Starch/clay aerogel reinforced by cellulose nanofibrils for thermal insulation

Cellulose ◽  
2021 ◽  
Vol 28 (6) ◽  
pp. 3505-3513
Author(s):  
Yan-Wen Zhao ◽  
Mao-Zhang Tian ◽  
Pei Huang
Keyword(s):  
Thermal Insulation ◽  
Cellulose Nanofibrils

scholarly journals Moisture uptake in nanocellulose: the effects of relative humidity, temperature and degree of crystallinity

Cellulose ◽  
2021 ◽  
Author(s):  
Mohit Garg ◽  
Varvara Apostolopoulou-Kalkavoura ◽  
Mathieu Linares ◽  
Tahani Kaldéus ◽  
Eva Malmström ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Water Uptake ◽  
Thermal Insulation ◽  
Cellulose Nanofibrils ◽  
Degree Of Crystallinity ◽  
Crystalline Cellulose ◽  
Moisture Uptake ◽  
Amorphous Cellulose ◽  
Hygroscopic Properties ◽  
Cellulose Nanomaterials

AbstractFoams made from cellulose nanomaterials are highly porous and possess excellent mechanical and thermal insulation properties. However, the moisture uptake and hygroscopic properties of these materials need to be better understood for their use in biomedical and bioelectronics applications, in humidity sensing and thermal insulation. In this work, we present a combination of hybrid Grand Canonical Monte Carlo and Molecular Dynamics simulations and experimental measurements to investigate the moisture uptake within nanocellulose foams. To explore the effect of surface modification on moisture uptake we used two types of celluloses, namely TEMPO-oxidized cellulose nanofibrils and carboxymethylated cellulose nanofibrils. We find that the moisture uptake in both the cellulose nanomaterials increases with increasing relative humidity (RH) and decreases with increasing temperature, which is explained using the basic thermodynamic principles. The measured and calculated moisture uptake in amorphous cellulose (for a given RH or temperature) is higher as compared to crystalline cellulose with TEMPO- and CM-modified surfaces. The high water uptake of amorphous cellulose films is related to the formation of water-filled pores with increasing RH. The microscopic insight of water uptake in nanocellulose provided in this study can assist the design and fabrication of high-performance cellulose materials with improved properties for thermal insulation in humid climates or packaging of water sensitive goods. Graphic abstract

Moisture Uptake in Nanocellulose: The Effect of Relative Humidity, Temperature and Degree of Crystallinity

2021 ◽  
Author(s):  
Mohit Garg ◽  
Varvara Apostolopoulou-Kalkavoura ◽  
Mathieu Linares ◽  
Tahani Kaldéus ◽  
Eva Malmström ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Water Uptake ◽  
Thermal Insulation ◽  
Cellulose Nanofibrils ◽  
Degree Of Crystallinity ◽  
Crystalline Cellulose ◽  
Moisture Uptake ◽  
Amorphous Cellulose ◽  
Hygroscopic Properties ◽  
Cellulose Nanomaterials

Abstract Foams made from cellulose nanomaterials are highly porous and possess excellent mechanical and thermal insulation properties. However, the moisture uptake and hygroscopic properties of these materials need to be better understood for their use in biomedical and bioelectronics applications, in humidity sensing and thermal insulation. In this work, we present a combination of hybrid Grand Canonical Monte Carlo and Molecular Dynamics simulations and experimental measurements to investigate the moisture uptake within nanocellulose foams. To explore the effect of surface modification on moisture uptake we used two types of celluloses, namely TEMPO-oxidized cellulose nanofibrils and carboxymethylated cellulose nanofibrils. We find that the moisture uptake in both the cellulose nanomaterials increases with increasing relative humidity (RH) and decreases with increasing temperature, which is explained using the basic thermodynamic principles. The measured and calculated moisture uptake in amorphous cellulose (for a given RH or temperature) is higher as compared to crystalline cellulose with TEMPO- and CM-modified surfaces. The high water uptake of amorphous cellulose films is related to the formation of water-filled pores with increasing RH. The microscopic insight of water uptake in nanocellulose provided in this study can assist the design and fabrication of high-performance cellulose materials with improved properties for thermal insulation in humid climates or packaging of water sensitive goods.

Calculation of tension in the three-layer pipe with viscoelastic thermal insulation

2019 ◽  
Vol 5 (3) ◽  
pp. 69-78
Author(s):  
V. V. Mozharovsky ◽  
◽  
D. S. Kuzmenkov ◽  
E. A. Golubeva ◽  
◽  
...  
Keyword(s):  
Thermal Insulation

Facile preparation of nanofiller-paper using mixed office paper without deinking

TAPPI Journal ◽  
2015 ◽  
Vol 14 (3) ◽  
pp. 167-174 ◽  
Author(s):  
QIANQIAN WANG ◽  
J.Y. ZHU
Keyword(s):  
Cellulose Nanofibrils ◽  
Ash Content ◽  
Raw Material ◽  
Mechanical Grinding ◽  
Microscope Imaging ◽  
Facile Preparation ◽  
Electron Microscope Imaging ◽  
Thermal Stability Of ◽  
Scanning Electron ◽  
Office Paper

Mixed office paper (MOP) pulp without deinking with an ash content of 18.1 ± 1.5% was used as raw material to produce nanofiller-paper. The MOP pulp with filler was mechanically fibrillated using a laboratory stone grinder. Scanning electron microscope imaging revealed that the ground filler particles were wrapped by cellulose nanofibrils (CNFs), which substantially improved the incorporation of filler into the CNF matrix. Sheets made of this CNF matrix were densified due to improved bonding. Specific tensile strength and modulus of the nanofiller-paper with 60-min grinding reached 48.4 kN·m/kg and 8.1 MN·m/kg, respectively, approximately 250% and 200% of the respective values of the paper made of unground MOP pulp. Mechanical grinding duration did not affect the thermal stability of the nanofiller-paper.

An effective method for determining the retention and distribution of cellulose nanofibrils in paper handsheets by dye labeling

TAPPI Journal ◽  
2018 ◽  
Vol 17 (03) ◽  
pp. 157-164 ◽  
Author(s):  
Shengdan Wang ◽  
Wenhua Gao ◽  
Kefu Chen ◽  
Jinsong Zeng ◽  
Jun Xu ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Congo Red ◽  
Kraft Pulp ◽  
Cellulose Nanofibrils ◽  
Standard Curve ◽  
Congo Red Dye ◽  
Mechanical Disintegration ◽  
Softwood Kraft Pulp ◽  
White Water ◽  
Red Dye

Cellulose nanofibrils (CNF) were prepared by cellulase in conjunction with mechanical disintegration from the bleached softwood kraft pulp and labelled by Congo red dye. The labelled CNF were used to investigate the retention and distribution of CNF in paper handsheets. The retention of the labelled CNF was obtained by measuring the absorbance of white water using an ultraviolet-visible spectrophotometer. The results showed that this method for measuring the retention was rapid, feasible, and sensitive, owing to the high correlation coefficient R2 (0.9993) of the standard curve. The labelled CNF showed even distribution in paper handsheets. The colorimetric values of paper handsheets were explored with a residual ink analyzer.

ANALYSIS OF TEMPERATURE SWING THERMAL INSULATION ON THE PERFORMANCE OF DIESEL ENGINES

2018 ◽  
Author(s):  
Arif Taibani ◽  
Shankar Krishnan ◽  
Milan Visaria
Keyword(s):  
Thermal Insulation ◽  
Diesel Engines ◽  
Temperature Swing
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