Online near-infrared measurements of an epoxy cure process compared to mathematical modeling based on differential scanning calorimetry measurements

2008 ◽  
Vol 110 (4) ◽  
pp. 2184-2194 ◽  
Author(s):  
H.-H. Friis-Pedersen ◽  
L. P. Houmøller ◽  
B. K. Storm
Keyword(s):  
Mathematical Modeling ◽  
Differential Scanning Calorimetry ◽  
Near Infrared ◽  
Cure Process ◽  
Scanning Calorimetry ◽  
Infrared Measurements

scholarly journals Synthesis, Mesomorphism and the Optical Properties of Alkyl-deuterated Nematogenic 4-[(2,6-difluorophenyl)ethynyl]biphenyls

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4653
Author(s):  
Jakub Herman ◽  
Piotr Harmata ◽  
Michał Czerwiński ◽  
Olga Strzeżysz ◽  
Marta Pytlarczyk ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Mass Spectrometry ◽  
Differential Scanning Calorimetry ◽  
Optical Properties ◽  
Liquid Crystalline ◽  
Near Infrared ◽  
Synthesis And Characterization ◽  
Molecular Approach ◽  
Scanning Calorimetry

The synthesis and characterization of new deuterated liquid crystal (LC) compounds based on phenyl tolane core is described in this paper. The work presents an alternative molecular approach to the conventional LC design. Correlations between molecular structure and mesomorphic and optical properties for compounds which are alkyl-hydrogen terminated and alkyl-deuterium, have been drawn. The compounds are characterized by mass spectrometry (electron ionization) analysis and infrared spectroscopy. They show enantiotropic nematic behavior in a broad temperature range, confirmed by a polarizing thermomicroscopy and differential scanning calorimetry. Detailed synthetic procedures are attached. Synthesized compounds show a significantly reduced absorption in the near-infrared (NIR) and medium-wavelength infrared (MWIR) radiation range, and stand as promising components of medium to highly birefringent liquid crystalline mixtures.

Thermal Behavior of Epoxy Resins Cured with an Amine-Containing, Thermoplastic Poly(arylene Ether Sulphone)

1999 ◽  
Vol 19 (3) ◽  
pp. 161-174 ◽  
Author(s):  
Oriana Motta ◽  
Antonino Rocca ◽  
Valentina Siracusa ◽  
Domenico Acierno
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermal Behavior ◽  
Kinetic Parameters ◽  
Epoxy Resins ◽  
Curing Agent ◽  
Cure Process ◽  
Scanning Calorimetry ◽  
Arylene Ether ◽  
Diaminodiphenyl Methane ◽  
Residual Heat

Abstract In this paper we carried out the crosslinking of the tetraglycidyl-4,4′- diaminodiphenyl methane epoxy resin by using a reactive poly(arylene ether sulphone) as curing agent. Differential scanning calorimetry was used to derive the kinetic parameters of the reactions involved in the cure process and to evaluate the extent of the reaction as a function of time by measuring the total (ΔHr) and the residual heat(ΔHresid) of the resin at different curing times. A comparatively slower reaction was found to take place when the resin was cured with the poly(arylene ether sulphone) that when it was cured with the conventional curing agent 4,4′-diaminodiphenyl sulphone.

Interactions of Phosphors in Glucose Glasses for Solid-Matrix Phosphorescence

2001 ◽  
Vol 55 (10) ◽  
pp. 1385-1393 ◽  
Author(s):  
Shaun D. Mendonsa ◽  
Robert J. Hurtubise
Keyword(s):  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Aromatic Amines ◽  
Near Infrared ◽  
Heterocyclic Aromatic Amines ◽  
Solid Matrix ◽  
Infrared Spectrometry ◽  
Scanning Calorimetry ◽  
Glass Transition Temperatures ◽  
Near Infrared Spectrometry

Quenching of the room-temperature solid-matrix phosphorescence (SMP), near-infrared spectrometry, differential scanning calorimetry, and a polarity probe were used to study interactions of heterocyclic aromatic amines in glucose glasses prepared using crystalline glucose and a glucose melt. A near-infrared spectrometry method was developed to determine the wt % moisture in the glucose glasses. The wt % moisture of the glucose glasses was then related to phosphorescence intensities and lifetime ratios of the heterocyclic aromatic amines. A modified form of the Stern–Volmer equation was used to describe the changes in phosphorescence intensity and lifetime ratios. In other experiments, the glass transition temperatures of the glucose glasses were determined using differential scanning calorimetry. The glass transition temperatures were then correlated to the SMP of the heterocyclic aromatic amines in the glucose glasses. Lastly, the micro-environmental polarities of the glucose glasses were studied using a polarity probe. From these results a model was developed that described the effects of several parameters on the glucose glass matrices. For example, water was able to diffuse through channels in the glucose glasses and cause dynamic quenching of the phosphorescence. Also, the hydrogen bonding network in the glucose glasses was disrupted by water. This resulted in matrix quenching of the phosphorescence signals.

Quality control of the cure process of thermosetting resins by means of differential scanning calorimetry

1985 ◽  
Vol 30 (6) ◽  
pp. 1349-1357 ◽  
Author(s):  
A. Apicella ◽  
C. A. Beretta ◽  
M. A. Castiglione-Morelli ◽  
E. Martuscelli ◽  
L. Nicolais ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Quality Control ◽  
Cure Process ◽  
Scanning Calorimetry ◽  
Thermosetting Resins

Thermal Stability of N-Heterocycle-Stabilized Iodanes – A Systematic Investigation

2019 ◽  
Author(s):  
Andreas Boelke ◽  
Yulia A. Vlasenko ◽  
Mekhman S. Yusubov ◽  
Boris Nachtsheim ◽  
Pavel Postnikov
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Thermogravimetric Analysis ◽  
Systematic Investigation ◽  
Scanning Calorimetry ◽  
Thermal Stability Of

<p>The thermal stability of pseudocyclic and cyclic <i>N</i>-heterocycle-stabilized (hydroxy)aryl- and mesityl(aryl)-l<sup>3</sup>-iodanes (NHIs) through thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) is investigated. NHIs bearing <i>N</i>-heterocycles with a high N/C-ratio such as triazoles show among the lowest descomposition temperatures and the highest decomposition energies. A comparison of NHIs with known (pseudo)cyclic benziodoxolones is made and we further correlated their thermal stability with reactivity in a model oxygenation. </p>

Optimasi Proses Pembuatan dan Karakterisasi Fisik Niosom Sinkonin

2019 ◽  
Vol 16 (2) ◽  
pp. 178
Author(s):  
Hariyanti Hariyanti ◽  
Sophi Damayanti ◽  
Sasanti Tarini
Keyword(s):  
Differential Scanning Calorimetry ◽  
Particle Size ◽  
Hair Follicle ◽  
Scanning Calorimetry ◽  
Span 60

Sinkonin praktis tidak larut dalam air, sedikit larut dalam kloroform dan alkohol. Hal ini berdampak pada rendahnya penetrasi transfollicular sinkonin, karena hanya bahan aktif hidrofilik yang mampu melewati hair follicle. Dengan demikian dibutuhkan satu sistem penghantaran yang mampu menurunkan hidrofobisitas sinkonin untuk meningkatkan penetrasi sinkonin ke follicle. Niosom merupakan vesikel ampifilik dengan struktur lapisan rangkap yang terbentuk dari hidrasi kombinasi surfaktan nonionik dan kolesterol yang mampu menurunkan hidrofobisitas sinkonin. Penelitian ini bertujuan untuk menentukan proses pembuatan niosom sinkonin yang optimum. Pembuatan niosom sinkonin diawali dengan menentukan temperatur gelasi (Tg) dari span 60 dengan Differential Scanning Calorimetry (DSC), kemudian dilanjutkan dengan optimasi proses meliputi: optimasi kecepatan rotavapor pembentukan film lapis tipis, temperatur hidrasi, kecepatan rotavapor hidrasi, waktu hidrasi, dan waktu sonikasi. Karakteristik vesikel niosom yang optimal meliputi: ukuran partikel dan indeks polidispersitas dengan menggunakan Particle Size Analized (PSA) serta efisiensi penjeratan sinkonin dengan menggunakan KCKT. Temperatur gelasi (Tg) span 60 45±2 oC, kecepatan rotavapor pembentukan film lapis tipis niosom 210 rpm, temperatur hidrasi 55±2 oC, kecepatan rotavapor hidrasi 210 rpm, waktu hidrasi 20 menit, waktu sonikasi suspensi niosom 1 menit. Ukuran vesikel yang diperoleh adalah 100–200 nm, indeks polidispersitas 0,2–0,4 dan efisiensi penjeratan niosom sinkonin 84,49±0,0025%. Proses pembuatan niosom sinkonin memiliki pengaruh besar terhadap hasil ukuran vesikel dan efisiensi penjeratan niosom sinkonin.

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