A purge and trap technique which was employed to collect and separate the chemicals desorbing from the space shuttle heat protection tiles is described. The instrumentation included a mass spectrometer and gas chromatograph

Blair, J. W.

Hoffman, J. H.

Proctor, B. L.

English

NASA Technical Reports Server

General Disclaimer 
One or more of the Following Statements may affect this Document 
 
 This document has been reproduced from the best copy furnished by the 
organizational source. It is being released in the interest of making available as 
much information as possible. 
 
 This document may contain data, which exceeds the sheet parameters. It was 
furnished in this condition by the organizational source and is the best copy 
available. 
 
 This document may contain tone-on-tone or color graphs, charts and/or pictures, 
which have been reproduced in black and white. 
 
 This document is paginated as submitted by the original source. 
 
 Portions of this document are not fully legible due to the historical nature of some 
of the material. However, it is the best reproduction available from the original 
submission. 
 
 
 
 
 
 
 
Produced by the NASA Center for Aerospace Information (CASI) 
https://ntrs.nasa.gov/search.jsp?R=19840026394 2020-03-20T21:36:04+00:00Z
06 110
FINAL REPORT
w	
FOR
STUDY OF OUTGASSING AND DECOMPOSITION
OF SPACE SHUTTLE HEAT PROTECTION 'TILES, FILLERS, AND ADHESIVE
NASA hESEARCIi GRANT NAG-1-256
(UTD ACCOUNT E0589-01; 22781-961)
SUBMITTED TO
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
LANGLEY RESEARCH CENTER
HAMPTON, VIRGINIA
23665
BY
THE UNIVERSITY OF TEY.AS AT DALLAS
CENTER FOR SPACE SCIENCES
P. 0. BOX 830688
RICHARDSON, TEXAS 75083-0688
i^
zz' 3 !!» %tom
ertha L. Proct6r	 John H. offman
Co-Investigator	 Principal Investigator
Environmental Sciences and Engineering Head, Physics Programs
JoN W. Blair
ReY,earch Associate
Enviornmental Sciences and Engineering
(NASA-CR-173974) STUDY OF G IGASSING AND	 N84-34465
DEC014POSITION 01- SPACE SHUTTLE HEAT
PROTECTION T.11ES, F111BES AVE ADHESIVE
.Final Report (Texas Univ.) 5 p	 Unc1as
HC A 02/Ml? A01	 CSCL 22B G3/16 01160
.1k 194, r
C
+*-^'wJ.:;yL=.s rJr . tL' ar i`n. r► .
If.
r:
4A,
t
f
COMPOUNDS DESORBING FROM THE SPACE SHUTTLE TILES
Bertha L. Proctor and John Blair
Graduate Program in Environmental Sciences & Engineering
University of Texas at Dallas
f
Q
t ;^
^I
311
4The purpose of this project was to determine the chemicals
desorbing from the space shuttle heat prot,-ction tiles. The
original protocol for this project; involved direct insertion
probe mass spectrometry (DIPMS) analysis of the outgassing
products from the tiles. 	 This procedure allowed us to examine
the desorbing chemicals for the tile material subjected to
temperatures ranging between ambient temperature to 500 0C at a
pressure of 10 -3 torn. however, this method proved
unsatisfactory due to the large number of compounds desorbing
from the tiles. Analysis by DIPMS does not allow for separation
of compounds with the same volatility (1). 	 The large number of
compounds desorbing from the tile material. resulted in unresolved
complex organic mixture.
A purge and trap technique (2) was then employed to collect
and separate the chemicals desorbing from the tiles. The maximum
temperature in this analysis was 280 0C which is the gas
chromatograph fused silica capillary column's temperature limit.
The desorption was also carried out at atmospheric pressure ^,Tith
helium as the purge gas. A description of the modified protocol
is given below. All compounds are Centatively identified and
have not been confirmed.
Material and Methods
Sample Collection
Interior Tile Material: A tared, preconditioned	 (1 hour at
550 0C) quartz tube (3 mm I.D. x 5 cm)
was inserted directl4y = into the tiles to
a depth ranging between 3-4.5 cm. The
:,C' J7 :-Gn....
a
rC
black protective skin on the surface of
the tiles was removed prior to insertion
of the quartz sample tube. care was
also  taken to avoid the adhesive
material on the bottom of the tiles.
Samples represented a vertical profile
of the upper half of ruost tiles tested.
Aliquots of the tile material ranged
between 0.8-1.1 grams. After collection
of tile material the samples were placed
in the purge and trap chamber for
analysis.
Exterior Tile Materials: The black protective skin (0.3-0.5 mm
thick) or the surface of the tiles was
carefully removed and quantitatively
transferred to the quartz desorption
tubes.	 Aliquots of this material
weighed between P.3-0.45 grams.
	 it
should be noted that it was virtually
impossible to separate all of the black
skin from the white subsurface tile
material.
i
^s
i
r	 y
7
Method
Purge: The quartz tube containing the tile
material was heated to 280 0C and held at
that temperature for 15 minutes. There
was a constant flow of helium through
the purge chamber to sweep the desorbing
The
	
inlet of	 the column was held	 at -
30 o C	 throughout	 the	 desorption
	
phase.
After desorption the purge chamber was
cooled	 to	 room	 temperature
	
and	 the
trapped compounds separated and analyzed
by gas	 chromatography-mass
	 spectrometry
(GC-MS) .
Instrumentation and Conditions;
Mass Spectrometer Nermag R-10-10
Conditions Electron Impact Mode
Filiment current 70eV
Mass Range 60-500 amu
Scan Rate	 2 msec per amu
Gas Chromatograph: Carlo Erba	 (model	 4160)	 equipped	 with a
purge and trap unit constructed at UT-
Dallas.
Conditions Column:	 30 meter-bonded	 fused	 silica
capillary _nlumn DB5
	 (J&W)
Carrier Gas:	 He.
Temperature Program: The	 initial	 column temperature of 0oC
was maintained for one minute.	 The oven
temperature was then raised at a rate of
5 0C per minute to a final temperature of
28' J C.	 The	 final	 temperature	 was
maintained	 for 15 minutes.
t
a
j
'a
4 ♦ 	 0 P
compounds into the gas chromatogr.aph
where they were cryogenically trapped
onto the fused silica capillary column.
a
"''^?i.:^=,3 rte. HC',^ ^..^^.y•	 nun'` w ,,.,;Y.. '^*^,wn,^rri°-rvvt^.-^+^


Study of outgassing and decomposition of Space Shuttle heat protection tiles, fillers and adhesive

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server