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Suffering from high inherent toxicity generated from heavy metals in semiconductor quantum dots and a complex preparation process, the medical application of conventional gadolinium(III)/semiconductor quantum dot-based magnetic resonance/fluorescence multimodal imaging (MRI/FI) contrast agent has been limited. In this paper, a new kind of biocompatible carbon quantum dot functionalized by gadolinium(III) chelates (named as Gd(III)/CQDs) was obtained through one-step pyrolysis of gadopentetate monomeglumine, which provides simultaneously a carbon source and a gadolinium(III) source. The Gd(III)/CQDs show good magnetic resonance response and photoluminescence properties with longitudinal relaxation rate and quantum yield of 5.5-6.4 mM L[sup -1] S[sup -1] [Gd(III)%, 0.5 mM] and 2.6-8.9%, respectively. The Gd(III)/CQDs with diameters in the range of 2-3 nm can be well dispersed in deionized water, phosphate-buffered saline buffer solution or culture medium to form a stable dispersion, which with low cytotoxicity can penetrate into cells and show green fluorescence (excitation at 488 nm), presenting a great potential to be used as an MRI/FI contrast agent. [ABSTRACT FROM AUTHOR]

In the autoclave curing process of phenolic resin composite at high pressure, uncured resin usually flows into the vacuum pipe through improperly used bleeder and blocks the vacuum orifice. Therefore, there are too many defects formed in the as-prepared composite because not all volatiles can be expelled from the laminate. In order to choosing or manufacturing the bleeder used in this special condition, the resin flow in the bleeder should be carefully investigated. However, the resin flow in the bleeder cannot be observed directly during the autoclave curing process, computer simulation is employed to describe the flow in the bleeder. The simulation results show that i) the resin flow near the vacuum orifice is quite different compared to that far away from the vacuum orifice, the resin can flow through the bleeder near the vacuum orifice within a shorter time; ii) a bleeder made from needle-punched nonwoven material with low porosity, small fibre diameter and small permeability could prevent the resin from flowing into the vacuum pipe in the autoclave curing process. [ABSTRACT FROM AUTHOR]

The article presents a study on the pyrolysis characteristics of hyperbranched polyborate (HBPB)-modified phenolic resin (PR) (PR-HBPB). Results of the study revealed that small volumes of HBPB added to PR can cause carbon yield increase traceable to the pyrolysis mechanism of PR-HBPB. The increase, which is greater than individual carbon yields of PR and HBPB, is significantly influenced by HBPB's high thermal resistance and the formation of certain chemicals during pyrolysis.

A novel adamantane‐containing epoxy resin diglycidyl ether of bisphenol‐adamantane (DGEBAda) was successfully synthesized from 1,3‐bis(4‐hydroxyphenyl)adamantane by a one‐step method. The proposed structure of the epoxy resin was confirmed with Fourier transform infrared, 1H‐NMR, gel permeation chromatography, and epoxy equivalent weight titration. The synthesized adamantane‐containing epoxy resin was cured with 4,4′‐diaminodiphenyl sulfone (DDS) and dicyandiamide (DICY). The thermal properties of the DDS‐cured epoxy were investigated with differential scanning calorimetry and thermogravimetric analysis (TGA). The dielectric properties of the DICY‐cured epoxy were determined from its dielectric spectrum. The obtained results were compared with those of commercially available diglycidyl ether of bisphenol A (DGEBA), a tetramethyl biphenol (TMBP)/epoxy system, and some other associated epoxy resins. According to the measured values, the glass‐transition temperature of the DGEBAda/DDS system (223°C) was higher than that of the DGEBA/DDS system and close to that of the TMBP/DDS system. TGA results showed that the DGEBAda/DDS system had a higher char yield (25.02%) and integral procedure decomposition temperature (850.7°C); however, the 5 wt % degradation temperature was lower than that of DDS‐cured DGEBA and TMBP. Moreover, DGEBAda/DDS had reduced moisture absorption and lower dielectric properties. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 [ABSTRACT FROM AUTHOR]

Polyaniline (PANI) was synthesized by chemical oxidative polymerization of aniline (ANI) in the presence of sulfonated crosslinked polystyrene (SCPS) particles in neutral water. The polymerization of ANI occurred preferentially on the surfaces of the SCPS particles, resulting in core/shell structured SCPS/PANI particles. The conductivities of the SCPS/PANI particles increased with increasing degree of sulfonation of the SCPS and with increasing ANI/SCPS weight ratios in the reactants. Conductive epoxy?based composites were prepared by curing the blend of SCPS/PANI particles and epoxy resin with an aromatic amine curing reagent, indicating the core/shell structured particles were stable, to some extent, to alkaline environments, which will be of significant importance for the practical application of PANI in many cases. [ABSTRACT FROM AUTHOR]