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The electrochemical-induced regioselective C-3 thiomethylation of imidazopyridines has been initially accomplished via a three-component cross-coupling strategy using thiocyanate as the sulfur source and methanol as the methyl reagent. This protocol provides a green method for the thiomethylation of imidazopyridines without the need for any exogenous oxidants and metal catalysts under room temperature conditions. A wide range of functional groups were tolerated to produce regioselective C-3 thiomethylated products in high yields. Importantly, such an electrochemical-oxidation-induced thiomethylated reaction could be easily scaled up with excellent efficiency. [ABSTRACT FROM AUTHOR]

A novel kind of fully carbon-based filler (f-MWCNT-g-rGO) is constructed by a reaction between melted urea functionalized multi-walled carbon nanotubes (f-MWCNTs) and graphene oxide (GO) followed by chemical reduction. The corresponding highly thermally conductive polyimide (f-MWCNT-g-rGO/PI) nanocomposites are then fabricated through the combined method of in situ polymerization, electrospinning and hot pressing. An improved thermal conduction model is also proposed and established considering the filler/matrix interfaces, filler dispersion and alignment, etc. The f-MWCNT-g-rGO fillers have a hierarchical “line-plane” structure. The fabricated f-MWCNT-g-rGO/PI nanocomposites possess an outstanding thermal conductivity coefficient (λ), and excellent thermal stabilities and mechanical properties. Specifically, the f-MWCNT-g-rGO/PI nanocomposites reach the maximum λ of 1.60 W m−1 K−1 at a relatively low loading of f-MWCNT-g-rGO fillers (10 wt%, the mass ratio of rGO to f-MWCNT is 2 : 1). In addition, the theoretical λ value calculated by our established thermal conduction model is more in line with the experimental λ values compared with other traditional models. Owing to the high thermal conductivities while preserving good mechanical properties and thermal stabilities at a relatively low loading of f-MWCNT-g-rGO filler, the f-MWCNT-g-rGO/PI nanocomposites are expected to be used as thermal pads in light emitting diode (LED) substrates and liquid crystal displays. [ABSTRACT FROM AUTHOR]

A novel aromatic polyamide (PA) reverse osmosis membrane with nanoscale water channels and hydrophilic molecular skin surface, similar to those of biomimetic neural networks, was realized for textile wastewater treatment via the facile strategy of interfacial polymerization with the addition of free radicals. The free-radical polymerization of diallyl dimethyl ammonium chloride, dispersed inside and on the surface of the PA functional layer, was initiated by irradiation to form a polyimide-hydrophilic polyolefin interpenetrating network structure as the functional layer and a molecular brush as the hydrophilic surface layer. Compared with the thin film composite (TFC) membrane, the water contact angle of the modified membrane was reduced drastically from 58.23° to 19.95°, and surface roughness and negative charge also decreased. Moreover, the water flux and salt rejection performances of the modified membrane improved simultaneously. The hydrophilic polyolefin network exhibited the same structure and function as those of neural networks, through which water molecules, but not salts, could pass through nanoscale water channels formed by polymerization. Then, contaminant rejection rates using TFC or modified membranes for textile wastewater treatment were investigated. The modified membrane yielded high rejection (＞99%) of ion salts and high chemical oxygen demand removal (＞99.3%) of organics with low molecular weights. Apart from its excellent anti-fouling property, the modified membrane was also satisfactorily stable for long-term separation. The integration of low-cost, high-performance, and facile strategy indicates the potential application of the proposed membrane for textile wastewater treatment. [ABSTRACT FROM AUTHOR]

Thermally conductive aligned cellulose/nanodiamond (CND) plastics were fabricated via gelation transition. The resulting plastics present an orderly layered structure in which cellulose is highly oriented along the in-plane direction. Nanodiamond (ND) could disperse effectively and form an orderly connection with cellulose because of hydrogen bonding. The thermal conductivity of CND plastics is 5.37 W m−1 K−1 at only 5 wt% filler content, which is a high level compared with common plastics at a filler content below 10 wt%. Moreover, the CND plastics also exhibit remarkable mechanical and insulation properties. Highly thermally conductive plastics with insulation and mechanical properties have great potential in the field of thermal management. [ABSTRACT FROM AUTHOR]

Both aminopropylisobutyl polyhedral oligomeric silsesquioxane (NH2-POSS) and hydrazine monohydrate were utilized to functionalize graphene oxide (GO), and to obtain chemically modified graphene (CMG), which was then used for preparing thermally conductive CMG/polyimide (CMG/PI) nanocomposites via a sequential in situ polymerization and electrospinning-hot press technology. NH2-POSS molecules were grafted on the GO surface, and CMG was obtained by the reaction between NH2-POSS and GO. The thermal conductivity coefficient (λ), glass transition temperature (Tg) and heat resistance index (THRI) of the prepared CMG/PI nanocomposites were all increased with increasing the CMG loading. The λ value of the CMG/PI nanocomposites with 5 wt% CMG was significantly improved to 1.05 W m−1 K−1, about 4 times higher than that of the pristine PI matrix (0.28 W m−1 K−1). The corresponding Tg and THRI values were also increased to 213.0 and 282.3 °C, respectively. Moreover, an improved thermal conductivity model was proposed and predicted the λ values of the nanocomposites more precisely than those obtained from the typical Maxwell, Russell and Bruggemen classical models. [ABSTRACT FROM AUTHOR]

In this contribution, we present a new strategy for the fabrication of modified cyanate ester resins combined with ultralow dielectric properties, improved mechanical properties and high thermal and dimensional stabilities. The fluoride-containing compound 2-((3-(trifluoromethyl)phenoxy)methyl)oxirane (TFMPMO), synthesized from m-(trifluoromethyl)phenol (TFMP) and epichlorohydrin (ECH), was used to modify bisphenol A dicyanate ester (BADCy) resins via copolymerization reaction. The BADCy resin modified with 15 wt% TFMPMO presented ultralow dielectric constant (ε, 2.75) and dielectric loss tangent values (tan δ, 6.7 × 10−3), high mechanical properties (impact strength of 15.4 kJ m−2 and flexural strength of 141.0 MPa), and superior thermal and dimensional stability (THeat-resistance index of 206 °C and coefficient of thermal expansion of 6.4 × 10−5), and it possesses great potential application in radomes and antenna systems of aircraft. [ABSTRACT FROM AUTHOR]