4 research outputs found
A Bottom-Up Synthesis of Vinyl-Cellulose Nanosheets and Their Nanocomposite Hydrogels with Enhanced Strength
Extracted
nanocellulose from natural resources commonly requires
modification before it is used as an effective nanofiller. In the
present study, through an enzymatic polymerization of α-d-glucose 1-phosphate from the primer 2-(glucosyloxy)Âethyl methacrylate
(GEMA), a novel type of two-dimensional methacrylate-containing cellulose
nanosheets (CNS) with a thickness of about 6 nm, named as GEMA-CNS,
was directly synthesized under a mild condition by a “bottom-up”
method. The structure and morphology of GEMA-CNS were characterized
by <sup>1</sup>H-nuclear magnetic resonance (NMR), matrix-assisted
laser desorption/ionization time-of-flight mass spectra (MALDI-TOF
MS), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction
(XRD), transmission electron microscopy (TEM), and atomic force microscopy
(AFM). Afterward, the obtained GEMA-CNS was covalently incorporated
into polyÂ(ethylene glycol) matrix through thiol–ene Michael
addition, fabricating a series of GEMA-CNS-based nanocomposite hydrogels.
The addition of GEMA-CNS effectively improved the mechanical strength
and altered the internal network structures of hydrogels; additionally,
the swelling/biodegradation behaviors of gels in phosphate buffer
saline (pH 7.4) at 37 °C were affected to some degree. This species
of property-tunable hydrogels with GEMA-CNS dosage demonstrates potential
applications in tissue engineering. The current presentation opens
a new road for direct enzymatic preparation of reactive nanocellulose
and its novel applications in nanocomposite materials
CQDs-Doped Magnetic Electrospun Nanofibers: Fluorescence Self-Display and Adsorption Removal of Mercury(II)
This
paper reports the carbon quantum dots-doped magnetic electrospinning
nanofibers for the self-display and removal of HgÂ(II) ions from water.
The fluorescent carbon quantum dots and magnetic Fe<sub>3</sub>O<sub>4</sub> nanoparticles were pre-prepared successfully, and they appeared
to be homogeneously dispersed in nanofibers via electrospinning. During
the sorption of HgÂ(II) ions, the significant fluorescence signals
of nanofibers gradually declined and exhibited a good linear relationship
with cumulative adsorption capacity, which could be easily recorded
by the photoluminescence spectra. The sorption performance of mercury
ions onto the nanofibers was investigated in terms of different experimental
factors including contact time, solution pH value, and initial ion
concentration. Considering the actual parameters, the nanofibers were
sensitive self-display adsorption system for HgÂ(II) ions in the existence
of other cation. The sorption data were described by different kinetic
models, which indicate that the whole sorption was controlled by chemical
adsorption. The intraparticle diffusion mass transfer was not obvious
in this system, which further proved the uniform adsorption and even
fluorescence quenching in nanofibers. Additionally, the nanocomposite
fiber could regenerate in several cycles with no significant loss
of adsorption capacity and fluorescence intensity. Thus, the nanofibers
are promising alternatives for environmental pollution incidents.
It is especially competent due to its high efficiency for self-display
and removal of high concentration of mercury ions
Cellulosic Biomass-Reinforced Polyvinylidene Fluoride Separators with Enhanced Dielectric Properties and Thermal Tolerance
Safety
issues are critical barriers to large-scale energy storage applications
of lithium-ion batteries (LIBs). Using an ameliorated, thermally stable,
shutdown separator is an effective method to overcome the safety issues.
Herein, we demonstrate a novel, cellulosic biomass-material-blended
polyvinylidene fluoride separator that was prepared using a simple
nonsolvent-induced phase separation technique. This process formed
a microporous composite separator with reduced crystallinity, uniform
pore size distribution, superior thermal tolerance, and enhanced electrolyte
wettability and dielectric and mechanical properties. In addition,
the separator has a superior capacity retention and a better rate
capability compared to the commercialized microporous polypropylene
membrane. This fascinating membrane was fabricated via a relatively
eco-friendly and cost-effective method and is an alternative, promising
separator for high-power LIBs
Thermally Stable Cellulose Nanocrystals toward High-Performance 2D and 3D Nanostructures
Cellulose
nanomaterials have attracted much attention in a broad range of fields
such as flexible electronics, tissue engineering, and 3D printing
for their excellent mechanical strength and intriguing optical properties.
Economic, sustainable, and eco-friendly production of cellulose nanomaterials
with high thermal stability, however, remains a tremendous challenge.
Here versatile cellulose nanocrystals (DM-OA-CNCs) are prepared through
fully recyclable oxalic acid (OA) hydrolysis along with disk-milling
(DM) pretreatment of bleached kraft eucalyptus pulp. Compared with
the commonly used cellulose nanocrystals from sulfuric acid hydrolysis,
DM-OA-CNCs show several advantages including large aspect ratio, carboxylated
surface, and excellent thermal stability along with high yield. We
also successfully demonstrate the fabrication of high-performance
films and 3D-printed patterns using DM-OA-CNCs. The high-performance
films with high transparency, ultralow haze, and excellent thermal
stability have the great potential for applications in flexible electronic
devices. The 3D-printed patterns with porous structures can be potentially
applied in the field of tissue engineering as scaffolds