Rheo-Optical Study of Polymers by Using Time-Resolved Soft-Pulse Compression Attenuated Total Reflection Step-Scan Fourier Transform Infrared Spectroscopy

2009 ◽  
Vol 63 (11) ◽  
pp. 1204-1210 ◽  
Author(s):  
Yuji Nishikawa ◽  
Tatsuhiko Nakano ◽  
Isao Noda
Keyword(s):  
Fourier Transform ◽  
Pulse Compression ◽  
Dynamic Compression ◽  
Pulse Frequency ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Type I ◽  
Type Ii ◽  
Time Resolved ◽  
2D Ir

A time-resolved soft-pulse dynamic compression attenuated total reflection (ATR) step-scan Fourier transform rheo-optical system has been developed. This system was used to observe different viscoelastic properties of polyethyleneterephthalate (PET) and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHx). Resonance features were observed in the dynamic compression ATR spectrum of PHBHx with 625 Hz soft-pulse frequency. In contrast, the dynamic compression ATR spectrum of PET showed no resonance features. The resonance feature of PHBHx was found at 1723 cm−1, which corresponds to the structural or morphological reorganization of a less ordered (Type II) crystalline form under compressive perturbation. The time-resolved evolution of infrared (IR) spectra was effectively analyzed by conventional generalized two-dimensional (2D) correlation analysis. The 2D-IR results indicate that the dynamic response of the well-ordered Type I crystalline state (1289 and 1261 cm−1) is faster than that of the Type II (1723, 1277, and 1228 cm−1). The present method shows promise for characterizing a wide variety of viscoelastic materials, including polymer alloys, blends, composites, and copolymers, and semicrystalline polymers.

Electric-Field-Induced Reorientation of Liquid Crystalline p-Cyanophenyl-p-n-Alkylbenzoates: A Time-Resolved Study by Fourier Transform Infrared Transmission and Attenuated Total Reflection Spectroscopy

2003 ◽  
Vol 57 (5) ◽  
pp. 499-505 ◽  
Author(s):  
E. Klimov ◽  
M. Fuelleborn ◽  
H. W. Siesler
Keyword(s):  
Fourier Transform ◽  
Electric Field ◽  
Liquid Crystalline ◽  
External Perturbation ◽  
Fourier Transform Infrared ◽  
Surface Region ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Infrared Transmission ◽  
Time Resolved

Time-resolved polarization Fourier transform infrared (FT-IR) transmission and attenuated total reflection (ATR) spectroscopy were applied to investigate the reorientation phenomena of the three members of the homologous series of nematic liquid crystalline p-cyanophenyl-p-n-alkylbenzoates 6CPB, 7CPB, and 10CPB under the external perturbation of an electric field. In conjunction with a newly constructed measurement cell, this method allowed us to differentiate the response of the LC system in the surface layer and in the bulk of the cell at different temperatures and voltages. The relaxation time of the LC molecules close to the wall of the cell was found to be shorter than in the bulk. However, at a field strength of 7 V, the initial orientation in the bulk preceeds the analogous process in the surface region.

Structural Differences between Type I and Type IV Collagen in Biological Tissues Studied in vivo by Attenuated Total Reflection/Fourier Transform Infrared Spectroscopy

1992 ◽  
Vol 46 (4) ◽  
pp. 626-630 ◽  
Author(s):  
Yukihiro Ozaki ◽  
Aritake Mizuno ◽  
Fumiko Kaneuchi
Keyword(s):  
Fourier Transform ◽  
Type Iv Collagen ◽  
Type I Collagen ◽  
Fourier Transform Infrared ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Random Coil ◽  
Type I ◽  
Type Iv ◽  
Helix Formation

Attenuated total reflection/Fourier transform infrared (ATR/FT-IR) spectra have been obtained in a nondestructive manner for the anterior surface, interior part, and posterior surface of the sclera, for the epithelium, Bowman's membrane, stroma, and endothelium of the cornea, and for the inner section of the Achilles' tendon of a rabbit. The corresponding spectra have been remeasured for the rabbit anterior and posterior lens capsule for purposes of comparison. The spectra of the three parts of the sclera and of the Bowman's membrane and stroma of the cornea are very close to the spectrum of purified type I collagen, confirming that their major components are type I collagen. The spectrum of the tendon is also very similar to that of purified type I collagen, but it contains a small contribution from hyaluronic acid in the 1100-1000 cm−1 region. The amide I bands of the type I collagen-containing tissues are sharp and symmetrical, and their frequencies (1642 cm−1) are almost identical to that (1640 cm−1) of polyglycine II, which takes a 3, helix formation, indicating that the secondary structure of type I collagen in the tissues examined is for practical purposes a slightly modified 31 helix. A comparison of the spectra of the type I collagen-containing tissues and those of the type IV collagen-containing tissues reveals that there are two major differences between them; one is the spectral features in the 1100-1000 cm1 region, where C-O stretching modes of polysaccharide are observed, and the other is the shape and frequency of the amide I band. Besides the peak at 1637 cm−1, the amide I bands of the type IV collagen-containing tissues have shoulders near 1650 and 1655 cm−1. This observation indicates that type IV collagen in the tissues examined assumes primarily a slightly modified 31 helix formation, but the percentages of α-helix and random coil structures are not negligible.

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