Dynamic viscoelasticity and structural changes of regenerated cellulose during water sorption

Polymer ◽  
1988 ◽  
Vol 29 (3) ◽  
pp. 566-570 ◽  
Author(s):  
Shoichiro Yano ◽  
Hyoe Hatakeyama
Keyword(s):  
Water Sorption ◽  
Structural Changes ◽  
Regenerated Cellulose ◽  
Dynamic Viscoelasticity

Structural changes in regenerated-cellulose film containing an inert filler

1979 ◽  
Vol 10 (4) ◽  
pp. 364-365
Author(s):  
I. F. Aleksandrovich ◽  
S. S. Gusev ◽  
�. P. Kalutskaya ◽  
A. B. Pakshver
Keyword(s):  
Structural Changes ◽  
Regenerated Cellulose ◽  
Cellulose Film ◽  
Inert Filler ◽  
Regenerated Cellulose Film

Experimental Design of Surface Modification of Expanded Obsidian and Determination of Water Sorption Capacity

2014 ◽  
Vol 1020 ◽  
pp. 823-826
Author(s):  
G.Sh. Hovsepyan ◽  
M.A. Kalantaryan ◽  
T.V. Yedoyan
Keyword(s):  
Experimental Data ◽  
Surface Modification ◽  
Sorption Capacity ◽  
Water Sorption ◽  
Structural Changes ◽  
Ir Spectrometry ◽  
Water Capacity ◽  
Series Of Experiments ◽  
Water Sorption Capacity

The aim of this paper is to study the possibility of expanded obsidian and its modified product use for oil sorption, in that tetraethoxisilane (TEOS) has been used as a modifier. The optimal concentration of the modifier was determined by 50 per cent weight of expanded obsidian. The expanded obsidian was previously activated with 0,1 M solution of hydrochloric acid. IR spectrometry was used to characterise structural changes in the modified expanded obsidian samples. To determine water sorption capacity a series of experiments has been carried out. The analysis of obtained experimental data showed that after surface modification of expanded obsidian water capacity is reduced 3 times after the surface modification of EO.

scholarly journals Modelling the moisture sorption isotherms of Roselle (Hibiscus sabdariffa L.) in the temperature range of 5–35 °C

2013 ◽  
Vol 61 (6) ◽  
pp. 1769-1777 ◽  
Author(s):  
Jitka Langová ◽  
Donludee Jaisut ◽  
Ratiya Thuwapanichayanan ◽  
Charotorn Phowong ◽  
Jiří Štencl ◽  
...  
Keyword(s):  
Moisture Content ◽  
Water Sorption ◽  
Structural Changes ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Ambient Air ◽  
Point Of View ◽  
Hibiscus Sabdariffa ◽  
Adsorption And Desorption ◽  
Moisture Sorption Isotherms

Water sorption tests of Roselle (Hibiscus sabdariffa L.) carried out under laboratory conditions are presented together with mathematical analyses of the moisture sorption isotherms (MSI’s). Moisture equilibrium data for adsorption and desorption of water from Roselle powder were investigated at near ambient air temperatures in the range of 5 and 35 °C and water activity (Aw) ranging from 0.11 to 0.97. The manometric method has been used for water sorption tests. Models for MSI’s are exponential equations. Coefficients of determination are 0.998 and 0.996 (for adsorption and desorption at 5 °C, respectively), 0.998 and 0.999 (for adsorption and desorption at 20 °C, respectively), and 0.998 and 0.999 (for adsorption and desorption at 35 °C, respectively). The equilibrium moisture content (EMC) of Roselle samples increased with an increase of Aw at a constant temperature both for adsorption and desorption. Adsorption curve equates to desorption curve at higher temperatures of tests carried out. Critical values of EMC of samples tested corresponding to the Aw equal to 0.6 were between 13.401% moisture content wet basis (MC w.b.) and 15.934% MC (w.b.) for moisture adsorption and desorption, respectively. These values are useful for storing conditions optimisation from point of view microorganisms grow and structural changes analyses. Crystal structure changes were observed during adsorption and desorption in the microscope, too. It was found out glass transition in dependence on the water content of samples tested.

Oxidation and structural changes in NMMO-regenerated cellulose films

Cellulose ◽  
2016 ◽  
Vol 23 (6) ◽  
pp. 3535-3541 ◽  
Author(s):  
Ralf Zimmermann ◽  
Yvonne Müller ◽  
Uwe Freudenberg ◽  
Dieter Jehnichen ◽  
Antje Potthast ◽  
...  
Keyword(s):  
Structural Changes ◽  
Regenerated Cellulose ◽  
Cellulose Films ◽  
Regenerated Cellulose Films

Activation of pine kraft lignin by Fenton-type oxidation for cross-linking with oligo(oxyethylene) diglycidyl ether

Holzforschung ◽  
2011 ◽  
Vol 65 (3) ◽  
Author(s):  
Lars Passauer ◽  
Klaus Fischer ◽  
Falk Liebner
Keyword(s):  
Ethylene Glycol ◽  
Water Sorption ◽  
Structural Changes ◽  
Kraft Lignin ◽  
Diglycidyl Ether ◽  
Fenton Oxidation ◽  
Cross Linking ◽  
Ferrous Chloride ◽  
Poly Ethylene Glycol ◽  
Poly Ethylene

Abstract Mechanically stable hydrogels featuring water absorption capacities of up to 75 gH2O ggel -1 can be obtained by cross-linking of activated technical lignins with poly(ethylene) glycol diglycidyl ether under strong alkaline conditions. Fenton oxidation prior to cross-linking by hydrogen peroxide and catalytic amounts of ferrous chloride has been found to be superior to an alkaline H2O2 pre-treatment with respect to gel formation, water sorption, and rheological properties of the resulting oligo(oxyethylene) lignin gels. Purified pine kraft lignin undergoes in the course of Fenton oxidation hydroxylation of both aliphatic and aromatic moieties. This is the main reason for the enhanced cross-linking density obtained after treatment with poly(ethylene) glycol diglycidyl ether. The oxidative changes have been demonstrated by principal component analysis of Curie point pyrograms, wet chemical methods, FT-IR, and 31P NMR spectroscopy. Cleavage of side-chains, radical 5,5′-coupling of phenylpropane units, formation of carbonyl and carboxyl groups, and cleavage of aromatic rings were observed. These structural changes may increase or decrease the water sorption capability of the cross-linked products.

Relationship Between Fatigue Behavior and Nonlinear Dynamic Viscoelasticity for High-Density Polyethylenes with Different Aggregation States

1998 ◽  
Vol 18 (1-2) ◽  
pp. 63-82
Author(s):  
Nam-Ju Jo ◽  
Kwang-Nak Koh
Keyword(s):  
Fatigue Strength ◽  
Nonlinear Dynamic ◽  
Structural Changes ◽  
Fatigue Behavior ◽  
Cyclic Fatigue ◽  
High Density ◽  
Viscoelastic Parameter ◽  
Dynamic Viscoelasticity ◽  
Crystallite Boundary ◽  
Cyclic Straining

Abstract Relationships between fatigue behavior and nonlinear dynamic viscoelastic properties for the annealed, isothermally crystallized, and oriented high-density polyethylenes (HDPEs) with different molecular aggregation states were intensively discussed. Nonlinear dynamic viscoelasticity under cyclic fatigue was estimated on the basis of nonlinear viscoelastic parameter (NVP) which was defined as the contribution of higher harmonics of Fourier expanded stress signal. Fatigue strength of specimens decreased with an increase in the magnitude of NVP. Thus, NVP can be used as an index of fatigue strength for polymeric solids. Also, higher-order structural changes of specimens by cyclic straining were investigated and it was concluded that the nonlinear dynamic viscoelasticity under cyclic fatigue became dominant with an increase in cyclic straining concentration at the amorphous and/or spherulite or crystallite boundary regions.

Investigating the interaction between internal structural changes and water sorption of MDF and OSB using X-ray computed tomography

2018 ◽  
Vol 52 (3) ◽  
pp. 701-716 ◽  
Author(s):  
Wanzhao Li ◽  
Jan Van den Bulcke ◽  
Jelle Dhaene ◽  
Xianxu Zhan ◽  
Changtong Mei ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Water Sorption ◽  
Structural Changes ◽  
X Ray ◽  
X Ray Computed
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