Infrared Spectra of Poly(Methyl Methacrylate) Labeled with Oxygen-18

1979 ◽  
Vol 33 (6) ◽  
pp. 551-555 ◽  
Author(s):  
Stoil Dirlikov ◽  
Jack L. Koenig

Fourier transform infrared spectrum of atactic poly(methyl methacrylate) (PMMA) is compared with that of atactic PMMA labeled with 18O in the ester groups. The results obtained define the assignment of the bands associated with vibrations of the ester groups of PMMA. Furthermore, the Fourier transform infrared spectroscopy provides a simple method for obtaining the spectra of “pure” derivatives containing 18O.

1979 ◽  
Vol 33 (6) ◽  
pp. 555-561 ◽  
Author(s):  
Stoil K. Dirlikov ◽  
Jack L. Koenig

The C—H stretching and C—H bending vibrations of the methylene, α-methyl, and ester methyl groups of poly(methyl methacrylate) are discussed and assigned on the basis of the infrared spectra of its three deuterated derivatives: PMMA—CD3—OCD3, PMMA—CD2—OCD3, and PMMA—CD2—CD3. The digital analog of PMMA is obtained by coaddition of the Fourier transform infrared spectra of the deuterated PMMA derivatives. The experimental and digital PMMA spectra are compared in the regions of the C—H stretching and C—H bending vibrations: the agreement in frequency is excellent and the relative intensities are practically the same in the C—H stretching vibrations region. However, their relative intensities strongly differ in the C—H bending region.


2021 ◽  
Author(s):  
Shreyas Patankar ◽  
Ekaterina Vassilenko ◽  
Mathew Watkins ◽  
Anna Posacka ◽  
Peter Ross

<p>Microplastic pollution in oceans is among the global environmental concerns of our time. Emerging research on ocean environments indicates that microfibers, such as those originating from textiles, are some of the most commonly occurring type of microplastic contaminants. While Fourier-transform infrared spectroscopy (FTIR) is commonly used to identify and characterize pollutant samples obtained from the environment, this identification is challenging because infrared spectra of materials can be modified by exposure to the ocean, air, UV light, and other ambient conditions, in a process referred to as “weathering”. We report preliminary efforts in improving FTIR characterization of microplastics by building a library of infrared spectra of common textile fibers weathered under a selection of ambient conditions. Consumer textile materials including polyester, nylon, cotton, and other, were exposed to a selection of ambient conditions: ocean, air, and wastewater treatment stages, in a controlled weathering experiment. Infrared spectra were monitored for up to 52 weeks, with the resulting data illuminating on the environmental fate and longevity of synthetic and natural fibers. Spectral changes caused by weathering were found to depend strongly on both the composition of the material and the specific ambient conditions. This library of weathered material spectra is useful not only in easier identification of environmental microfibers, but also in helping us estimate the duration and manner of weathering that a given environmental microfiber may have experienced.</p>


2014 ◽  
Vol 926-930 ◽  
pp. 1116-1119 ◽  
Author(s):  
Li Jun Yang ◽  
Jing Wang ◽  
Zhao Jie Li ◽  
Xiao Hua Song ◽  
Yu Min Liu ◽  
...  

Fourier transform infrared spectroscopy (FTIR) combined with multivariate statistical analysis was applied to differentiate and identify Shigella sonnei and Escherichiacoli O157: H7. FTIR absorption spectra from 4000-600 cm-1 were collected from sampling 10 μL of bacterial suspention. The spectra between 1800 and 900 cm-1 highlighted the most distinctive variations and were the most useful for characterizing the selected microorganisms. Spectra of the two bacteria were noticeably segregated with distinct clustering by principal component analysis (PCA). Further more, another cluster model of hierarchical cluster analysis (HCA) was established and could also gave a good separation between the two bacteria. These results demonstrate that FTIR technology has considerable potential as a rapid, accurate and simple method for differentiating and identifying bacteria.


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