).
3. Bottenbruch, L., "Polycarbonates," Encyl. of Polymer Science
and Technology, N. M. Bikales Eds., John Wiley & Sons, N. Y.,
10, 710 (1969).
4. Matzner, M., Kurkjg, R. P. and Cotter, R. J., J. Appl. Polymer
Science, 9, 3295 (1965).
5. Kambour, R. P., Corn, J. E., Miller, S. and Nizhik, G. E. ,
"Tough Transparent Heat- and Flame-Resista'nt Thermoplastics
Via Silicon Block-Modified Bidphenols Fluorenone Polycarbonate,"
J. Appl. Polymer Sci., 20, 3275 (1976).
6. Morgan, P. W., Macro-molecules, 3, 536 (1970).
7. Angew. Cheat.
 a 68, 688 (1956).
APPENDIX C
IR DATA FOR THE CAST FILMS MB-1, MB-2, MB-3 and MB-4.
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1. Report No.
NASA CR- 166276
2. Government Accession No. 3. Recipient's Catalog No.
4. Title and Subtitle
Manufacture of DPFC-DMS Polymer in the SKG Range
5. Report Date
1979
6. Performing Organization Code
7. Author)*)
 B Mason Hughes, Donald R. Owen, Jean H.
Futrell
8. Performing Organization Report No.
9. Performing Organization Name and Address
University of Utah
Flammability Research Center
Salt Lake City, Utah 84108
10. Work Unit No.
505-44-21
11. Contract or Gram No.
NAS2-10064
12. Sponsoring Agency Name and Address
NASA-Ames Research Center
Moffett Field, California
13. Type of Report and Period Covered
Final Report
94035 14. Sponsoring Agency Code
IS. Supplementary Notes
Technial Monitor, D. A. Kourtides
NASA, Ames Research Center, Moffett Field, California 94035
16. Abstract
BPFC-DMS block copolymers have been synthesized on a pre-pilot scale
(i.e., to 5 Kg lots) and subsequently fabricated into clear, colorless films.
Details of the synthesis procedures, property determinations, and film casting
techniques are presented. Solubility, viscosity and molecular weight character-
istics of the resulting product are reported.
17. Key Words (Suggested by Author(sl)
Polycarbonates
19. Security Qassif. (of this report)
Unclassified
20. Security Clanii. 101 tnis page)
Unclassified
21. No. of Pages
22
22. Price*


Manufacture of DPFC-DMS polymer in the SKG range

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