ABSTRACT
This work aims to study the hydrogen bond energy and distance for different samples of alfa fibers treated with thymol. The treatment duration and thymol concentration were varied and seem to have a great influence on infrared band intensities and positions. The number of hydrogen bonds is related to the infrared band intensity, whereas their energy and distance depend on the infrared band position. It was proven that the free hydroxyl groups are weakened and tend to disappear with fiber treatment. It is the same for intermolecular hydrogen bands between cellulosic chains that present a decrease in both intensity and frequency. The two intramolecular hydrogen bands increase in intensity but exhibit different behaviors regarding the calculated energy: while the band at 3268â¯cm-1 is weakened and shifted to higher wavenumbers, that at 3338â¯cm-1 keeps the same peak position and energy.
ABSTRACT
FTIR spectroscopy is a powerful method to analyse materials and especially fiber structure. This technique is largely used to obtain quick information on the fiber composition and to detect possible transformations after physical and chemical treatments. Unlike other techniques, FTIR is a quick method which demands a reduced amount of fibers. Furthermore, it is a non destructive method especially for Attenuated Total Reflectance (ATR), and Near Infrared (NIR) spectroscopy which are nowadays widely used. In this work, FTIR spectrum of agave fiber has been thoroughly investigated. Because of its complexity, the spectrum was separated into two regions: CH and hydrogen bond stretching (>2500cm-1) and "fingerprint" region (<2000cm-1). A detailed study of intermolecular and intramolecular chains was made. Infrared ratios (Lateral Order Index, Total Crystallinity Index, and Hydrogen Bond Intensity) were used to study the crystallinity and the degree of regularity of agave fiber.
