scholarly journals Hemp-Straw Composites: Gluing Study and Multi-Physical Characterizations

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1199 ◽  
Author(s):  
Marie Viel ◽  
Florence Collet ◽  
Sylvie Prétot ◽  
Christophe Lanos
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Sustainable Development ◽  
Wheat Straw ◽  
Feasibility Study ◽  
Building Materials ◽  
Environmentally Friendly ◽  
Insulating Materials ◽  
Low Thermal Conductivity

In order to meet the requirement of sustainable development, building materials are increasingly environmentally friendly. They can be partially or fully bio-based or recycled. This paper looks at the development of fully bio-based composites where agro-resources are valued as bio-based aggregates (hemp) and as binding materials (wheat). In a previous work, a feasibility study simultaneously investigated the processing and ratio of wheat straw required to ensure a gluing effect. In this paper, three kinds of hemp-straw composites are selected and compared with a hemp-polysaccharides composite. The gluing effect is analyzed chemically and via SEM. The developed composites were characterized multi-physically. They showed sufficiently high mechanical properties to be used as insulating materials. Furthermore, they showed good thermal performances with a low thermal conductivity (67.9–69.0 mW/(m · K) at 23 ° C, dry).

Preparation and Properties of SiC/Phenolic Resin for the Heat of LED

2016 ◽  
Vol 848 ◽  
pp. 454-459
Author(s):  
Cong Wu ◽  
Kang Zhao ◽  
Yu Fei Tang ◽  
Ji Yuan Ma
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Powder Metallurgy ◽  
Phenolic Resin ◽  
Bending Strength ◽  
Experimental Results ◽  
Low Thermal Conductivity ◽  
Industry Standard ◽  
Insulation Performance

In order to solve the problem that low thermal conductivity of the plastics for the heat of LED, SiC/Phenolic resin for the heat of LED were fabricated combining powder metallurgy. The effects of particles diameters, content and adding nanoparticles on thermal conductivity of the fabricated composites were investigated, the mechanical properties were also characterized. The experimental results showed that the materials were obtained, and the insulation performance of the fabricated SiC/Phenolic resin was higher than the industry standard one, the thermal conductivity reached 4.1W/(m·k)-1. And the bending strength of the fabricated composites was up to 68.11MPa. The problem of low thermal conductivity of the material is expected to be solved. In addition, it is meaningful for improving LED life.

Cellulose Fibres as a Reinforcing Element in Building Materials

2017 ◽  
Author(s):  
Viola Hospodarova ◽  
Nadezda Stevulova ◽  
Vojtech Vaclavik ◽  
Tomas Dvorsky ◽  
Jaroslav Briancin
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Building Materials ◽  
Reference Sample ◽  
Physical And Mechanical Properties ◽  
Natural Fibre ◽  
Cement Composites ◽  
Cellulose Fibres ◽  
Cellulosic Fibres

Nowadays, construction sector is focusing in developing sustainable, green and eco-friendly building materials. Natural fibre is growingly being used in composite materials. This paper provides utilization of cellulose fibres as reinforcing agent into cement composites/plasters. Provided cellulosic fibres coming from various sources as bleached wood pulp and recycled waste paper fibres. Differences between cellulosic fibres are given by their physical characterization, chemical composition and SEM micrographs. Physical and mechanical properties of fibre-cement composites with fibre contents 0.2; 0.3and 0.5% by weight of filler and binder were investigated. Reference sample without fibres was also produced. The aim of this work is to investigate the effects of cellulose fibres on the final properties (density, water absorbability, coefficient of thermal conductivity and compressive strength) of the fibrecement plasters after 28 days of hardening. Testing of plasters with varying amount of cellulose fibres (0.2, 0.3 and 0.5 wt. %) has shown that the resulting physical and mechanical properties depend on the amount, the nature and structure of the used fibres. Linear dependences of compressive strength and thermal conductivity on density for plasters with cellulosic fibres adding were observed.

Study and Application of Plastic Construction Materials

2011 ◽  
Vol 99-100 ◽  
pp. 1117-1120 ◽  
Author(s):  
Mao Quan Xue
Keyword(s):  
Thermal Conductivity ◽  
Corrosion Resistance ◽  
Energy Saving ◽  
Thermal Insulation ◽  
Flame Retardancy ◽  
Building Materials ◽  
Construction Materials ◽  
Low Thermal Conductivity ◽  
Building Walls

As new building materials, plastic has light weigh, corrosion resistance, low thermal conductivity, thermal insulation, waterproof, energy-saving, molding convenient, high recycling characteristic, widely used in building materials. According to the research of improving its flame retardancy, strength, thermal insulation, waterproof properties, the application of plastic use in doors and windows, pipeline, building walls and roofs of buildings, etc. were reviewed, and the developing direction was discussed.

A Study on Chemical Foaming Geopolymer Building Materials

2013 ◽  
Vol 853 ◽  
pp. 202-206 ◽  
Author(s):  
Tsung Yin Yang ◽  
Chuan Chi Chien
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Sound Absorption ◽  
Building Materials ◽  
Reaction Rate ◽  
Hydrogen Gas ◽  
Aluminum Powders ◽  
Foaming Agents ◽  
Low Thermal Conductivity ◽  
Base Solution

Zinc and aluminum powders were used as foaming agents and organosilane was innovatively used as a modifier to synthesize a foamed geopolymer. The produced foamed geopolymer with enhanced compressive strength and low thermal conductivity is an ideal material for fire protection, sound absorption and thermal insulation. The low thermal conductivity was achieved by increasing the porosity in the foamed geopolymer and the enhanced compressive strength was realized by adding the modifier. The pore numbers in the foamed geopolymer were greatly increased by releasing the hydrogen gas, which was produced from the chemical reaction of zinc and aluminum powders in a base solution. The modifier decreased the foaming reaction rate and generated homogeneously-distributed small pores in the foamed geopolymer with improved compressive strength.

High thermoelectric performance of superionic argyrodite compound Ag8SnSe6

2016 ◽  
Vol 4 (24) ◽  
pp. 5806-5813 ◽  
Author(s):  
Lin Li ◽  
Yuan Liu ◽  
Jiyan Dai ◽  
Aijun Hong ◽  
Min Zeng ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Material ◽  
Power Factor ◽  
High Power ◽  
Figure Of Merit ◽  
Environmentally Friendly ◽  
Thermoelectric Performance ◽  
Low Thermal Conductivity ◽  
High Power Factor ◽  
High Figure

A good thermoelectric material usually has a high power factor and low thermal conductivity for high figure of merit (ZT), and is also environmentally friendly and economical.

scholarly journals Thermal Conductivity of Building Materials in Iraq

2021 ◽  
Vol 28 (4) ◽  
pp. 37-49
Author(s):  
Madgeed A. Al-Doury ◽  
Atif Ali Hasan ◽  
Raheem Kadhim Mohammed ◽  
Riyadh H. Al-Jawad
Keyword(s):  
Thermal Conductivity ◽  
Thermal Performance ◽  
Air Conditioning ◽  
Building Materials ◽  
Thermal Loads ◽  
Insulating Materials ◽  
Materials Properties ◽  
Wire Method ◽  
Air Conditioning Systems ◽  
The Relationship

Thermophysical Properties of Building Materials are Considered to have high importance in predicting building thermal performance, calculating thermal loads inside building, and optimizing the use of a building and insulating materials. Due to the lack of measurements of local building materials properties, designers and air- conditioning engineers have no choice but to use the published foreign data, which probably leads to inaccurate predictions of thermal loads and may give a false thermal performance. At the same time, it leads to an over-designed capacity of air- conditioning systems that lead to increased energy consumption in the building. Thus, it is clear that it was important to conduct this research to evaluate the thermal conductivity and thermal resistance of Iraqi building materials. The number of the local building materials were listed, and specimens were collected from their sites, factories, and suppliers such as bricks, stones, concrete products, gypsum, etc. Those samples were dimensioned to the specific size required when a measurement was conducted by the Hot Wire method. All measurements were carried out at room temperature. The relationship between thermal conductivity, density, moisture content, and pressure for a number of materials was Studied. A comparison between the measurements of the Iraqi building materials and results published in the ASHRAE, CIBS Guide, Australian Specifications, and Jordanian Specifications was made. However, the availability of such data is important for the climatic design of buildings, thermal load calculations for air- conditioning, and choosing the insulating materials.

scholarly journals Mechanically Strong, Low Thermal Conductivity and Improved Thermal Stability Polyvinyl Alcohol–Graphene–Nanocellulose Aerogel

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 170
Author(s):  
Xiuya Wang ◽  
Pengbo Xie ◽  
Ke Wan ◽  
Yuanyuan Miao ◽  
Zhenbo Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Thermal Stability ◽  
Polyvinyl Alcohol ◽  
Low Density ◽  
Composite Aerogel ◽  
Ternary Composite ◽  
Low Thermal Conductivity ◽  
Good Thermal Stability ◽  
Composite Aerogels

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.

Sign in / Sign up

Export Citation Format

Share Document