EV Systems for NR. II. Further Development of Curing Systems and Vulcanizate Properties

1969 ◽  
Vol 42 (2) ◽  
pp. 418-440 ◽  
Author(s):  
R. M. Russell ◽  
T. D. Skinner ◽  
A. A. Watson
Keyword(s):  
Thermal Stability ◽  
Zinc Oxide ◽  
Fatigue Cracking ◽  
Oxide System ◽  
Oxidative Aging ◽  
Thermal Oxidative Aging ◽  
Further Development ◽  
Resistance To Heat ◽  
Thermal Stability Of ◽  
Simple Network

Abstract It was shown in Part I that the use of EV systems in NR provides a simple network in which the crosslinks are mainly monosulfidic. Part II describes in some detail the properties of vulcanizates obtained by the use of EV systems and their relationship to conventional and TMTD-zinc oxide cured vulcanizates. The disadvantages of short scorch time and heavy bloom which accompany the TMTD-zinc oxide system are overcome by the new EV systems. The monosulfidic network obtained by the use of EV systems confers on NR good overall physical properties together with much improved resistance towards thermal and thermal oxidative aging. The thermal stability of this type of network is reflected in the outstanding resistance of the vulcanizates to set and reversion, and their good resistance to heat build-up under dynamic conditions. Vulcanizates derived from EV systems have increased resistance to thermal oxidative aging due to the inherent thermal stability of the networks and good response to antioxidant protection. This increased resistance results in much better retention of tensile properties, tear resistance and fatigue cracking resistance on aging, relative to that of conventionally cured vulcanizates.

scholarly journals Development of Novel Silica-Based Formulation of α-Lipoic Acid: Evaluation of Photo and Thermal Stability of the Encapsulated Drug

Pharmaceutics ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 228 ◽  
Author(s):  
Ekaterina S. Dolinina ◽  
Elizaveta Yu. Akimsheva ◽  
Elena V. Parfenyuk
Keyword(s):  
Thermal Stability ◽  
Thermal Degradation ◽  
Lipoic Acid ◽  
Sol Gel ◽  
Silica Matrix ◽  
Matrix Modification ◽  
Drug Stabilization ◽  
Further Development ◽  
Kinetics Of ◽  
Thermal Stability Of

Powerful antioxidant α-lipoic acid (LA) is easily degraded under light and heating. This creates difficulties in its manufacture, storage and reduces efficiency and safety of the drug. The purpose of this work was to synthesize novel silica-based composites of LA and evaluate their ability to increase photo and thermal stability of the drug. It was assumed that the drug stabilization can be achieved due to LA-silica interactions. Therefore, the composites of LA with unmodified and organomodified silica matrixes were synthesized by sol-gel method at the synthesis pH below or above the pKa of the drug. The effects of silica matrix modification and the synthesis pH on the LA-silica interactions and kinetics of photo and thermal degradation of LA in the composites were studied. The nature of the interactions was revealed by FTIR spectroscopy. It was found that the rate of thermal degradation of the drug in the composites was significantly lower compared to free LA and mainly determined by the LA-silica interactions. However, photodegradation of LA in the composites under UV irradiation was either close to that for free drug or significantly more rapid. It was shown that kinetics of photodegradation was independent of the interactions and likely determined by physical properties of surface of the composite particles (porosity and reflectivity). The most promising composites for further development of novel silica-based formulations were identified.

scholarly journals “Dirty nanostructures”: aerosol-assisted synthesis of temperature stable mesoporous metal oxide semiconductor spheres comprising hierarchically assembled zinc oxide nanocrystals controlled via impurities

Nanoscale ◽  
2014 ◽  
Vol 6 (3) ◽  
pp. 1698-1706 ◽  
Author(s):  
Daniela Lehr ◽  
Dennis Großmann ◽  
Wolfgang Grünert ◽  
Sebastian Polarz
Keyword(s):  
Thermal Stability ◽  
Zinc Oxide ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Zno Nanostructures ◽  
Impurity Atoms ◽  
Mesoporous Zno ◽  
Mesoporous Metal ◽  
Thermal Stability Of ◽  
Intentional Introduction

The thermal stability of mesoporous ZnO nanostructures could be enhanced by intentional introduction of impurity atoms like Al or S.

scholarly journals Improvements of Developed Graphite Based Composite Anti-Aging Agent on Thermal Aging Properties of Asphalt

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4005 ◽  
Author(s):  
Zhihui Hu ◽  
Tao Xu ◽  
Pengfei Liu ◽  
Markus Oeser ◽  
Haopeng Wang
Keyword(s):  
Thermal Stability ◽  
Synergetic Effect ◽  
Expanded Graphite ◽  
Scanning Calorimetry ◽  
Chain Reactions ◽  
Oxidative Aging ◽  
Caco3 Nanoparticles ◽  
Before And After ◽  
Light Components ◽  
Thermal Oxidative Aging

To reduce the thermal-oxidative aging of asphalt and the release amount of harmful volatiles during the construction of asphalt pavement, a new composite anti-aging agent was developed. Since the volatiles were mainly released from saturates and aromatics during the thermal-oxidative aging of asphalt, expanded graphite (EG) was selected as a stabilizing agent to load magnesium hydroxide (MH) and calcium carbonate (CaCO3) nanoparticles for preparing the anti-aging agents of saturates and aromatics, respectively. Thermal stability and volatile constituents released from saturates and aromatics before and after the thermal-oxidative aging were characterized using the isothermal Thermogravimetry/Differential Scanning Calorimetry-Fourier Transform Infrared Spectrometer test (TG/DSC-FTIR test). Test results indicate that anti-aging agents of EG/MH and EG/CaCO3 effectively inhibit the volatilization of light components in asphalt and improve the thermal stability of saturates and aromatics. Then, the proportions of EG, MH, and CaCO3 added in the developed composite anti-aging agent of EG/MH/CaCO3 are 2:1:3 by weight. EG/MH/CaCO3 plays a synergetic effect on inhibiting the thermal-oxidative aging of asphalt, and reduces the release amount of harmful volatiles during the thermal-oxidative aging after EG/MH/CaCO3 is added into asphalt at the proposed content of 10 wt.%. EG plays a synergistic role with MH and CaCO3 nanoparticles to prevent the chain reactions, inhibiting the thermal-oxidative aging of asphalt.

Thermal Stability of Aluminum Doped Zinc Oxide Thin Films

2011 ◽  
Vol 685 ◽  
pp. 147-151 ◽  
Author(s):  
Jin Hua Huang ◽  
Rui Qin Tan ◽  
Jia Li ◽  
Yu Long Zhang ◽  
Ye Yang ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Thermal Stability ◽  
Zinc Oxide ◽  
Solar Cells ◽  
Electrode Materials ◽  
Thin Film Solar Cells ◽  
Oxide Thin Films ◽  
Aluminum Doped Zinc Oxide ◽  
Thermal Stability Of

Transparent conductive oxides are key electrode materials for thin film solar cells. Aluminum doped zinc oxide has become one of the most promising transparent conductive oxide (TCO) materials because of its excellent optical and electrical properties. In this work, aluminum doped zinc oxide thin films were prepared using RF magnetron sputtering of a 4 at% ceramic target. The thermal stability of aluminum doped zinc oxide thin films was studied using various physical and structural characterization methods. It was observed that the electrical conductivity of aluminum doped zinc oxide thin films deteriorated rapidly and unevenly when it was heated up to 350 °C. When the aluminum doped zinc oxide thin films were exposed to UV ozone for a short time before heating up, its thermal stability and large area homogeneity were significantly improved. The present work provided a novel method for improving the durability of aluminum doped zinc oxides as transparent conductive electrodes in thin film solar cells.

Effect of zinc maleate/zinc oxide complex on thermal stability of poly(vinyl chloride)

2014 ◽  
Vol 132 (7) ◽  
pp. n/a-n/a ◽  
Author(s):  
Guoxing Li ◽  
Ming Wang ◽  
Xingliang Huang ◽  
Haixia Li ◽  
Hong He
Keyword(s):  
Thermal Stability ◽  
Zinc Oxide ◽  
Vinyl Chloride ◽  
Poly Vinyl Chloride ◽  
Thermal Stability Of
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