1
|
White RL. Thermal analysis by variable temperature infrared spectroscopy with a button sample holder and Peltier heating/cooling. Talanta 2023; 258:124474. [PMID: 36963150 DOI: 10.1016/j.talanta.2023.124474] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/08/2023] [Accepted: 03/19/2023] [Indexed: 03/26/2023]
Abstract
An apparatus and methodology for variable temperature infrared spectroscopy measurements of neat samples contained in a button sample holder are described. Sample heating and cooling are achieved by applying voltage to stacked Peltier thermoelectric devices. Between 0 and 150 °C, samples can be heated and cooled at 2 °C s-1 rates, facilitating temperature step heating/cooling profiles with minimal delay between isothermal infrared spectrum measurements. Examples of correlating temperature-dependent spectral variations with specific sample changes are provided for α-quartz heating/cooling, ibuprofen melting, and acetylsalicylic acid thermal decomposition. Trends in α-quartz infrared spectra obtained with a step heating/cooling temperature profile are used to evaluate spectrum measurement reproducibility. Detection of vibration band intensity variations of less than 1% resulting from a 10 °C sample temperature increment illustrates the measurement sensitivity. By comparing infrared spectra obtained at different temperatures, reversible and irreversible sample changes are identified. Infrared spectra acquired during linear ramp heating are employed to determine the ibuprofen melting point, which confirms the temperature measurement accuracy of the apparatus. Selective analysis is demonstrated by determining isoconversion effective activation energies for processes involved in the thermal decomposition of the acetylsalicylic acid component of a commercial pharmaceutical tablet.
Collapse
Affiliation(s)
- Robert L White
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, 73019, USA.
| |
Collapse
|
2
|
Yu S, Li X, Zou M, Li Z, Wang S, Wang D. Tetrafunctional Epoxy Resin-Based Buoyancy Materials: Curing Kinetics and Properties. Polymers (Basel) 2020; 12:polym12081732. [PMID: 32756404 PMCID: PMC7463793 DOI: 10.3390/polym12081732] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 07/27/2020] [Accepted: 07/27/2020] [Indexed: 11/30/2022] Open
Abstract
In order to synthesize a new kind of buoyancy material with high-strength, low-density and low-water-absorption and to study the curing reaction of tetraglycidylamine epoxy resin with an aromatic amine curing agent, the non-isothermal differential scanning calorimeter (DSC) method is used to calculate the curing kinetics parameters of N,N,N′,N′-tetraepoxypropyl-4,4′-diaminodiphenylmethane epoxy resin (AG-80) and the m-xylylenediamine (m-XDA) curing process. Further, buoyancy materials with different volume fractions of hollow glass microsphere (HGM) compounded with a AG-80 epoxy resin matrix were prepared and characterized. The curing kinetics calculation results show that, for the curing reaction of the AG-80/m-XDA system, the apparent activation energy increases with the conversion rates increasing and the reaction model is the Jander equation (three-dimensional diffusion, 3D, n = 1/2). The experimental results show that the density, compressive strength, saturated water absorption and water absorption rate of the composite with 55 v % HGM are 0.668 g·cm−3, 107.07 MPa, 0.17% and 0.025 h−1/2, respectively. This kind of composite can probably be used as a deep-sea buoyancy material.
Collapse
|
3
|
Spectroscopic, thermal, non-isothermal decomposition kinetics and quantum chemical computational studies of Ni(II)- and Cu(II)-Schiff base complexes. RESEARCH ON CHEMICAL INTERMEDIATES 2017. [DOI: 10.1007/s11164-016-2722-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
4
|
Bartha C, Secu CE, Matei E, Secu M. Crystallization kinetics mechanism investigation of sol–gel-derived NaYF4:(Yb,Er) up-converting phosphors. CrystEngComm 2017. [DOI: 10.1039/c7ce01265a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The crystallization mechanism of sol–gel-derived NaYF4:(Yb,Er) up-converting phosphors has been studied by differential scanning calorimetry analysis using both model-free and model fitting approaches.
Collapse
Affiliation(s)
- C. Bartha
- National Institute for Materials Physics
- Bucharest-Magurele
- Romania
| | - C. E. Secu
- National Institute for Materials Physics
- Bucharest-Magurele
- Romania
| | - E. Matei
- National Institute for Materials Physics
- Bucharest-Magurele
- Romania
| | - M. Secu
- National Institute for Materials Physics
- Bucharest-Magurele
- Romania
| |
Collapse
|
5
|
|
6
|
Raval MK, Patel JM, Parikh RK, Sheth NR. Dissolution enhancement of chlorzoxazone using cogrinding technique. Int J Pharm Investig 2015; 5:247-58. [PMID: 26682195 PMCID: PMC4675006 DOI: 10.4103/2230-973x.167689] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
PURPOSE The aim of the present work was to improve rate of dissolution and processing parameters of BCS class II drug, chlorzoxazone using cogrinding technique in the presence of different excipients as a carrier. MATERIALS AND METHODS The drug was coground with various carriers like polyethylene glycol (PEG 4000), hydroxypropyl methylcellulose (HPMC) E50LV, polyvinylpyrrolidone (PVP)K30, Kaolin and Neusilin US2 using ball mill, where only PEG 4000 improved dissolution rate of drug by bringing amorphization in 1:3 ratio. The coground mixture after 3 and 6 h was evaluated for various analytical, physicochemical and mechanical parameters. RESULTS The analysis showed conversion of Chlorzoxazone from its crystalline to amorphization form upon grinding with PEG 4000. Coground mixture as well as its directly compressed tablet showed 2.5-fold increment in the dissolution rate compared with pure drug. Directly compressible tablets prepared from pure drug required a large quantity of microcrystalline cellulose (MCC) during compression. The coground mixture and formulation was found stable in nature even after storage (40°C/75% relative humidity). CONCLUSIONS Cogrinding can be successfully utilized to improve the rate of dissolution of poorly water soluble drugs and hence bioavailability.
Collapse
Affiliation(s)
- Mihir K Raval
- Department of Pharmaceutical Sciences, Saurashtra University, Rajkot, Gujarat, India
| | - Jaydeep M Patel
- Department of Pharmaceutical Sciences, Saurashtra University, Rajkot, Gujarat, India
| | - Rajesh K Parikh
- Department of Pharmaceutical Technology, L. M. College of Pharmacy, Navrangpura, Ahmedabad, Gujarat, India
| | - Navin R Sheth
- Department of Pharmaceutical Sciences, Saurashtra University, Rajkot, Gujarat, India
| |
Collapse
|
7
|
Elçin S, Çılgı GK, Bayrakdar A, Deligöz H. The synthesis and characterization of azocalix[4]arene based chemosensors and investigation of their properties. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2015; 142:178-187. [PMID: 25703362 DOI: 10.1016/j.saa.2015.01.087] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 01/14/2015] [Accepted: 01/29/2015] [Indexed: 06/04/2023]
Abstract
In the present study, azocalix[4]arenes were prepared by linking 4-methoxy, 4-methyl, 4-ethyl, 4-chloro, 4-bromo and 4-nitroaniline to calix[4]arene through a diazo-coupling reaction. A new family of azocalix[4]arene tetraester derivatives, (4a-f), have been prepared with the incorporation of ethyl ester units to azocalix[4]arene. Characterization of the synthesized azocalix[4]arenes was carried using elemental analyses, UV-vis, FT-IR and (1)H NMR spectroscopic techniques. The effect of varying pH levels and solvent types on the absorption ability of azocalix[n]arenes substituted with electron-donating and electron-withdrawing groups was examined. Thermal decomposition of azocalix[4]arene derivatives (4a-f) was investigated by means of thermogravimetry (TG), differential thermogravimetry (DTG) and differential thermal analysis (DTA) analyses. In conclusion of the examination of the extraction we found a selectivity characteristic of these compounds toward Ag(+), Hg(+) and Hg(2+) cations.
Collapse
Affiliation(s)
- Serkan Elçin
- Department of Chemistry Engineering, Faculty of Engineering, Pamukkale University, 20017 Denizli, Turkey.
| | - Gülbanu Koyundereli Çılgı
- Materials Science and Engineering Department Technology Faculty, Pamukkale University, 20017 Denizli, Turkey
| | - Alpaslan Bayrakdar
- Department of Physics, Faculty of Science, Pamukkale University, 20017 Denizli, Turkey
| | - Hasalettin Deligöz
- Department of Chemistry Engineering, Faculty of Engineering, Pamukkale University, 20017 Denizli, Turkey
| |
Collapse
|
8
|
Roumeli E, Markoulis A, Kyratsi T, Bikiaris D, Chrissafis K. Carbon nanotube-reinforced crosslinked polyethylene pipes for geothermal applications: From synthesis to decomposition using analytical pyrolysis–GC/MS and thermogravimetric analysis. Polym Degrad Stab 2014. [DOI: 10.1016/j.polymdegradstab.2013.12.027] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
9
|
Abstract
In materials research, the development of polymer nanocomposites (PN) is rapidly emerging as a multidisciplinary research field with results that could broaden the applications of polymers to many different industries. PN are polymer matrices (thermoplastics, thermosets or elastomers) that have been reinforced with small quantities of nano-sized particles, preferably characterized by high aspect ratios, such as layered silicates and carbon nanotubes. Thermal analysis (TA) is a useful tool to investigate a wide variety of properties of polymers and it can be also applied to PN in order to gain further insight into their structure. This review illustrates the versatile applications of TA methods in the emerging field of polymer nanomaterial research, presenting some examples of applications of differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical thermal analysis (DMTA) and thermal mechanical analysis (TMA) for the characterization of nanocomposite materials.
Collapse
|
10
|
Chiu MH, Prenner EJ. Differential scanning calorimetry: An invaluable tool for a detailed thermodynamic characterization of macromolecules and their interactions. J Pharm Bioallied Sci 2011; 3:39-59. [PMID: 21430954 PMCID: PMC3053520 DOI: 10.4103/0975-7406.76463] [Citation(s) in RCA: 190] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Revised: 10/05/2010] [Accepted: 10/19/2010] [Indexed: 11/04/2022] Open
Abstract
Differential Scanning Calorimetry (DSC) is a highly sensitive technique to study the thermotropic properties of many different biological macromolecules and extracts. Since its early development, DSC has been applied to the pharmaceutical field with excipient studies and DNA drugs. In recent times, more attention has been applied to lipid-based drug delivery systems and drug interactions with biomimetic membranes. Highly reproducible phase transitions have been used to determine values, such as, the type of binding interaction, purity, stability, and release from a drug delivery mechanism. This review focuses on the use of DSC for biochemical and pharmaceutical applications.
Collapse
Affiliation(s)
- Michael H Chiu
- Department of Biological Sciences, University of Calgary, T2N 1N4 Calgary, AB, Canada
| | | |
Collapse
|
11
|
Investigation on the Reaction of Powdered Tin as a Metallic Fuel with Some Pyrotechnic Oxidizers. PROPELLANTS EXPLOSIVES PYROTECHNICS 2011. [DOI: 10.1002/prep.200900082] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
12
|
Lee D, Park Y, Cho SH, Yoo M, Jung N, Yun M, Ko W, Jeon S. Microthermogravimetry of a single microcapsule using silicon microresonators. Anal Chem 2010; 82:5815-8. [PMID: 20521765 DOI: 10.1021/ac100913k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A chlorobenzene-containing polyurethane microcapsule was placed on the free end of a silicon cantilever, and the temperature dependence of the resonance frequency was measured. As the cantilever was heated, the resonance frequency showed steplike increases at 109 and 270 degrees C that were due to the rupture of the capsule and the thermal degradation of the polyurethane shell, respectively. The frequency changes due to the rupture of a single capsule measured by the cantilever were much sharper than the transitions measured by conventional thermogravimetric analysis (TGA), which measures the average mass change of a collection of capsules characterized by a large size distribution. When two capsules were placed on the cantilever, their individual rupture temperatures could be clearly identified. In addition, the permeability of the polyurethane shell, with respect to chlorobenzene, was measured, and the rupture temperature was observed to decrease with increasing permeability.
Collapse
Affiliation(s)
- Dongkyu Lee
- Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, Korea
| | | | | | | | | | | | | | | |
Collapse
|
13
|
Skrdla PJ, Harrington C, Lin Z. Use of real-time FT-IR monitoring of a pharmaceutical compound under stress atmospheric conditions to characterize its solid-state degradation kinetics. INT J CHEM KINET 2009. [DOI: 10.1002/kin.20458] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|