Non-destructive Analyses of 16th Century Printed Book "Osorio" with the Colorful Fore-edge Miniatures

In our study we are trying to illuminate the palette used by the artist who decorated the fore-edge of the Middle Age printed book description of the military campaign of the Spanish king Emanuel Hieronymus Osorio and try to give a temporal boundary on the moment of their creation. Our experiments show that a pigment palette is a common one for the period between 16th and 19th century. Several pigments were identified, like vermilion and minium, white lead and massicot. Further, we identified the ink used for the book cover inscriptions. Three complementary, non-invasive spectroscopic techniques were used: micro-Raman spectroscopy, PIXE spectroscopy and UV-VIS FORS spectroscopy. The challenges which occurred during the study are presented, such as the positioning of the book underneath the microscope or even the fiber optic probe holder, the roughness of the fore-edge surface and the thinness of the color layers.(doi: 10.5562/cca2040

X-ray fluorescence applied to yellow pigments based on lead, tin and antimony: comparison of laboratory and portable instrumentation

X-ray fluorescence is a diagnostic approach particularly suited to be utilized in cultural heritage sector since it falls in the non-destructive and non-invasive analytical tools. However there are big differences between portable and laboratory instrumentation that make difficult to perform a comparison in terms of quality and reliability of the results. The present study is specifically addressed to investigate these differences in respect of the same analytical sample-set. To reach this goal a comparison was thus carried out between portable and bench top devices X-ray fluorescence devices and techniques were used on different type of yellow pigments based on lead, tin and antimony obtained in laboratory, reproducing the instructions described in “old” recipes, that is: i) mortar of lead and tin produced on the basis of the recipe 13 /c V of the “Manuscript of Danzica” and “ Li tre libri dell’arte del Vasaio” by Cipriano Piccolpasso; ii) two types of lead and tin yellow (Pb2SnO4 and PbSnO3) produced starting from the indications of the 272 and 273 recipes of the “Bolognese Manuscript”; iii) lead antimonate (Pb2Sb2O7) obtained by following the instructions of the Piccolpasso’s treatise and those contained on the “Istoria delle pitture in maiolica fatte in Pesaro e ne’ luoghi circonvicini di Giambattista Passeri” and finally iv) lead, tin and antimony yellow (Pb2SnSbO6,5) obtained starting from the information contained in the paper 30 R of “Manuscript of Danzica” [1]. The XRF analysis were performed using a laboratory instrumentation (Bruker M4 Tornado) and a handset analytical device (Assing Surface Monitor). In order to perform a significant statistical comparison among acquired and processed data, all the analyses have been carried out utilizing the same sample, the same acquisition set up and operative conditions. A chemometric approach, based on the utilization of Principal Component Analysis (PCA) and multivariate analytical based tools [2], was utilized in order to verify the spectral differences, and related informative content, among the different produced yellow pigments. The multivariate approach on the results revealed instrumental differences between the two systems and allowed to compare the common characteristics of the set of pigments analyzed

POISONS IN THE BASEMENT: AN ANALYSIS OF X-RAY FLUORESCENCE TESTS FOR HEAVY METAL PESTICIDES IN THE UNIVERSITY OF MONTANA’S ETHNOGRAPHIC COLLECTION

This thesis focuses on the X-Ray Fluorescence (XRF) testing that was performed on the University of Montana’s (UM) ethnographic collection. This collection is housed in a repository in the UM Anthropological Curation Facility (UMACF). The main concern over the artifacts and the reason behind the decision to perform such testing was to determine if any hazardous pesticides were used as part of past conservation treatments on the collection over the course of its history at the University of Montana. The XRF tests were performed during the winter of 2011-2012 on over 350 artifacts. The results had been previously unanalyzed. The result of the scanning yielded 844 graphs showing the levels of nine different heavy metals and elements. These elements included arsenic, lead, mercury, bromine, barium, selenium, cadmium, chromium, and antimony, all of which can be hazardous to humans who may interact with the artifacts. Further, the presence of some of these elements, such as bromine, may indicate that items were treated with pesticides. A sample of 131 of the artifacts and 258 of the test results showed high concentrations of arsenic, lead, and antimony on a majority of the artifacts. The cause of the readings could be from a variety of means ranging from the manufacturing process of the items, environmental influences, or pesticide dust from a previous application. The pesticide lead arsenate, however, uses all three of the metals, lead, arsenic, and antimony. The presence of these three metals and the high correlation between the concentration of lead and the concentration of arsenic could be indicators that this pesticide was used in the collection. The conclusion of the testing showed that although these elements may be detected on the artifact, the results of XRF testing are inconclusive. XRF can provide researchers with the information that the element is present but lacks any method to explain the reason behind it. Further tests at the UMACF could prove vital in explaining these results. Until these additional tests are complete, caution, such as using nitrile gloves and respirators should be used in the collection when handling the artifacts

Colour and light in the seventeenth-century churches of Arbanassi, Bulgaria

This thesis evaluates the use of colour and light in four seventeenth-century church interiors in Arbanassi, Bulgaria. The aim is to elucidate the appearance of the wall paintings in these churches in the context of the specific use of colour and in the lighting conditions pertaining when they were painted. The investigation both uses existing methods and also creates new scientifically-based ones to address questions concerning the extent to which colour and light were intentionally employed in ways evidenced by common patterns. The underlying hypothesis is that the decoration can be asserted as an embodiment of the ways colour and light were employed in Eastern Church decoration at that period in the Bulgarian province of the Ottoman Empire. In all the churches examined the artists used palettes restricted to a small but constant number of hues. I discuss how they used light and colour contrast to manipulate the appearance of the images. As present the interiors are lit by electric light. The investigation into the interior lighting reveals that the natural lighting is of an even but low intensity, allowing the artificial lighting to dominate. I devised a methodology to assess the effect of the original interior illumination on the appearance of the naves in the con-text of Professor Chalmers and others in the computer reconstruction of historic sites under their original illumination. By departing from conventional art-historical assessments, without merely accumulating technical data, my research challenges previously accepted presumptions and offers a means of revealing the optical complexity of the interiors. While this provides increased knowledge and understanding of the visual practices employed by the artists, the wider significance of this thesis lies in the way it bridges the existing division between science and the humanities and in its development of new methods for art historical research

La tinta de escritura en los manuscritos de archivo valencianos, 1250-1600. Análisis, identificación de componentes y valoración de su estado de conservación

La significativa aportación tanto artística como documental de los manuscritos hace de ellos instrumentos únicos de conocimiento que debemos custodiar y proteger. Bibliotecas y archivos de muy diversa índole atesoran cuantiosos códices con el mayor celo posible, pero los materiales inherentes a su elaboración y las condiciones en las que han estado almacenados durante siglos los hacen vulnerables a importantes procesos de deterioro. Las tintas metalogálicas, ya conocidas desde la Antigüedad, suponen el sustrato más habitual de la escritura en la cultura occidental desde el Medievo hasta el siglo XX. Ya desde el siglo XVII tenemos evidencias de la preocupación por los graves problemas de oxidación que las degradan y que pueden provocar la perforación del soporte escriptorio e incluso fragmentar la caja de escritura hasta hacerla desaparecer. Los archivos valencianos conservan, por fortuna, numerosos fondos documentales desde el período posterior a la Conquista -incluso anteriores en algunos casos-, pero los de la etapa comprendida entre 1450 y 1600 destacan por un estado de conservación más deficiente de sus manuscritos. Por este motivo, la línea de investigación de esta tesis se dirige a profundizar en el conocimiento de las tintas valencianas y la caracterización de sus componentes en relación con su preservación. Lo hacemos desde cuatro puntos de vista diferentes: la recopilación y examen de recetas antiguas a partir de fuentes escritas, la experimentación práctica de su elaboración, el análisis físico-químico de muestras originales de tintas valencianas anteriores a 1600 y el estudio de los escribanos y el mundo de la escritura a partir de las representaciones artísticas. La conservación y restauración del patrimonio histórico ha adquirido, con los años, una naturaleza cada vez más científica. Actualmente no concebimos una intervención rigurosa en una pieza sin someterla previamente a una exhaustiva investigación de sus componentes y problemas de alteración, con el apoyo de sistemas de análisis científicos muy diversos. Pero ciertas carencias de formación científica separan en ocasiones a los técnicos del campo de la restauración de otros profesionales específicos (químicos, biólogos, físicos) que a su vez tienden a desaprovechar la información de fuentes historiográficas. Trabajos como la presente tesis pretenden facilitar y promover la conexión entre ambas formas de acercarse al patrimonio histórico, para que los distintos profesionales que hoy en día se implican en tareas de conservación de manuscritos puedan ampliar sus criterios ante una intervención en un bien patrimonial. Conviene destacar que nos preceden estudios similares en el campo de las tintas metalogálicas. El primero es el de Jana Kolar, quien analizó tintas de noventa y siete documentos para su tesis doctoral. Su labor ha supuesto el punto de partida de muchos trabajos posteriores, y constituye una referencia fundamental para todos ellos desde la escuela holandesa que desarrolló. Otro trabajo paralelo y similar en su planteamiento es el que ha desarrollado un equipo mexicano y norteamericano sobre las tintas del Archivo Nacional de México, donde se han seleccionado dos mil treinta y dos documentos, aunque su estudio se ha centrado en el análisis de los componentes inorgánicos con fluorescencia de rayos X, que no necesita toma de muestras. Nuestro trabajo, aunque con menor número de tintas estudiadas -novecientas ochenta y nueve-, quiere diferenciarse de los demás por intentar ampliar el ámbito de la investigación y sumar a los datos que nos aporta la ciencia, la importancia de las fuentes documentales escritas e iconográficas. En primer lugar ofrecemos un panorama de las fuentes documentales primarias y secundarias que nos ha servido para el conocimiento fundamental de las recetas, sus componentes y sus métodos de elaboración. Entre las primarias destacamos dieciséis recetas inéditas que muy generosamente nos han cedido archiveros, bibliotecarios y amigos para esta investigación y que revelan algunos aspectos desconocidos. Sobre las fuentes secundarias, se ha efectuado un recorrido por la historia de estas tintas a través de libros de secretos, tratados, recetarios y manuales del arte de escribir y a partir de ellas se ha realizado una recopilación de ciento sesenta recetas publicadas en diversas fuentes y épocas, referidas a los reinos hispánicos y andalusíes. Las conclusiones que hemos podido extraer resultan fundamentales para poder conocer los ingredientes, su evolución, y los procesos de fabricación. Antes de seleccionar el sistema de análisis científico con el que estudiar las muestras de tintas valencianas recopilamos más de cuatrocientos artículos referidos al estudio de libros y documentos. Su lectura nos ha permitido obtener un panorama bastante amplio de las posibilidades de cada sistema, que hemos procurado organizar conforme a sus características y posibilidades. Esperamos que constituya una guía eficaz para quienes deseen realizar estudios científicos del patrimonio librario y documental. Las aportaciones que ofrecían las recetas procedentes de las fuentes escritas nos permitieron experimentar con la reproducción de algunas de ellas, lo que ha supuesto, sin duda, un punto necesario y de sustento para la comprensión del trabajo. Conocer los componentes de primera mano, aplicar los procesos y ver las reacciones en directo nos ha enseñado el fundamento de las tintas. Además, poder analizar cada uno de los ingredientes por separado y las tintas resultantes, -por sí solas y sobre papel- ha ampliado el conocimiento que teníamos de los materiales y los procesos de elaboración; incluso hemos descubierto procedimientos que se daban por supuestos en la bibliografía y se han revelado como imposibles. Respecto al sistema de análisis seleccionado, quizá había otros más precisos como el PIXE, o en los que no era necesaria la toma de muestras, pero optamos por las facilidades que nos ofrecía el laboratorio de materiales del IVC+R CulturArts, y la disponibilidad del microscopio electrónico de barrido acoplado a un equipo de dispersión de rayos X (SEM-EDX). Con este sistema se hace necesaria la recogida in situ de micromuestras, pero a cambio nos permite analizarlas posteriormente en el laboratorio de dicho instituto. Además, este sistema de análisis es capaz de detectar la concentración de elementos inorgánicos con amplia fiabilidad e incluso ofreciendo una semicuantificación que resultaba útil a nuestro objetivo de estudio. Por otro lado, se hacía necesario un estudio en detalle de los componentes fundamentales de las tintas. Hemos podido localizar diferentes tipos de agallas que, además, citan las fuentes; hemos tratado de investigar sobre los sulfatos metálicos y la disponibilidad que había de ellos en la Comunidad Valenciana y, a través del comercio, fuera de nuestras fronteras; así como sobre todos los componentes que se nombran en la relación de recetas que adjuntamos en una tabla como anexo. Con el objeto de completar el estudio hemos considerado estas recetas para hacer un desarrollo justificado de la evolución de las mismas en el tiempo y establecer, si cabe, enlaces territoriales. Hemos comparado aquellas recetas que tienen valores de medida reconocibles y extrapolables a unas proporciones con el fin de comprobar si existía una correlación con el resultado de los análisis de las muestras valencianas. Dado que uno de los objetivos principales consiste en hallar una posible relación entre la presencia de elementos inorgánicos y el estado de conservación de los documentos, hemos dedicado un capítulo a la química de las tintas, donde se revelan los problemas de conservación, la tipología de daños que durante nuestra experiencia laboral hemos localizado, y el estado de la cuestión sobre la resolución de estos problemas de conservación. La aplicación de diversos estudios estadísticos y los diferentes enfoques que se pueden obtener de los datos han dado como resultado un capítulo muy amplio en el que se analiza la presencia de los elementos principales -como el hierro, responsable en gran medida de los procesos de oxidación-, así como la relación entre algunos de ellos, como el calcio-hierro, potasio-hierro y el cobre-zinc, ya que pensamos que son los más influyentes. El trabajo se ha enfocado en función de la datación y de la procedencia (archivo) con el fin de ver si se pueden establecer relaciones y paralelismos con estos parámetros. Además, hemos completado el estudio de los elementos con la relación que tienen dependiendo el estado de conservación de las tintas de las muestras obtenidas -en el que anotábamos si estaban en una fase final de perforación del soporte. Con otro sistema estadístico se ha estudiado la probabilidad de cada uno de ellos de influir en el deterioro de las tintas y, a pesar de las limitaciones descritas por el ámbito de estudio y la aplicación del método, hemos obtenido resultados sorprendentes que no habíamos detectado en la bibliografía específica. Por otro lado trabajamos sobre el solvente utilizado, ya que la dicotomía agua/vino ha sido una constante, pero ha variado su elección en función, sobre todo, de la datación, porque, tal como documentan las recetas, desde antiguo los escribanos observaron el deterioro de las tintas y algunos achacaron estos avance a la oxidación al vino blanco empleado. El aspecto artístico de algunos códices iluminados nos ha resultado de gran ayuda: estudiar los instrumentos de escritura y el entorno de los escribanos a través de los autorretratos y otras representaciones en las que aparecen en actitud de escribir. Dada la proliferación de estas imágenes en los manuscritos medievales, hemos propuesto una cierta clasificación de este tipo de escenas, con los ejemplos más sobresalientes que hemos podido localizar. No son desdeñables otro tipo de imágenes espontáneas que los notarios realizaban en sus escritos con el fin de probar la pluma -provationes calami- o, simplemente, desarrollar otra forma de expresión.The meaningful contribution of manuscripts, both artistic and documentary, renders them a valuable source of knowledge that must be guarded and protected. Even with the various efforts made by libraries and archives of different nature to upkeep their respective collections of manuscripts, the materials inherent to their fabrication and the conditions under which they have been stored for Centuries make them vulnerable to significant deterioration processes. Metal-gall ink, known since ancient times, is the most common medium for writing in Western culture since the Middle Ages up until the 20th Century. Already in the 17th Century, we find evidence of preoccupation about oxidation causing the degradation of the ink and the perforation of the writing support, fragmenting even the letter page until it disappears. Fortunately, The Valencian Archives conserve numerous documentary sources dating from the period after the Conquest (even prior in some cases), but those from the period between 1450 and 1600 stand out as the manuscripts with the poorest state of conservation. For this reason, the line of research of this doctoral thesis is to deepen the knowledge of Valencian inks and the characterisation of their components in relation to their preservation. We do so from 4 different points of view: the collection and analysis of all recipes from various writing sources, the practical experimentation during the preparation process, the physical and chemical analysis of original samples of Valencian ink prior to 1600 and the study of the world of scribes and handwriting based on artistic representations. The conservation and restoration of historical heritage have acquired a more scientific approach over the years. Today, any rigorous analysis on a piece cannot be conceived without previously performing a thorough research of its components and preservation problems by using diverse systems of scientific analysis. However, insufficient scientific expertise creates a breach between the technicians in the field of restoration and other specialized professionals (chemists, biologists, and physicists) who, on their side, tend to not take profit in the information from historiographical sources. Research studies like this thesis intend to facilitate and promote the connection between these two approaches to analysing historical heritage; this way, the different professionals that are nowadays involved in manuscript conservation related activities can improve their criteria when doing an intervention on a heritage good. It is important to underline that other similar studies precede this analysis in the field of metal-gall ink. The first one, by Jana Kolar, analyses inks from 97 documents for her doctoral thesis. Her work was the starting point of many other studies and constitutes a fundamental reference for the Dutch school she developed. Another parallel study, following a similar approach, is the one developed by a Mexican and North American team about the inks from the National Mexican Archives, where 2.032 documents were selected. The study focused on the analysis of inorganic components with X-ray fluorescence for which sample collection is not required. Our study, despite a smaller number of analysed inks (989), intends to distinguish itself from other similar studies by broadening the field of research and data provided by science with the importance of written and iconographic documentary sources. First of all, we provide a review of the primary and secondary documentary sources used for the fundamental analysis of the recipes, their components and the methods of preparation. Among the primary sources, 16 of them have been generously, for the first time, made available for analysis by archivists, librarians and friends to accomplish our study and the conclusions reveal some unknown facts. On the other hand, using the secondary sources, this study reviews the history of these inks through books of secrets, treaties, recipe books and manuals about the art of writing. Based on these sources, we have compiled 160 recipes that were published in different sources and periods with reference to the Hispanic and Al-Andalus Kingdoms. The conclusions obtained are fundamental in knowing the ingredients, their evolution and the methods of preparation. Prior to selecting the system of scientific analysis to study the samples of Valencian inks, we compiled more than 400 articles referring to the study of books and documents. The acquired information has allowed us to obtain a wide scope of the possibilities of each system, which we have tried to organise according to characteristics and possibilities. Our goal is for it to become an efficient guide for those who wish to perform scientific studies on library and documentary heritage. The contribution of these recipes from written sources has allowed us to experiment with the reproduction of some of them, which has been with no doubt, a necessary and fundamental part for the comprehension of this study. Having first hand knowledge of the components, applying the processes described and seeing all the reactions live have provided us with a comprehensive understanding of the inks. Also, being able to analyse each ingredient separately as well as the resulting inks on their own and once on the paper has enriched our knowledge of the materials and the processes of fabrication; we also discovered that some of the procedures considered in the literature have been found to be impossible. The selected system of analysis was perhaps not as precise as others such as the PIXE or those for which the collection of samples is not required. Nevertheless, we chose to take advantage of the IVC+R CulturArts´ laboratory of materials and of the availability of the scanning electron microscope connected to an energy dispersive X-ray spectroscopy system (SEM-EDX). This system requires the in situ collection of the micro-samples; however, in exchange, it allows us to analyse them afterwards in the laboratory of the aforementioned institute. In addition, this system of analysis is capable of detecting the concentration of inorganic elements with extensive reliability while offering semi-quantification, which is very useful for the object of our study. On the other hand, it became necessary to study in detail the main components of the inks. We were able to identify different types of galls also referred to in the sources; we attempted to research the metal sulphates and their availability in the Valencian Community and outside of our frontiers due to commerce, as well as the components included in the recipes listed in the annexed table. To complete this study, we took into account these recipes in order to justify their evolution over time and to establish, when appropriate, territorial links. We compared these recipes to standard values of measurement, from which we can then extrapolate using other proportions the existence of correlations within the results of the analysis of the Valencian samples. Considering that one of the main objectives is to find a possible relationship between the presence of inorganic elements and the state of conservation of the documents, we have devoted one chapter to the chemistry of the inks, where we present the conservation problems, the typology of damages identified throughout our work experiences and the state of play of solutions related to the described conservation problems. The application of different statistical studies and approaches that can be obtained from the data have led to a very comprehensive chapter analysing the presence of the main components (such as iron, greatly responsible for the oxidation processes), as well as the relationship among the components we consider to be most influential (such as calcium-iron, potassium-iron and copper-zinc). The study focuses on the date and place of their origins (archives) with the goal of establishing possible relationships and parallelisms between these parameters. In addition, we have analysed the relationship of these elements with the state of conservation of the inks sampled in order to complete our study, making note when the perforation of the support was in a final stage. Using another statistical system, we have studied the probability of influence of each in the deterioration of the inks and, despite the limitations described by the field of study and the application of the method, we have obtained surprising results that have not been detected in the specific literature. On the other hand, because the dichotomy between water and wine remains constant, we have worked on the solvent used varying its selection according, mainly, to the dates of origin, seeing as though the scribes had documented in their recipes their observations regarding the deterioration, which some attributed to the oxidation of the white wine used. The artistic aspect of some illuminated manuscripts has been of great help to us: by learning about the writing tools used and the environment of the scribes through the self-portraits and other representations of the scribes during the act of writing. Given the proliferation of these images in medieval manuscripts, we have proposed a classification for these kinds of scenes, using the most relevant examples we could find. Other types of images that should not be discounted are those spontaneously drawn by notaries on their writings when testing the quill (provationes calami) or, simply, as other forms of expression

The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry

The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry was held on 1–15 July 2021. The scope of this online conference was to gather experts that are well-known worldwide who are currently working in chemical sensor technologies and to provide an online forum for the presention and discussion of new results. Throughout this event, topics of interest included, but were not limited to, the following: electrochemical devices and sensors; optical chemical sensors; mass-sensitive sensors; materials for chemical sensing; nano- and micro-technologies for sensing; chemical assays and validation; chemical sensor applications; analytical methods; gas sensors and apparatuses; electronic noses; electronic tongues; microfluidic devices; lab-on-a-chip; single-molecule sensing; nanosensors; and medico-diagnostic testing

Microplastics Degradation and Characterization

In the last decade, issues related to pollution from microplastics in all environmental compartments and the associated health and environmental risks have been the focus of intense social, media, and political attention worldwide. The assessment, quantification, and study of the degradation processes of plastic debris in the ecosystem and its interaction with biota have been and are still the focus of intense multidisciplinary research. Plastic particles in the range from 1 to 5 mm and those in the sub-micrometer range are commonly denoted as microplastics and nanoplastics, respectively. Microplastics (MPs) are being recognized as nearly ubiquitous pollutants in water bodies, but their actual concentration, distribution, and effects on natural waters, sediments, and biota are still largely unknown. Contamination by microplastics of agricultural soil and other environmental areas is also becoming a matter of concern. Sampling, separation, detection, characterization and evaluating the degradation pathways of micro- and nano-plastic pollutants dispersed in the environment is a challenging and critical goal to understand their distribution, fate, and the related hazards for ecosystems. Given the interest in this topic, this Special Issue, entitled “Microplastics Degradation and Characterization”, is concerned with the latest developments in the study of microplastics

Vegetation Index and Dynamics

The book contemplates different ways of approaching the study of vegetation as well as the type of indices to be used. However, all the works pursue the same objective: to know and interpret nature from different points of view, either through knowledge of nature in situ or the use of technology and mapping using satellite images. Chapters analyze the ecological parameters that affect vegetation, the species that make up plant communities, and the influence of humans on vegetation

Living in the Plastic Age: Perspectives from Humanities, Social Sciences and Environmental Sciences

Plastikmüll ist überall auf unserem Planeten zu finden. Er hinterlässt einen augenscheinlichen Fußabdruck des menschlichen Konsumverhaltens und der Massenproduktion. Unser ungebremster Plastikkonsum und dessen Auswirkungen prägen die gesellschaftlichen Naturverhältnisse in einer so tiefgreifenden Weise, dass wir vom Plastikzeitalter sprechen. Um Ansätze für einen Umgang mit diesem Problem zu entwickeln, müssen wir das Phänomen umfassend verstehen: Die Autor:innen beleuchten es aus interdisziplinärer Perspektive. Sie zeigen, welche Rolle Kunststoffe in unserer Gesellschaft spielen und welche Auswirkungen sie auf die Umwelt und die menschliche Gesundheit haben

Bio-Based Polymeric Films

These days, massive consumer demands for short-term single-use plastic materials have produced huge plastic waste, which in turn has created tremendous environmental pollution. Biodegradable polymers or biopolymers can be used to develop alternatives to synthetic petroleum-based plastics. Different sources of biopolymers, like carbohydrates, proteins, and lipids, as well as biodegradable polymers such as polyesters, polyamides, polyurethanes, etc., have been utilized recently to make environmentally benign biodegradable plastic