The Effect of Surface Hydroxyl Groups on the Properties of SR/Al2O3 Composites

2009 ◽  
Vol 66 ◽  
pp. 277-279 ◽  
Author(s):  
Yuan Lu Xiong ◽  
Qiang Shen ◽  
Fei Chen ◽  
Jin Zheng ◽  
Lian Meng Zhang
Keyword(s):  
Heat Treatment ◽  
Flexural Strength ◽  
Relative Density ◽  
Heat Treatment Temperature ◽  
Treatment Temperature ◽  
Hydroxyl Groups ◽  
Surface Hydroxyl ◽  
Surface Hydroxyl Groups ◽  
Sandy Alumina ◽  
Effect Of Surface

SR/Al2O3 composites were fabricated from different heat treatment temperatures of alumina. The results show that the relative density is over 94% and flexural strength is 66.5MPa when silicone content is 33wt.%. The flexural strength of the obtained SR/Al2O3 composites is decreased when increasing the heat treatment temperature of sandy alumina, indicating that the surface hydroxyl groups directly influence the flexural strength of SR/Al2O3 composites.

scholarly journals Self-Toughening and Self-Enhancement Poly(arylene ether nitrile) with Low Dielectric Constant by Solid Crosslinking Reaction

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1403 ◽  
Author(s):  
Lifen Tong ◽  
Xiting Lei ◽  
Guangyao Yang ◽  
Xiaobo Liu
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Dielectric Constant ◽  
Thermal Properties ◽  
Heat Treatment Temperature ◽  
Treatment Temperature ◽  
Cross Linking ◽  
Hydroxyl Groups ◽  
Crosslinking Reaction ◽  
Arylene Ether

A novel poly(arylene ether nitrile) terminated with hydroxyl groups (PEN–OH) was synthesized successfully. The effects of heat-treatment temperature on the thermal properties, mechanical properties, and dielectric properties of the PEN–OH films were studied in detail. Due to the cross-linking reaction occurring, at high temperature, among the nitrile groups on the side of the PEN–OH main chain to form a structurally stable triazine ring, the structure of materials changes from a linear structure to a bulk structure. Thus, the thermal properties and mechanical properties were improved. In addition, the occurrence of cross-linking reactions can reduce the polar groups in the material, leading to the decrease of dielectric constant. As the heat-treatment temperature increased, the glass-transition temperature increased from 180.6 °C to 203.6 °C, and the dielectric constant decreased from 3.4 to 2.8 at 1 MHz. Proper temperature heat-treatment could improve the tensile strength, as well as the elongation, at the break of the PEN–OH films. Moreover, because of the excellent adhesive property of PEN–OH to copper foil, a double-layer flexible copper clad laminate (FCCL) without any adhesives based on PEN–OH was prepared by a simple hot-press method, which possessed high peel strength with 1.01 N/mm. Therefore, the PEN–OH has potential applications in the electronic field.

Phase transition of capillary condensed liquids in porous silica: effect of surface hydroxyl groups

1995 ◽  
Vol 267 ◽  
pp. 159-167 ◽  
Author(s):  
T. Takei ◽  
T. Konishi ◽  
M. Fuji ◽  
T. Watanabe ◽  
M. Chikazawa
Keyword(s):  
Phase Transition ◽  
Porous Silica ◽  
Hydroxyl Groups ◽  
Surface Hydroxyl ◽  
Surface Hydroxyl Groups ◽  
Effect Of Surface

Effect of surface hydroxyl groups on heat capacity of mesoporous silica

2018 ◽  
Vol 112 (20) ◽  
pp. 201903 ◽  
Author(s):  
Michal Marszewski ◽  
Danielle Butts ◽  
Esther Lan ◽  
Yan Yan ◽  
Sophia C. King ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Mesoporous Silica ◽  
Hydroxyl Groups ◽  
Surface Hydroxyl ◽  
Surface Hydroxyl Groups ◽  
Effect Of Surface

Evolution mechanism of surface hydroxyl groups of silica during heat treatment

2020 ◽  
Vol 513 ◽  
pp. 145766
Author(s):  
Zhimin Cheng ◽  
Hongwei Shan ◽  
Ying Sun ◽  
Ling Zhang ◽  
Haibo Jiang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Hydroxyl Groups ◽  
Evolution Mechanism ◽  
Surface Hydroxyl ◽  
Surface Hydroxyl Groups

Effect of activation temperature on acidity of alumina, silica-alumina and cobalt-molybdenum-alumina catalysts

1985 ◽  
Vol 50 (6) ◽  
pp. 1268-1273 ◽  
Author(s):  
Zdeněk Vít
Keyword(s):  
Acid Sites ◽  
Hydroxyl Groups ◽  
Activation Temperature ◽  
Cumene Cracking ◽  
Surface Hydroxyl ◽  
Catalytic Activities ◽  
Surface Hydroxyl Groups ◽  
Silica Alumina ◽  
Effect Of Surface ◽  
Alumina Catalysts

The effect of surface dehydration on the acidity of silica-alumina and cobalt-molybdenum-alumina catalysts has been studied and compared with alumina. The catalysts were characterized by surface hydroxyl groups concentrations, acid sites concentrations and by catalytic activities in paraldehyde depolymerisation and cumene cracking. It was found that the acidity of alumina and cobalt-molybdenum-alumina catalysts increases significantly with surface dehydration and attains maximum after activation at 500-550 °C. Silica-alumina is strongly acidic even in the hydrated state, the acidity being formed already at relatively low temperature around 100 °C.

scholarly journals Effects of Heat Treatment Temperature on Microstructure and Mechanical Properties of M2 High-Speed Steel Selective Laser Melting Samples

2020 ◽  
Author(s):  
Huan Ding ◽  
Xiong Xiang ◽  
Rutie Liu ◽  
Jie Xu
Keyword(s):  
Heat Treatment ◽  
Flexural Strength ◽  
Selective Laser Melting ◽  
Heat Treatment Temperature ◽  
High Speed ◽  
High Speed Steel ◽  
Treatment Temperature ◽  
Laser Melting ◽  
Average Value ◽  
M2 High Speed Steel

At different heat treatment temperatures, the hardness and flexural strength of M2 high-speed steel selective laser melting (SLM) parts show mixed trends. When the heat treatment temperature is 260°C, the hardness and flexural strength of the M2 high-speed steel SLM part are decreased, but the hardness difference between the upper and lower surfaces of the M2 high-speed steel SLM part is also reduced. When the heat treatment temperature is 560°C, the hardness and flexural strength of the M2 high-speed steel SLM part are almost close to that of the original M2 high-speed steel SLM part, and the performance gradient in the sample is improved, and the overall structure is uniform. When the subsequent heat treatment temperature is 860 °C, the hardness of the SLM parts reaches a minimum, with an average value of 24 HRC. However, the flexural strength exceeds that of the original SLM parts. Moreover, the microstructure of the sample is uniform, which significantly improves the anisotropy of performance.

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