Thermal Stability Studies on 1, 3, 5, 7 - Tetramethylcyclotetra-Siloxane(TMCTS), a Low к CVD Precursor

2002 ◽  
Vol 716 ◽  
Author(s):  
C. Xu ◽  
A. S. Borovik ◽  
Z. Wang ◽  
J. Arno ◽  
T. H. Baum
Keyword(s):  
Thermal Stability ◽  
Elevated Temperatures ◽  
Degradation Kinetics ◽  
Water Concentration ◽  
Proton Nuclear Magnetic Resonance ◽  
Thermal Degradation Kinetics ◽  
Gas Chromatography Mass Spectrometry ◽  
Resonance Spectroscopy ◽  
Residual Water ◽  
Degradation Rates

AbstractChemical studies on 1,3,5,7-tetramethylcyclotetrasiloxane (TMCTS) were conducted to elucidate its thermal behaviors with water and under various reaction conditions. TMCTS was heated in the presence of 316L stainless steel and in the presence of water. The heated TMCTS then was evaluated using 1H NMR (proton nuclear magnetic resonance) spectroscopy, GC-MS (gas chromatography-mass spectrometry) as a function of time, temperature and residual water concentration. The thermal degradation kinetics of gas-phase TMCTS were investigated using FTIR (Fourier transform infrared) spectroscopy at elevated temperatures. These initial results indicated that TMCTS degradation rates increased with both temperature and water concentration. This work spawned the development of a “dry” TMCTS that is expected to exhibit enhanced thermal stability relative towards uncontrolled decomposition.

scholarly journals Thermal Stability and Decomposition Mechanism of PLA Nanocomposites with Kraft Lignin and Tannin

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2818
Author(s):  
Nina Maria Ainali ◽  
Evangelia Tarani ◽  
Alexandra Zamboulis ◽  
Klementina Pušnik Črešnar ◽  
Lidija Fras Zemljič ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Degradation ◽  
Food Packaging ◽  
Degradation Kinetics ◽  
Kraft Lignin ◽  
Thermal Degradation Kinetics ◽  
Gas Chromatography Mass Spectrometry ◽  
Poly Lactic Acid ◽  
Pyrolysis Gas ◽  
Thermal Stability Of

Packaging applications cover approximately 40% of the total plastics production, whereas food packaging possesses a high proportion within this context. Due to several environmental concerns, petroleum-based polymers have been shifted to their biobased counterparts. Poly(lactic acid) (PLA) has been proved the most dynamic biobased candidate as a substitute of the conventional polymers. Despite its numerous merits, PLA exhibits some limitations, and thus reinforcing agents are commonly investigated as fillers to ameliorate several characteristics. In the present study, two series of PLA-based nanocomposites filled with biobased kraft-lignin (KL) and tannin (T) in different contents were prepared. A melt–extrusion method was pursued for nanocomposites preparation. The thermal stability of the prepared nanocomposites was examined by Thermogravimetric Analysis, while thermal degradation kinetics was applied to deepen this process. Pyrolysis–Gas Chromatography/Mass Spectrometry was employed to provide more details of the degradation process of PLA filled with the two polyphenolic fillers. It was found that the PLA/lignin nanocomposites show better thermostability than neat PLA, while tannin filler has a small catalytic effect that can reduce the thermal stability of PLA. The calculated Eα value of PLA-T nanocomposite was lower than that of PLA-KL resulting in a substantially higher decomposition rate constant, which accelerate the thermal degradation.

Thermal degradation kinetics of Opuntia Ficus Indica flour and talc-filled poly (lactic acid) hybrid biocomposites by TGA analysis

2021 ◽  
pp. 002199832110082
Author(s):  
Azzeddine Gharsallah ◽  
Abdelheq Layachi ◽  
Ali Louaer ◽  
Hamid Satha
Keyword(s):  
Thermal Stability ◽  
Lactic Acid ◽  
Thermal Degradation ◽  
Degradation Kinetics ◽  
Degradation Mechanism ◽  
Melt Processing ◽  
Thermal Degradation Kinetics ◽  
Poly Lactic Acid ◽  
Opuntia Ficus Indica ◽  
Model Free

This paper reports the effect of lignocellulosic flour and talc powder on the thermal degradation behavior of poly (lactic acid) (PLA) by thermogravimetric analysis (TGA). Lignocellulosic flour was obtained by grinding Opuntia Ficus Indica cladodes. PLA/talc/ Opuntia Ficus Indica flour (OFI-F) biocomposites were prepared by melt processing and characterized using Wide-angle X-ray scattering (WAXS) and Scanning Electron Microscope (SEM). The thermal degradation of neat PLA and its biocomposites can be identified quantitatively by solid-state kinetics models. Thermal degradation results on biocomposites compared to neat PLA show that talc particles at 10 wt % into the PLA matrix have a minor impact on the thermal stability of biocomposites. Loading OFI-F and Talc/OFI-F mixture into the PLA matrix results in a decrease in the maximum degradation temperature, which means that the biocomposites have lower thermal stability. The activation energies (Ea) calculated by the Flynn Wall Ozawa (FWO) and Kissinger Akahira Sunose (KAS) model-free approaches and by model-fitting (Kissinger method and Coats-Redfern method) are in good agreement with one another. In addition, in this work, the degradation mechanism of biocomposites is proposed using Coats-Redfern and Criado methods.

scholarly journals Thermal Degradation Kinetics and Modeling Study of Ultra High Molecular Weight Polyethylene (UHMWP)/Graphene Nanocomposite

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1597
Author(s):  
Iman Jafari ◽  
Mohamadreza Shakiba ◽  
Fatemeh Khosravi ◽  
Seeram Ramakrishna ◽  
Ehsan Abasi ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Molecular Weight ◽  
Thermal Degradation ◽  
High Molecular Weight ◽  
Degradation Kinetics ◽  
Graphene Nanosheets ◽  
Thermal Degradation Kinetics ◽  
Graphene Nanocomposites ◽  
Kinetics Of ◽  
Ultra High Molecular Weight

The incorporation of nanofillers such as graphene into polymers has shown significant improvements in mechanical characteristics, thermal stability, and conductivity of resulting polymeric nanocomposites. To this aim, the influence of incorporation of graphene nanosheets into ultra-high molecular weight polyethylene (UHMWPE) on the thermal behavior and degradation kinetics of UHMWPE/graphene nanocomposites was investigated. Scanning electron microscopy (SEM) analysis revealed that graphene nanosheets were uniformly spread throughout the UHMWPE’s molecular chains. X-Ray Diffraction (XRD) data posited that the morphology of dispersed graphene sheets in UHMWPE was exfoliated. Non-isothermal differential scanning calorimetry (DSC) studies identified a more pronounced increase in melting temperatures and latent heat of fusions in nanocomposites compared to UHMWPE at lower concentrations of graphene. Thermogravimetric analysis (TGA) and derivative thermogravimetric (DTG) revealed that UHMWPE’s thermal stability has been improved via incorporating graphene nanosheets. Further, degradation kinetics of neat polymer and nanocomposites have been modeled using equations such as Friedman, Ozawa–Flynn–Wall (OFW), Kissinger, and Augis and Bennett’s. The "Model-Fitting Method” showed that the auto-catalytic nth-order mechanism provided a highly consistent and appropriate fit to describe the degradation mechanism of UHMWPE and its graphene nanocomposites. In addition, the calculated activation energy (Ea) of thermal degradation was enhanced by an increase in graphene concentration up to 2.1 wt.%, followed by a decrease in higher graphene content.

Thermal Stabilities and the Thermal Degradation Kinetics Study of the Flame Retardant Epoxy Resins

2014 ◽  
Vol 1053 ◽  
pp. 263-267 ◽  
Author(s):  
Xiu Juan Tian
Keyword(s):  
Thermal Stability ◽  
Thermal Degradation ◽  
Flame Retardant ◽  
Epoxy Resin ◽  
Epoxy Resins ◽  
Degradation Kinetics ◽  
Thermal Degradation Kinetics ◽  
Thermal Stabilities ◽  
Degradation Kinetic ◽  
Modified Epoxy

Thermal stability and thermal degradation kinetics of epoxy resins with 2-(Diphenylphosphinyl)-1, 4-benzenediol were investegated by thermogravimetric analysis (TGA) at different heating rates of 5 K/min, 10 K/min, 20 K/min and 40 K/min. The thermal degradation kinetic mechanism and models of the modified epoxy resins were determined by Coast Redfern method.The results showed that epoxy resins modified with the flame retardant had more thermal stability than pure epoxy resin. The solid-state decomposition mechanism of epoxy resin and the modified epoxy resin corresponded to the controlled decelerating ځ˽̈́˰̵̳͂͆ͅ˼˰̴̱̾˰̸̵̈́˰̵̸̳̱̹̽̾̓̽˰̶̳̹̾̈́̿̾̓ͅ˰̶˸ځ˹˰̵̵͇͂˰̃˸́˽ځ˹2/3. The introduction of phosphorus-containing flame retardant reduced thermal degradation rate of epoxy resins in the primary stage, and promote the formation of carbon layer.

Thermo-oxidative and thermal degradation kinetics of silica/polymethyl methacrylate composites with electrostatic interaction phase interfaces

2019 ◽  
Vol 39 (2) ◽  
pp. 105-116 ◽  
Author(s):  
Hongyan Li ◽  
Yongqiang Fu ◽  
Hongli Liu ◽  
Cong Sun ◽  
Ruyi Li ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Degradation ◽  
Polymethyl Methacrylate ◽  
Electrostatic Interaction ◽  
Degradation Kinetics ◽  
Thermal Degradation Kinetics ◽  
Degradation Kinetic ◽  
Further Development ◽  
Kinetics Of ◽  
Insulation Performance

AbstractThe thermo-oxidative and thermal degradation kinetic parameters of polymethyl methacrylate-methacryloxyethyltrimethyl ammonium chloride/silica aerogel composites (PMMA-MTC/SA) were investigated in this paper and were compared with the thermal stability and thermal conductivity of different types of composites. As a composite with electrostatic interaction, the thermo-oxidative and thermal degradation activation energies (E) of PMMA-MTC/SA were 173.97 and 188.05 kJ/mol, respectively. The results indicated that the electrostatic interaction could indeed enhance the thermal stability of silica/polymethyl methacrylate composites on the premise of good mechanical properties and heat insulation performance. It is of great significance for the further development of silica-based thermal insulation composites.

Non-isothermal crystallization and thermal degradation kinetics of MXene/linear low-density polyethylene nanocomposites

e-Polymers ◽  
2017 ◽  
Vol 17 (5) ◽  
pp. 373-381 ◽  
Author(s):  
Xinxin Cao ◽  
Mengqi Wu ◽  
Aiguo Zhou ◽  
You Wang ◽  
Xiaofang He ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Thermal Degradation ◽  
Isothermal Crystallization ◽  
Degradation Kinetics ◽  
Thermal Degradation Kinetics ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Linear Low Density Polyethylene ◽  
Kinetics Of

AbstractA novel two-dimensional material MXene was used to synthesize nanocomposites with linear low-density polyethylene (LLDPE). The influence of MXene on crystallization and thermal degradation kinetics of LLDPE was investigated. Non-isothermal crystallization kinetics was investigated by using differential scanning calorimetry (DSC). The experimental data was analyzed by Jeziorny theory and the Mo method. It is found that MXene acted as a nucleating agent during the non-isothermal crystallization process, and 2 wt% MXene incorporated in the nanocomposites could accelerate the crystallization rate. Findings from activation energy calculation for non-isothermal crystallization came to the same conclusion. Thermal gravity (TG) analysis of MXene/LLDPE nanocomposites was conducted at different heating rates, and the TG thermograms suggested the nanocomposites showed an improvement in thermal stability. Apparent activation energy (Ea) of thermal degradation was calculated by the Kissinger method, and Ea values of nanocomposites were higher than that of pure LLDPE. The existence of MXene seems to lead to better thermal stability in composites.

Preparation and characterization of a novel amphoteric polymer for oil well cementing with superior performances

2020 ◽  
Vol 29 (1) ◽  
pp. 29-39
Author(s):  
Tang Xin ◽  
Hu Xuzeng ◽  
Wan Haodong
Keyword(s):  
Thermal Stability ◽  
Orthogonal Experiment ◽  
Radical Copolymerization ◽  
Proton Nuclear Magnetic Resonance ◽  
Fluid Loss ◽  
Resonance Spectroscopy ◽  
Oil Well ◽  
Cement Slurry ◽  
Synthesis Conditions ◽  
Th 1

A novel amphoteric polymer TH-1 was synthesized using the monomers of 2-acrylamido-2-methylpropane sulfonic acid, acrylic acid, acrylamide, and cationic monomer through radical copolymerization as filtrate loss reducer in oil well cementing. Optimal synthesis conditions of TH-1 were obtained by an orthogonal experiment. The composition of copolymer (TH-1) was characterized by Fourier-transform infrared spectrum and proton nuclear magnetic resonance spectroscopy. The thermal stability of the synthesized copolymer was tested by thermogravimetric analysis. The fluid loss (FL) control and thickening performance of cement slurry incorporating TH-1 were evaluated at different temperatures. The filtration reduction mechanism of TH-1 was finally discussed. Results suggest that the amphoteric polymer is the target product polymerized by all the monomers, which presents excellent filtrate reduction property, high thermal stability, and strong saline tolerance under 200°C. The amphoteric polymer TH-1 includes cationic and anionic group in a molecule structure, which can adsorb firmly onto the surface of cement particles through electrostatic attraction and form adsorption membrane of viscoelastic polymer. In this way, compact cement filter cakes are formed, thereby efficiently reducing the FL.

Heat-resistant and photoluminescent indole-based poly(ether sulfone)s

2017 ◽  
Vol 30 (4) ◽  
pp. 475-479 ◽  
Author(s):  
Wenxuan Wei ◽  
Li Yang ◽  
Guanjun Chang
Keyword(s):  
Thermal Stability ◽  
High Performance ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Condensation Polymerization ◽  
High Glass Transition Temperature ◽  
Scanning Calorimetry ◽  
Good Thermal Stability ◽  
High Performance Polymers ◽  
Good Agreement

Indole-based poly(ether sulfone)s (PINESs), as novel high-performance polymers, have been obtained by the condensation polymerization of 4-hydroxyindole and hydroquinone with activated difluoro monomers via a catalyst-free nucleophilic substitution reaction. The structures of the polymers are characterized by means of Fourier transform infrared and proton nuclear magnetic resonance spectroscopy, and the results show good agreement with the proposed structures. Differential scanning calorimetry and thermogravimetric analysis measurements exhibit that polymers possess high glass transition temperature ( Tgs > 245°C) and good thermal stability with high decomposition temperatures ( Tds > 440°C). In addition, due to their special structure, PINESs are endowed with significantly strong photonic luminescence in N, N-dimethylformamide.

Thermal properties and thermal degradation kinetics of phenolic and wood flour-reinforced phenolic foams

2016 ◽  
Vol 51 (1) ◽  
pp. 125-138 ◽  
Author(s):  
JC Domínguez ◽  
B del Saz-Orozco ◽  
M Oliet ◽  
MV Alonso ◽  
F Rodriguez
Keyword(s):  
Thermal Stability ◽  
Thermal Degradation ◽  
Degradation Kinetics ◽  
Wood Flour ◽  
Activation Energies ◽  
Thermal Degradation Kinetics ◽  
Kinetic Methods ◽  
Model Free ◽  
Phenolic Foam ◽  
Kinetics Of

In the present work, the thermal stability, changes in chemical structure during thermal degradation, and the kinetics of thermal degradation of a phenolic foam were studied. An 8.5 wt% of Pinus radiata wood flour reinforcement was added to the phenolic foam. A commercial phenolic resol was used as the matrix for the foam. The wood flour-reinforced foam showed a structure similar to the phenolic foam according to the Fourier transform infrared spectroscopy results. The wood flour increased the thermal stability of the phenolic foam in the first stage of thermal degradation ( T 5%), decreased it in the second step ( T 25%), and negligibly influenced the final stage. The activation energies of the degradation processes of the studied materials were obtained by the Kissinger-Akahira-Sunose and Flynn-Wall-Ozawa model-free kinetic methods and a 2-Gaussian distributed activation energy model. The values of the activation energies obtained by the model-free kinetic methods for the first degradation stage of the phenolic foams were in a range between 110 and 170 kJ mol−1, whereas for the wood flour it was 162 kJ mol−1 for almost all of the conversion range of its main degradation stage. The applied models showed good fits for all the materials, and the activation energies calculated were in agreement with the values found in the literature.

Sign in / Sign up

Export Citation Format

Share Document