Barbie Dolls Under the Microscope and FT-IR ATR: Unveiling the Secrets of Iconic Toy Degradation

Barbie dolls collection at flea market in the street © pixarno - stock.adobe.com

Since their debut in 1959, Mattel’s Barbie dolls have become cultural icons, reflecting societal trends and historical moments. Despite their popularity, these plastic toys face significant degradation over time, posing challenges for collectors and museum conservators. A recent study by researchers from various Italian institutions investigated the material composition and degradation processes of Barbie dolls produced between 1959 and 1976 (1).

The study was conducted by Andrea Macchia, Chiara Biribicchi, Camilla Zaratti, Katiuscia Testa Chiari, Martina D’Ambrosio, Denise Toscano, Francesca Caterina Izzo, and Mauro Francesco La Russa from YOCOCU, Youth in Conservation of Cultural Heritage in Rome, Italy; the University of Calabria in Rende, Italy; Sapienza University of Rome; Interventi Conservativi Storico Artistici in Sesto Calende, Italy; and Ca’ Foscari University of Venice, Italy (1).

Their research employed a multi-analytical approach to examine 15 Barbie dolls. The research aimed to bridge the information gap regarding the changes in Barbie manufacturing processes and to understand the degradation phenomena affecting these iconic toys. The study was published in the journal Polymers, showcasing a significant advancement in understanding the preservation needs of one of the world's most iconic toys.

Initially, Barbie dolls were made from plasticized polyvinyl chloride (PVC). However, over time, the migration of additives, particularly plasticizers, led to a tacky and glossy exudate on the dolls' surfaces. This study revealed that while newer Barbies are made with more stable polymers, degradation still occurs but at a slower rate. The researchers used multispectral photography in visible (vis) and ultraviolet (UV) light, microscopic observations, and Fourier transform infrared spectroscopy with attenuated total reflection (FT-IR ATR) sample presentation to analyze the constituent materials and degradation products of the dolls (1).

FT-IR ATR is employed for non-destructive analysis of polymer surfaces by utilizing an infrared beam that interacts with the sample's surface through an ATR crystal. When the infrared light is directed onto the sample, it undergoes multiple internal reflections within the crystal, penetrating only a few micrometers into the sample surface. This interaction generates an evanescent wave, which is absorbed by the sample at specific wavelengths characteristic of the sample’s molecular composition. The resulting spectrum provides detailed information about the chemical structure and composition of the polymer without causing damage to the surface, making FT-IR ATR particularly suitable for analyzing valuable or delicate artifacts like historical Barbie dolls.

Read More: FT-IR Microscopic Analysis of Polymer Laminate Samples Including Transmission and ATR Spectroscopy

The study highlighted significant changes in Barbie's material composition over the years. The early Barbies (1959-1960) were predominantly made of PVC, which suffered from additive migration. By the 1970s, the constituent materials had changed to include more stable polymers like ethylene-vinyl acetate (EVA) and acrylonitrile butadiene styrene (ABS). These changes were driven by both technological advancements and regulatory pressures, such as laws limiting plasticizer content in toys for safety reasons (1).

The research provided detailed insights into the degradation mechanisms of Barbie dolls. The migration of phthalate-based plasticizers from the bulk polymer to the surface was identified as a primary cause of deterioration. This migration leads to embrittlement and the formation of a tacky patina, detectable under VIS and UV light. The study's multi-analytical approach allowed for the identification of specific degradation products and the polymers from which they originated. Also, items like copper containing earrings catalyze further oxidation reactivity in the polymers to cause blueish green streaks in the plastic skin; furthermore a brownish coloration can also occur in those areas exposed to sunlight (2).

The findings underscore the challenges in conserving plastic artifacts like Barbie dolls. The rapid degradation of these toys highlights the need for innovative preservation strategies. Future research will focus on deeper investigations into polymeric fractions, additives, and their degradation products, with the goal of developing effective conservation methods to prevent further deterioration.

This study offers a valuable understanding of the material composition and degradation processes of Barbie dolls, providing more detailed information for collectors, conservators, and cultural heritage professionals. By unraveling the chemical secrets of these beloved toys, the researchers have laid the groundwork for better preservation techniques, ensuring that Barbie's cultural legacy endures for future generations.

References

(1) Macchia, A., Biribicchi, C.; Zaratti, C.; Testa Chiari, K.; D’Ambrosio, M.; Toscano, D.; Izzo, F.C.; La Russa, M. F. Mattel’s Barbie: Investigation of a Symbol—Analysis of Polymeric Matrices and Degradation Phenomena for Sixteen Dolls from 1959 to 1976. Polymers 2022, 14 (20), 4287. DOI: 10.3390/polym14204287

(2) Brazil, R. Saving Barbie From Her Own Inherent Vice. Chem. World 2024, 21 (5), 24–27. https://www.chemistryworld.com/features/conserving-barbie-from-degradation/4019354.article (accessed 2024-06-03).