scholarly journals Isothermal Vulcanization and Non-Isothermal Degradation Kinetics of XNBR/Epoxy/XNBR-g-Halloysite Nanotubes (HNT) Nanocomposites

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2872
Author(s):  
Seyed Mohamad Reza Paran ◽  
Ghasem Naderi ◽  
Elnaz Movahedifar ◽  
Maryam Jouyandeh ◽  
Krzysztof Formela ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Degradation Kinetics ◽  
Halloysite Nanotubes ◽  
Butadiene Rubber ◽  
Order Model ◽  
Scanning Calorimetry ◽  
Theoretical Methods ◽  
Vulcanization Kinetics ◽  
Kinetics Of ◽  
Thermal Stability Of

The effect of several concentrations of carboxylated nitrile butadiene rubber (XNBR) functionalized halloysite nanotubes (XHNTs) on the vulcanization and degradation kinetics of XNBR/epoxy compounds were evaluated using experimental and theoretical methods. The isothermal vulcanization kinetics were studied at various temperatures by rheometry and differential scanning calorimetry (DSC). The results obtained indicated that the nth order model could not accurately predict the curing performance. However, the autocatalytic approach can be used to estimate the vulcanization reaction mechanism of XNBR/epoxy/XHNTs nanocomposites. The kinetic parameters related to the degradation of XNBR/epoxy/XHNTs nanocomposites were also assessed using thermogravimetric analysis (TGA). TGA measurements suggested that the grafted nanotubes strongly enhanced the thermal stability of the nanocomposite.

Synthesis and Thermal Stability of Unsaturated Polyamides

1992 ◽  
Vol 4 (2) ◽  
pp. 67-71
Author(s):  
N. R. Patel ◽  
N. Z. Patel ◽  
R. M. Patel
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Thermogravimetric Analysis ◽  
Scanning Calorimetry ◽  
Aromatic Diamines ◽  
Good Thermal Stability ◽  
Kinetics Of Decomposition ◽  
Glutaconic Acid ◽  
Kinetics Of ◽  
Thermal Stability Of

Unsaturated polyamides were prepared by condensing /3(4-ethoxyphenyl) glutaconic acid with various aromatic diamines. The polycondensates were characterized by IR spectroscopy, vapor phase osmometry, thermogravimetric analysis, differential scanning calorimetry and elemental analysis. All resins were found to decompose in the range '-210-600 °C. The kinetics of decomposition were studied. The results indicated that the resins possess reasonably good thermal stability.

scholarly journals Degradation Kinetics and Solvent Effects of Various Long-Chain Quaternary Ammonium Salts

2021 ◽  
Author(s):  
Roel Kleijwegt ◽  
Wyatt Winkenwerder ◽  
Wim Baan ◽  
John van der Schaaf
Keyword(s):  
Thermal Stability ◽  
Solvent Effects ◽  
Quaternary Ammonium ◽  
Degradation Kinetics ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Polar Solvents ◽  
Kinetics Of ◽  
Thermal Stability Of ◽  
Long Chain

<div>Surfactants such as quaternary ammonium salts (QAS) have been in increasing demand, for emerging new applications. Recent attempts at process intensification of</div><div>their production, have disclosed the need for a better understanding of QAS thermal stability. This work aims to determine degradation kinetics of various QASs, and the</div><div>associated solvent effects. Degradation kinetics of four methyl carbonate QASs were determined in various</div><div>polar solvents in stainless steel batch autoclaves. <sup>1</sup>H NMR spectrometry was employed for online analysis of the reaction mixtures. The kinetic parameters were then used</div><div>to compare the thermal stability of the four compounds in the polar solvents. Water showed not degradation, and methanol (MeOH) was the solvent that provided the</div><div>second-best stability. Water-MeOH mixtures may provide an overall optimum. More, and longer long-chain substituents increased the degradation rate. Thermogravimetric Analysis was used to obtain the thermal stability in a solid-</div><div>state, i.e. solventless environment. Isoconversional analysis showed that no reliable kinetic parameters could be determined. Nevertheless, the data did allow for a compar-</div><div>ison of the thermal stability of 14 different QASs. Furthermore, the relative instability of the compounds in solid-state demonstrated the challenges of solventless QAS production.</div>

scholarly journals Dispersibility of Kaolinite-Rich Coal Gangue in Rubber Matrix and the Mechanical Properties and Thermal Stability of the Composites

Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1388
Author(s):  
Kenan Zhang ◽  
Hao Zhang ◽  
Linsong Liu ◽  
Yongjie Yang ◽  
Lihui Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Coal Gangue ◽  
Rubber Matrix ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Scanning Calorimetry ◽  
Laser Scattering ◽  
X Ray ◽  
Thermal Stability Of

The aim of this work was to investigate the dispersibility of kaolinite-rich coal gangue in rubber matrix, the mechanical properties and thermal stability of coal gangue/styrene butadiene rubber (SBR) composites, and to compare these properties to those of the same coal gangue but had undergone thermal activation and modification. Several experimental techniques, such as X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric-differential scanning calorimetry (TG-DSC), laser-scattering particle analyzer were adopted to characterize the coal gangue particles and then the obtained composites. The results demonstrated the raw coal gangue (RCG) was mainly composed of kaolinite. Calcination led to amorphization of thermal activated coal gangue (ACG), increased hydrophilicity and void volume, and decreased pH. The grain size of ACG became coarser than RCG, but ACG turned loose confirmed by higher degree of refinement after grinding. Modification enhanced the hydrophobicity of the coal gangue and improved its dispersibility than fillers without modification. Calcined samples had better dispersibility than uncalcined fillers. Additionally, the coal gangue treated by calcinating, grinding and modifying (MGA) had the best dispersion in rubber matrix. Either calcination or modification could improve the mechanical properties and thermal stability of coal gangue filled rubber, while the performance of MGA reinforced SBR (MGA-SBR) was the best. The enhanced performance of the MGA-SBR was owed to better dispersion of particles as well as stronger interactions between particles and rubber macromolecules.

scholarly journals Thermostability and surface morphology of nano- and micro-filled NBR/CSM rubber blends

2004 ◽  
Vol 69 (2) ◽  
pp. 167-173 ◽  
Author(s):  
G. Markovic ◽  
Blaga Radovanovic ◽  
J. Simendic-Budinski ◽  
Milena Marinovic-Cincovic
Keyword(s):  
Thermal Stability ◽  
Surface Morphology ◽  
Attenuated Total Reflectance ◽  
Butadiene Rubber ◽  
Nano Particle ◽  
Scanning Calorimetry ◽  
Rubber Blends ◽  
Ethylene Thiourea ◽  
Chlorosulphonated Polyethylene ◽  
Thermal Stability Of

Acrylonitrile-butadiene rubber (NBR), polychloroprene rubber (CR) chlorosulphonated polyethylene rubber (CSM) and their blends were cross-linked with sulphur, ethylene- thiourea, magnesium oxide or their combination. The effect of nano- and micro- particle sized of 35 pphr SiO2 on the thermostability and surface morphology of all the crosslinked systems was investigated. Identification of the structure of nano- and micro- particle sized SiO2 filled NBR/CSM and CR/CSM crosslinked systems was carried out by Fourier transform infrared spectroscopy (FTIR) with an attenuated total reflectance (ATR) extension. The thermal stability of the nano- and micro particle sized SiO2 filled NBR/CSM and CR/CSM crosslinked systems were carried out by thermogravimetric analysis (TGA). The glass transition temperature (Tg) of the samples was determined by differential scanning calorimetry (DSC). The morphology of the fracture surface of the crosslinked systems was carried out by scanning electron microscope (SEM). The results show when filledwith nano-particle sized of SiO2 NBR/CSM and CR/CSM polymer matrix have a strong peak from SiO?C at 1079 cm-1. This suggests the an interaction between the SiO2, which should lead to an increased thermal stability, higher values of Tg, better dispersion the nano-SiO2 andmore polish, without cracks than micro-filled NBR/CSM and CR/CSM crosslinked systems.

Effect of Coupling Treatment and Nanoclay on Thermal Stability of Bamboo Flour-Filled High Density Polyethylene Composites

2010 ◽  
Vol 113-116 ◽  
pp. 2349-2352 ◽  
Author(s):  
Guang Ping Han ◽  
Wan Li Cheng
Keyword(s):  
Thermal Stability ◽  
High Density Polyethylene ◽  
Degradation Kinetics ◽  
High Density ◽  
Thermal Decomposition Process ◽  
Thermal Behaviors ◽  
Melt Compounding ◽  
Bamboo Flour ◽  
Kinetics Of ◽  
Thermal Stability Of

Nanocomposites with high density polyethylene (HDPE)/nanoclay/bamboo flour were fabricated by melt compounding. Their thermal behaviors and degradation kinetics of the composites with different clay contents were characterized through dynamic and isothermal Thermogravimetric (TG) analysis. It was found that the use of nanoclay improved the thermal stability of the composites. The nanolayers could act as a barrier for the degradation of HDPE/bamboo hybrids. The addition of compatibilizer also improved the thermal stability of HDPE/bamboo composites, but the effect was less significant than clay. It seems that there is no much difference in the thermal behaviors between HDPE/nanoclay/bamboo systems with and without the addition of compatibilizer. The activation energy values varied very little for different clay contents in the composites. Thermal decomposition process of HDPE/bamboo composites with various clay additions had similar TG curves.

Influence of Organomodified Ni-Al Layered Double Hydroxide (LDH) Content on the Thermal Properties and Degradation Kinetics of Polystyrene (PS)/Ni-Al LDH Nanocomposites Prepared via Solvent Blending Method

2013 ◽  
Vol 747 ◽  
pp. 23-26 ◽  
Author(s):  
Manish Kumar Sinha ◽  
G. Pugazhenthi
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Degradation Kinetics ◽  
Decomposition Temperature ◽  
Thermal Degradation Kinetics ◽  
Blending Method ◽  
Friedman Method ◽  
Double Hydroxide ◽  
Kinetics Of ◽  
Thermal Stability Of

A series of polystyrene (PS) nanocomposites with various concentration of organomodified Ni-Al LDH (3, 7 wt%) were synthesized by solvent blending method and the effect of Ni-Al LDH content on the thermal properties and degradation kinetics of PS/ Ni-Al LDH nanocomposites was examined. Thermogravimetric analysis (TGA) was employed to evaluate the thermal properties of the prepared PS nanocomposites with various content of Ni-Al LDH. The obtained TGA results reveal that the PS/Ni-Al LDH nanocomposites exhibits enhanced thermal stability when compared with pure PS and the thermal stability of the nanocomposites increase with an increase in the LDH content from 3 to 7 wt%. When 15% weight loss is selected as a point of comparison, the thermal decomposition temperature of the PS/Ni-Al LDH nanocomposite containing 7 wt% of LDH is about 28°C higher than that of pure PS. The thermal degradation kinetics of the nanocomposite materials are investigated using two kinetic models such as Flynn-Wall-Ozawa method and Friedman method. The improvement of thermal stability of the nanocomposites with increasing LDH content is also validated by increasing the activation energies.

Curing Kinetics of Cyano Functionalized Benzoxazine

2011 ◽  
Vol 233-235 ◽  
pp. 2337-2340
Author(s):  
Wen Jin Chen ◽  
Xiao Bo Liu
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Theoretical Calculations ◽  
Curing Kinetics ◽  
High Thermal Stability ◽  
Order Model ◽  
Scanning Calorimetry ◽  
Autocatalytic Model ◽  
Kinetics Of

A multifunctional benzoxazine monomer (BZCN) was synthesized, which has several outstanding properties, such as high thermal stability and high glass transition. To better understand the curing kinetics of BZCN, isothermal differential scanning calorimetry measurements were used to determine the kinetic parameters and the kinetic models of the curing processes of benzoxazine monomer with cyano functionality. The result shows the mechanism of the curing reaction of BZCN exhibits autocatalytic model, but doesn’t meet nth-order model. Owing to the effects of catalysis of cyano functionality, the activation energy is 89.65KJ•mol-1and the total order of reaction is 1.84, which is quite different from that of normal benzoxazine. The theoretical calculations matched reasonably well with the experimental results.

scholarly journals Nonisothermal Cold Crystallization Kinetics of Poly(lactic acid)/Bacterial Poly(hydroxyoctanoate) (PHO)/Talc

2019 ◽  
Vol 17 (1) ◽  
pp. 1266-1278
Author(s):  
Omaima Alhaddad ◽  
Safaa H. El-Taweel ◽  
Yasser Elbahloul
Keyword(s):  
Thermal Stability ◽  
Lactic Acid ◽  
Crystallization Kinetics ◽  
Crystallization Rate ◽  
Cold Crystallization ◽  
Poly Lactic Acid ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Kinetics Of ◽  
Thermal Stability Of

AbstractThe effects of bacterial poly(hydroxyoctanoate) (PHO) and talc on the nonisothermal cold crystallization behaviours of poly(lactic acid) (PLA) were analysed with differential scanning calorimetry (DSC), and the thermal stability of the samples was observed with thermal gravimetric analysis (TGA). The modified Avrami’s model was used to describe the nonisothermal cold crystallization kinetics of neat PLA and its blends. The activation energies E for nonisothermal cold crystallization were calculated by the isoconversional method of Kissinger-Akahira-Sunose (KAS). The DSC results showed that the PLA/PHO blends were immiscible in the whole studied range, and as the PHO and talc content increased, the crystallization rate of PLA accelerated, and the crystallinity of PLA in the PLA samples increased. The values of the Avrami exponent indicated that the nonisothermal cold crystallization of the neat PLA and its blends exhibited heterogeneous, three-dimensional spherulitic growth. The E values were strongly dependent on PHO and talc. The TGA results showed that the presence of PHO and talc slightly influenced the thermal stability of PLA.

Research on Thermal Degradation Kinetics of Polyphenylene Sulfide Filter Media

2013 ◽  
Vol 300-301 ◽  
pp. 1171-1174 ◽  
Author(s):  
De Qiang Chang ◽  
Jing Xian Liu ◽  
Ning Mao ◽  
Bao Zhi Chen
Keyword(s):  
Thermal Stability ◽  
Thermal Degradation ◽  
Degradation Kinetics ◽  
Decomposition Temperature ◽  
Polyphenylene Sulfide ◽  
Thermal Degradation Kinetics ◽  
Filter Media ◽  
Initial Decomposition Temperature ◽  
Kinetics Of ◽  
Thermal Stability Of

In order to study the thermal stability of PPS (polyphenylene sulfide) filter media, by means of thermogravimetry(TG), thermal degradation kinetics behavior of two kinds of PPS filter media were analyzed. The kinetic parameters of PPS filter media were obtained according to Flynn-Wall-Ozawa method. Thermal stability of PPS filter media was discussed. It was found that the initial decomposition temperature and activation energy of N3 sample are all higher than B1 sample, the thermal stability of N3 sample is better than B1 sample, and kinetic analysis can be used as an important method to evaluate the thermal stability of filter media.

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