Characterization of the water retention curves of Everglades wetland soils

The Nafion membranes are widely used in electrochemical applications such as fuel cells, chlor-alkali cells, and actuators–sensors. In this work, the thermal-optical characterization of Nafion in acid form was performed by photoacoustic spectroscopy, thermogravimetry, and differential scanning calorimetry. In the experimental procedure three distinct hydration levels were considered: (1) pristine membrane (λ ≅ H2O/–SO3H ≅ 5.6); (2) swelling process (λ ≅ 17.4); and (3) drying at controlled room temperature after swelling process (λ ≅ 6.5). The discovered behaviors showed significant irreversible structural changes induced by water retention in the membrane. These structural changes depend on the water population present in the clusters and also affect the directional thermal diffusivity of the membrane irreversibly.

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Preparation and Characterization of Bacterial Cellulose/TiO2 Hydrogel Nanocomposite

Journal of Nano Research ◽

10.4028/www.scientific.net/jnanor.43.73 ◽

2016 ◽

Vol 43 ◽

pp. 73-80 ◽

Cited By ~ 5

Author(s):

Ricardo Brandes ◽

Letícia de Souza ◽

Vanessa Vargas ◽

Eliana Oliveira ◽

Alexandre Mikowski ◽

...

Keyword(s):

Bacterial Cellulose ◽

Water Retention ◽

Morphological Analysis ◽

Sol Gel ◽

Absorption Capacity ◽

Ex Situ ◽

High Tensile Strength ◽

Hydrogel Nanocomposite ◽

High Absorption

Bacterial cellulose (BC) is a biopolymer with interesting properties, such as biocompatibility, high tensile strength, high absorption capacity, water retention and high crystallinity. Nanoparticles of titanium dioxide (TiO2) are extremely important in electrical applications, photocatalysis, sensors and biomedical areas. Multifunctional materials, based on bacterial cellulose, with differentiated properties can be designed from the BC/TiO2 nanocomposite by ex situ method of sol-gel immersion. It was manufactured as a nanocomposite consisting of BC/TiO2 hydrogel. Characterizations were carried out by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and fourier transform infrared spectroscopy (FTIR). The morphological analysis of nanocomposite revealed the existence of molecular interaction and adhesion between TiO2 nanoparticles and cellulosic nanofibers matrix, where the presence of Ti peaks in EDS spectra was discovered, proving the successful incorporation of nanoparticles. The FTIR showed modification on the functional groups, suggesting interaction between the components. The manufacturing of a BC/TiO2 nanocomposite by method of sol-gel immersion has a great potential for future applications.

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Mercerization and Characterization of Straw Pulp Fibers

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.781-784.2645 ◽

2013 ◽

Vol 781-784 ◽

pp. 2645-2649

Author(s):

Yan Na Yin ◽

Quan Xiao Liu ◽

Yu Bin Lyu

Keyword(s):

Cell Wall ◽

Processing Time ◽

Water Retention ◽

Fiber Cell ◽

Pulp Fibers ◽

Water Retention Value ◽

Treatment Conditions ◽

Fiber Cell Wall

Effects of mercerizing treatment on water-retention value of straw pulp fibers were discussed and the mercerizing treatment conditions were optimized. The best conditions of mercerizing treatment is NaOH concentration of 4mol/L, temperature of 40°C and processing time of 60min. SEM showed that the fiber cell wall swelling increase after mercerization.

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