scholarly journals Molecular Insights on Successful Reconstitution of Freeze-Dried Nanofibrillated Cellulose Hydrogel

2021 ◽  
Vol 4 (9) ◽  
pp. 7157-7167
Author(s):  
Elle Koivunotko ◽  
Arto Merivaara ◽  
Akseli Niemelä ◽  
Sami Valkonen ◽  
Kalle Manninen ◽  
...  
Keyword(s):  
Nanofibrillated Cellulose ◽  
Freeze Dried ◽  
Cellulose Hydrogel

Wood‐Derived Nanofibrillated Cellulose Hydrogel Filters for Fast and Efficient Separation of Nanoparticles

2019 ◽  
Vol 3 (9) ◽  
pp. 1900063 ◽  
Author(s):  
Yushu Wang ◽  
Jialiang Wang ◽  
Shengjie Ling ◽  
Haiwei Liang ◽  
Ming Dai ◽  
...  
Keyword(s):  
Nanofibrillated Cellulose ◽  
Efficient Separation ◽  
Cellulose Hydrogel

COST-FP1105: Properties of PLA films reinforced with unmodified and acetylated freeze dried nanofibrillated cellulose

Holzforschung ◽  
2016 ◽  
Vol 70 (12) ◽  
pp. 1125-1134 ◽  
Author(s):  
Vesna Žepič ◽  
Ida Poljanšek ◽  
Primož Oven ◽  
Matjaž Čop
Keyword(s):  
Heterogeneous System ◽  
Cellulose Nanofibrils ◽  
Composite Films ◽  
Hydrophobic Surface ◽  
Nanofibrillated Cellulose ◽  
Nanocomposite Films ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry ◽  
Elongation At Break ◽  
Freeze Dried

Abstract Freeze dried nanofibrils were acetylated in a heterogeneous system with acetic anhydride, pyridine, and dimethylformamide and the obtained acetylated cellulose nanofibrils (CNFac) were combined with poly(lactic acid) (PLA) to a composite. CNFac with its partially hydrophobic surface showed a good compatibility with PLA resulting in composite films with improved properties. Tensile strength (TS), modulus of elasticity (MOE), and elongation at break (EB) of PLA/CNF increased significantly when 2–5% of CNFac was added to the PLA matrix, while the addition of 10% and higher amounts CNFac decreased the EB at a higher TS and MOE. Mechanical parameters did not improve in the case of unmodified CNF addition. The addition of CNFac maintained transparency and had absorbance values between those of pure PLA film and PLA film with 2% CNF, while films formed with the addition of 5 and 10% of CNF were less transparent. The addition of CNF did not essentially affect the thermal properties of nanocomposite films. The addition of 2–10% of CNFac increased the enthalpy and maximal temperature of cold crystallization as opposed to higher loading of CNFac. The results of differential scanning calorimetry (DSC) coincide with those of the mechanical properties. Tailoring properties of PLA/CNF are only reproducible in case of homogenously distributed CNF within the PLA matrix and by an improved interphase adhesion between PLA and CNFac.

Spray freeze-dried nanofibrillated cellulose aerogels with thermal superinsulating properties

2017 ◽  
Vol 157 ◽  
pp. 105-113 ◽  
Author(s):  
Clara Jiménez-Saelices ◽  
Bastien Seantier ◽  
Bernard Cathala ◽  
Yves Grohens
Keyword(s):  
Nanofibrillated Cellulose ◽  
Freeze Dried

Morphological, thermal, and structural aspects of dried and redispersed nanofibrillated cellulose (NFC)

Holzforschung ◽  
2014 ◽  
Vol 68 (6) ◽  
pp. 657-667 ◽  
Author(s):  
Vesna Žepič ◽  
Erika Š. Fabjan ◽  
Marta Kasunič ◽  
Romana C. Korošec ◽  
Aleš Hančič ◽  
...  
Keyword(s):  
Spray Drying ◽  
Network Formation ◽  
Fine Powder ◽  
Nanofibrillated Cellulose ◽  
Freeze Dried ◽  
Drying Treatment ◽  
Dehydration Processes ◽  
Structural Behaviors ◽  
Structural Aspects ◽  
Aggregation Phenomena

Abstract The effects of various drying techniques, such as air, oven, freeze, and spray drying, on the morphological, thermal, and structural behaviors of two different nanofibrillated cellulose (NFC) materials were investigated. Field emission scanning electron microscopy (FE-SEM) observations indicated an interlaced network formation of predominantly in-plane fibrillar orientation for air- and oven-dried samples, while freeze and spray drying resulted in the formation of coarse and fine powder fractions. Comparison of redispersed powders obtained by freeze and spray drying indicated that aggregation phenomena are significantly reduced in freeze-dried specimens. Rheological and sedimentation analysis revealed that the freeze-dried NFC powders are more stable than spray-dried NFC powders when redispersed in water. Aggressive dehydration processes, such as freezing or heating, significantly influence the thermal stability of the dried cellulose samples. On the contrary, the crystallinity properties of dried NFC materials are very similar regardless of the drying treatment.

A Zero-Valent Pd/Fe Loaded and Nanofibrillated Cellulose-Reinforced Carboxymethyl Cellulose Hydrogel for Dechlorination of 2,4,6-Trichlorophenol

2019 ◽  
Vol 19 (11) ◽  
pp. 7261-7268 ◽  
Author(s):  
Xiao-Fang Wan ◽  
Congbao Guo ◽  
You-Ming Li ◽  
Xin-Sheng Chai ◽  
Ke Lin ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carboxymethyl Cellulose ◽  
Bimetallic Nanoparticles ◽  
Spherical Shape ◽  
Nanofibrillated Cellulose ◽  
X Ray ◽  
Surface Areas ◽  
Hydrogel Matrix ◽  
Fe Nanoparticles ◽  
Cellulose Hydrogel

A full-cellulose derived hydrogel, composed of carboxymethyl cellulose (CMC) and nanofibrillated cellulose (NFC), was successfully manufactured and immobilized with Pd/Fe bimetallic nanoparticles for the dechlorination of 2,4,6-trichlorophenol. The NFC-reinforced CMC hydrogels with or without loading of bimetallic nanoparticles were characterized by Fourier transform infrared spectroscopy, Transmission electron microscopy, Scanning electron microscopy-energy dispersive X-ray, and X-ray diffraction analyses. The effect of amounts of NFC on the loading capacity of Pd/Fe, mechanical properties and specific Brunauer-Emmett-Teller surface areas of NFC-reinforced CMC hydrogel was also investigated. The experimental results showed that Pd/Fe bimetallic nanoparticles were dispersed and fixed in the hydrogel matrix with the nanosize spherical shape. The hydrogel would protect the Pd/Fe nanoparticles from oxidation, and thus providing long-term stability in comparison with only NFC-coated Pd/Fe nanoparticles. The hydrogel loaded with Pd/Fe nanoparticles, as a soft material catalytic system, was investigated to dechlorinate 2,4,6-trichlorophenol and was found to be very effective.

Three-Dimensional Reconstruction Using Stereo Pairs from Serial Thick Sections

1977 ◽  
Vol 35 ◽  
pp. 562-563
Author(s):  
Robert Glaeser ◽  
Thomas Bauer ◽  
David Grano
Keyword(s):  
Three Dimensional ◽  
Dimensional Structure ◽  
Serial Sections ◽  
Thin Sections ◽  
3 Dimensional ◽  
Transmission Electron ◽  
Freeze Dried ◽  
Dimensional Reconstruction ◽  
Stereo Imagery ◽  
Whole Mounts

In transmission electron microscopy, the 3-dimensional structure of an object is usually obtained in one of two ways. For objects which can be included in one specimen, as for example with elements included in freeze- dried whole mounts and examined with a high voltage microscope, stereo pairs can be obtained which exhibit the 3-D structure of the element. For objects which can not be included in one specimen, the 3-D shape is obtained by reconstruction from serial sections. However, without stereo imagery, only detail which remains constant within the thickness of the section can be used in the reconstruction; consequently, the choice is between a low resolution reconstruction using a few thick sections and a better resolution reconstruction using many thin sections, generally a tedious chore. This paper describes an approach to 3-D reconstruction which uses stereo images of serial thick sections to reconstruct an object including detail which changes within the depth of an individual thick section.

Scanning and Transmission Microscopy of Nematocyst Batteries in Epitheliomuscular Cells of Hydra

1971 ◽  
Vol 29 ◽  
pp. 410-411 ◽  
Author(s):  
Jane A. Westfall ◽  
S. Yamataka ◽  
Paul D. Enos
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Osmium Tetroxide ◽  
External Surface ◽  
Three Dimensional ◽  
Surface Structures ◽  
Transmission Microscopy ◽  
Transmission Electron ◽  
Freeze Dried ◽  
Scanning Electron

Scanning electron microscopy (SEM) provides three dimensional details of external surface structures and supplements ultrastructural information provided by transmission electron microscopy (TEM). Animals composed of watery jellylike tissues such as hydras and other coelenterates have not been considered suitable for SEM studies because of the difficulty in preserving such organisms in a normal state. This study demonstrates 1) the successful use of SEM on such tissue, and 2) the unique arrangement of batteries of nematocysts within large epitheliomuscular cells on tentacles of Hydra littoralis.Whole specimens of Hydra were prepared for SEM (Figs. 1 and 2) by the fix, freeze-dry, coat technique of Small and Màrszalek. The specimens were fixed in osmium tetroxide and mercuric chloride, freeze-dried in vacuo on a prechilled 1 Kg brass block, and coated with gold-palladium. Tissues for TEM (Figs. 3 and 4) were fixed in glutaraldehyde followed by osmium tetroxide. Scanning micrographs were taken on a Cambridge Stereoscan Mark II A microscope at 10 KV and transmission micrographs were taken on an RCA EMU 3G microscope (Fig. 3) or on a Hitachi HU 11B microscope (Fig. 4).

Characterization of microtubules by dark-field STEM and replication

1991 ◽  
Vol 49 ◽  
pp. 152-153
Author(s):  
S.B. Andrews ◽  
R.D. Leapman ◽  
P.E. Gallant ◽  
T.S. Reese
Keyword(s):  
Protein Interactions ◽  
Low Dose ◽  
Unit Length ◽  
Dark Field ◽  
Carbon Films ◽  
Microtubule Associated Proteins ◽  
Molecular Weights ◽  
Freeze Dried ◽  
Protein Motors ◽  
Associated Proteins

As part of a study on protein interactions involved in microtubule (MT)-based transport, we used the VG HB501 field-emission STEM to obtain low-dose dark-field mass maps of isolated, taxol-stabilized MTs and correlated these micrographs with detailed stereo images from replicas of the same MTs. This approach promises to be useful for determining how protein motors interact with MTs. MTs prepared from bovine and squid brain tubulin were purified and free from microtubule-associated proteins (MAPs). These MTs (0.1-1 mg/ml tubulin) were adsorbed to 3-nm evaporated carbon films supported over Formvar nets on 600-m copper grids. Following adsorption, the grids were washed twice in buffer and then in either distilled water or in isotonic or hypotonic ammonium acetate, blotted, and plunge-frozen in ethane/propane cryogen (ca. -185 C). After cryotransfer into the STEM, specimens were freeze-dried and recooled to ca.-160 C for low-dose (<3000 e/nm2) dark-field mapping. The molecular weights per unit length of MT were determined relative to tobacco mosaic virus standards from elastic scattering intensities. Parallel grids were freeze-dried and rotary shadowed with Pt/C at 14°.

The Effects of Drying Techniques on Clay-Rich Soil Texture

1974 ◽  
Vol 32 ◽  
pp. 466-467
Author(s):  
T. G. Naymik
Keyword(s):  
Critical Point ◽  
Liquid Nitrogen ◽  
Liquid Nitrogen Temperature ◽  
Drying Methods ◽  
Air Drying ◽  
Freeze Dried ◽  
Critical Point Drying ◽  
Set Up ◽  
The Relationship ◽  
Quartz Grains

Three techniques were incorporated for drying clay-rich specimens: air-drying, freeze-drying and critical point drying. In air-drying, the specimens were set out for several days to dry or were placed in an oven (80°F) for several hours. The freeze-dried specimens were frozen by immersion in liquid nitrogen or in isopentane at near liquid nitrogen temperature and then were immediately placed in the freeze-dry vacuum chamber. The critical point specimens were molded in agar immediately after sampling. When the agar had set up the dehydration series, water-alcohol-amyl acetate-CO2 was carried out. The objectives were to compare the fabric plasmas (clays and precipitates), fabricskeletons (quartz grains) and the relationship between them for each drying technique. The three drying methods are not only applicable to the study of treated soils, but can be incorporated into all SEM clay soil studies.

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