Synthesis, Characterization and Thermooxidative Properties of Hybrid Block Poly(silane-b-arylacetylene)

2014 ◽  
Vol 1004-1005 ◽  
pp. 527-532
Author(s):  
Ying Jie Xu ◽  
Hui Min Qi ◽  
Ya Ping Zhu ◽  
Fan Wang
Keyword(s):  
Weight Loss ◽  
Oxidative Stability ◽  
Lewis Acid ◽  
Grignard Reagent ◽  
Room Temperature ◽  
Condensation Polymerization ◽  
Thermooxidative Stability ◽  
Thermal Cure ◽  
Inorganic Hybrid ◽  
Thermal And Oxidative Stability

Organic-inorganic hybrid block Poly (silane-b-arylacetylene) (PSbA) have been synthesized through condensation polymerization between chloro-terminated polysilane and diethynylbenzene Grignard reagent, and chloro-terminated polysilane was synthesized through condensation polymerization of dichloromethylvinylsilane in the presence of Mg metal and Lewis acid (ZnCl2, LiCl). The structures of PSbAs were characterized by FTIR, 1H, 13C, 29Si NMR, and GPC. The PSbAs are orange viscous liquid and can be soluble in common organic solvents at room temperature. The thermal cure behavior of PSbAs was determined by DSC, and the thermal and oxidative stability of the cured PSbAs were investigated using TGA. The results showed that the cured PSbAs exhibit high thermal and thermooxidative stability. The degradation temperatures at 5% weight loss for the cured PSbAs are 470-533°C under N2 and 378-456°C under air, and the residue yields at 1000°C are 77.9-82.8% under N2 and 40.4-50.5% under air.

Thermal and Oxidation Behavior of Boron-Silicon-Containing Arylacetylene Polymer

2012 ◽  
Vol 560-561 ◽  
pp. 179-183
Author(s):  
Xin Xin Sun ◽  
Hui Min Qi ◽  
Kang Kang Guo ◽  
Fa Rong Huang ◽  
Lei Du
Keyword(s):  
Differential Scanning Calorimetry ◽  
Oxidative Stability ◽  
Grignard Reagent ◽  
Oxidation Behavior ◽  
Resonance Spectroscopy ◽  
Polycondensation Reaction ◽  
Scanning Calorimetry ◽  
Thermal And Oxidative Stability ◽  
Ft Ir ◽  
C Nmr

Boron-silicon-containing arylacetylene polymer (PBSA) was synthesized through polycondensation reaction among diacetylenebenzene Grignard reagent, boron trichloride and dimethyldichlorosilane, and its structure was characterized by Infrared spectroscopy (FT-IR), Nuclear Magnetic Resonance spectroscopy (13C-NMR). The cure behavior of PBSA was investigated by using Differential Scanning Calorimetry (DSC), and the thermal and oxidative stability of cured PBSA were studied by Thermogravimetric Analysis (TGA) under nitrogen and air, respectively, the results indicated that ceramics derived from PBSA offer high thermal and oxidative stability.

On the use of Ozawa/Flynn/Wall method to determine aging activation energy for elastomers

2021 ◽  
pp. 009524432110203
Author(s):  
Sudhir Bafna
Keyword(s):  
Mechanical Properties ◽  
Activation Energy ◽  
Weight Loss ◽  
Oxygen Consumption ◽  
Dwell Time ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Degradation Mechanism ◽  
Kinetics Of ◽  
Wall Method

It is often necessary to assess the effect of aging at room temperature over years/decades for hardware containing elastomeric components such as oring seals or shock isolators. In order to determine this effect, accelerated oven aging at elevated temperatures is pursued. When doing so, it is vital that the degradation mechanism still be representative of that prevalent at room temperature. This places an upper limit on the elevated oven temperature, which in turn, increases the dwell time in the oven. As a result, the oven dwell time can run into months, if not years, something that is not realistically feasible due to resource/schedule constraints in industry. Measuring activation energy (Ea) of elastomer aging by test methods such as tensile strength or elongation, compression set, modulus, oxygen consumption, etc. is expensive and time consuming. Use of kinetics of weight loss by ThermoGravimetric Analysis (TGA) using the Ozawa/Flynn/Wall method per ASTM E1641 is an attractive option (especially due to the availability of commercial instrumentation with software to make the required measurements and calculations) and is widely used. There is no fundamental scientific reason why the kinetics of weight loss at elevated temperatures should correlate to the kinetics of loss of mechanical properties over years/decades at room temperature. Ea obtained by high temperature weight loss is almost always significantly higher than that obtained by measurements of mechanical properties or oxygen consumption over extended periods at much lower temperatures. In this paper, data on five different elastomer types (butyl, nitrile, EPDM, polychloroprene and fluorocarbon) are presented to prove that point. Thus, use of Ea determined by weight loss by TGA tends to give unrealistically high values, which in turn, will lead to incorrectly high predictions of storage life at room temperature.

scholarly journals Preparation and Electrochemical Characterization of Organic–Inorganic Hybrid Poly(Vinylidene Fluoride)-SiO2 Cation-Exchange Membranes by the Sol-Gel Method Using 3-Mercapto-Propyl-Triethoxyl-Silane

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3265 ◽  
Author(s):  
Li ◽  
Li ◽  
Li ◽  
Guan ◽  
Zheng ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Oxidative Stability ◽  
Water Uptake ◽  
Polyvinylidene Fluoride ◽  
Vinylidene Fluoride ◽  
Sol Gel ◽  
Synthesis Method ◽  
Co2 Production ◽  
Inorganic Hybrid ◽  
Poly Vinylidene Fluoride

A new synthesis method for organic–inorganic hybrid Poly(vinylidene fluoride)-SiO2 cation-change membranes (CEMs) is proposed. This method involves mixing tetraethyl orthosilicate (TEOS) and 3-mercapto-propyl-triethoxy-silane (MPTES) into a polyvinylidene fluoride (PVDF) sol-gel solution. The resulting slurry was used to prepare films, which were immersed in 0.01 M HCl, which caused hydrolysis and polycondensation between the MPTES and TEOS. The resulting Si-O-Si polymers chains intertwined and/or penetrated the PVDF skeleton, significantly improving the mechanical strength of the resulting hybrid PVDF-SiO2 CEMs. The -SH functional groups of MPTES oxidized to-SO3H, which contributed to the excellent permeability of these CEMs. The surface morphology, hybrid structure, oxidative stability, and physicochemical properties (IEC, water uptake, membrane resistance, membrane potential, transport number, and selective permittivity) of the CEMs obtained in this work were characterized using scanning electron microscope and Fourier transform infrared spectroscopy, as well as electrochemical testing. Tests to analyze the oxidative stability, water uptake, membrane potential, and selective permeability were also performed. Our organic–inorganic hybrid PVDF-SiO2 CEMs demonstrated higher oxidative stability and lower resistance than commercial Ionsep-HC-C membranes with a hydrocarbon structure. Thus, the synthesis method described in this work is very promising for the production of very efficient CEMs. In addition, the physical and electrochemical properties of the PVDF-SiO2 CEMs are comparable to the Ionsep-HC-C membranes. The electrolysis of the concentrated CoCl2 solution performed using PVDF-SiO2-6 and Ionsep-HC-C CEMs showed that at the same current density, Co2+ production, and current efficiency of the PVDF-SiO2-6 CEM membrane were slightly higher than those obtained using the Ionsep-HC-C membrane. Therefore, our novel membrane might be suitable for the recovery of cobalt from concentrated CoCl2 solutions.

Analysis of thermal and oxidative stability of biodiesel from Jatropha curcas L. and beef tallow

2012 ◽  
Vol 113 (2) ◽  
pp. 437-442 ◽  
Author(s):  
Erisandro S. Silva ◽  
Marta M. Conceição ◽  
Eduardo H. S. Cavalcanti ◽  
Valter J. Fernandes ◽  
Ana C. D. Medeiros ◽  
...  
Keyword(s):  
Oxidative Stability ◽  
Beef Tallow ◽  
Jatropha Curcas ◽  
Jatropha Curcas L ◽  
Thermal And Oxidative Stability

Above-room-temperature coupling between ferroelastic domains and magnetism in an organic-inorganic hybrid: CsCu(HCOO)2Cl

2021 ◽  
Vol 5 (7) ◽  
Author(s):  
Junyan Zhou ◽  
Shifeng Jin ◽  
Ruijin Sun ◽  
Congcong Chai ◽  
Munan Hao ◽  
...  
Keyword(s):  
Room Temperature ◽  
Inorganic Hybrid ◽  
Ferroelastic Domains

scholarly journals Linseed oil: Characterization and study of its oxidative degradation

2020 ◽  
Vol 71 (1) ◽  
pp. 337 ◽  
Author(s):  
B. M. Berto ◽  
R. K.A. Garcia ◽  
G. D. Fernandes ◽  
D. Barrera-Arellano ◽  
G. G. Pereira
Keyword(s):  
Fatty Acid ◽  
Oxidative Stability ◽  
Induction Period ◽  
Room Temperature ◽  
Linseed Oil ◽  
Oxidative Degradation ◽  
Acid Value ◽  
Quality Parameters ◽  
Time Intervals ◽  
Accelerated Oxidation

This paper proposes to characterize and monitor the degradation of linseed oil under two oxidation conditions using some traditional oxidative and quality parameters. The experimental section of this study was divided into 2 stages. In the first one, three commercial linseed oil samples (OL1, OL2, and OL3) were characterized according to oxidative stability (90 °C) and fatty acid composition. In the second stage, the OL1 sample, selected due to its availability, was subjected to the following oxidation procedures: storage at room temperature conditions with exposure to light and air (temperature ranging from 7 to 35 °C) for 140 days and accelerated oxidation at 100 °C for 7h. Samples were collected at different time intervals and analyzed for oxidative stability (90 °C), peroxide value, and acid value. The results showed that all the samples presented a similar fatty acid profile and that the OL3 sample showed a higher induction period (p < 0.05). Regarding the oxidative degradation, the induction period of the OL1 sample reduced from 9.7 to 5.7 and 9.7 to 6.3 during 140 days of storage under room temperature and 7 h of accelerated oxidation, respectively. The end of induction period of the OL1 sample is expected to occur within 229 days according to an exponential mathematical model fitted to the induction period values at different temperatures. In addition, the OL1 sample met the limits proposed by Codex and Brazilian regulations for peroxide and acid values during the oxidation time intervals.

scholarly journals Preparation of Room Temperature Curable Organic-inorganic Hybrid Thermal Control Coatings

2018 ◽  
Vol 33 (8) ◽  
pp. 914 ◽  
Author(s):  
LIU Ding ◽  
YU Yang ◽  
MI Le ◽  
YU Yun ◽  
SONG Li-Xin
Keyword(s):  
Room Temperature ◽  
Thermal Control ◽  
Inorganic Hybrid ◽  
Thermal Control Coatings

Lewis Acid Catalyzed Room-Temperature Michaelis–Arbuzov Rearrangement

2003 ◽  
Vol 42 (21) ◽  
pp. 2389-2392 ◽  
Author(s):  
Pierre-Yves Renard ◽  
Philippe Vayron ◽  
Eric Leclerc ◽  
Alain Valleix ◽  
Charles Mioskowski
Keyword(s):  
Lewis Acid ◽  
Room Temperature ◽  
Acid Catalyzed
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