Construction of a 3D multiple network skeleton by the thiol-Michael addition click reaction to fabricate novel polymer/graphene aerogels with exceptional thermal conductivity and mechanical properties

2017 ◽  
Vol 5 (42) ◽  
pp. 22352-22360 ◽  
Author(s):  
Shiqiang Song ◽  
Yong Zhang

Novel porous polymer/graphene composite aerogels with a multiple network structure, enhanced compressive properties and high thermal conductivity are first fabricated by adsorbing water vapour, reduction, and freeze-drying procedures.

2018 ◽  
Vol 6 (46) ◽  
pp. 12739-12745 ◽  
Author(s):  
Yapeng Chen ◽  
Xiao Hou ◽  
Ruiyang Kang ◽  
Yun Liang ◽  
Liangchao Guo ◽  
...  

A highly flexible cellulose nanofiber/graphene composite film with metal-like thermal conductivity and outstanding strength was fabricated via simple vacuum-assisted filtration.


Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 170
Author(s):  
Xiuya Wang ◽  
Pengbo Xie ◽  
Ke Wan ◽  
Yuanyuan Miao ◽  
Zhenbo Liu ◽  
...  

Porous aerogel materials have advantages of a low density, low thermal conductivity and high porosity, and they have broad application prospects in heat insulation and building energy conservation. However, aerogel materials usually exhibit poor mechanical properties. Single-component aerogels are less likely to possess a good thermal stability and mechanical properties. It is necessary to prepare multiple-composite aerogels by reinforcement to meet practical application needs. In this experiment, a simple preparation method for polyvinyl alcohol (PVA)–graphene (GA)–nanocellulose (CNF) ternary composite aerogels was proposed. This is also the first time to prepare ternary composite aerogels by mixing graphene, nanocellulose and polyvinyl alcohol. A GA–CNF hydrogel was prepared by a one-step hydrothermal method, and soaked in PVA solution for 48 h to obtain a PVA–GA–CNF hydrogel. PVA–GA–CNF aerogels were prepared by freeze drying. The ternary composite aerogel has advantages of excellent mechanical properties, a low thermal conductivity and an improved thermal stability, because strong hydrogen bonds form between the PVA, GA and CNF. The composite aerogels were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffractometry, Brunauer–Emmett–Teller analysis, dynamic thermal analysis, thermogravimetry and thermal constant analysis to characterize the properties of the ternary composite aerogels. The lightweight, low-density and porous PVA–GA–CNF composite aerogels withstood 628 times their mass. The thermal conductivity of the composite aerogels was 0.044 ± 0.005 W/mK at room temperature and 0.045 ± 0.005 W/mK at 70 °C. This solid, low thermal conductivity and good thermal stability PVA–GA–CNF ternary composite aerogel has potential application in thermal insulation.


2020 ◽  
Vol 44 (6) ◽  
pp. 2256-2267 ◽  
Author(s):  
Chuting Feng ◽  
Penggang Ren ◽  
Zhen Li ◽  
Wenzhen Tan ◽  
Hua Zhang ◽  
...  

Waste-newspaper cellulose/graphene composite aerogels were facilely synthesized via the sol–gel and freeze-drying processes for dye wastewater treatment.


2017 ◽  
Vol 14 (3) ◽  
pp. 335-343 ◽  
Author(s):  
Yixin Wang ◽  
Xi Chen ◽  
Ying Kuang ◽  
Man Xiao ◽  
Yuehong Su ◽  
...  

Abstract This study presents the preparation and measurement of a novel environmentally friendly konjac glucomannan (KGM)-based composite aerogels enhanced with wheat straw (WS) via a sol–gel and freeze-drying progress. With the addition of WS, the porosity of aerogels could be increased from 50 to 88.13%, the filtration resistance of aerogels could be reduced from 500 to 205 Pa, and the filtration efficiency could be improved to 90.38%. The addition of WS also enhances the mechanical properties of composite aerogels with compression modulus of 2000.66 Pa, compressive strength of 501.56 Pa and elasticity of 0.603. The results demonstrate the high potential of KGM-based composite aerogels enhanced with WS for applications in air filtering.


2015 ◽  
Vol 10 (2) ◽  
pp. 2663-2681
Author(s):  
Rizk El- Sayed ◽  
Mustafa Kamal ◽  
Abu-Bakr El-Bediwi ◽  
Qutaiba Rasheed Solaiman

The structure of a series of AlSb alloys prepared by melt spinning have been studied in the as melt–spun ribbons  as a function of antimony content .The stability  of these structures has  been  related to that of the transport and mechanical properties of the alloy ribbons. Microstructural analysis was performed and it was found that only Al and AlSb phases formed for different composition.  The electrical, thermal and the stability of the mechanical properties are related indirectly through the influence of the antimony content. The results are interpreted in terms of the phase change occurring to alloy system. Electrical resistivity, thermal conductivity, elastic moduli and the values of microhardness are found to be more sensitive than the internal friction to the phase changes. 


2020 ◽  
Vol 38 (10A) ◽  
pp. 1522-1530
Author(s):  
Rawnaq S. Mahdi ◽  
Aseel B. AL-Zubidi ◽  
Hassan N. Hashim

This work reports on the incorporation of Flint and Kaolin rocks powders in the cement mortar in an attempt to improve its mechanical properties and produce an eco-friendly mortar. Flint and Kaolin powders are prepared by dry mechanical milling. The two powders are added separately to the mortars substituting cement partially. The two powders are found to improve the mechanical properties of the mortars. Hardness and compressive strength are found to increase with the increase of powders constituents in the cement mortars. In addition, the two powders affect water absorption and thermal conductivity of the mortar specimens which are desirable for construction applications. Kaolin is found to have a greater effect on the mechanical properties, water absorption, and thermal conductivity of the mortars than Flint. This behavior is discussed and analyzed based on the compositional and structural properties of the rocks powders.


2020 ◽  
Vol 38 (3B) ◽  
pp. 104-114
Author(s):  
Samah M. Hussein

This research has been done by reinforcing the matrix (unsaturated polyester) resin with natural material (date palm fiber (DPF)). The fibers were exposure to alkali treatment before reinforcement. The samples have been prepared by using hand lay-up technique with fiber volume fraction of (10%, 20% and 30%). After preparation of the mechanical and physical properties have been studied such as, compression, flexural, impact strength, thermal conductivity, Dielectric constant and dielectric strength. The polyester composite reinforced with date palm fiber at volume fraction (10% and 20%) has good mechanical properties rather than pure unsaturated polyester material, while the composite reinforced with 30% Vf present poor mechanical properties. Thermal conductivity results indicated insulator composite behavior. The effect of present fiber polar group induces of decreasing in dielectric strength, and increasing dielectric constant. The reinforcement composite 20% Vf showed the best results in mechanical, thermal and electrical properties.


Alloy Digest ◽  
1983 ◽  
Vol 32 (3) ◽  

Abstract BRUSH Alloy 3 offers the highest electrical and thermal conductivity of any beryllium-copper alloy. It possesses an excellent combination of moderate strength, good corrosion resistance and good resistance to moderately elevated temperatures. Because of its unique physical and mechanical properties, Brush Alloy 3 finds widespread use in welding applications (RWMA Class 3), current-carrying springs, switch and instrument parts and similar components. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fatigue. It also includes information on corrosion resistance as well as casting, forming, heat treating, machining, joining, and surface treatment. Filing Code: Cu-454. Producer or source: Brush Wellman Inc..


Alloy Digest ◽  
1988 ◽  
Vol 37 (9) ◽  

Abstract 850.0 ALUMINUM Alloy can be considered the general purpose light metal bearing alloy. Its good thermal conductivity keeps operating temperatures low. It has high ductility. In many applications it has been found to be superior to steel backed bearings. 852.0 ALUMINUM Alloy has higher mechanical properties making it suitable for heavier load and higher temperature applications. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength. It also includes information on corrosion resistance as well as heat treating and machining. Filing Code: Al-290. Producer or source: Federated Bronze Products Inc..


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