Thermally stable oligomer—Metal complexes based on oligo-ortho-aminophenol and oligophenylazomethinephenol

2006 ◽  
Vol 60 (4) ◽  
Author(s):  
H. Mart ◽  
M. Koç ◽  
V. Muradoğlu ◽  
H. Yürük

AbstractThe oligo-ortho-aminophenol was synthesized by the oxidative polycondensation of ortho-aminophenol with air oxygen. The oligophenylazomethinephenol was synthesized by the condensation of aniline with oligosalicylaldehyde. Metal complexes of these oligomers with Cu(II), Co(II), Zn(II), and Ni(II) were synthesized and characterized. Based on the results of thermogravimetric analysis, synthesized oligomer—metal complexes were more stable against heat and thermooxidative decomposition than some polymeric Schiff bases and polymer—metal complexes. Additionally, the presence of metal ions increased the thermal stability of oligo-ortho-aminophenol, while the thermal stability of oligophenylazomethinephenol was lowered.

Author(s):  
Mohammad Mizanur Rahman Khan ◽  
Yee Keat Wee ◽  
Saif Uddin Ahmed ◽  
Masnun Naher ◽  
Muhammad Younus ◽  
...  

AbstractThe control of thermal stability of polyaniline (PANI) nanofibers is reported by systematically varying the loadings of CaO in the range from 0.005 g to 1.0 g. It was found to gradually increase the yield of synthesized PANI nanofibers with the increase of CaO addition. The highest yield, 1.103 g was obtained for 1.00 g loading of CaO. The incorporation of CaO into PANI matrix was revealed by energy-dispersive X-ray spectroscopy (EDX). Thermogravimetric analysis (TGA) data showed that the thermal stability of PANI nanofibers was greatly improved when CaO was added to the system. 1.00 g loading of CaO is favorable to obtain comparatively more thermally stable PANI. The degradation of PANI chains started at 330 °C for the PANI-CaO composites obtained at 1.00 g CaO addition, which is the highest temperature compared to PANI and the samples synthesized at other amount of CaO loadings. Furthermore, the increasing trend of thermal stability was observed with the increasing of CaO loading.


2019 ◽  
Author(s):  
Andreas Boelke ◽  
Yulia A. Vlasenko ◽  
Mekhman S. Yusubov ◽  
Boris Nachtsheim ◽  
Pavel Postnikov

<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>


Author(s):  
J. S. Mills ◽  
F. R. Edwards

The propensity of aviation turbine fuels to produce deposits in the oil-cooler and filter sections of aircraft fuel systems has been examined using a rig that simulates the fuel system of an aircraft and which employs realistic flow rates. All the fuels examined were found to be thermally stable up to temperatures in excess of those currently attained in engine oil coolers. Comparison with results obtained with the JFTOT indicates that this is not suited for use as a research tool.


2021 ◽  
Vol 875 ◽  
pp. 116-120
Author(s):  
Muhammad Alamgir ◽  
Faizan Ali Ghauri ◽  
Waheed Qamar Khan ◽  
Sajawal Rasheed ◽  
Muhammad Sarfraz Nawaz ◽  
...  

In this study, the effect of SBR concentration (10 Phr, 20 Phr & 30 Phr ) on the thermal behavior of EPDM/SBR blends was studied. Thermogravimetric analysis (TGA) was used to check weight loss of samples as function of temperature by heating upto 600°C. X-ray diffraction (XRD) was performed to determine quality and % crystallinity of the elastomer blends. It was seen that % crystallinity improved with an increase in the content of SBR in EPDM/SBR blends. TGA revealed that the thermal stability of EPDM/SBR blends has improved by 17% than neat EPDM. Carbon nano-coatings produced by sputtering have no beneficial influence on thermal behaviour of elastomers.


2018 ◽  
Vol 19 (12) ◽  
pp. 3723 ◽  
Author(s):  
Shaoyun Chen ◽  
Min Xiao ◽  
Luyi Sun ◽  
Yuezhong Meng

The terpolymerization of carbon dioxide (CO2), propylene oxide (PO), and cyclohexene oxide (CHO) were performed by both random polymerization and block polymerization to synthesize the random poly (propylene cyclohexene carbonate) (PPCHC), di-block polymers of poly (propylene carbonate–cyclohexyl carbonate) (PPC-PCHC), and tri-block polymers of poly (cyclohexyl carbonate–propylene carbonate–cyclohexyl carbonate) (PCHC-PPC-PCHC). The kinetics of the thermal degradation of the terpolymers was investigated by the multiple heating rate method (Kissinger-Akahira-Sunose (KAS) method), the single heating rate method (Coats-Redfern method), and the Isoconversional kinetic analysis method proposed by Vyazovkin with the data from thermogravimetric analysis under dynamic conditions. The values of ln k vs. T−1 for the thermal decomposition of four polymers demonstrate the thermal stability of PPC and PPC-PCHC are poorer than PPCHC and PCHC-PPC-PCHC. In addition, for PPCHC and PCHC-PPC-PCHC, there is an intersection between the two rate constant lines, which means that, for thermal stability of PPCHC, it is more stable than PCHC-PPC-PCHC at the temperature less than 309 °C and less stable when the decomposed temperature is more than 309 °C. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and thermogravimetric analysis/infrared spectrometry (TG/FTIR) techniques were applied to investigate the thermal degradation behavior of the polymers. The results showed that unzipping was the main degradation mechanism of all polymers so the final pyrolysates were cyclic propylene carbonate and cyclic cyclohexene carbonate. For the block copolymers, the main chain scission reaction first occurs at PC-PC linkages initiating an unzipping reaction of PPC chain and then, at CHC–CHC linkages, initiating an unzipping reaction of the PCHC chain. That is why the T−5% of di-block and tri-block polymers were not much higher than that of PPC while two maximum decomposition temperatures were observed for both the block copolymer and the second one were much higher than that of PPC. For PPCHC, the random arranged bulky cyclohexane groups in the polymer chain can effectively suppress the backbiting process and retard the unzipping reaction. Thus, it exhibited much higher T−5% than that of PPC and block copolymers.


Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1105 ◽  
Author(s):  
Palin ◽  
Rombolà ◽  
Milanesio ◽  
Boccaleri

Plasticized–Poly(vinyl chloride) (P-PVC) for cables and insulation requires performances related to outdoor, indoor and submarine contexts and reduction of noxious release of HCl-containing fumes in case of thermal degradation or fire. Introducing suitable nanomaterials in polymer-based nanocomposites can be an answer to this clue. In this work, an industry-compliant cable-grade P-PVC formulation was added with nanostructured materials belonging to the family of Polyhedral Oligomeric Silsesquioxane (POSS). The effects of the nanomaterials, alone and in synergy with HCl scavenging agents as zeolites and hydrotalcites, on the thermal stability and HCl evolution of P-PVC were deeply investigated by thermogravimetric analysis and reference ASTM methods. Moreover, hardness and mechanical properties were studied in order to highlight the effects of these additives in the perspective of final industrial uses. The data demonstrated relevant improvements in the thermal stability of the samples added with nanomaterials, already with concentrations of POSS down to 0.31 phr and interesting additive effects of POSS with zeolites and hydrotalcites for HCl release reduction without losing mechanical performances.


2019 ◽  
Vol 35 (2) ◽  
pp. 785-791
Author(s):  
AZZA ABDULLAH Al-GHAMDI

Acrylonitrile (AN) was copolymerized with itaconic acid metal complexes [Co(II),Ni(II),Cu(II)] aiming to synthetize self-colored acrylonitrile fiber. The copolymerization occurred in water at 60°C using sodium bisulfite and potassium persulfate as redox initiators. The resulting copolymers are colored and exhibited high thermal stability as shown from their TGA curves. The investigated copolymers exhibited comparable thermal stability as that of PAN. The AN/ itaconic acid Co(NO3)2copolymer was considerably the most thermal stable copolymer while that of Ni(II) copolymer was the less stable one. Cu(II) copolymer showed an intermediate stability. The data also revealed that the maximum degradation occurred after 300°C (the cyclization temperature). Thus, neither the copolymerization nor the complexation affected the nitrile oligomerization reaction. The effect of adding ammonium hydroxide solution to acrylonitrile – itaconic acid copper(II) complex copolymer on the thermal stability of copolymer was also studied.


2011 ◽  
Vol 1312 ◽  
Author(s):  
Rafael Villegas ◽  
Yun Zhai ◽  
Hailan Xu ◽  
Dorina Magdalena Chipara ◽  
David Hui ◽  
...  

ABSTRACTNanocomposites of polystyrene loaded with various amounts of anatase (ranging between 0 % wt. and 20 % wt.) have been synthesized and investigated by thermal analysis. The research was focused on the simulation of Thermogravimetric Analysis data, aiming to a refined understanding of the interactions between of polystyrene and TiO2 nanoparticles. The dependence of the first derivative of residual mass on temperature has been used to determine more accurately the temperature at which the mass loss is maxim. Several functions have been used to simulate the dependence of the first derivative of mass loss on the temperature of the sample. The highest correlation coefficient was obtained for the asymmetric Gaussian combination, which connects two halves of a Gaussian line with different linewidth. An increase of the thermal stability of the polymeric matrix upon loading with TiO2 is reported.


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