To develop new composites with sufficiently high thermal conductivity and suitably controlled D k value for PCBs application, the composites were prepared from epoxy and AlN or BN fillers, and the effects of content, size, size distribution, and morphology of two fillers on the thermal and dielectric properties of the composites were investigated. The results showed that either AlN or BN fillers can greatly increase T g and thermal conductivity, decreasing CTE and D f , and suitably controlling the increase of D k . At the same filler content, BN-filled composites exhibit better thermal performance and dielectric properties compared to AlN-filled composites. In the case of BN-filled composites, it is found that plateletshaped micro-BN filled composite has lower T g and higher CTE compared with particle-shaped nano-BN filled composite, but its thermal conductivity is remarkably higher than that of nano-BN filled composite. When hybrid BN fillers are used, thermal conductivity further increases. For micro-or nano-BN filled composite, the composite shows decreased T g and increased D k at high fraction of BN, but hybrid BN-filled composite still has high T g and similar D k with epoxy even if at high fraction of BN. Compared with single-sized AlN-filled composite, it is found that hybrid-sized AlN-filled composite has higher T g and lower CTE, but has lower thermal conductivity. To predict thermal conductivity and D k in the investigated materials system, different models reported in the literature were analyzed and compared with the experimental data. Finally, suitable models were recommended.

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A copper-mediated C-S/N-S bond-forming reaction via C-H activation that uses elemental sulfur has been developed. The addition of TBAI was found to be crucial for the success of this transformation. The method is scalable, shows excellent functional group tolerance, and is compatible with heterocycle substrates, providing efficient and practical access to benzoisothiazolones. The direct diversification of the benzoisothiazolone products into a variety of sulfur-containing compounds is also demonstrated.

Polymer matrix composites, based on brominated epoxy, a type of material widely used in printed circuit boards (PCBs), as matrix and AlN particle as filler were prepared. The influences of AlN content on the mechanical, thermal, and electrical properties of the composites were investigated by uniaxial tensile test, TMA, thermal conductivity measurement, DMA, and dielectric properties measurement. It was found that the properties of composites monotonically varied with AlN content except that maximum tensile strength and strain of composites corresponded to a filler content of 10 wt %. The results of DMA also showed the AlN reinforcement was more pronounced above Tg, and the peak area of tan δ versus T curves decreased with AlN content, which implied the damping capacity of the composite gradually decreased. The increase in Tg and decrease in damping were probably due to strong interaction between the AlN and epoxy matrix inhibiting the mobility of the epoxy chain. In addition, different theoretical models reported in the literature were used to predict the E, CTE, k, and Dk, and compared with the experimental data. Finally, suitable models were recommended in the present materials system. For the significant improvement of performance of epoxy, we can conclude that these composite materials may be promising for PCB substrate. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1662–1674, 2007

Four types of hollow glass microspheres, having the density of 0.125–0.60 g/cm3, were filled into epoxy-matrix, and volume fraction of hollow glass microsphere was varied from 0% to 60%. The thermal, dielectric and compressive properties of the composites were investigated. The results show that the thermal conductivity, dielectric constant (Dk) and loss (Df) and compressive modulus and strength of the composites show decreased trend with increasing hollow glass microsphere content or decreasing hollow glass microsphere density, which indicates that the properties of the composites are mainly dependent on the characteristics of hollow glass microsphere. By comparing the experimental data and theoretical predictions, it is found that the properties of the composites, especially for thermal conductivity, are also related to the voids in epoxy-matrix. To conveniently predict thermal conductivity and Dk in the investigated materials system, theoretical models reported in the literature are analyzed and compared with the experimental data. Finally, suitable models are recommended. In addition, the thermal conductivity and dielectric properties of the composites were investigated as a function of testing temperature. This work indicates that thermal, dielectric and compressive properties of epoxy-matrix composites can be tailored by adjusting hollow glass microsphere content and density, which makes hollow glass microsphere filled composites a promising candidate in related fields.

The conversion of GO to RGO, using biodegradable CNC, offers a sustainable approach to large-scale preparation of highly biocompatible and easily dispersed RGO.

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Nitrogen-containing heterocyclic compounds are important motifs of pharmaceuticals and functional materials, and there has been a growing interest in new synthetic methods for their preparation. In this paper, we report a direct cross-coupling reaction of heteroarenes with N,N-dimethylanilines in the presence of copper catalyst. Oxygen and/or air are successfully used as the oxidant, which is of great importance to the industrialized economies. The reaction is compatible with a wide range of heterocycles, including indolizines, imidazoles, indoles, and aniline, to enable the formation of various alkylated heteroarenes under very mild reaction conditions.