Thermal behavior of PVDF/PMMA blends by differential scanning calorimetry and vibrational spectroscopies (Raman and Fourier-Transform Infrared)

2015 ◽  
Vol 48 ◽  
pp. 120-124 ◽  
Author(s):  
M. Veitmann ◽  
D. Chapron ◽  
S. Bizet ◽  
S. Devisme ◽  
J. Guilment ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Fourier Transform ◽  
Thermal Behavior ◽  
Fourier Transform Infrared ◽  
Scanning Calorimetry ◽  
Vibrational Spectroscopies ◽  
Pmma Blends

scholarly journals Comparative thermal research on tetraazapentalene-derived heat-resistant energetic structures

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jing Zhou ◽  
Li Ding ◽  
Yong Zhu ◽  
Bozhou Wang ◽  
Xiangzhi Li ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermal Decomposition ◽  
Fourier Transform ◽  
Energetic Materials ◽  
Great Influence ◽  
Fourier Transform Infrared ◽  
Thermal Decomposition Mechanism ◽  
Scanning Calorimetry ◽  
In Situ Ftir Spectroscopy ◽  
Heat Resistant

AbstractOrganic inner salt structures are ideal backbones for heat-resistant energetic materials and systematic studies towards the thermal properties of energetic organic inner salt structures are crucial to their applications. Herein, we report a comparative thermal research of two energetic organic inner salts with different tetraazapentalene backbones. Detailed thermal decomposition behaviors and kinetics were investigated through differential scanning calorimetry and thermogravimetric analysis (DSC-TG) methods, showing that the thermal stability of the inner salts is higher than most of the traditional heat-resistant energetic materials. Further studies towards the thermal decomposition mechanism were carried out through condensed-phase thermolysis/Fourier-transform infrared (in-situ FTIR) spectroscopy and the combination of differential scanning calorimetry-thermogravimetry-mass spectrometry-Fourier-transform infrared spectroscopy (DSC-TG-MS-FTIR) techniques. The experiment and calculation results prove that the arrangement of the inner salt backbones has great influence on the thermal decompositions of the corresponding energetic materials. The weak N4-N5 bond in “y-” pattern tetraazapentalene backbone lead to early decomposition process and the “z-” pattern tetraazapentalene backbone exhibits more concentrated decomposition behaviors.

scholarly journals New insight into single phase formation of capric acid/menthol eutectic mixtures by Fourier-transform infrared spectroscopy and differential scanning calorimetry

2020 ◽  
Vol 19 (2) ◽  
pp. 361-369 ◽  
Author(s):  
Hiba H. Ali ◽  
Mowafaq M. Ghareeb ◽  
Mayyas Al-Remawi ◽  
Faisal T. Al-Akayleh
Keyword(s):  
Differential Scanning Calorimetry ◽  
Hydrogen Bond ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared Spectroscopy ◽  
Bond Formation ◽  
Capric Acid ◽  
Fourier Transform Infrared ◽  
Scanning Calorimetry ◽  
Hydrogen Bond Formation

Purpose: To examine the structural changes of a eutectic mixture comprising capric acid and menthol which are commonly used in pharmaceutical applications. Methods: A phase diagram was constructed by quantitative mixing of capric acid and menthol under controlled conditions until a single liquid phase was formed. Eutectic mixtures of capric acid: menthol at the ratios of 3:2, 1:4, 1:1, 2:3, and 1:4 were prepared. Hydrogen bond formation and conformational changes were analyzed using Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). Microscopic imaging was carried out to capture phase change events upon increasing temperature. Results: Menthol confirmed the intact structure of a hexagonal ring. The high degree of broadening of the menthol O-H groups indicates hydrogen bond formation. FTIR band changes related to capric acid suggest a break-up of the methylene arrangement structure due to changes in the C-H band frequencies. The red shift encountered in C=O stretching band emphasizes hydrogen bond formation taking place between the oxygen atom of the hydroxyl group comprising the carboxylic moiety of capric acid and the hydrogen atom of menthol hydroxyl group. DSC results indicate the presence of two polymorphs of the capric acid/ menthol complex. Both exhibited crystallization and conformational change exotherms in addition to two melting endotherms as result of transformation of crystalline components to become partially crystalline due to hydrogen bond formation. Conclusion: The interaction between capric acid and menthol results in a typical preparation of deep eutectic systems that can act as natural-based solvents in numerous pharmaceutical applications. Keywords: Eutectic system, Capric acid, Menthol, Differential scanning calorimetry, DSC, Fourier transform infrared spectroscopy, FTIR

193 IN VITRO DEVELOPMENT OF A LESS INVASIVE HORMONE DELIVERY SYSTEM TO SUPEROVULATE TIGERS

2010 ◽  
Vol 22 (1) ◽  
pp. 255
Author(s):  
J. T. Aaltonen ◽  
S. Singh ◽  
L. R. Fogueri ◽  
N. S. Mulla ◽  
N. M. Loskutoff
Keyword(s):  
Differential Scanning Calorimetry ◽  
Fourier Transform ◽  
Benzyl Alcohol ◽  
Release Rate ◽  
Fourier Transform Infrared ◽  
Release Profile ◽  
Infrared Spectrometry ◽  
Burst Release ◽  
Fourier Transform Infrared Spectrometry ◽  
Scanning Calorimetry

Current administration of FSH for the purpose of superovulation of tigers is achieved through serial injections or subcutaneous osmotic pump (Blevins B et al. 2009 J. Reprod. Fertil. 21, 153 abst). Both have limitations, which are pulsatile hormone fluctuations and multiple anesthesia events for pump insertion and removal, respectively. In vivo attempts to superovulate tigers using aluminum hydroxide gel [Al(OH)3] proved unsuccessful by fecal hormone enzyme immunoassay. In addition, Al(OH)3 raises the potential for an immune response to foreign FSH. An inert, biodegradable, and FDA-approved polylactide-co-glycolide polymer-based in situ gel forming system eliminates the problems above with a single injection delivery, allowing a more natural sustained release of FSH. Polymer solutions were made using a solvent mixture of benzyl benzoate (BB), or benzyl alcohol (BA), or both. Porcine FSH (Folltropin®-V, Bioniche, Belleville, Ontario, Canada) was incorporated into the polymer solution via sonication, which gelled upon contact with interstitial fluid. Polymer composition (ratio of lactide to glycolide) and concentration and ratio of BB to BA parameters can be manipulated to achieve a desired release profile. Two formulations (F1 and F2) were created with differing percentages of composition for the purpose of recreating a controlled release rate of 100 NIH-FSH-P1 reference standard mg/day (pump output). The FSH polymer was injected into 15 mL of PBS (pH 7.4 in a 37°C shaker bath at 30 rpm), which instantly formed a gel. One milliliter of PBS was sampled every 24 h and replenished with fresh PBS. The amount of FSH was determined by measuring UV absorbance at 290 nm (Shimadzu 1600 UV-visible spectrophotometer; Shimadzu Scientific Instruments, Columbia, MD, USA). Formulation F1 showed a higher initial burst release than F2 (61.5% v. 35.8% of total incorporated hormone) as a result of the use of 100% BA as a solvent. Benzyl alcohol is more hydrophilic than BB, leaching out of the polymer-FSH solution faster and leading to a greater release of the hydrophilic FSH. Both formulations showed a biphasic release pattern in which the first phase was relatively faster than the second phase. Although F2 (80% BA-20% BB solvent) was successful in reducing the burst release by half, the day-to-day profile is below target. Our results indicate that F2 has a better release profile than F1 for inducing folliculogenesis and can be improved by manipulating formulation parameters such as increasing the polymer concentration and BA:BB ratio of the solvents. Using Fourier transform infrared spectrometry and differential scanning calorimetry, hormones before gel incorporation were compared to those released. Fourier transform infrared spectrometry and differential scanning calorimetry data suggest that the gel does not affect the conformational stability of FSH. It is therefore possible to manipulate a gel to mimic the release rate of a proven osmotic pump without compromising the functionality of the protein hormone, potentially reducing the number of surgeries or injections to superovulate tigers.

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