ART CONSERVATOR
DIGITAL
A PUBLICATION OF THE WILLIAMSTOWN + ATLANTA ART CONSERVATION CENTER
VOLUME 16. NO.1 OVER
AND
UNDER
OVER AND UNDER : INVESTIGATING THORNTON DIAL'S USE OF SPLASH ZONE COMPOUND
SALLY GUNHEE KIM | POST GRADUATE FELLOW IN OBJECTS CONSERVATION
Thornton Dial (1928 –2016) was not much of a talker despite the prolific narratives behind his art. Throughout the years Dial was active, various interviews reveal a humble man who preferred to let his artwork speak for itself. Making art—whether it be a drawing, sculpture, painting, or one of his complex assemblages—was a spiritual action that formed an honest narrative for Thornton Dial’s ideas concerning the world around him. His three-dimensional assemblages mesmerize the viewer through an intricate network of found materials, things he was familiar with and could be used to illustrate his voice. The freedom he found through the use of found objects echoes in conversation with his art dealer, William Arnett:
“I like to use the stuff that I know about, stuff that I know the feel of. There’s some kind of things I always liked to make stuff with. I’m talking about tin, steel, copper, and aluminum, and also old wood, carpet, rope, old clothes, sand, rocks, wire, screen, toys, tree limbs, and roots. You could say, “If Dial see it, he know what to do with it.” —thornton dial TO WILLIAM ARNETT [1]
This freedom resulted in experimentation with a variety of materials and the use of found objects ensured that no two assemblages are alike. Surprisingly, there is one material that remained constant in most, if not all, of his assemblages: Splash Zone A-788, which has an appearance of green putty (fig.1). Unsurprisingly, it is a marine-grade epoxy that Dial would have been familiar with; both his brother, Arthur Dial and Thornton had experience with pipe fitting where the epoxy compound was frequently used to prevent or patch leaks [2].
FIGURE 1a. A sample of the green Splash Zone A-788 compound after mixing.
FIGURE 1b. An illustrated can of Splash Zone A-788 Compound Part A
The focus of this paper is to provide a comprehensive understanding of how Thornton Dial used this industrial material in his assemblages and provide results from preliminary organic analysis into Splash Zone’s chemical composition and associated methods of deterioration.
Nineteen samples from seventeen of Thornton Dial’s assemblages that were analyzed with Fourier-transform infrared spectroscopy (FT-IR) confirmed the presence of Splash Zone A-788 throughout most of his works from 1987 to 2004; twelve out of the seventeen assemblages surveyed were confirmed to contain Splash Zone A-788. Samples of fresh Splash Zone A-788 were also made, utilizing different mixing times to understand Dial’s method of application in comparison to samples taken from his artworks. The mock-up samples were attached to an uncoated wire and a PVC-coated wire to reflect the common material relationships used in Dial’s assemblages (i.e., metal and plastic objects); they were attached to a backing board similar to what Dial would have used, artificially aged, and then empirically tested for bond strength by exposing the mock-ups to a constant weight for four weeks.
The results of the analysis will be discussed in-depth to observe potential curing and deterioration reactions in Splash Zone A-788. Also, this paper will discuss the experimental parameters and results. FT-IR analysis was used to discern methods of chemical deterioration in the artificially aged samples to identify points of further research. Overall, this preliminary investigation will help inform conservation methodology for Dial’s assemblages and outline areas for additional analytical investigation.
THE GENESIS OF SPLASH ZONE AS AN INDUSTRIAL ADHESIVE
FIGURE 5. A clip from the the four-time Emmy-winning film , Mr. Thornton Has Something to Say, from Alabama Public Television. Click or tap the video clip to see Thornton Dial mix and use Splash Zone A-788 compound.
In his 30-year career, Dial was known to have used Splash Zone A-788 as an adhesive and molding material. Loose elements such as wood branches and strips of clothes in Heading for the Higher Paying Jobs are held together with green putty underneath the paint; Splash Zone was also used to build up elements of the face in the upper left portion of the composition (fig.2). The dynamic surfaces in the Driving to the End of World Series (salvaged car parts and various other metal objects) are held onto a backing support with Splash Zone (fig.3). When it is used as an adhesive, the compound often looks like pieces of aged chewing gum. Thornton Dial oftentimes covered these sculpted elements and points of attachment with paint to conceal the use of Splash Zone.
FIGURE 2. Details of the face in Heading for Higher Paying Jobs have been achieved with Splash Zone A-788
FIGURE 3. The yellow circles indicate the use of Splash Zone in detail taken from Driving to the End of the World (Silver).
The extent to which he used Splash Zone, how he applied it, and the impact it has on the stability of his artwork has not been well understood. As part of the High Museum of Art’s Bank of America-funded conservation study, examination utilizing Reflectance Transformation Imaging (RTI) and FT-IR analysis confirmed its use in twelve out of seventeen art works by Thornton Dial owned by the High Museum. As the largest public collection of Dial’s assemblages, spanning from 1987 to 2004, this finding is significant. The identification of this epoxy and the characterization of its chemical composition is important to understand both Dial’s technique and the condition of his assemblages.
As the Splash Zone A-788 has aged, several of Dial’s assemblages have displayed adhesive failure, resulting in delamination or detachment of materials (fig.4), visible with both RTI and X-radiography. The chemical composition and associated deterioration processes of Splash Zone A-788 are not well understood, so analysis of this material forms an integral part of the museum’s focus on the preservation and understanding of Thornton Dial’s assemblages.
FIGURE 4. The highlighted areas in Driving to the End of the World (Gold) indicate the use of Splash Zone Compound "over and under" the objects that were attached to the backing board. Several areas of adhesion are failing where Splash Zone has been attached to the cloth clad backing board or used when attaching heavy metal objects.
Characteristics of Underwater Epoxies
The information on the chemical composition of Splash Zone A-788 is provided in the safety data sheets by Kop-Coat, INC/Pettit Marine Paint®. The epoxy resin comes in two parts: A and B.
• Part A is a yellow resin that contains Bisphenol-A-(epichlorhydrin) epoxy resin and fillers.
• Part B is a hardener composed of polymers of c-18 unsaturated fatty acid dimers, triethylenetetramine (TETA),
2,4,6-tris(dimethylaminomethyl)phenol and talc. The hardener is colored with carbon black pigment. The two parts are mixed in a 1:1 ratio by volume, turning into a green putty (fig.6, video clip). The putty then dries to a hard, abrasion- and impact-resistant product that provides protection against corrosion, erosion and deterioration of metals, woods and concrete.
2,4,6-tris(dimethylaminomethyl)phenol and talc. The hardener is colored with carbon black pigment. The two parts are mixed in a 1:1 ratio by volume, turning into a green putty (fig.6, video clip). The putty then dries to a hard, abrasion- and impact-resistant product that provides protection against corrosion, erosion and deterioration of metals, woods and concrete.
FIGURE 6. Sally Kim mixes Splash A-788 Compound parts A and B. Click or tap the video clip to see Sally demonstrate how to mix Splash Zone A-788 compound. (video credit: Lila Reid)
The unique feature of Splash Zone A-788 is that it can be both applied and cured underwater. In general, the main challenge of marine epoxies lies in trying to achieve high adhesive force that can replace absorbed water layers on the substrate’s surface. For this reason, the key ingredient in the Splash Zone A-788 is triethylenetetramine (TETA), which is used as a cost-effective, low temperature curing agent for epoxides [3].
In addition to the TETA, other ingredients in Splash Zone A-788 play important roles in making it useable and popular in marine industries (table 1,2). For example, despite its advantages, TETA on its own is slow at opening epoxide rings in the reaction product of bisphenol-A-(epichlorhyrin) epoxy resin from part A. So, 2,4,6 tris(dimethylaminomethyl)phenol from part B is added to help accelerate the reaction with its own reactive alcohol groups.
The information provided on the safety data sheets clarifies the roles of the key ingredients in part A and B of Splash Zone A-788 and characterizes the product as a polyamide epoxy. Furthermore, this information will help identify the chemical components in mixed epoxy putty samples taken from Dial’s assemblages and explain the curing and deterioration reactions observed in the FT-IR spectra.
TABLE 1. The chemical ingredients in Splash Zone A-788 part A
TABLE 2. The chemical ingredients in Splash Zone A-788 part B
Thornton Dial’s Use of Splash Zone Compound
FIGURE 7. In Crossing Waters (2006-2011), Thornton Dial has used Splash Zone to adhere various objects such as the shoe (shown left), conceal nails, and model plywood. The paint and matrix of objects conceal its use.
“The piece going to have Mr. Dial in it, under it, and over it, and everybody can know it.”
—thornton dial TO WILLIAM ARNETT [4]
The presence of Splash Zone A-788 in twelve of Dial's works was confirmed by detection of the ingredients listed in the safety data sheet for Splash Zone A-788 with FT-IR. This technique was used to analyze nineteen fragment samples from his assemblages at the High Museum of Art; the analyses confirmed the presence of Bisphenol-A-(epichlorhydrin) epoxy resin, TETA, 2,4,6-tris(dimethylaminomethyl)phenol, and fillers in all nineteen samples (figs.8-9). This observation signifies that Dial used Splash Zone A-788 in his assemblages made between 1987 and 2004.
FIGURE 8. Spectrum of a Splash Zone A-788 sample from Dial’s latest work, Driving to the End of the World: Gold (2004)
FIGURE 9. Identification of the yellow component in Splash Zone A-788 sample as Bisphenol-A-(epichlorhydrin) epoxy resin
Dial professed that he used materials that he was familiar with and knew how to fix: how did Thornton Dial come across an industrial material like Splash Zone A-788? The answer was provided by Lonnie Holley, a celebrated artist that befriend Dial in the late 1980s. Lonnie mentions that it came from a conversation with his younger brother, Arthur Dial [5]. Like Thornton Dial, Arthur was an artist working with found objects and also borrowed techniques from the industries in which he was a skilled craftsman. Arthur had 37-years of experience working for (Alabama) and the “Pipe Shop” (i.e., the U.S. Pipe company) [6] whom Thornton Dial also worked; the genesis of Dial’s use of Splash Zone A-788 is suggested by these known relationships and consistency in his working methods. However, how he mixed the two-part epoxy and applied it in his assemblages remains unknown. Therefore, Dial’s methodology for working with Splash Zone A-7888 and its impact on his artwork prompted analysis of samples from both his assemblages and mock-ups using the same material at various cure times.
INVESTIGATING DIAL’S METHOD OF MIXING AND APPLYING SPLASH ZONE A-788
FIGURE 10. In the 2007 documentary, Mr. Dial Has Something to Say, Thornton Dial mixes the Splash Zone A-788 with a bucket of water.
FIGURE 11. In the 2007 documentary, Mr. Dial Has Something to Say, we can see Dial's process of kneading the two components in Splash Zone A-788
To analyze Splash Zone’s working properties in relation to Dial’s artistic style, fresh batches of Splash Zone A-788 were requested from the original manufacturer of the material in Dial’s times: Kop-Coat, INC/Pettit Marine Paint®.
Splash Zone A-788 has a working period of two hours and cures in six hours at 75°F. As a marine-grade epoxy compound, it is recommended to mix the components in water. The mixture was prepared with a bucket of tap water at a temperature of 62.6°F (fig. 12); each mixture was kneaded thoroughly to ensure that there were no yellow or black streaks.
The epoxy cures rapidly at a temperature above 80°F, as evidenced by its hardening at around 90 minutes after mixture. Throughout the process of sample preparation, the working properties of Splash Zone were recorded at six different time intervals. It was observed that the epoxy putty had optimal molding properties when it was left alone for an hour; in that timeframe, the epoxy was kneadable and left little residue on the hands, with or without gloves dampened with water, as observed in the table below (table 3):
FIGURE 12. Sally Kim kneads Splash Zone components A and B
TABLE 3. Changes in working properties of Splash Zone A-788 over the course of two hours
While optimal working properties were achieved after one hour, Splash Zone A-788 became crumbly and was difficult to manipulate immediately after ninety minutes. This indicates a practical working time of about thirty minutes to an hour; a half-hour is not a long time and neither is an hour when considering the complexity of Dial’s assemblages. It is thus hypothesized that Dial manipulated Splash Zone beyond its optimal working time.
It was interesting to note that various mixtures of yellow, black and green parts (respectively part A, part B and mixed portions of the epoxy resin) were observed in the samples taken from Thornton Dial’s assemblages. In other words, both cured and uncured components were found in Dial’s samples. In addition to the length of working time, the remaining, uncured parts of the epoxy may also have had an impact on the aging of this material as an adhesive and molding material.
EFFECT OF WORKING AND MIXING TIMES ON THE ADHESIVE FAILURE
Sample Preparation
The most common backing boards and primary materials were surveyed from the nineteen assemblages at the High Museum of Art. There was a consistency in the backing boards that Dial used to apply Splash Zone A-788, that is, a plywood board with canvas over it. Additionally, the most common material relationships observed in Dial’s works were between Splash Zone and either plastic or metals. Therefore, this paper prioritizes the investigation of these materials.
A backing board used by Dial was simulated with a 4” x 8” unprimed plywood frame with ¾”-deep cradle, covered with raw, unprimed canvas fabric held in place with zinc-plated steel staples. To reflect the two main material relationships from the survey, two different metals were used (fig.13):
• Splash Zone to Metal Bond: Mild steel wire (diameter of 1/16”; dark gray; matte), with the average length of 1 2/5” ± 1/25
• Splash Zone to Plastic Bond: Mild steel wire coated with PVC (diameter of 1/16”; black) with the average length of 1 1/5” ± 1/25
FIGURE 13. Balls of Splash Zone A-788 attaching two kinds of wires to the prepared, simulated back boards
Splash Zone A-788 was rolled into tiny balls with a diameter of 1” ± 1/8, and applied to the wires and backing boards with gentle, constant pressure of index and middle fingers at six different time intervals in the time frame of two hours: 0 minutes, 30 minutes, 60 minutes, 90 minutes and 110 minutes after mixing. The room in which the samples were prepared had a temperature range of 79 +/- 1°F and relative humidity of 30%, which best simulated the average climate in Alabama, where Dial lived and worked.
Each mock-up backing board contained samples from the five different mixing times; a sample from each mixing time was attached to either the uncoated or plastic-covered wire. This resulted in ten samples per board (fig.13). A total of 24 test boards were made, resulting in a total of 240 Splash Zone samples. Then, the 24 test boards were divided into two sets of twelve boards each (fig.14). One set was artificially aged for a period of four weeks (14 December - 11 January); the other set would be tested without aging.
FIGURE 14. A set of artificially aged twelve mock-ups
Environmental chambers were not available in the building, so one set of twelve mock-ups were placed indoors and outdoors at scheduled hours to subject the samples to two extreme environmental conditions:
• Highest temperature & Lowest relative humidity: 91.0°F (32.8°C), 31% RH for 15 hours
• Lowest temperature & Highest relative humidity: 16.0°F (- 8.9°C), 91% RH for 9 hours
It was proposed that the large fluctuations in temperature and humidity each day would help accelerate the samples’ aging. The aging effects on the Splash Zone A-788 was immediately evident (fig.15). There were visual alterations as it shrank, became more yellowed, and cracked.
FIGURE 15. Comparison of Splash Zone A-788 samples before and after artificial aging (credit: Matt Hamilton)
All of the mock-ups were attached to a DIBOND® aluminum composite sheet as a backing, before placing a bag of lead weighing an average of 300.01g on aged and non-aged samples over four weeks (fig. 16). The size of the weight was a practical choice and chosen to reflect the relative weight of a small found object used in one of Dial’s assemblages. The samples were checked for failures between the backing board, Splash Zone A-788, and either metal or plastic wire (fig.17).
FIGURE 16. Weights placed on each Splash Zone A-788 sample attaching a wire to the backing board
FIGURE 17. Checking for failures between the backing board, Splash Zone A-788, and either metal or plastic wire
Results + Discussion
It is possible that Dial forcefully pressed cured Splash Zone A-788 to the backing boards even when it had largely lost its adhesive properties. It can be observed from X-radiographs that Dial continued working with Splash Zone even when it was curing, as evidenced by internal cracks and stresses in the molded areas (fig. 18). The cracks in Dial’s assemblages are similar to the external and internal cracks observed in the Splash Zone samples that were pressed to the backing boards to hold the wires in place after sitting for at least 60 minutes after mixture.
FIGURE 18. The red circles indicate cracked Splash Zone A-788 in an X-radiograph of Heckle and Jeckle: Pleasure for the People (credit: Matthew Hamilton)
There are large areas of overlap between adhering time lengths (approximated bond strength) of aged and non-aged samples (fig.19). This suggests that that there is not much difference between the quality of adhesion between the aged and non-aged samples over time. Overall, the wires wrapped with PVC did not remain well-adhered to the aged Splash Zone samples. Where there had been failures in the joinery, uncoated steel wires remain embedded in Splash Zone samples. This demonstrates that Splash Zone works well on metals but not on plastics, such as PVC. This would explain why adhesion is failing between the epoxy and PVC-covered materials in Dial’s assemblages; for example, electrical cording and PVC wheels in Thornton Dial’s Driving to the End of the World (Gold) exhibit failure between the plastic surface and Splash Zone A-788.
FIGURE 19. Chart on the bond strength and join failure of Splash Zone A-788 in the mock-ups. Please note that, the latter two sets of tests on both aged and non-aged samples remained well-adhered to the backing support past the timeframe of the experiment, so these data sets were not included in the chart. Whiskers here represent ranges.
DETERIORATION REACTION OF SPLASH ZONE A-788 COMPOUND IN DIAL’S ASSEMBLAGES
FIGURE 20. FT-IR spectra of the Splash Zone A-788 sampled from four of Dial’s assemblages
Over time, the characteristic peaks of Splash Zone A-788 becoming sharper or shallower in the spectra illustrate chemical reactions happening in the epoxy as it deteriorates for two decades:
1. Change in the alcohol group at 3000 – 3700 cm-1 (chemical formula: R–O–H): In this stretch, the “trough” becomes shallower with older samples. This indicates that over time and with exposure to air and light, the content of alcohol groups in Splash Zone A-788 is decreasing. These groups are oxidizing into ketone (chemical formula: R=O) or carboxylic (chemical formula: R–OOH) functional groups. (fig. 21).
FIGURE 21. Oxidation reaction for alcohol functional groups
2. Change in the C – H sp3 stretch at 2800-3000 cm-1: This stretch becomes less sharp with older samples [7]. Splash Zone A-788, when freshly mixed, becomes harder because of cross-linking in its backbone [8]. The decrease in the C-H sp3 peaks demonstrates that a chain scission is occurring, resulting in Splash Zone A-788 becoming brittle (fig.22). By comparison, the peak of double bonded carbons (alkene groups; chemical formula: C=C) stretch is becoming sharper and more defined at 1700 cm-1 with older samples. It is possible that the single-bonded carbons form a double bond during chain scission, and therefore and break away from the backbone (fig. 22) [9].
FIGURE 22. Chain Scission and cross linking reactions
3. Change in ketone and carboxylic groups at 1700-1725 cm-1 (chemical formula: C=O and COOH, respectively): These stretches become more pronounced with older samples. This supports that the decrease in alcohol functional groups at 3000 – 3700 cm-1 are being oxidized to ketone and carboxylic groups.
4. Change in primary amine groups at 1020-665 cm-1 (chemical formula: C–N): The stretch for this group become less pronounced with older samples [10]. Amine groups are important for the curing of epoxy putties. In this case, part B of Splash Zone A-788 contains TETA, an amine-based curing agent. So, when the two parts of the product is mixed, the content of amine groups will be prevalent in the newer samples. As the mixed Splash Zone cures over time, primary amine groups become less present in older samples, hence less-pronounced in the spectra of older samples.
Cured epoxy compounds, in general, are known to degrade through the types of oxidation and chain-scission reactions described above [11]. Thornton Dial’s technique of mixing the epoxy affects how much uncured resin remains in the mixture after it cross-links and hardens. The amount of uncured epoxy resin detected in most of Dial’s assemblages is of concern. Over time, phenolic hydroxyl groups of the uncured components of Splash Zone A-788 part A will no longer be able to react with the amine from part B and may become polymerized by the “etherification” (fig.23) [12]. Many alcohol groups (chemical formula: R–O–H) previously available in part A for crosslinking with amine groups in part B will not react together to cure but become converted to ether groups (R–O–R”), thus affecting physical stability of the epoxy. Also, the shelf life of the individual Splash Zone components is limited to 24 months at 75°F; if parts A and B are used past this date, the putty will not cure properly. If Dial used old cans of Splash Zone, this could have an impact on the structural integrity of the epoxy putty as an adhesive and molding material.
FIGURE 23. Etherification reaction
cONCLUSION
The experiment of mock-ups, while empirical, helped demonstrate that Splash Zone A-788 fails in both aged and unaged samples if used at the end of its working time frame. This may explain the reason why some areas of Splash Zone failed in Dial’s assemblages: Dial applied them past their “working time frame” of 60 minutes. This preliminary research also confirmed the physical stability between metallic surfaces and Splash Zone Compound. Most structural failures between Splash Zone and metal elements in Dial’s assemblages occurred because the metal itself had previous corrosion. If Splash Zone is applied on clean, degreased metal, it adheres well for both aged and non-aged samples; however, it does not adhere well to plastic. The failure of joinery between Splash Zone and PVC, while observed, was not explored in depth. Additional interactions between the epoxy putty and various types of plastics should be investigated. For example, investigations between Splash Zone and raw wood would also be of interest; while not common, some of his backing boards are raw wood without canvas covers.
Overall, the analyses into the physical properties of Splash Zone A-788, supplemented by FT-IR analyses on its four deterioration reactions, offer insight into the stability of this material that was predominantly part of Dial’s fascinating working style. While helpful, these preliminary investigations are just the beginning to understanding the ramifications of Thornton Dial’s unique working materials and techniques. Relationships between Splash Zone and several of the materials Dial used have yet to be researched in-depth. Further investigation into material relationships and deterioration mechanisms of both cured and uncured samples of Splash Zone should be investigated further. Testing the tensile strength of Splash Zone and determining its Transition Glass Phase Temperature would be beneficial in defining preventative care parameters for transportation, storage, and display. Most importantly, by improving our understanding of Splash Zone A-788, we will be able to conserve structural integrity in Dial’s works.
Acknowledgement
Funding for the conservation of this artwork was generously provided through a grant from the Bank of America Art Conservation Project. I would like to express my thanks and gratitude to Hélène Woodard-Gillette for encouraging me to research the topic of Splash Zone A-788 during my postgraduate fellowship at WACC. I would also like to thank Christine Puza for her help in obtaining liquid nitrogen needed for data collection with FT-IR and Matthew Hamilton for his photography. Finally, my special thanks go to Maggie Barkovic for her excellent, magical editing skills.
Photography Credit | Sally Gunhee Kim, Matt Hamilton, Lila Reid, Kristen Gilette, Maggie Barkovic, & the High Museum of Art
REFERENCES
[1] Souls Grown Deep Foundation. “Thornton Dial: Taken from interviews with Thornton Dial by William Arnett in 1995 and 1996.”, soulsgrowndeep.org, www.soulsgrowndeep.org/artists/thornton-dial. Accessed 14 Sept 2021.
[2] Jentleson, Dr. Katherine. Interview. By Maggie Barkovic. 17 Sept. 2021. .
[3] Shukla, V., Bajpai, M. and Habib, F., “Mannich Base: a cost effective, low temperature curing agent for epoxides,” In Pigment & Resin Technology, Vol. 36 (3): 169-171. DOI: 10.1108/03699420710749036
[4] Souls Grown Deep Foundation. “Thornton Dial: Taken from interviews with Thornton Dial by William Arnett in 1995 and 1996.”, soulsgrowndeep.org, www.soulsgrowndeep.org/artists/thornton-dial. Accessed 14 Sept 2021.
[5] Jentleson, Dr. Katherine. Interview. By Maggie Barkovic. 17 Sept. 2021. .
[6] Souls Grown Deep Foundation. “Thornton Dial: Taken from interviews with Thornton Dial by William Arnett in 1995 and 1996.”, soulsgrowndeep.org, www.soulsgrowndeep.org/artists/thornton-dial. Accessed 14 Sept 2021.
[7] “sp3” is a classification that a hydrogen atom is attached to a carbon atom with a single bond to the neighboring atom.
[8] Cross-linking is a chemical reaction where a molecule that contains two or more reactive ends attaches to specific functional groups in other molecules
[9] Chain scission is a reaction where the molecular chain is broken at random points in its backbone to form two or more molecular fragments
[10] The term, “primary”, is a classification of different C–N bonds that a carbon and a nitrogen have a single bond between them, not a triple bond like nitrile groups; in short, “primary” is similar to “sp3” for C–H bonds.
[11] Mailhot-Jensen, Bénédicte, Sandrine Therias, and Jean-Luc Gardette. (2005). “Study of the degradation of an epoxy/amine resin. Part 1: Photo- and thermo-chemical mechanisms.” In Macromolecular Chemistry and Physics 206: p.575-584. DOI: 10.1002/macp.200400395.
[12] Pethrick, Richard A. (2015). “Design and ageing of adhesives for structural adhesive bonding – A review.” In Journal of Materials: Design and Applications 229 (5): p.349 – 379. DOI: 10.1177/1464420714522981.
[13] Gillette-Woodard, Hélène, Gillette, Kristen, Gunhee Kim, Sally and Puza, Christine; Thornton dial: an examination of 17 assemblages and 1 sculpture at the High Museum of Art. Bank of America Conservation Grant, April 2021.