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Received March 2008
Degradation of ‘Lumarith’  
Cellulose Acetate
EXAMINATION AND CHEMICAL ANALYSIS OF A SALESMAN’S 
SAMPLE KIT
Jia-sun Tsang, Odile Madden, Mary Coughlin, Anthony Maiorana, Judy Watson, 
Nicole C. Little and Robert J. Speakman
INTRODUCTION
The plastics industry is now in its second century and 
plastic materials are increasingly common in both 
museum and fine art collections. As more and more 
of these objects begin to exhibit signs of degradation, 
plastics are facing scrutiny about their permanence and 
the potential of deteriorating objects to contaminate 
the surrounding collection through the release of 
degradation products. A year-long survey of plastic 
objects at the Smithsonian Institution’s National Museum 
of American History (NMAH) [1] determined that the 
most common plastics in the collections are cellulose 
nitrate, cellulose acetate (cellulose ethanoate), polyvinyl 
chloride (polychloroethene), polyurethane, rubber and 
phenol formaldehyde (phenol methanal). These plastics, 
with the exception of phenol formaldehyde, are termed 
‘malignant’ [2], because their deterioration products can 
adversely affect other materials, including paper, metal 
and other plastics that may be stored in the immediate 
vicinity. Thus, it has become crucial to identify these 
Objects manufactured from cellulose acetate comprise one of the most problematic groups of plastic in the collections of the 
Smithsonian Institution’s National Museum of American History (NMAH). To understand better cellulose acetate degradation, 
a ‘salesman’s sample kit’ of ‘Lumarith’ brand, injection-molded, cellulose acetate color samples, manufactured by the Celluloid 
Company in the early twentieth century and now in the NMAH collection, was studied using minimally invasive analytical 
techniques at the Smithsonian Institution’s Museum Conservation Institute (MCI). The kit includes 49 plastic coupons that vary 
in color, transparency, chemical composition and current state of degradation. Results of analysis were compared with Celluloid 
Company records at the NMAH Archives Center and Celanese Corporation in Narrows, Virginia, in order to determine the 
causes for their current level of preservation or degradation. The possible reasons for the degradation of some coupons are discussed; 
methods are proposed for identifying cellulose acetate objects that are at risk and for early detection of degradation.
malignant plastics and investigate the causes of their 
deterioration. Many factors may influence the state of 
preservation of such materials, including their chemical 
composition, the manufacturing processes by which 
they were created, as well as their subsequent history 
of use, collection, conservation treatment, storage and 
exhibition.
NMAH has in its collection an early salesman’s 
marketing and promotion sample kit of 49 colored, 
injection-molded ‘Lumarith’ coupons that are strung 
together on a beaded metal chain (Figure 1). Lumarith 
was an injection-moldable cellulose acetate plastic 
produced by the Celluloid Corporation beginning in 
the mid-1920s. The Lumarith coupons are identical in 
shape and size and appear to have been manufactured 
by the same injection-molding process. It is assumed 
that the coupons have remained together on the metal 
chain since their manufacture and, consequently, share 
a common history. However, the coupons differ in 
their composition and current state of preservation. 
As the Lumarith sample kit offers an excellent case 
study of naturally aged cellulose acetate coupons that 
were manufactured in the 1920s or 1930s, Museum 
90 
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Conservation Institute (MCI) staff were granted a two 
month loan of the object with permission to conduct a 
technical study using non-destructive techniques (with 
one exception, discussed below). This loan provided 
a rare opportunity to study the effects of chemical 
composition on the long-term stability of three-
dimensional, injection-molded cellulose acetate objects 
with a limited number of experimental variables.
The coupons and their connecting metal chain 
were examined visually, using both the unaided eye 
and magnification to understand the process by which 
they were manufactured and to assess their current state 
of preservation. The dimensions and weight of each 
sample were measured. Information about the molecular 
structure of the plastic components was obtained by 
Fourier transform Raman spectroscopy (FT-Raman) 
and Fourier transform infrared spectroscopy (FTIR). 
Elemental data were generated using X-ray fluorescence 
spectroscopy (XRF) and scanning electron microscopy 
with energy-dispersive spectroscopic (SEM-EDX) 
mapping. X-ray diffraction (XRD) was performed on a 
small white crystal from the metal chain.
Of the 49 coupons in the sample kit, 31 did not 
show any signs of degradation (Figure 2). Some signs 
of degradation were shown by 18; three of these were 
severely degraded (Figure 3). The condition of the 
coupons was found to correlate strongly with the 
presence of triphenyl phosphate (TPP).
BACKGROUND: CELLULOSE ACETATE AND 
‘LUMARITH’ PRODUCTS
The development of cellulose acetate grew out of a 
commercial need to improve upon cellulose nitrate. 
By 1909, the Celluloid Corporation, until then a 
manufacturer of CELLULOID brand cellulose nitrate 
products, was searching for a suitable additive to 
reduce the flammability of Celluloid [3]. Instead 
they discovered a substitute in the form of cellulose 
acetate. Almost immediately, the Celluloid Corporation 
began production, and in 1910 made the first serious 
commercial attempt to market ‘non-flammable safety 
film’ made of cellulose acetate [4]. Development of 
cellulose acetate as an injection-moldable plastic to 
create three-dimensional objects was in commercial 
production by 1926 under the trade name Lumarith 
Figure 1 ‘Lumarith’ (cellulose acetate) color samples kit manufactured 
in the late 1920s or 1930s. The sample kit consists of 49 coupons, each 
roughly 3.8 × 6.3 cm, looped on a 35 cm metal chain. Coupons have aged 
differently through time: some are in good condition, some samples exhibit 
signs of deterioration and some have undergone advanced deterioration.
Figure 2 Example of a coupon (Coupon 40) in good condition.
92 J.-S. TSANG, O. MADDEN, M. COUGHLIN, A. MAIORANA, J. WATSON, N. C. LITTLE AND R. J. SPEAKMAN
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[5]. Lumarith, described by the manufacturer as a 
thermoplastic colloidal or solid solution of cellulose 
acetate and plasticizers, with solvents, dyes and pigments 
[6], was produced in sheets, rods, tubes and injection-
molding powders that in turn were used in the 
manufacture of spectacle frames, lampshades, handbags, 
novelties, watch crystals, radio dials, records and 
thousands of other everyday articles. Transparent sheets 
of Lumarith were used as windows for airplanes and gas 
masks during World War II and as non-flammable film 
base for motion pictures and transparencies. Transparent 
and colored versions quickly found popularity as toys, 
household implements, jewelry and spectacle frames, 
among many other uses. 
The mater ial came to be used in some high-
temperature applications, such as lampshades, for which 
the flammable cellulose nitrate was an inappropriate 
choice. Company records suggest that specific recipes 
and processes were customized for individual clients 
in order to realize the desired mechanical properties 
of their finished object [5]. Recipes were modified by 
varying the colors, fillers, and the type and concentration 
of plasticizer. A stamped number at the bottom of each 
coupon appears to be a unique product number which 
imparts information about pricing, color and flow 
properties of the material during production. Lists of 
product numbers in the company records from 1936 
appear to correlate each product number with a use for 
the plastic, such as fountain pen casings, and the name 
of the company for which the product was developed. 
Thus, it seems that the Celluloid Corporation may have 
developed its various Lumarith compositions on an ‘as-
needed’ basis. Once a satisfactory product formulation 
was developed for one company, the specific formulation 
was assigned a product number that Lumarith salesmen 
could then market to other clients. 
According to the Celluloid Corporation’s company 
records [5], its cellulose acetate products were made from 
the reaction of cellulose, derived from cotton fibers, 
linters and/or paper, with acetic acid (ethanoic acid) or 
acetic anhydride (ethanoic anhydride) in the presence 
of sulfuric acid. The final material was a cellulose ester 
polymer on which hydrogen atoms of the cellulose ring 
were substituted with acetate groups. Unlike cellulose, 
cellulose acetate can be solubilized in organic solvents, 
and the solubility parameters depend upon the degree 
of acetylation. Di-acetate and tri-acetate varieties of 
cellulose acetate refer to the degree of acetylation of the 
cellulose. These two materials are very similar in terms of 
their mechanical properties and spectral characteristics, 
though they differ in their solubility in organic solvents 
and long-term stability. 
Because cellulose acetate decomposes at temperatures 
lower than the softening temperature, plasticizers were 
added to the product in order to lower the softening 
temperature and improve the flow properties of the 
molten plastic during the injection-molding process 
[7]. Addition of plasticizers also modified other material 
properties of the final plastic, including strength, 
flexibility, heat distortion temperature and fire retardance 
[7]. Plasticizers could be incorporated into the cellulose 
acetate either by a solvent-casting process or by using 
the liquid plasticizer as a solvent, as in the case of diethyl 
phthalate. Plasticizers known to have been used in 
Lumarith include diethyl phthalate, dimethyl phthalate, 
triphenyl phosphate and dimethoxy ethyl phthalate [8].
In making Lumarith, the Celluloid Corporation 
Figure 3 Example of a coupon (Coupon 9) in an advanced stage of 
deterioration.
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aimed to achieve a product that could be formed into 
many shapes, was durable, had minimal heat shrinkage 
during processing, and was clear and vibrant in color.
EXPERIMENTAL
The aim of this study was to use non-invasive and non-
destructive analytical methods to identify the constituents 
of the Lumarith coupons, to assist in determining the 
factor or factors responsible for, or contributing to, the 
onset and progression of degradation. Exceptions to the 
non-invasive protocol were FTIR analysis of the liquid 
exuding from Coupon 9, and X-ray diffraction analysis 
of white crystals on the surface of one severely degraded 
coupon and the metal chain that linked the coupons 
together. All coupons were examined visually, weighed, 
measured and photographed at various magnifications. 
In addition, organic and inorganic chemical analyses 
were performed using a variety of complementary 
techniques.
Technical description and condition of the 
Lumarith samples
Each coupon is a solid, rectangular piece of plastic. The 
undegraded coupons measure approximately 3.8 × 6.3 
cm. The thickness of each coupon varies from top to 
bottom in a series of four descending steps (Figure 2); the 
uppermost step of the coupon (which includes the point 
at which the molten plastic was injected into the mold as 
well as the LUMARITH logo) is c. 6 mm thick and each 
successive tier is c. 1.5 mm thinner than the preceding 
tier. The name ‘LUMARITH’ was embossed across the 
top of each coupon in raised letters during the molding 
process. Traces of white powder that are probably a 
mold-release agent remain in recessed areas along the 
edges of the letters (Figure 4). A unique product code 
(e.g., X-XXXX) is stamped onto the lower edge of each 
coupon. The coupons are strung together using a 35 
cm metal chain through a hole at the upper right-hand 
corner of each coupon. The order of the coupons on the 
chain was documented by numbering them 1 through 
49 (i.e. Coupon 4 was located between Coupons 3 and 
5) to track trends in the onset, as well as the spread, of 
degradation.
Initial visual examination revealed that 18 of the 
49 coupons in the sample kit showed some signs of 
degradation; three of these were severely degraded. The 
three most degraded samples exhibited severe cracking, 
distortion and shrinkage. In each of the most degraded 
coupons, the damage was most severe at the top of the 
coupon, whereas the bottom of the coupon appeared 
undegraded. The cracking included long open cracks 
that emanate from the injection point at the top of the 
coupon and radiate down and outward. A network of 
finer, crizzled cracks also was visible throughout the 
degraded sections. White crystalline efflorescence was 
visible on the surface of degrading areas (Figure 5). 
Figure 4 White residue found in and around the logo at the top, most 
likely the remains of residue from a mold-releasing agent, commonly used 
during injection or compression molding of plastic (see Figure 15b).
Figure 5 Detail of Coupon 9. Triphenyl phosphate (one of three 
plasticizers identified in the ‘Lumarith’ coupons) has leached out of the 
cellulose acetate and redeposited as feather-like crystals on the surface of 
coupon (image width: 0.25 cm).
94 J.-S. TSANG, O. MADDEN, M. COUGHLIN, A. MAIORANA, J. WATSON, N. C. LITTLE AND R. J. SPEAKMAN
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A thin film of liquid was observed on the surface of 
Coupon 9 (Figure 3). Some degradation was also noted 
on the coupons adjacent to the three that were degraded 
most. A brown stain that permeated the plastic near 
the chain hole on Coupon 1 (Figure 1) appeared to be 
caused by interaction with the metal of the chain.
The metal chain exhibited green-blue corrosion 
(Figure 6) that is concentrated on the metal at the points 
where the chain was in contact with the three degraded 
coupons and has transferred to the surface of the holes 
of all 49 coupons. The condition of each coupon is 
described in Table 1.
Fourier transform Raman spectroscopy  
(FT-Raman)
Components of the plastic were analyzed by FT-Raman 
spectroscopy using a Thermo Electron NXR FT-
Raman module attached to a Thermo/Nicolet 6700 
FTIR spectrometer. The Raman module incorporates 
a continuous wave NdYVO
4
 excitation laser that emits 
at 1064 nm. The instrument employs two detectors: 
an electronically cooled InGaAs detector and a more 
sensitive germanium detector cooled with liquid 
nitrogen. Two beam splitters are available – an extended 
KBr beam splitter, and a more sensitive CaF
2
 beam 
splitter.
Coupons were analyzed directly without sampling. 
Each was subjected to 256 or 512 scans. The power 
density of the excitation laser and the gain were adjusted 
for each coupon to maximize signal and minimize the 
potential for damage to the sample.
Fourier transform infrared spectroscopy (FTIR)
A Thermo/Nicolet 6700 FTIR spectrometer was 
used to identify liquid on degraded Coupon 9; white 
crystalline efflorescence from the Lumarith coupons; and 
a white deposit, suspected to be a mold-release agent, on 
the Lumarith company logo on one coupon. A Thermo/
Nicolet Smart Golden Gate diamond attenuated total 
reflectance (ATR) accessory and a Centaurus FTIR 
microscope with diamond anvil cell were used for these 
analyses.
X-ray fluorescence spectrometry (XRF)
The elemental composition of the Lumarith coupons 
was measured using an ElvaX energy-dispersive X-
ray fluorescence (XRF) spectrometer. The instrument 
consists of an X-ray generator (i.e. the tube), an X-ray 
detector, and a multi-channel analyzer (MCA). The 
detector is a solid state Si-pin-diode with a resolution 
of about 165 eV at 5.9 keV (at 1000 counts per second) 
with an active area of 6 mm2. The tungsten anode X-ray 
tube is air-cooled and has a 140 µm beryllium end-
window.
Two measurements were made for each sample. For 
the first analysis, samples were analyzed for 200 s (live 
time) at a voltage of 45 kV and current of 20 µA using 
an aluminum-nickel filter. These settings optimized 
the identification of the following elements: As, Ba, Br, 
Co, Cd, Cr, Cu, Mn, Fe, Nb, Pb, Rb, Se, Sr and Zn. For 
the second analysis, samples were analyzed for 200 s 
(live time) at a voltage of 10 kV and current of 30 µA 
using an aluminum filter. These settings facilitated the 
identification of low-Z elements, including Ca, Cl, K, 
P, S and Ti.
Scanning electron microscopy with energy 
dispersive spectroscopy (SEM-EDX)
Several coupons were examined and elemental maps 
were generated using a Hitachi S-3700N scanning 
electronic microscope (SEM) with a Bruker-AXS 
XFlash energy-dispersive spectrometer (EDX). Analyses 
were performed at low vacuum (100–270 Pa), with an 
accelerating voltage of 10 or 15 kV. The coupons were 
introduced into the sample chamber in their entirety 
with no alteration.
Figure 6 Green corrosion covers the surface of the metal ball (0.2 cm 
in diameter) from the nickel-plated metal chain. White flakes found in the 
corroded surface were identified as triphenyl phosphate by FT-Raman and 
XRD analysis.
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Table 1 Description of ‘Lumarith’ coupons and elements identified by XRF analyses
Coupon 
no.
Product no. 
(imprinted on 
coupon)
Color and transparency Condition Weight  
(g)
Elements detected 
by XRF
Condition 
ranking*
1 P-5965-A pale blue/green, opaque brown stain near hole, white silica 
near logo
8.87 Ca, Ti, Cu, Fe, Pb D
2 O-2881-B deep blue, transparent abrasion, white silica near logo 8.63 Ca, Fe, Cu, Pb ND
3 O-5801-A deep blue, opaque white bloom on back, white silica 
near logo
8.65 Si, Ca, Ti, Mn, Fe, Zn, 
Pb, Rb, Sr, Zn, Nb
ND
4 O-387 dark blue, transparent white silica near logo, trace of brown 
deposits
9.11 Si, S, Ca, Fe, Cu, Pb ND
5 O-5958-A dark dull blue, opaque white silica near logo, abrasion 8.91 Si, Ca, Ti, Fe, Cu, 
Co, Pb
ND
6 O-4005-A ocean blue, opaque white silica near logo, mark 8.86 P, Ca, Ti, Fe, Co, 
Zn, Pb
D
7 O-5724-A medium blue, transparent white silica near logo, abrasion, dull 8.66 Ca, Fe, Cu, Pb ND
8 O-5743-A dark blue, opaque excess silica near logo, dull, abrasion 9.00 S, Ca, Ti, Fe, Cu, 
Zn, Pb
D
9 O-3581-A dark blue, transparent weeping, cracking, shrinkage 6.68 P, Ca, Fe, Cu, Pb, Br SD (Figure 4)
10 O-5723-A orange, transparent excess green corrosion near chain 
hole
8.76 Ca, Ti, Fe, Cu, Pb D
11 O-4621-A light orange, transparent white silica near logo 8.57 Ca, Fe, Cu, Pb ND
12 O-5837-A light yellow, transparent visible green corrosion near chain hole 8.51 Ca, Fe, Cu, Pb ND
13 O-2901-A orange-yellow, translucent visible green corrosion near chain hole 8.85 P, Ca, Ti, Fe, Cu, Pb D
14 O-2253-A light orange, transparent severe cracking, severe shrinkage 5.86 P, Ca, Fe, Cu, Zn, Pb SD
15 O-5799-A amber, transparent severe green corrosion near chain 
hole, cracking
8.93 Ca, Fe, Cu, Pb D
16 O-5678-A light orange, transparent minor green corrosion near chain hole 8.79 Ca, Fe, Cu, Pb ND
17 MO-5829-A glitter-flecked cherry red, 
transparent
no noticeable degradation, 
fluorescence (UV)
8.96 Ca, Fe, Cu ND
18 P-5848-A sky blue with white marble swirl, 
opaque
no noticeable degradation 8.82 P, Ca, Ti, Fe, Cu, Pb ND
19 M-5629-A light brown with lighter brown 
swirls, opaque
white silica near logo, scratch marks 8.55 Ca, Ti, Cr, Mn, Fe, Cu, 
Pb, Sr
ND
20 M-4903-A dark brown with light brown 
swirls, opaque
white silica near logo 9.11 S, Ca, Ti, Cr, Fe, Cu, 
As, Pb
ND
21 M-4863-A dark red-brown with swirls, 
opaque
white silica near logo 8.76 S, Ca, Cr, Fe, Se, Cd ND
22 M-4003-A brown with lighter brown swirls, 
opaque
white silica near logo 8.94 Ca, Ti, Cr, Fe, Cu, Pb, 
Se, Cd 
ND
23 O-4515-A bright orange, transparent no noticeable degradation 8.99 Ca, Fe, Cu, Pb ND
24 O-2250-A pale yellow-green, very 
transparent
no noticeable degradation 8.54 Ca, Ba, Fe, Cu, Pb, Sr ND
25 O-5683-A bright yellow-orange, very 
transparent
bloom, abrasion 8.99 Ca, Fe, Cu, Pb D
26 O-4485-A yellow-orange, transparent severe cracking, severe shrinkage 6.03 P, Ca, Fe, Cu, Pb SD
27 O-3717-A yellow-orange, transparent discoloration top left, cracking on 
back top 
8.76 Ca, Fe, Cu, Pb D
28 O-5820-A plum, opaque white silica near logo 9.24 Ca, Ti, Fe, Co, Cu, Zn, 
Se, Cd 
ND
29 P-5847-A pale pink with white marble swirls, 
opaque
noticeable stress marks radiate from 
top to second tier of the coupon
8.76 P, Ca, Ti, Fe, Pb, Se D
30 PO-4002-A metallic brown, opaque noticeable stress marks and uneven 
stains
9.07 Ca, Fe, Cu, Zn D
31 PO-5759-A dark brown-purple, opaque white silica near logo 8.98 Ca, Ti, Fe, Cu, Zn ND
32 M-5721-A purple with white marble effect, 
opaque
no noticeable degradation 8.72 Ca, Ti, Mn, Fe, Co, Cu, 
Zn, Pb
ND
33 MO-652 brown with yellow-brown swirls, 
opaque
cloudy 9.21 Ca, Ti, Fe, Cu, Pb ND
96 J.-S. TSANG, O. MADDEN, M. COUGHLIN, A. MAIORANA, J. WATSON, N. C. LITTLE AND R. J. SPEAKMAN
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X-ray diffraction spectrometry (XRD)
Samples of white crystals on the surface of one coupon 
and the metal chain were submitted for analysis by 
XRD. The instrument used was a Rigaku D/Max 
Rapid Micro X-ray diffractometer with a copper X-ray 
source and a 0.3 mm collimator, operated at 50 kV and 
40 µA for 15 minutes for maximum peak intensity. The 
radiation parameter is copper Kα, goniometer ki: fixed 
at 45°, and goniometer speed of 1°/s. 
RESULTS
Weight
The average weight of the 49 coupons was 8.66 g with 
a standard deviation of 0.68 g. Figure 7 shows that the 
weights were consistent for all coupons except the three 
most degraded, the weight of each being 25–35% less 
than the average. The weight of each of these three 
degraded coupons diverges from the mean by more than 
three standard deviations (Table 1).
FT-Raman spectroscopy
Fourteen coupons, including the three most degraded, 
were analyzed by FT-Raman spectroscopy. The Raman 
spectra of the coupons match well with a prepared 
sample of cellulose acetate plasticized with diethyl 
phthalate (Figure 8). The spectra of five coupons also 
indicate the presence of TPP. The three degraded 
coupons number among these, and the concentration of 
TPP in these coupons is significantly greater than that 
found in the other two (Coupons 18 and 37), which 
contain very low concentrations of TPP and are not 
visibly degraded.
34 M-3984-F deep red with lighter red swirls, 
opaque
excess white silica near logo 8.93 Ca,Cr, Fe, Cu, Se ND
35 M-4634-C bright green with white swirls, 
opaque
no noticeable degradation 8.51 P, Ca, Ti, Fe, Cu, Pb D
36 O-5716-A salmon, transparent noticeable darkening near chain hole 8.71 Ca, Fe, Cu, Pb ND
37 P-5845-A teal with white marble effect, 
opaque
no noticeable degradation 8.72 P, Ca, Cr, Fe, Cu, Pb D
38 M-5134-A light sky blue with marble effect, 
opaque
dull darkening 8.54 P, Ca, Ti, Fe. Cu, 
Zn, Pb
D
39 O-5771-A dull blue-gray, opaque no noticeable degradation 9.00 S, Ca, Ba, Mn, Fe, Cu, 
Pb, Sr, Nb, Sn
ND
40 P-5964-A pink with white swirl, opaque no noticeable degradation 8.60 Ca, Ti, Fe, Cu, Pb ND (Figure 3)
41 PO-5856-A grey-green, opaque no noticeable degradation 8.67 Ca, Cr, Fe, Cu, Ga, Pb ND
42 O-5872 dark salmon, opaque no noticeable degradation 9.25 Ca, Ti, Cr, Fe, Cu, 
Ga, Pb
ND
43 O-5815-A hunter green, opaque noticeable white silica near chain hole 8.68 Ca, Ti, Cr, Fe, Cu, Pb ND
44 P-5101-A purple and green with white swirl, 
opaque
no noticeable degradation 8.85 P, Ca, Ti, Fe, Cu, Pb D
45 M-5781-A off-white with green swirl, opaque no noticeable degradation 8.67 Ca, Ti, Fe, Cu, Pb ND
46 O-5810-A dark burgundy, opaque no noticeable degradation 8.62 S, Ca, Cr, Fe, Cu, 
Ga, Pb
ND
47 PO-5948-A metallic brown, opaque dull 9.52 P, Fe, Cu, Zn D
48 M-5803-A pale yellow-green, opaque dull 8.74 Ca, Ti, Fe, Cu, Pb ND
49 P-5849-A mustard, opaque no noticeable degradation 8.82 Ti, Fe, Cu, Zn, Pb ND
Notes: Green corrosion was observed in the chain hole located on the top right corner of all 49 coupons. It resulted from close contact with the corroded 
nickel-plated chain. Deterioration signs appear both on the front and back of the coupons.
Metal chain: copper-zinc alloy plated with nickel, confirmed by XRF. Green corrosion deposits cover the surface of the metal beads that are in close contact 
with the coupons (Figure 7). The most corroded metal beads are near Coupons 9, 14, and 26. Metal beads not in direct contact with the coupons have no 
visible corrosion. White flakes found in association with the green corrosion were identified as TPP by FT-Raman and XRD analysis.
*SD: severe degradation, D: degradation, ND: no degradation.
Table 1 (Continued)
Coupon 
no.
Product no. 
(imprinted on 
coupon)
Color and transparency Condition Weight  
(g)
Elements detected 
by XRF
Condition 
ranking*
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Figure 7 Comparison of coupon number versus weight. The weight of the three most degraded 
coupons is nearly 30% lower than that of the undegraded coupons.
Figure 8 (From top to bottom) FT-Raman spectra of an undegraded 
coupon (Coupon 1); a prepared reference of cellulose acetate plasticized 
with diethyl phthalate; a sample of pure diethyl phthalate; and a sample of 
pure cellulose acetate flake. Medium-strong peaks at 1377, 906 and 513, 
and a group of peaks at 200–170 cm−1 are unique to cellulose acetate. 
(Prepared reference of cellulose acetate plasticized with diethyl phthalate 
and the cellulose acetate reference courtesy of Dr Ray Robertson, 
Celanese Corporation.)
The peak values for cellulose acetate, diethyl phthalate 
and TPP are presented in Table 2, along with peak values 
for a degraded and an undegraded Lumarith coupon. 
Cellulose acetate and the two plasticizers share many 
overlapping peaks. Peaks unique to cellulose acetate 
include medium-strong signals at 1377, 906 and 513 
cm−1. Peaks unique to diethyl phthalate include 1041, 
1601 and 3075 cm−1. TPP is identifiable from its strong 
signal at 1007 cm−1, a benzene ring vibration, as well as 
the strong peak at 3066 cm−1 that overlaps with diethyl 
phthalate, and weaker peaks at 1232, 726–719, and 616 
cm−1 (Figure 9).
The FT-Raman spectra compared in Figure 9 
demonstrate that Lumarith plasticized with both 
Table 2 FT-Raman peak table for undegraded and degraded Lumarith 
coupons, pure cellulose acetate, diethyl phthalate and triphenyl phosphate 
(Raman shift, cm−1)
Undegraded 
coupons
Degraded 
coupons 
Cellulose 
acetate
Diethyl 
phthalate
Triphenyl 
phosphate
3076 3070 2939 3075 3176
2939 2939 1739 3034 3066
1728 2895 1435 2970 3020
1601 1724 1377 2938 1593
1581 1599 1155 2900 1294
1454 1465 1122 2875 1232
1379 1377 1082 2787 1194
1300 1288 1049 2725 1174
1165 1234  987 1724 1156
1112 1165  906 1601 1076
1041 1115  837 1580 1030
 910 1090  658 1489 1007
 848 1041  604 1454  933
 848 1028  513 1413  791
 652 1007  376 1394  771
 513  931  199 1367  726
 902  181 1279  616
 727  170 1165  385
 650 1113  234
 617 1041  213
 424 1018  184
 361  866
 848
 785
 652
 403
 350
diethyl phthalate and TPP, in this example Coupon 14, 
undergoes molecular changes upon degradation rather 
than simple leaching of plasticizer. Most noticeably, the 
magnitude of the strong peak at 2939 cm−1 decreases, 
broadens and shifts to lower wavenumbers. The 2939 
98 J.-S. TSANG, O. MADDEN, M. COUGHLIN, A. MAIORANA, J. WATSON, N. C. LITTLE AND R. J. SPEAKMAN
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FTIR
Analysis of a liquid on the surface of the degraded 
Coupon 9 resulted in spectra that are consistent with 
a mixture of TPP and dimethyl or diethyl phthalate 
(Figure 11).
Figure 9 (From top to bottom) FT-Raman spectra of a degraded area of 
Coupon 14, which contains a significant concentration of TPP; Coupon 
18, which contains a very small concentration of TPP and is not degraded; 
Coupon 1, in which TPP was not detected and which is undegraded; and 
a pure sample of TPP. Peaks that are diagnostic for TPP in the coupons are 
shaded in gray.
cm−1 peak is associated with both cellulose acetate and 
diethyl phthalate.
For the most part, each coupon spectrum resembles 
the sum of the spectra of the components. However, 
some peak shift is evident in spectra of the coupons that 
contain TPP. Pure TPP has a peak at 726 cm−1. Lumarith 
coupons that contain high concentrations of TPP do 
show a Raman peak in the general region of 726 cm−1, 
but the exact position of this peak may vary over the 
range of 719–726 cm−1. Furthermore, there appears to 
be a correlation between the shape and position of this 
peak and the degree of degradation visible in any one 
coupon. In areas without visible degradation, the main 
peak is centered at 719 cm−1 with a shoulder toward 
the higher wavenumber. In areas that exhibit low to 
moderate degradation, the main peak shifts to higher 
wavenumber, such that there appears a doublet at 719 
and 726 cm−1 with varying ratio of peak areas. In the 
most severely degraded areas, there is a peak diminution 
of the lower wavenumber component to a faint shoulder 
and formation a distinct strong peak at 726 cm−1, 
which is similar to the pure Raman spectrum of TPP 
(Figure 10). Whether the effect observed here is due to 
a gradual x-shift of the peak or to overlapping of two 
distinct peaks has not been determined. The causes of 
this phenomenon have been investigated and will be the 
subject of a separate upcoming publication.
Figure 10 FT-Raman spectra taken of four areas of Coupon 14. The 
uppermost was taken of an intact area of the coupon with no visible 
sign of degradation. The next three spectra were taken of areas in which 
degradation is visible: slightly degraded in the second from the top and 
more so in the two below. The lowest spectrum is a pure sample of TPP.
Figure 11 (From top to bottom) FTIR spectra of liquid exuded from 
Coupon 9 and reference spectra of diethyl phthalate and triphenyl 
phosphate. The liquid and triphenyl phosphate have about ten peaks in 
common. Peaks at 1725, 1366 and 1128 cm−1 are consistent with diethyl 
phthalate.
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Two white residues were identified. The spectrum 
of the white efflorescence from a degraded surface is 
consistent with TPP. The FTIR spectrum of the white 
powder thought to be a release agent present in some 
recessed areas near the company logo was consistent 
with silica.
XRF
A list of elements identified in each coupon by XRF is 
provided in Table 1. With the exception of phosphorus, 
no correlation was observed between any element 
identified by XRF and degradation.
Copper, zinc and nickel were detected in the metal 
chain. It is likely that the white metal surface of the 
chain is nickel plating that covers a brass core.
SEM-EDX
SEM-EDX analysis of 13 coupons confirmed the XRF 
results, but with the advantage of elemental mapping, a 
process in which an image of the sample is overlaid with 
colored pixels that represent different elements relative to 
their location on the sample. In intact areas, phosphorus 
is evenly distributed in the coupon, but as degradation 
develops and advances, the formation of phosphorus-
rich crystals is clearly visible.
The elemental maps were used to observe the 
different stages of degradation in Coupon 9. Figure 12a 
is a SEM-EDX image of the unaffected area – notably 
no cracks or crystals are visible near the bottom (thinnest 
section) of Coupon 9. Figure 12b isolates the element 
map for phosphorus, clearly showing that it is not 
migrating and is evenly distributed across this area.
Figures 13a and 13b were obtained from an area near 
the middle of the Coupon 9 in the second thickest tier. 
The degradation has begun to spread into this area. The 
SEM-EDX image (Figure 13a) shows a fairly smooth 
surface with some white areas along the left side of the 
image and a white scratch running vertically near the 
center. Also visible are some acicular/dendritic crystals in 
the top right and along the right side of the image. These 
crystals are rich in phosphorus (Figure 13b).Figures 14a 
and 14b also were obtained from Coupon 9, but in a 
thicker region closer to the top of the sample, where the 
degradation is more advanced. Phosphorus-rich crystals 
and a crack are visible in the SEM image of this area.
Figures 15a and 15b are from Coupon 26, a yellow-
orange coupon that is among the most degraded of the 
samples. The images depict the area surrounding the ‘U’ 
in ‘LUMARITH’ along the top of the coupon. A fine 
powder is visible along the edges of the ‘U’, and several 
possible crystalline lumps are present (Figure 15a). The 
elemental map (Figure 15b) shows that the powder 
is higher in silicon and that the crystals are higher in 
phosphorus.
XRD
XRD analysis of the white flakes from the metal chain 
identified peaks consistent with TPP and paraffin wax 
(Figure 16) [9]. Although it is conceivable that TPP 
Figure 12 Non-degraded area of Coupon 9: (a) scanning electron micrograph; and (b) elemental map of the same area, showing oxygen (orange), carbon 
(green), and phosphorus (purple).
(a) (b)
100 J.-S. TSANG, O. MADDEN, M. COUGHLIN, A. MAIORANA, J. WATSON, N. C. LITTLE AND R. J. SPEAKMAN
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could hydrolyze to diphenyl phosphate (DPP), this is 
not the case given that DPP was not present in the 
XRD pattern. Several minor phases were tentatively 
identified in the sample; these include copper acetate 
tetrahydropyr imidinone, zinc aluminum formate 
hydrate and/or silicon dioxide. Although copper acetate 
tetrahydropyrimidinone is an excellent match with the 
XRD reference pattern, it is not possible to account for 
the presence of tetrahydropyrimidinone. However, given 
the nature of the chain (a highly corroded nickel-plated 
copper chain) and the fact that it was in contact and 
interacting with an actively degrading cellulose acetate 
object, it is reasonable to assume that the identification 
of copper acetate is accurate. Because zinc aluminum 
formate hydrate and silicon dioxide share a similar 
crystalline structure (primarily with their major peak), 
it was not possible to determine which of these phases 
were present in the sample. Zinc aluminum formate 
Figure 13 An area in the upper-middle section of Coupon 9 where early signs of deterioration were detected: (a) scanning electron micrograph, showing 
formation of acicular crystals in the upper right area of the image; and (b) elemental map of the same area, showing the distribution of oxygen (orange), 
carbon (green), phosphorus (purple) and silicon (pink). Note that the crystals in the upper right area of the image have noticeable concentrations of 
phosphorus.
Figure 14 The top (most degraded) section of Coupon 9: (a) scanning electron micrograph, showing well-developed, phosphorus-rich crystals and a 
crack; and (b) elemental map of the same area, showing oxygen (orange), carbon (green) and phosphorus (purple). The crystals are enriched in phosphorus 
in comparison to the surrounding area.
(a) (b)
(a) (b)
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hydrate and silicon dioxide could result from (1) the 
presence of zinc on the chain; (2) the possibility of dirt, 
dust and grime on the chain (e.g. Si, Al, O, Fe); or (3) 
the fact that silicon was used as a release agent during 
manufacture of the coupons. Inconclusive identifications 
are denoted in Figure 16 by a ‘?’. 
DISCUSSION AND CONCLUSIONS
Of the 49 Lumarith color samples, three are severely 
degraded and 15 others exhibit slight signs of degradation. 
The most degraded coupons exhibit shrinkage, cracking, 
efflorescence of white crystals of triphenyl phosphate 
and, in the case of Coupon 9, the appearance of a 
thin film of diethyl phthalate plasticizer on the plastic 
surface. The 15 coupons that exhibit degradation to a 
lesser degree show some localized fine cracks, areas of 
discoloration, and/or subtle changes in surface gloss; 
however, these coupons are intact and of similar weight 
to those coupons for which no degradation was noted. 
All 49 coupons share a similar composition of 
a cellulose acetate polymer and diethyl phthalate 
plasticizer. Although the coupons contain a variety of 
colorants, opacifiers and, in one coupon, pieces of glitter, 
there does not seem to be any correlation between these 
components and observed degradation. The one apparent 
feature that the three severely degraded coupons share is 
the presence of triphenyl phosphate – a plasticizer that is 
known to have been used in cellulose acetate to impart 
fire retardancy, moisture resistance and other qualities. 
Triphenyl phosphate was identified definitively by 
FT-Raman spectroscopy, both in the degraded plastic 
coupons and as white crystals on the surface. TPP was 
also detected in a few coupons that exhibited no sign 
of degradation. However, the concentration is much less 
Figure 15 The ‘U’ in the Lumarith logo at the top of the Coupon 26: (a) scanning electron micrograph, showing white dust in various places on the ‘U’, 
especially near the bottom and upper left corner; several cracks and crystals are also visible; and (b) elemental map of the same area, showing oxygen 
(orange), carbon (green), phosphorus (purple) and silicon (pink). The white dust on the surface of the coupons is silica, probably the release agent used 
in the molding process (see Figure 4). The presence of these phosphorus-rich crystals supports the hypothesis that plasticizer loss is occurring in the 
degrading coupons.
Figure 16 XRD results from the analysis of the white crystal removed 
from the corroded chain. The white crystal was identified as triphenyl 
phosphate using FT-Raman, and as phosphorus-containing by low vacuum 
SEM. Triphenyl phosphate has leached from the degraded Lumarith 
coupons, migrated to the metal chains and possibly corroded the metal 
balls that chained the Lumarith coupons together.
(a) (b)
102 J.-S. TSANG, O. MADDEN, M. COUGHLIN, A. MAIORANA, J. WATSON, N. C. LITTLE AND R. J. SPEAKMAN
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than in the degraded examples, and the strongest peak for 
TPP at 1007 cm−1 is barely visible in the spectrum. The 
inorganic elemental composition of each coupon was 
identified by XRF, and the distribution of phosphorus 
among the coupons agrees with the FT-Raman data. 
TPP was also identified by XRD on the metal chain that 
bound the coupons together.
Of the samples that show some sign of degradation 
but do not contain TPP, six out of seven are adjacent to 
a degrading coupon that contains TPP. Coupon 18 is the 
single TPP-containing coupon that has not yet begun 
to exhibit signs of degradation. These facts strongly 
suggest that TPP plays a role in the degradation observed 
in these objects and that the degree of degradation is 
correlated with TPP concentration. 
Other researchers have studied the effects of TPP on 
cellulose acetate [10–12], mainly focusing on cellulose 
tr iacetate films (both for photography and paper 
lamination), rather than three-dimensional injection-
molded forms.
Wilson and Forshee identified the benefits of TPP 
in paper lamination as ‘increasing the hardness and 
durability of the film’, even at a suggested concentration 
of 5% by weight [10]. Allen et al. stated that ‘(p)lasticizer 
is incorporated in cellulose triacetate photographic film 
in order to render the base flexible’ and suggested that 
‘(b)oth the plasticizer and the emulsion layer impart 
some stability to the film substrate, probably associated 
with their ability to neutralize and scavenge the acid’ [11]; 
a concentration of 20% TPP is indicated. Some further 
effects of TPP are noted by Allen et al.: ‘It is seen that 
moisture regain is markedly inhibited by the plasticizer 
and this is consistent with a better retention of viscosity. 
The TPP is therefore imparting some protection to the 
polymer film probably by undergoing hydrolysis’; and 
‘The presence of acetic acid … is also seen to markedly 
accelerate the loss of the plasticizer… These results are 
interesting since they relate closely to what is observed 
in real archival condition where the process of acetic acid 
release is the precursor to plasticizer loss’ [11]. Wilson and 
Forshee make clear that for the use of cellulose acetate 
in lamination, inclusion of an antioxidant and an acid 
acceptor is necessary for stability, state that unplasticized 
cellulose acetate is more stable than plasticized, and 
suggest that TPP can be left out of the plastic film if 
desired (and when included, recommend it only at 
5%) [10]. Allen et al. also say ‘it appears that diffusion 
or migration of the plasticizer is more associated with 
hydrolysis and deacetylation of the cellulose triacetate 
film. Under these conditions the plasticizer would be 
incompatible with the substrate and therefore migrate 
to the film surface and crystallize’ [11]. Shinagawa and 
colleagues conducted accelerated aging tests on cellulose 
triacetate film and investigated the effects of TPP on its 
deterioration [12]. According to their study, cellulose 
triacetate is fairly stable, even at elevated humidity and 
temperature, but it is very vulnerable to attack by acids. 
They assert that TPP, incorporated into cellulose acetate 
film, readily hydrolyzes in wet conditions to form a more 
acidic diphenyl phosphate and phenol. When present 
in sufficient concentration, the diphenyl phosphate 
increases the acidity of the plastic and catalyzes rapid 
degradation of cellulose acetate. In the current study 
of Lumarith, triphenyl phosphate was identified on 
the metal chain that bound the coupons, using XRD. 
It is also suspected that a growth in a sharp peak in the 
1025–1028 cm−1 region of the FT-Raman spectra of the 
coupons that contain a relatively high concentration of 
TPP is associated with increased phenol concentration 
in degrading Lumarith coupons.
Given the above descriptions of cellulose acetate 
degradation and interaction with TPP, a possible 
progression of the degradation of the Lumarith coupons 
might begin with the catalyzation of cellulose acetate 
by some undetermined factor, such as elevated heat, 
humidity, ultraviolet light, and/or repeated cycling of 
any or all of these variables. Acetic acid is then released as 
a product of the degradation, and the physical structure 
of the coupons becomes visibly changed, with shrinkage, 
cracking, distortion and efflorescence all evident.
Cracking and warping of the degraded Lumarith 
coupons appears to result from shrinkage brought about 
by deacetylation, leading to acetic acid loss and plasticizer 
loss, and scission of the cellulose acetate polymer chain. 
Each of the most degraded coupons has shrunk by 
nearly 30% relative to the undegraded coupons. The 
visual appearance of the warped and cracked coupons 
also suggests shrinkage. The warping is primarily a 
narrowing of the coupon width at its center. The major 
cracks that run through the degraded coupons run from 
the injection point at the center of the top edge and 
radiate down and outward. They appear to run parallel 
to the polymer chain. Loss of acetyl side groups and 
plasticizer from between the polymer strands would 
presumably result in this kind of crack pattern. Analysis 
of Coupon 9 with A-D Strips indicates that acidic vapors 
are emanating from the coupon, and given the analyzed 
composition of the coupon the acid is probably acetic 
acid. (A-D Strips are paper test strips that can detect 
acid vapor and are commonly used to monitor cellulose 
acetate film deterioration.) Other types of cracking, 
particularly the smaller network of cracks that resembles 
DEGRADATION OF ‘LUMARITH’ CELLULOSE ACETATE 103
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crizzling in glass, may be caused by scission of the 
polymer chain. The glycosidic linkages that connect the 
cellulose chain are broken in acidic conditions resulting 
in a cracked, brittle and weakened material.
The data suggest that TPP in cellulose acetate plastic 
is a risk factor for degradation. This study shows that 
cellulose acetate plastics can be surveyed non-invasively 
using XRF, FT-Raman and FTIR, all of which are 
available as portable instruments. Also, it seems that 
FT-Raman could be used to evaluate the degree of 
deterioration in at-risk cellulose acetate plastics. In 
FT-Raman, the increased intensity of the 726 cm−1 
peak of TPP as cellulose acetate degradation increases 
may indicate a loss of compatibility between TPP and 
cellulose acetate which has resulted in TPP migration 
out of the plastic. 
This preliminary investigation is the beginning of 
much-needed systematic study to identify properly the 
components of cellulose acetate plastics [13–17], to 
isolate and measure the markers of degradation, to study 
the mechanisms that trigger the deterioration, and to 
design the best practices for storage and exhibition. 
ACKNOWLEDGEMENTS
The authors would like to acknowledge Richard Barden 
(NMAH) and Ann Seeger (NMAH) for their support of 
plastic preservation research with NMAH collections; 
the Celanese Corporation for providing access to 
some of their historic archives and, in particular, Dr 
Ray Robertson for sharing his knowledge of cellulose 
acetate processing and samples of material; Doug 
Nishimura and Dr James Riley at Image Permanence 
Institute, Rochester Institute of Technology for sharing 
their knowledge of cellulose acetate deterioration in 
film; and Robert Koestler (MCI) and Paula DePriest 
(MCI) for their support of modern materials research. 
Walter Hopwood (MCI) performed the Four ier 
transform infrared spectroscopy. Special thanks to the 
Kress Foundation for supporting Mary Coughlin’s 
conservation fellowship in 2005–2006 on the plastic 
survey project at NMAH, which laid the foundation and 
focus for this research.
SUPPLIERS
A-D Strips: Image Permanence Institute, Rochester Institute of 
Technology, www.imagepermanenceinstitute.org/shtml_sub/cat_
adstrips.asp (accessed 6 April 2009)
REFERENCES
 1 Coughlin, M., Preservation and Storage of Plastics, Samuel H. Kress 
Fellowship Report, Preservation Services, National Museum of 
American History, Smithsonian Institution (2006).
 2 Williams, R.S., ‘Care of plastics: Malignant plastics’, WAAC 
Newsletter 24(1) January 2002, http://palimpsest.stanford.edu/
waac/wn/wn24/wn24-1/wn24-102.html (accessed 6 October 
2008). 
 3 Meikle, J., American Plastic, Rutgers University Press, New 
Brunswick (1995).
 4 Anderson, E.H., and Thompson, C.W., ‘Plastics – a debutante 
industry’, Southern Economic Journal 17(2) (1950) 174–186.
 5 Harding, R.S., and Etu, E.S., CELLULOID Corporation Records 
(1892–1935) #9 (3 cu. ft.: 2 DB, 1 F/O), NMAH Archives 
Center.
 6 Boehmer, G.H., Celluloid – Grand Daddy of ’Em All, The 
Celluloid Corporation, Newark, New Jersey (1935).
 7 Brydson, J.A., Plastic Mater ials, 7th edn, Butterworth-
Heinemann, Oxford (1999) 613–634.
 8 Lumarith Archives, Celanese Corporation, Narrows, Virginia.
 9 Powder Diffraction File – Organic and Organometallic Phases Search 
Manual for Experimental Patterns, Sets 1–55, International Centre 
for Diffraction Data, Newton Square, PA (2005).
10 Wilson, W.K., and Forshee B.W., Preservation of Documents 
by Lamination, National Bureau of Standards Monograph, 
Government Printing Office, Washington, DC (1959).
11 Allen, N.S., Edge, M., Appleyard, J.H., Jewitt, T.S., Horie, C.V., 
and Francis, D., ‘Acid-catalysed degradation of historic cellulose 
triacetate cinematographic film: Influence of various film 
parameters’, European Polymer Journal 24(8) (1988) 707–712.
12 Shinagawa, Y., Murayama, M., and Sakaino, Y., ‘Investigation of 
the archival stability of cellulose triacetate film: The effect of 
additives to CTA support’, in Polymers in Conservation, ed. N.S. 
Allen, M. Edge and C.V. Horie, Royal Society of Chemistry, 
Cambridge (1992) 139–149.
13 Shashoua, Y.R., Inhibiting the Deterioration of Plasticized Poly 
(Vinyl Chloride): A Museum Perspective, PhD dissertation, 
Technical University of Denmark (2001).
14 Allen, N.S., ‘Action of light on dyed and pigmented polymers’, 
in Polymers in Conservation, ed. N.S. Allen, M. Edge, and C.V. 
Horie, Royal Society of Chemistry, Cambridge (1992) 193–
213.
15 Coxon, H. C., ‘Practical pitfalls in the identification of plastics’, 
in Saving the Twentieth Century: The Conservation of Modern 
Materials, ed. D.W. Grattan, Canadian Conservation Institute, 
Ottawa (1993) 395–406.
16 Quye, A., and Williamson, C., Plastics: Collecting and Conserving, 
NMS Publishing Ltd., Edinburgh, (1999).
17 Reilly, J.A., ‘Celluloid objects: Their chemistry and preservation’, 
Journal of the American Institute for Conservation, 30(2) (1991) 
145–162.
104 J.-S. TSANG, O. MADDEN, M. COUGHLIN, A. MAIORANA, J. WATSON, N. C. LITTLE AND R. J. SPEAKMAN
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AUTHORS
JIA-SUN TSANG is a senior paintings conservator at the 
Smithsonian’s Museum Conservation Institute, USA. 
She has a MS degree in art conservation from the 
Winterthur/University of Delaware (USA) program in 
art conservation and a MS degree in chemistry from 
Bowling Green State University, USA. Her research 
interests include non-destructive instrumental analysis 
and modern materials and varnishes. Address: Smithsonian 
Museum Conservation Institute (MCI), Suitland, MD, USA. 
Email: tsangj@si.edu 
ODILE MADDEN is a research scientist at the Smithsonian’s 
Museum Conservation Institute, USA. She received 
a MA degree in history of art and archaeology and a 
diploma in conservation from New York University, 
USA in 2001 and is currently completing her PhD in 
materials science and engineering at the University of 
Arizona, USA. Her research interests include technical 
art history, characterization of polymeric materials, 
challenges surrounding pesticide residues on cultural 
materials, and Raman spectroscopy. Address: as Tsang. 
Email: maddeno@si.edu
MARY COUGHLIN is an objects conservator at the 
Smithsonian’s National Museum of American History. 
She received a Samuel H. Kress Fellowship to survey 
plastic collections at NMAH after she graduated from 
the Winterthur/University of Delaware program in 
art conservation in 2005. Address: Smithsonian National 
Museum of American History (NMAH), Washington, DC, 
USA. Email: coughlinm@si.edu 
ANTHONY MAIORANA was an intern at the Smithsonian’s 
Museum Conservation Institute and is currently 
pursuing a BS degree in chemistry at the University of 
Maryland at College Park, USA. His main interests are in 
instrumental methods of analysis. Address: Department of 
Chemistry, University of Maryland, College Park, MD, USA. 
Email: maioranaa@si.edu 
JUDY WATSON is a physical scientist at the Smithsonian’s 
Museum Conservation Institute. She received a BSc 
(Hons) in archaeological science from the University 
of Bradford, UK. Her research interests include the 
use of minimally destructive analytical techniques in 
conservation. Address: as Tsang. Email: watsonj@si.edu 
NICOLE C. LITTLE is a physical scientist at the Smithsonian’s 
Museum Conservation Institute. She received MA 
and BA degrees from the University of Missouri at 
Columbia, USA. Her research interests include the use 
of XRD and LA-ICP-MS to study cultural materials. 
Address: as Tsang. Email: littlen@si.edu 
ROBERT J. SPEAKMAN is a physical scientist and head 
of technical studies at the Smithsonian’s Museum 
Conservation Institute. His research interests include the 
application of ICP-MS, XRF and neutron activation 
analysis to the study of cultural materials. Address: as 
Tsang. Email: speakmanj@si.edu 
Résumé — Les objets manufacturés en acétate de cellulose constituent un des groupes les plus problématiques de matières 
plastiques de la collection du National Museum of American History (NMAH) de la Smithsonian Institution. Afin de mieux 
comprendre la dégradation de l’acétate de cellulose, on a étudié au Museum Conservation Institute (MCI) de la Smithsonian 
Institution, par des techniques les moins invasives possibles, une trousse de représentant des ventes constituée de coupons d’acétate 
de cellulose colorés moulés par injection de marque Lumarith fabriqués au début du XXe siècle par la Celluloid Company, 
et faisant aujourd’hui partie de la collection du NMAH. La trousse comprend 49 coupons de plastique dont la couleur, la 
transparence, la composition chimique et l’état de dégradation varient. Les résultats d’analyse ont été comparés avec les documents 
de la Celluloid Company conservés au centre d’archives du NMAH et à ceux de Celanese Corporation à Narrows, en Virginie, 
afin de déterminer les causes de l’état de préservation actuel. On discute des causes possibles de la dégradation de certains 
coupons, et on propose des méthodes pour identifier les objets en acétate de cellulose à risque et pour détecter les premiers signes de 
dégradation. 
Zusammenfassung — In den Sammlungen des National Museum of American History (NMAH) des Smithonian Instituts 
stellen Objekte aus Celluloseacetat die problematischste Gruppe von Kunststoffen dar. Um den Abbau des Celluloseacetats besser 
verstehen zu können, wurde am Museum Conservation Institute (MCI) des Smithonian Instituts die Mustersammlung für 
Handlungsreisende der Marke ‘Lumarith’, bestehend aus spritzgeformten, farbigen Celluloseacetatproben mit minimalinvasiven 
Mmthoden untersucht, der im frühen 20. Jahrhundert von der Celluloid Company hergestellt worden war. Der Mustersatz 
DEGRADATION OF ‘LUMARITH’ CELLULOSE ACETATE 105
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enthält 49 Plastiktafeln, die sich in Farbe, Transparenz und chemischer Zusammensetzung unterscheiden – und heute höchst 
unterschiedlich erhalten sind. Die Analysenergebnisse wurden mit Aufzeichnungen der Celloloid Company im NMAH Archives 
Center and Celanese Corporation in Narrows, Virginia verglichen, um so den Ursachen der heutigen Zustände der einzelnen 
Proben auf den Grund zu kommen. Die möglichen Ursachen werden diskutiert. Es werden Methoden vorstellt, Objekte aus 
Celluloseacetat zu identifizieren, die mit hohem Risiko behaftet sind und frühe Anzeichen von Abbaureaktionen zu entdecken. 
Resumen — Los objetos manufacturados con acetato de celulosa constituyen uno de los grupos de plásticos más problemáticos en 
las colecciones de la Smithsonian Institution en el National Museum of American History (NMAH). Para comprender mejor la 
degradación del acetato de celulosa, un “set de muestras de vendedor” de la marca ´Lumarith´, moldeados por inyección, muestras 
de color de acetato de celulosa manufacturadas por la Celluloid Company a comienzos del siglo XX y actualmente en la colección 
del NMAH, fueron estudiadas utilizando técnicas analíticas minimamente invasivas en el Museum Conservation Institute 
(MCI) del Smithsonian Institution. El kit incluye 49 muestras que varían en color, transparencia, composición química y grado 
de degradación. El resultado de los análisis fueron comparados con los archivos de la Celluloid Company en el NMAH Center 
and Celanese Corporation en Narrows (Virginia), para determinar las causas del nivel de conservación o degradación. Las posibles 
razones de por qué algunas de las muestras se degradaron han sido sometidas a discusión, se proponen métodos para identificar los 
objetos de acetato de celulosa a riesgo de degradación y para detectar la degradación con anticipación.