Thermogravimetric study of water affinity of gelatin materials

Abstract

Gelatin materials in the form of thin films were prepared using film-forming gelatin solutions with pH value of 2.5-6.8; interaction of gelatin with water in the films and in the solutions was studied. Thermogravimetric analysis at temperature up to 200°C was used to identify and characterize free and bound water present in dried films. To simulate the water-gelatin interaction and to interpret thermogravimetric data, quantum chemical calculations along with the studies on the films swelling were performed. For both free water and bound water, the parameters of thermal desorption process were found to be affected by pH of film-forming solution. The observed changes in content of free and bound water and in apparent activation energies of water thermal desorption may be attributed to the growth of the quantity of negatively charged groups in gelatin molecules upon pH increase and to the changes in film structure and water affinity resulting from the charged groups interaction. Thus, by varying pH of the solution, one may influence the affinity of the films with respect to water and change the properties and usability of gelatin materials.

Detection of 1H-Triphosphirene (c-HP3) and 2-Triphosphenylidene (HP3): The Isovalent Counterparts of 1H-Triazirine (c-HN3) and Hydrazoic Acid (HN3)

“…This reveals that the sublimation event with 8.53 eV photons can be associated with isomer 4 , which cannot be ionized at a photon energy of 8.20 eV. Deconvolution of the TPD profile with a bimodal Gaussian functional (Figure B) − reveals the integrated ratio of the ion counts for both sublimation events at 215 and 229 K to be (7.4 ± 0.1):1 at a photon energy of 10.49 eV. These findings provide compelling evidence for the formation and detection of both 1 H -triphosphirene ( c -HP 3 , 3 ) and 2-triphosphenylidene (HP 3 , 4 ).…”

Swelling effects in cross-linked polymers by thermogravimetry

“…organic copolymers [27][28][29][30][31][32] and various hydrogels [33][34][35][36][37][38][39]), but to our knowledge it is the first reported approach to pore size distribution estimation in swollen cross-linked polymers with the employment of thermogravimetric analysis combined with microscopic measurements. A standard procedure based on quasiisothermal programme of heating applied for desorption of liquid from porous solid and the Kelvin equation, along with a simple mathematic calculation, provides information concerning free spaces in the swollen material.…”

Robust and Wide Temperature‐Range Zinc Metal Batteries with Unique Electrolyte and Substrate Design

“…This method is also widely applied to the quantitative analysis of free and bound water in materials. [22] In the TG-FTIR spectra (Figure 4c), the characteristic C=O peak of γvalerolactone represents the relative content of volatilized solvent, which enhances with the increase of temperature and then decreases with the consumption of free solvent after reaching the peak. The C=O peak increases again when the temperature reaches the volatilization temperature of the non-free solvent and decreases subsequently after a large loss of the non-free solvent.…”