Two-dimensional infrared correlation spectroscopy and multivariate curve resolution methods: application to quantitative monitoring of curing process

Author

Spegazzini, Nicolás

Director

Larrechi García, Maria Soledad

Codirector

Ruisánchez Capelastegui, Itziar

Date of defense

2010-04-29

ISBN

9788469340493

Legal Deposit

T.998-2010



Department/Institute

Universitat Rovira i Virgili. Departament de Química Analítica i Química Orgànica

Abstract

Goal and Scope of this thesis<br/><br/>The curing process of epoxy resin directly affects the properties of the final polymer, so it is of great interest to develop analytical methods that allows knowing the pathway of the curing processes. There have been numerous research studies about the evolution of the curing and on the quantification of the corresponding kinetic parameters using several techniques such as: Differential Scanning Calorimetry (DSC), Differential Scanning Calorimetry with Temperature Modulation (MTDSC), Thermogravimetric analysis (TGA), Fluorescence, Raman spectroscopy, Nuclear Magnetic Resonance (NMR), High-Resolution Liquid Chromatography (HPLC), Infrared spectroscopy Fourier Transform (FTIR) and Near infrared spectroscopy (NIR). <br/>Usually, those studies are done in model reactions due to the fact that is very difficult, and sometimes even impossible, to isolate the intermediate products that are involved in the curing process. In that sense, the goal of the present thesis is to explore the possibilities of the multidimensional correlation spectroscopy for the quantitative monitorization of curing processes by means of infrared spectroscopy and curve resolution methods. The thesis is focused in a complex reaction in which several and side reactions might take place, most or all of them almost at the same time. <br/>This main goal is structured in the following items: <br/>1. Analysis of Generalized two-dimensional correlation spectroscopy and Perturbation-correlation mowing-windows two-dimensional correlation spectroscopy as a tool to obtain information about the reaction pathway.<br/>2. Analysis of sample-sample two-dimensional correlation spectroscopy as a tool to obtain concentration profiles of the chemical species involved in the curing process.<br/>3. Quantitative resolution of the curing process by means of multivariate curve resolution methods - alternating least squares (MCR-ALS) taking into account the information coming from multidimensional correlation spectroscopy analysis. <br/><br/>Structure<br/><br/>The thesis is structured in different chapters each one containing the following information.<br/><br/>Chapter 1: This chapter presents the background of the thesis, so it is highlighted the interest of the study of resins epoxy. A brief review of the theory of the multidimensional spectroscopy and the chemometrics tools (multivariate curve resolution methods) used is presented focusing on the novelties introduced in the thesis and offering the proper references for the basic concepts already known.<br/>Chapter 2: This chapter concerns the experimental work done. It has been included a brief description of the instrumental analytical techniques used to monitor the curing process. Two main curing reactions are described: experimental conditions and scheme of the reaction between the phenylglycidylether (PGE) and &#61543;-butyrolactone monitored by NIR and of the copolymerization between the diglycidyl ether of bisphenol A (DGEBA) and &#61543;-valerolactone by FTIR/ATR. Also the conditions of the DGEBA homopolymerization are presented. And finally, the 1H and 13C NMR experimental condition to obtain the spectrum of the final product in the first reaction between PGE and &#61543;-butyrolactone is described.<br/>Chapter 3: This chapter is addressed to the results obtained as a consequence of the studies done. It is articulated in five published works and each one is introduced by a brief description of the main goal and the content of it. The five articles are presented in a sequential order according the main goal of the thesis.<br/>Chapter 4: Finally, the thesis ends with a conclusion chapter in which the achieved goals are outlined.<br/>As each paper presented in chapter 3, contains its specific conclusion section, in this chapter there are emphasized the thesis conclusions according to the goals formulated in the scope. In that sense the first and general conclusion is that Multidimensional correlation spectroscopy and multivariate curve resolution method are useful spectroscopic and chemometric methods to quantitative monitoring a curing process using infrared spectroscopy.<br/>Concretely it can be also stated that: <br/> - Generalized and perturbation-correlation moving-windows two-dimensional correlation spectroscopy, are valuable methods to obtain information about the reaction pathway in the case studied which is representative of a curing process.<br/>- Sample-sample two-dimensional correlation spectroscopy is very useful method to obtain concentration profiles of the chemical species involved in the curing process.<br/>- And finally, MCR-ALS is a very useful method for the quantitative resolution of the curing process.


El proceso de curado la resina epoxi afecta directamente las propiedades finales del polímero, por lo que es de gran interés para el desarrollo de métodos de análisis que permite conocer la vía de los procesos de polimerización. Por lo general, esos estudios se hacen en reacciones modelo, debido al hecho, que es muy difícil, a veces o incluso imposible, aislar los productos intermedios que intervienen en el proceso de curado. En ese sentido, el objetivo de la tesis es explorar las posibilidades de la espectroscopia de correlación multidimensional para la monitorización cuantitativa de los procesos de curado por medio de espectroscopia infrarrojo y métodos de resolución de la curva. La tesis se centra en una reacción compleja en la que varias reacciones secundarias y puede tener lugar, la mayoría o la totalidad de ellos casi al mismo tiempo.<br/>Las conclusiones de la tesis de acuerdo a los objetivos son formulados en el ámbito de aplicación, métodos espectroscópicos y quimiométricos. En ese sentido, la primera conclusión general y es que la espectroscopia de correlación multidimensional y método de resolución de curva multivariante son útiles para el seguimiento de un proceso de curado mediante espectroscopía de infrarrojo.<br/>Concretamente, puede ser también señaló que:<br/> - La espectroscopia generalizada de correlación bidimensional y espectroscopia de correlación de la perturbación por ventana móvil, son métodos valiosos para obtener información sobre el camino de reacción en el caso estudiado, que es representativa de un proceso de curado.<br/>- La espectroscopia de correlación bidimensional muestra-muestra es un metodo útil para obtener perfiles de concentración de las especies químicas involucradas en el proceso de curado.<br/>- Por último, MCR-ALS es un método muy útil para la resolución cuantitativa del proceso de curado.

Keywords

Alternating Least Squares; Multivariate Crve Resolution; Inrared Spectrocopu; Curing Process; Two-Dimensional Correlation Spectyroscopu

Subjects

543 - Analytical chemistry; 544 - Physical chemistry; 547 - Organic chemistry

Documents

Thesis.pdf

50.71Mb

 

Rights

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