Recently, there has been an expanding interest in the packaging industry concerning thermoplastic film laminations. These types of materials provide a packaging material that can be tailored to the consumers' needs. An understanding of the bonding mechanisms between plastics might prove useful in the improvement or development of film lamination. Infrared spectrometry has been used to study the structures of plastics in the 3.0 - 100 micron region. It was decided that a study of infrared spectrometry in the 1.0 - 3.5 region could provide a tool for studying bonding mechanisms between thermoplastic material. The results of the qualitative study of the structural groups of nine polymers showed that the spectral identification in the 1.0 - 3.5 micron region was possible. These results could provide a means of determining the groups involved in bonding mechanisms. Beer's law has normally been applied to the quantitative analysis of homogeneous gaseous and liquid mixtures. A study shewed that Beer's law was applicable, with limited quantitative accuracy, to solid thermoplastic mixtures. The results indicate that a base-line analysis technique, based on Beer's law can be used to determine concentration gradients. A study of such concentration gradients across the interface of a lamination could indicate the types of bending mechanisms. All samples were analyzed in the form of films with a Beckman DK-2 ratio recording spectrophotometer. An improved method for the preparation of film samples was developed. Thermoplastic resins were pressed between 10 mil Mylar and Teflon FEP films on a Carver laboratory press. / Master of Science

Indiana University-Purdue University Indianapolis (IUPUI) / Toner analysis has become an area of increased interest due to the wide availability of laser printers and photocopiers. Toner is most often encountered on paper in questioned document analysis. Because of this, it is important to develop methods that limit the interference of paper without damaging or destroying the document. Previous research using Fourier transform infrared spectroscopy (FTIR) has differentiated toners based on their polymer resin components. However, Raman spectroscopy and chemometric analysis are not typically used for the examination of this material. Raman spectroscopy is a popular tool for the chemical analysis of pigmented samples and was used to characterize cyan, yellow, and magenta toners. Analyses were performed using a dispersive micro-Raman spectrometer equipped with a 785nm diode laser, a CCD detector, and an objective at 20X magnification. One hundred samples of each color toner were collected. Three different and separate methods were developed for cyan, yellow, and magenta toners on paper to optimize results. Further analysis of the magenta toners was excluded due to a weak signal and significant paper interference. The data collected from the analyses of the blue and yellow toners was then processed using a combination of statistical procedures, including principal component analysis (PCA), agglomerative hierarchal clustering (AHC), and discriminative analysis (DA). Ninety-six blue toners were analyzed by PCA and three classes of spectra were suggested. Discriminant analysis showed that the three classes were well-differentiated with a cross-validation accuracy of 100% for the training set and 100% cross-validation accuracy for the external validation set. Eighty-eight yellow toners were analyzed by AHC and four classes of spectra were suggested. Discriminant analysis showed good differentiation between the classes with a cross-validation accuracy of 95.45% for the training set, but showed poor differentiation for the external validation set with a cross-validation accuracy of 72%. While these toners were able to be discriminated, no correlation could be made between the manufacturer, printer make and model, and the toner sample.

Indiana University-Purdue University Indianapolis (IUPUI) / Clear coats have been part of automotive field paint finishes for several decades. Originally a layer of paint with no pigment, they have evolved into a protective layer important to the appearance and longevity of the vehicle's finish. These clear coats have been studied previously using infrared spectroscopy and other spectroscopic techniques. Previous studies focused on either all the layers of an automobile finish or on chemometric analysis of clear coats using other analytical techniques. For this study, chemometric analysis was performed on preprocessed spectra averaged from five separate samples. Samples were analyzed on a Thermo-Nicolet Nexus 670 connected to a Continuμm™ FT-IR microscope. Two unsupervised chemometric techniques, Agglomerative Hierarchical Clustering (AHC) and Principal Component Analysis (PCA), were used to evaluate the data set. Discriminant analysis, a supervised technique, was evaluated using several known qualifiers; these included cluster group from AHC, make, model, and year. Although discriminant analysis confirmed the AHC and PCA results, no correlation to make, model, or year was indicated.