scholarly journals Photoinduced Polymerization of Eugenol-Derived Methacrylates

Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3444 ◽  
Author(s):  
Samantha Molina-Gutiérrez ◽  
Sara Dalle Vacche ◽  
Alessandra Vitale ◽  
Vincent Ladmiral ◽  
Sylvain Caillol ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Contact Angle ◽  
Chain Transfer ◽  
Radical Addition ◽  
Polymerization Rate ◽  
Low Energy ◽  
Scanning Calorimetry ◽  
Biobased Polymers ◽  
Photoinduced Polymerization ◽  
Energy Consuming

Biobased monomers have been used to replace their petroleum counterparts in the synthesis of polymers that are aimed at different applications. However, environmentally friendly polymerization processes are also essential to guarantee greener materials. Thus, photoinduced polymerization, which is low-energy consuming and solvent-free, rises as a suitable option. In this work, eugenol-, isoeugenol-, and dihydroeugenol-derived methacrylates are employed in radical photopolymerization to produce biobased polymers. The polymerization is monitored in the absence and presence of a photoinitiator and under air or protected from air, using Real-Time Fourier Transform Infrared Spectroscopy. The polymerization rate of the methacrylate double bonds was affected by the presence and reactivity of the allyl and propenyl groups in the eugenol- and isoeugenol-derived methacrylates, respectively. These groups are involved in radical addition, degradative chain transfer, and termination reactions, yielding crosslinked polymers. The materials, in the form of films, are characterized by differential scanning calorimetry, thermogravimetric, and contact angle analyses.

PHASE TRANSFORMATIONS DURING HEATING OF AMORPHOUS/NANOCRYSTALLINE Ni–Ti POWDERS

2010 ◽  
Vol 24 (09) ◽  
pp. 1137-1140 ◽  
Author(s):  
M. M. VERDIAN ◽  
M. SALEHI ◽  
K. RAEISSI
Keyword(s):  
Differential Scanning Calorimetry ◽  
Solid State ◽  
Phase Transformations ◽  
Low Energy ◽  
Heating Process ◽  
Study Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Niti Phase

Amorphous/nanocrystalline 50 Ni –50 Ti powders were synthesized from elemental Ti and Ni powders by solid state synthesis utilizing low energy mechanical alloying with times up to 100 h. The produced powders were investigated by X-ray diffraction and differential scanning calorimetry to study phase transformations that occurred during heating in the calorimeter. It was found that at the first stage of the heating process, a disordered NiTi phase was formed at temperature of about 400°C. Further investigations indicated that this phase transformed into the Ni 3 Ti and Ti 2 Ni intermetallic compounds after heating at a temperature of about 800°C.

scholarly journals Development of Sn-9Zn Solder Alloy by Adding Bismuth

2020 ◽  
Vol 13 (4) ◽  
pp. 37-43
Author(s):  
Abbas AL-ALbawee
Keyword(s):  
Differential Scanning Calorimetry ◽  
Contact Angle ◽  
Solder Alloy ◽  
Mechanical Characteristics ◽  
Electric Resistivity ◽  
Solid Surfaces ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Electronic Application ◽  
Pasty Range

Tin-Zinc based on solder is a probable changing of lead element solder as a result of its enhanced mechanical characteristics. This alloy needs to be studied and explored to get a usable solder alloy having better properties. In this work Our objective of the accompanying investigation for alteration the warm, physical and bind qualities of eutectic tin-9Zinc fastening alloy by expansion various ratios of bismuth content to give elective without lead solder alloy to utilize this compound for efferent electronic ventures. We found that the addition of bismuth element content improved the thermal, physical and electrical features and qualities. We got the mentioned results by using x-ray diffractometer, differential scanning calorimetry and LCR instrument to calculate electric resistivity and the contact edge (CA) is the most important factor used for assessing the solid surfaces wettability. Sn91Zn3Bi6 alloy has best solder properties as low melting temperature, pasty range and contact angle. And has the beast soldering properties for electronic application compared to commercial Pb- Sn alloy

scholarly journals Blocking and Deblocking of Diisocyanate to Synthesize Polyurethanes

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2875
Author(s):  
Sourita Jana ◽  
Debasis Samanta ◽  
Mirmuhammad Fahad ◽  
Sellamuthu N. Jaisankar ◽  
Hongdoo Kim
Keyword(s):  
Differential Scanning Calorimetry ◽  
Contact Angle ◽  
Thermogravimetric Analysis ◽  
Toluene Diisocyanate ◽  
Resonance Spectroscopy ◽  
Spectroscopic Techniques ◽  
Scanning Calorimetry ◽  
Molecular Weights ◽  
Contact Angle Analysis

Diisocyanates, particularly toluene diisocyanate (TDI), are useful for the preparation of various polyurethanes with specific applications as leather-like materials, adhesives and insoles, etc. Blocking agents can be used for the operational simplicity and to reduce the hazards of TDI. In this paper, we reported the use of 3-(4-bromo-phenyl)-1H-pyrazole to block toluene diisocyanate (TDI). FTIR, NMR, thermogravimetric analysis, contact angle analysis and differential scanning calorimetry (DSC) were used for the characterization. The effectiveness of the blocking was confirmed by spectroscopic techniques. The DSC thermogram showed that blocked adducts deblock at 240 °C, causing the regeneration of TDI, and causing the diisocyanates to react with polyols of different molecular weights, forming polyurethanes. The characterization of the polyurethanes was performed by infrared spectroscopy, nuclear magnetic resonance spectroscopy, thermogravimetric analysis, differential scanning calorimetry and a contact angle study.

Preparation of Antimicrobial PHEMA-g-PCBMAE Hydrogels with Improved Mechanical Properties

2014 ◽  
Vol 576 ◽  
pp. 49-53
Author(s):  
Ren Chang Zeng ◽  
Jiang Cheng ◽  
Shou Ping Xu ◽  
Qin Liu ◽  
Xiu Fang Wen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Differential Scanning Calorimetry ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Antimicrobial Properties ◽  
Hydroxyethyl Methacrylate ◽  
Scanning Calorimetry ◽  
Reversible Addition ◽  
Mechanical Study ◽  
Mechanical Strengths

A series of poly (hydroxyethyl methacrylate)-g-polycarboxybetaine methacrylate ester (PHEMA-g-PCBMAE) hydrogels were synthesized using reversible addition-fragmentation chain transfer (RAFT) polymerization in the presence of crosslinker. Then differential scanning calorimetry (DSC) was used to characterize PHEMA-g-PCBMAE hydrogels. The compression stresses of these hydrogels were investigated to evaluate the mechanical properties. The mechanical study suggested that PHEMA-g-PCBMAE hydrogels presented improved mechanical strengths comparing with polycarboxybetaine methacrylate ester (PCBMAE) hydrogel. Besides, the antimicrobial properties of PHEMA-g-PCBMAE hydrogels also estimated by usingStaphylococcus aureusas a model bacterial.

scholarly journals Blocking and Deblocking of Diisocyanate to Synthesize Polyurethanes

2021 ◽  
Author(s):  
Sourita Jana ◽  
Debasis Samanta ◽  
Mir Muhammad Fahad ◽  
Sellamuthu N Jaisankar ◽  
Hongdoo Kim
Keyword(s):  
Differential Scanning Calorimetry ◽  
Contact Angle ◽  
Thermogravimetric Analysis ◽  
Toluene Diisocyanate ◽  
Resonance Spectroscopy ◽  
Spectroscopic Techniques ◽  
Scanning Calorimetry ◽  
Molecular Weights ◽  
Blocking Agents

Diisocyanates, particularly toluene diisocyanate (TDI) are useful for the preparation of various polyurethanes with specific applications as leather-like materials, adhesives, insoles etc. Blocking agents can be used for the operational simplicity and reducing the hazards of TDI. In this paper we reported the use of 3-(4-bromo-phenyl)-1H-pyrazole to block toluene diisocyanate (TDI). FTIR, NMR, thermogravimetric analysis, contact angle and differential scanning calorimetry (DSC) and were used for characterization. Effectiveness of blocking was confirmed by spectroscopic techniques. DSC thermogram shows that blocked adducts deblock at 240 °C causing the regeneration of TDI and blocking agents to react with polyols of different molecular weights forming polyurethanes. The characterization of polyurethanes has been done by Infrared spectroscopy, Nuclear magnetic resonance spectroscopy, thermogravimetric analysis, differential scanning calorimetry and contact angle study.

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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