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In order to achieve efficient and durable oil-water emulsion separation, the membranes possessing high separation efficiency and mechanical strength attract extensive attention and are in great demand. In present study, a kind of polytetrafluoroethylene (PTFE)-based bilayer membrane was fabricated by electrospinning fibrous PTFE (fPTFE) on an expanded PTFE (ePTFE) substrate. The morphological observation revealed that the fibrous structure of the fPTFE layer could be tailored by controlling the formulation of spinning solution. The addition of appropriate polyoxyethylene (PEO) would make the fibers in the fPTFE layer finer and more uniform. As a result, the compounded membrane exhibited a small pore size of approximately 1.25 µm and a substantial porosity nearing 80%. This led to super-hydrophobicity, characterized by a high water contact angle (WCA) of 149.8°, and facilitated rapid oil permeation. The water-in-oil emulsion separation experiment further confirmed that the compounded membrane not only had a high separation efficiency closing 100%, but such an outstanding separation capacity could be largely retained, either through multiple cycles of use or through strong acid (pH=1), strong alkali (pH=12), or high-temperature (100 °C) treatment. Additionally, the mechanical behavior of the bilayer membrane was basically contributed by that of each layer in terms of their volume ratio. More significantly, the poor creep resistance of fPTFE layer was suppressed by compounding with ePTFE substrate. Hence, this study has laid the groundwork for a novel approach to create PTFE-based compounded membranes with exceptional overall characteristics, showing promise for applications in the realm of emulsion separation. [ABSTRACT FROM AUTHOR]

Against the backdrop of a global paper resource shortage, there is a growing need to identify fast-growing tree species capable of producing long-lasting paper. Three plant species namely Broussonetia kazinoki, Broussonetia papyrifera and hybrid paper mulberry, belong to the Broussonetia genus, were collected from China to study their white bark suitability for pulp and papermaking. Their chemical composition revealed that the holocellulose content in Broussonetia kazinoki and Broussonetia papyrifera was more than 80%. The molecular weight distribution of several holocellulose/α-cellulose is observed by GPC, which allows us to better observe the changes of various components on the molecular weight. The yield, lignin, whiteness, and molecular weight of the pulps obtained by NaOH treatment were determined. Optical microscope was used to characterize the fiber length-width ratio and rigidity. Finally, the improvement of the fiber rigidity method based on the Kratky-Porod chain model makes it more theoretical and further reveals the influencing factors of fiber rigidity. This study demonstrates the high potentiality of these three species for papermaking applications. [ABSTRACT FROM AUTHOR]

A new method for characterizing fiber bending flexibility was developed by worm-like chain model proposed by Kratky-Porod,[1] which was first introduced to the pulp and paper field in this study. For the three types of pulps, the experimental results were compared with the KP chain model, and the resulting determination coefficients were all above 0.95, which proved that the model was feasible to be applied to these three fibers. The relation between fiber bending rigidity and that of cellulosic chains inside was discussed to deduce the fiber bending flexibility. The flexibility of an individual fiber can be approximated as the contribution of that of all the cellulose chains inside. By this method, the fiber flexibility values were determined to be in the range of 0.6×1011−3.5×1011 N−1·m−2, which was comparable to that of the conventional methods recorded in the literature. [ABSTRACT FROM AUTHOR]

In this work, we modify the traditional Brusselator model to incorporate the intermolecular interactions, based on which a systematic study is performed on the pattern formation mediated by chemical reaction and phase separation. It is found that if the chemical reaction dominates, the pattern formation will be inhibited by the phase separation while if the phase separation dominates, the chemical reaction will prevent, under certain conditions, the domain size from growing which results in dissipative patterns other than macroscopic phase separations. [ABSTRACT FROM AUTHOR]