In this paper, reduced graphite oxide (RGO) was prepared using thiourea dioxide as reductant and polyvinylpyrrolidone (PVP) as stabilizer. Thiourea dioxide, a cheap and nontoxic industrialized material, was demonstrated to be an efficient reducing agent for graphite oxide (GO) in this paper. Ultraviolet and visible (UV–vis) spectroscopy results revealed that the reduction of GO could be readily achieved in 10 min, a reaction time which is much shorter than those required in common reduction reactions. The procedures of reduction including the by-products are all nontoxic, thus it is absolutely environmentally friendly. To the best of our knowledge, this is the first time that thiourea dioxide was successfully used to prepare RGO. Moreover, the stabilizer, PVP, which could be easily absorbed onto the surface of RGO, provided RGO with good water and organic solvents solubility, with low conductivity though. However, by controlling the content of PVP, RGO with balanced solubility and conductivity can be obtained. The resultant RGO could be used as nanofillers to prepare conductive materials and biomaterials with potential applications as electrical devices or biosensors.Graphical abstractHighlights► Thiourea dioxide is reported to reduce graphite oxide for the first time.► Reduction procedure is quite fast and absolutely environmentally friendly.► Polyvinylpyrrolidone (PVP) is used to stabilize the reduced graphite oxide.► Influences of PVP loading on re-dispersion, thickness and conductivity of graphene are studied.

Polar β and γ crystalline forms, especially the β form, are of great importance to the piezoelectric/ferroelectric property of poly(vinylidene fluoride) (PVDF). Dominant polar crystal forms (containing both β and γ forms) are induced in PVDF by simply adding a small amount of dioctadecyl dimethyl ammonium chloride (DDAC, a kind of alkyl ammonium salt used to treat clay). By comparing with the PVDF/clay and PVDF/DDAC modified-clay systems, it is demonstrated that it is DDAC that induces polar β and γ forms of PVDF rather than organoclay itself. The widely accepted mechanism that crystal lattice matching between PVDF and clay induces β form in PVDF/organoclay composite might be wrong. It is also interesting to find that super tensile toughness can be achieved by adding a small amount of DDAC. These new findings are very important for the understanding of the formation mechanism of polar forms of PVDF and its application.

The morphology and mechanical properties of poly(ethylene-octene) copolymers (POE) obtained by dynamic packing injection molding were investigated by mechanical tests, differential scanning calorimetry (DSC), fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The mechanical tests found that only POE with low octene content and high molecular weight show apparent response for external shear field. Further investigation has been done by DSC, FT-IR, and SEM in order to make clear the reason of that phenomenon. Finally, the hypothetical mechanism of POE microstructure formation under shear field has been proposed. For POE with low octene content and high molecular weight, orientation degree and mechanical properties both increase substantially under shear field. For POE with low octene content and low molecular weight, orientation degree and crystallinity increase under shear field, but it is not dramatically benefit for the mechanical properties. For POE with high octene content and high molecular weight, the shear field has little effect on the morphology and mechanical properties.