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Abstract  

Serials of halloysite nanotubes/polystyrene (HNTs/PS) nanocomposites with different contents of organo-modified halloysite nanotubes (organo-HNTs) were successfully prepared by the in situ bulk polymerization of styrene with the organo-HNTs as macromonomers. The percentage of grafting (PG%) of more than 230% was achieved, calculated from the results of the thermogravimetric analysis (TG). The TG results also showed that the thermal stabilities of the HNTs/PS nanocomposites prepared via the bulk polymerization were better than the pure polystyrene. And the maximum thermal degradation temperature of the nanocomposites increased with the increasing of the amount of the HNTs fillers added.

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Abstract  

Blends of poly(ether-sulfone) (PES) and poly(phenylene sulfide) (PPS) with various compositions were prepared using an internal mixer at 290C and 50 rpm for 10 min. The thermal and dynamic mechanical properties of PES/PPS blends have been investigated by means of DSC and DMA. The blends showed two glass transition temperatures corresponding to PPS-rich and PES-rich phases. Both of them decreased obviously for the blends with PES matrix. On the other hand, Tg of PPS and PES phase decreased a little when PPS is the continuous phase. In the blends quenched from molten state the cold crystallization temperature of PPS was detected in the blends of PES/PPS with mass ratio 50/50 and 60/40. The melting point, crystallization temperature and the crystallinity of blended PPS were nearly unaffected when the mass ratio of PES was less than 60%, however, when the amount of PES is over 60% in the blends, the crystallization of PPS chains was hindered. The thermal and the dynamic mechanical properties of the PPS/PES blends were mainly controlled by the continued phase.

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Abstract  

The freezing and melting of water in semi-dilute (0.5–3.0%) solutions of the polysaccharide hyaluronanhave been investigated by modulated differential scanning calorimetry.High molecular weight hyaluronan inhibited nucleation of ice and significantly depressed thefreezing temperature in a dynamic scan conducted at –3.0°C min–1. Low molecular weight hyaluronan had a weaker and more variable effect on nucleation. Theeffects on nucleation, especially by the high molecular weight hyaluronan, are attributed tothe influence of a hyaluronan network on the formation of critical ice nuclei.Both high and low molecular weight hyaluronan reduced the melting temperature of ice by 0.4–1.1°C, depending on concentration. The enthalpy change associated with this transitionwas significantly reduced. If all of the enthalpy difference is attributed to the presence of non-freezing water, approximately 3.65 g water/g hyaluronan would be non-freezing. This result appears incompatible with published studies on hyaluronan samples of low water content. An alternative hypothesis and quantitative approach to analysis of the data are suggested. The data are interpreted in terms of a small amount of non-freezing water, and amuch larger boundary layer of water surrounding hyaluronan chains, which has slightly altered thermodynamic properties relative to those of bulk water. The boundary layer water behaves similarly to water trapped in small pores in solid materials and hydrogels.

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Abstract  

Nuclear-based analytical techniques: INAA, PIXE and photon activation permit simultaneous multielemental determination of concentrations in environmental materials, which data are often found sufficiently precise and free of uncontrolled, random errors among the various elements such that the data sets can yield valuable information on elemental communality through multi-variant statistical factor analysis. Characteristic factor patterns obtained in this way can provide clues to the likely sources in the environment of various components. Recent studies in three different environmental situations: solid waste incinerators, Chinese soils, and iron and steel industry, involving measurements of 30–35 elements, have yielded distinct elemental patterns or, environmental signatures, with factor loading coefficients ranging mostly in the ranges: 0.7–0.96.

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Abstract  

In this paper, a brief survey of hydrogen production methods is presented with a focus on S-I cycle. Based on heat duty data of sulfuric acid decomposition in S-I cycle, optimization models are developed to explore the minimum utility consumption and the minimum number of heat exchangers. Finally an optimal heat exchanger network for S-I thermochemical cycle is defined by a mixed integer optimization model.

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Isothermal cure characterization of dicyclopentadiene

The glass transition temperature and conversion

Journal of Thermal Analysis and Calorimetry
Authors:
X. Liu
,
X. Sheng
,
J. Lee
, and
M. Kessler

Abstract  

Conversion (α) and the glass transition temperature (T g) were investigated during the isothermal cure of endo-dicyclopentadiene (DCPD) with a Grubbs catalyst for different temperatures using differential scanning calorimetry. Conversion vs. In (time) data at an arbitrary reference temperature were superposed by horizontal shift and the shift factors were used to calculate an Arrhenius activation energy. Glass transition temperature vs. conversion data fell on a single curve independent of cure temperature, implying that reaction of the norbornene and cyclopentene ring of DCPD proceeds in a sequential fashion. Implications of the isothermal reaction kinetics for self-healing composites are discussed.

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Abstract  

In order to identify the kinetic process of self-heating in DSC experiment for Ti+3Al→TiAl3 reaction, two approaches, linear-fitting approach developed from Semenov"s theory of spontaneous ignition and variation of Friedman method, were carried out with cylindrical Ti-75 at% Al samples. Following these approaches, two identical activation energies are obtained as 16915 kJ mol-1 and 1705 kJ mol-1, respectively. Compared with the activation energies of reactions and interdiffusions between Ti and Al, the possible rate-controlling process of self-heating in DSC experiment for Ti+3Al→TiAl3 reaction is the interdiffusion between Ti and Al through TiAl3-layer.

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Thioacetamide (TAA) is a potent hepatotoxicant in acute and chronic hepatic injury. The study examined the protective effect of sesame oil against TAA-induced hepatic injury in rats. Hepatic injury was induced by intraperitoneal injection of 100 mg/kg of TAA for 24 h. Triple doses of sesame oil (1, 2, or 4 mL/kg) was given orally 0, 6, and 12 h after TAA treatment. TAA significantly increased serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels. Sesame oil decreased serum AST and ALT levels and significantly inhibited hepatic lipid peroxidation and nitric oxide levels compared with TAA-alone group. Further, sesame oil significantly inhibited TAA-induced hepatic neutrophil activation marker myeloperoxidase activity. However, sesame oil did not affect hepatic tumor necrosis factor, IL-1β and IL-10 generation in TAA-treated group. In conclusion, sesame oil protects against TAA-induced hepatic injury and oxidative stress via the inhibition of neutrophil activation. However, inflammatory cytokines may not be involved in sesame-oil-associated hepatic protection against TAA in rats.

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