Polyvinylidene fluoride (PVDF) and its blend films were prepared by melt-blending the binary mixture of PVDF/dibutyl phthalate (DBP) and the ternary mixture of PVDF/CaCO 3 /DBP in combination of TIPS. Their morphologies were characterized by scanning electron microscope depended on preparation condition, such as the diluent and CaCO 3 weight fraction, and the cooling rate, and the crystallization information was also investigated by DSC. The results showed that CaCO 3 influenced the morphology of PVDF in the TIPS process regardless of the cooling conditions, and the formation of the spherulitic morphology can be disturbed by CaCO 3 at the quenching condition. The effect of CaCO 3 weight fraction on the tensile strength of PVDF was measured, which indicated CaCO 3 had a negative effect on PVDF tensile strength.

In this study, the polyvinylidene fluoride (PVDF) hollow fiber hemodialysis membranes were prepared by non-solvent induced phase separation (NIPS). The influences of PVDF membrane thickness and polyethylene glycol (PEG) content on membrane morphologies, pore size, mechanical and permeable performance were investigated. It was found that membrane thickness and PEG content affected both the structure and performance of hollow fiber membranes. The tensile strength and rejection of bovine serum albumin (BSA) increased with increasing membrane thickness, while the Ultrafiltration flux (UF) flux of pure water was the opposite. The tensile strength, porosity and rejection of BSA increased with increasing PEG content within a certain range. Compared with commercial F60S membrane, the PVDF hollow fiber membrane showed higher mechanical and permeable performance. It was proven that PVDF material had better hydrophilicity and lower BSA adsorption, which was more suitable for hemodialysis. All the results indicate that PVDF hollow fiber membrane is promising as a hemodialysis membrane.

a b s t r a c tState-of-the-art nanofiltration (NF) membranes generally positively or negatively charged could not remove both multivalent cations and anions once and for all according to the Donnan Exclusion. Designing NF membranes with facile approach for effective removal of multivalent-salt without compromising the permeation is still a tough challenge. In this work, we demonstrate a sort of novel NF membrane consists of a positively charged interlayer sandwiched between substrate and negatively charged outermost surface. The restructured NF membranes with dually charged composite layer were fabricated via amination-interfacial polymerization (A-IP) on poly (vinyl chloride) (PVC) substrate. The resultant NF membranes exhibited super high salts rejection of up to 99.0% MgCl 2 , 99.0% MgSO 4 , 98.5% CaCl 2 , 95.7% Pb(NO 3 ) 2 , and 96.0% Na 2 SO 4 . Additionally, reasonably high flux (8.7 L m À 2 h À 1 bar À 1 , (pure water permeability (PWP))) approaching those of commercial NF membranes was obtained due to the relatively loose structure of the composite layer. Furthermore, the transport and separation mechanism of the restructured NF membranes reveals that the significant upgraded separation performance could be attributed to the synergistic effect of the dually charged layer. Moreover, the dually charged composite layer shown none unfavorable interaction and the resultant NF membranes possessed good interfacial stability.

The effects of a mixed diluent (MD) composition [dibutyl phthalate/dioctyl phthalate (DOP)] on poly (vinylidene fluoride) (PVDF) membrane morphology were investigated with scanning electron microscopy, and a bicontinuous morphology could be obtained with MD in a thermally induced phase-separation process. The reasons for the morphology formation were explained according to the effect of MD on the phase diagrams. In addition, the effects of the PVDF concentration on the membrane morphology were examined. For the system with less DOP, the large spherulite morphology was obvious under all investigated concentrations, whereas no large spherulite structure existed in the membrane as the DOP content increased to concentrations other than 20%.

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Purpose The purpose of this paper is to describe the design and development of “Pylon-Climber”, a pole climbing robot (PCR) for climbing along the corner columns of electricity pylon and assisting the electricians to complete maintenance tasks. Design/methodology/approach Introduces a PCR that is composed of a simple climbing mechanism and two novel grippers. The gripper consists of two angle-fixed V-blocks, and the size of V-block is variable. The clamping method of the angle bar meets the requirement of the force closure theorem. The whole design adopts symmetrical design ideas. Findings The developed prototype proved possibility of application of PCRs for inspection and maintenance of pylon. The novel gripper can provide enough adhesion force for climbing robot. Practical implications The robot is successfully tested on a test tower composed of different specification steel angles, oblique ledges and overlapping steel struts. Originality/value Design and development of a novel climbing assistive robot for pylon maintenance. The robot is able to climb along the column of electricity pylon and pass all obstacles. The gripper can reliably grasp the angle bar with different specification and overlapping steel struts from multiple directions.

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