Starch nanoparticles (SN) were prepared by delivering ethanol as the precipitant into starch-paste solution dropwise. Citric acid (CA) modified SN (CASN) were fabricated with the dry preparation ...technique. According to the characterization of CASN with Fourier transform infrared, X-ray diffraction, rapid visco analyzer, and scanning electron microscopy (SEM), amorphous CASN could not be gelatinized in hot water because of the cross-linking, and most of CASN ranged in size from about 50 to 100 nm. The nanocomposites were also prepared using CASN as the filler in glycerol plasticized-pea starch (GPS) matrix by the casting process. SEM revealed that CASN was dispersed evenly in the GPS matrix. As shown in dynamic mechanical thermal analysis, the introduction of CASN could improve the storage modulus and the glass transition temperature of CASN/GPS composites. The tensile yield strength and Young’s modulus increased from 3.94 to 8.12 MPa and from 49.8 to 125.1 MPa, respectively, when the CASN contents varied from 0 to 4 wt %. Moreover, the values of water vapor permeability decreased from 4.76 × 10−10 to 2.72 × 10−10 g m−1 s−1 Pa−1. The improvement of these properties could be attributed to the good interaction between CASN filler and GPS matrix. The comprehensive application of green chemistry principles were demonstrated in the preparation of CASN and CASN/GPS composites.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM
Chitosan nanoparticles (CNs), obtained by physical crosslinking between tripolyphosphate and protonised chitosan, were used as filler in a glycerol plasticised-starch (GPS) matrix to be used in food ...packaging. In GPS/CN composites, the chemical structures of the matrix and the filler are similar because they are both polysaccharides. The influences of the filler content on the morphology, viscosity, mechanical properties, dynamic mechanical properties, water vapour permeation and thermal degradation of GPS/CN composites were studied. It was shown that the obvious improved effect on the tensile strength, storage modulus, glass transition temperature, water vapour barrier and thermal stability could be attributed to the filler/matrix interactions, which occurred when CN was dispersed uniformly in the GPS matrix at low content. However, higher CN loads (8
wt.%) resulted in the aggregation of CN in the composites.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Contrary to the most recognizable whiskers of slender parallelepiped rods, unique nanoparticles of about 50–100
nm were obtained from chitin after consecutive acid hydrolysis and mechanical ...ultrasonication treatments. Chitin nanoparticles (CNP) exhibited lower crystallinity when compared to conventional chitin whisker. Glycerol plasticized-potato starch (GPS) was combined with CNP to prepare all-natural nanocomposites by casting and evaporation. The morphology, structural, thermal and mechanical properties of the nanocomposites were evaluated by electron microscopy, X-ray diffraction, dynamic mechanical thermal analysis, and tensile tests. At low loading levels, CNP were uniformly dispersed in the GPS matrix and had good interaction between the filler and matrix, which led to improvements in tensile strength, storage modulus, glass transition temperature, and water vapor barrier properties of the GPS/CNP composites. However, at higher loading (greater than 5 wt.%), aggregation of CNP had a negative effect on these properties.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
In this paper, cellulose nanoparticles (CN) were coagulated from a NaOH/urea/H
2O solution of microcrystalline cellulose (MC) using an ethanol/HCl aqueous solution as the precipitant. CN ranged in ...size from about 50 to 100
nm. Compared to MC, CN formed a new crystalline lattice of cellulose II. The glycerol plasticized-wheat starch (GPS)/CN nanocomposites were prepared using CN as filler in GPS matrix by a casting process. At a low loading level, CN was dispersed evenly in the GPS matrix. The tensile strength increased from 3.15 to 10.98
MPa when CN content went from 0 to 5
wt.%. CN may increase the thermal stability of GPS/CN composites. Moreover, water vapor permeability decreased from 5.75
×
10
−10 to 3.43
×
10
−10
g
m
−1
s
−1
Pa
−1. The improvements in these properties may be attributed to the good interaction between CN filler and GPS matrix because of the similar polysaccharide structures of cellulose and starch.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
In this paper, cellulose nanoparticles (CN) were coagulated from a NaOH/urea/H2O solution of microcrystalline cellulose (MC) using an ethanol/HCl aqueous solution as the precipitant. CN ranged in ...size from about 50 to 100 nm. Compared to MC, CN formed a new crystalline lattice of cellulose II. The glycerol plasticized-wheat starch (GPS)/CN nanocomposites were prepared using CN as filler in GPS matrix by a casting process. At a low loading level, CN was dispersed evenly in the GPS matrix. The tensile strength increased from 3.15 to 10.98 MPa when CN content went from 0 to 5 wt.%. CN may increase the thermal stability of GPS/CN composites. Moreover, water vapor permeability decreased from 5.75 × 10(−10) to 3.43 × 10(−10) g m−1 s−1 Pa−1. The improvements in these properties may be attributed to the good interaction between CN filler and GPS matrix because of the similar polysaccharide structures of cellulose and starch.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Inorganic solid electrolytes have distinguished advantages in terms of safety and stability, and are promising to substitute for conventional organic liquid electrolytes. However, low ionic ...conductivity of typical candidates is the key problem. As connective diffusion path is the prerequisite for high performance, we screen for possible solid electrolytes from the 2004 International Centre for Diffraction Data （ICDD） database by calculating conduction pathways using Bond Valence （BV） method. There are 109846 inorganic crystals in the 2004 ICDD database, and 5295 of them contain lithium. Except for those with toxic, radioactive, rare, or variable valence elements, 1380 materials are candidates for solid electrolytes. The rationality of the BV method is approved by comparing the existing solid electrolytes＇ conduction pathways we had calculated with those from ex- periments or first principle calculations. The implication for doping and substitution, two important ways to improve the conductivity, is also discussed. Among them LizCO3 is selected for a detailed comparison, and the pathway is reproduced well with that based on the density functional studies. To reveal the correlation between connectivity of pathways and conductivity, a/γ-LiAlO2 and Li2CO3 are investigated by the impedance spectrum as an example, and many experimental and theoretical studies are in process to indicate the relationship between property and structure. The BV method can calculate one material within a few minutes, providing an efficient way to lock onto targets from abundant data, and to investigate the struc- ture-property relationship systematically.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Theoretically, nanosecond phase dispersion is an effective method to optimize the performance of thermoelectric materials due to the energy filtering effect and strong phonon scattering. Because of ...the chemical stability of La
2
O
3
, it may be used as a second phase material in Bi
2
Te
2.7
Se
0.3
matrixes. After the introduction of La
2
O
3
, its electric transport performance decreases slightly, but its thermal transport performance increases further. Finally, its thermoelectric performance is optimized. At 455 K, the maximum dimensionless thermoelectric figure of merit (
ZT
) value of Bi
2
Te
2.7
Se
0.3
+ 0.5
wt%
La
2
O
3
reaches 0.97. The experimental results demonstrate that La
2
O
3
dispersion can improve the thermoelectric properties of Bi
2
Te
2.7
Se
0.3
effectively
.
Full text
Available for:
DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
•Carbon nanodots dispersant.•Simultaneous optimization of power factors (S2σ) and thermal conductivity (κ).•A high ZT value of ~0.91 at 423 K and averaged ZT of ~0.81 at 320–520 K.
With excellent ...performance at room temperature as well as being the most mature n-type thermoelectric material in commercialization, Bi2Te2.7Se0.3 has been attracting increased attention. In this study, its carrier concentration and mobility were optimized by introducing excessive Te. When the excessive content of Te was 0.4, its power factor was the largest, and its thermal conductivity declined slightly. Based on Te excess, carbon nanodots were introduced as the dispersed nanosecond phase. The power factors were improved further due to the energy filter effect. In particular, the lattice thermal conductivity was depressed remarkably due to enhanced phonon scattering. Finally, at 423 K, the maximum ZT value of the sample reached 0.91, which was approximately 42% higher than that of the pure Bi2Te2.7Se0.3. The experimental results demonstrate that carbon nanodots dispersion acting as a nanosecond phase is an effective method to improve the thermoelectric performance of n-type Bi2Te2.7Se0.3-based materials.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Airway remodeling is one of the characteristics for chronic obstructive pulmonary disease (COPD). The mechanism underlying airway remodeling is associated with epithelial-mesenchymal transition (EMT) ...in the small airways of smokers and patients with COPD. Sirtuin 1 (SIRT1) is able to reduce oxidative stress, and to modulate EMT. Here, we investigated the effects and mechanisms of hydrogen sulfide (H2S) on pulmonary EMT in vitro and in vivo. We found that H2S donor NaHS inhibited cigarette smoke (CS)-induced airway remodeling, EMT and collagen deposition in mouse lungs. In human bronchial epithelial 16HBE cells, NaHS treatment also reduced CS extract (CSE)-induced EMT, collagen deposition and oxidative stress. Mechanistically, NaHS upregulated SIRT1 expression, but inhibited activation of TGF-β1/Smad3 signaling in vivo and in vitro. SIRT1 inhibition by a specific inhibitor EX527 significantly attenuated or abolished the ability of NaHS to reverse the CSE-induced oxidative stress. SIRT1 inhibition also abolished the protection of NaHS against CSE-induced EMT. Moreover, SIRT1 activation attenuated CSE-induced EMT by modifying TGF-β1-mediated Smad3 transactivation. In conclusion, H2S prevented CS-induced airway remodeling in mice by reversing oxidative stress and EMT, which was partially ameliorated by SIRT1 activation. These findings suggest that H2S may have therapeutic potential for the prevention and treatment of COPD.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
PDF