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In this work, graphene nanoplatelet (GNP) filled polymethyl methacrylate (PMMA) composites were prepared using solution method via a specially designed route and relatively high thermal conductivities of the composites were achieved at a low GNP loading. The effect of GNP content on rheological behavior, thermal and electrical conductivity of the composites was intensively investigated. Thermorheological complexity was displayed at elevated GNP loading, and the rheological percolation threshold of GNP in PMMA decreased from 7.96 wt% at 220 °C to 4.02 wt% at 260 °C according to Winter - Chambon method, suggesting that GNP was more likely to form a seepage network at higher temperature. The DMTA results showed that the increase in moduli of the composites should be ascribed to the formation of the GNP-GNP network structure. The electrical conductivity of the composites underwent a sudden jump by seven orders of magnitude, which also indicated the formation of a GNP conductive pathway in the matrix with an electrical percolation threshold of 2–4 wt%. The results of transient temperature measurement were in good consistent with the thermal conductivity versus GNP loading, which was compared with various thermal conduction models with a modified Agari model presenting an acceptable evaluation of the dispersion status of GNP in the matrix. The experimental electrical and thermal conductivities as a function of GNP content could well be interpreted by the filler network structure as observed in morphological studies. • Thermorheological complexity displayed at elevated GNP loadings. • Temperature dependence of rheological percolation threshold of GNP in PMMA. • Electrical percolation threshold of GNP in PMMA within concentration of 2–4 wt%. • Thermal conductivity versus GNP loading reasonably predicted by a modified Agari model. • Relatively high thermal conductivities of composites achieved at low GNP loadings. [ABSTRACT FROM AUTHOR]

Diffusion dialysis (DD) separation process is shackled by the ion flux and selectivity. To solve this problem, the development of membrane materials is very important. In this study, mesoporous silica has been synthesized first and then phosphotungstic acid was adsorbed in the mesopores under vacuum condition. The obtained functionalized mesoporous silica materials (MS-HPW) have been then blended with pre-crosslinked polyvinyl alcohol (PVA) solution to prepare a series of hybrid membranes. The as-prepared membranes possess ion exchange capacities (IECs) of 0.015–0.030 (mmol/g) and water uptake (W R) of 98.3%–196.6%, as well as good thermal and mechanical stability. Alkali resistance of the hybrid membranes has been tested in 2 M NaOH solution at 25 °C and the results are acceptable: swelling degree is in the range of 134.3%–160.2% and mass loss is in the range of 3.2%–12.2%. The as-prepared membranes have been used for alkaline diffusion dialysis (DD) process of NaOH/Na 2 WO 4 system and the results are encouraging: PVA/MS-HPW hybrid membranes exhibit higher ion flux and selectivity than that of PVA and PVA/MS membranes. The mesoporous structure and OH− adsorption ability of MS-HPW material are considered to play important roles during the ion transport. Image 1 • Hybrid membranes were prepared by blending PVA solution and functionalized mesoporous silica (MS-HPW) materials. • The PVA-based hybrid membranes were used for alkali recovery via diffusion dialysis. • Involvement of MS-HPW could improve U OH and S of the hybrid membranes simultaneously. [ABSTRACT FROM AUTHOR]