Green and Rapid Preparation of Fluorosilicone Rubber Foam Materials with Tunable Chemical Resistance for Efficient Oil-Water Separation.

Polydimethylsiloxane (PDMS) foam materials with lightweight, excellent oil resistance and mechanical flexibility are highly needed for various practical applications in aerospace, transportation, and oil/water separation. However, traditional PDMS foam materials usually present poor chemical resistance and easily swell in various solvents, which greatly limits their potential application. Herein, novel fluorosilicone rubber foam (FSiRF) materials with different contents of trifluoropropyl lateral groups were designed and fabricated by a green (no solvents used) and rapid (<10 min foaming process) foaming/crosslinking approach at ambient temperature. Typically, vinyl-terminated poly(dimethyl-co-methyltrifluoropropyl) siloxanes with different fluorine contents of 0−50 mol% were obtained through ring-opening polymerization to effectively adjust the chemical resistance of the FSiRFs. Notably, the optimized FSiRF samples exhibit lightweight (~0.25 g/cm−3), excellent hydrophobicity/oleophilicity (WCA > 120°), reliable mechanical flexibility (complete recovery ability after stretching of 130% strain or compressing of >60%), and improved chemical resistance and structural stability in various solvents, making them promising candidates for efficient and continuous oil−water separation. This work provides an innovative concept to design and prepare advanced fluorosilicone rubber foam materials with excellent chemical resistance for potential oil−water separation application.

Ultrafast Flame-Induced Pyrolysis of Poly(dimethylsiloxane) Foam Materials toward Exceptional Superhydrophobic Surfaces and Reliable Mechanical Robustness.

Superhydrophobic surfaces are imperative in flexible polymer foams for diverse applications; however, traditional surface coatings on soft skeletons are often fragile and can hardly endure severe deformation, making them unstable and highly susceptible to cyclic loadings. Therefore, it remains a great challenge to balance their mutual exclusiveness of mechanical robustness and surface water repellency on flexible substrates. Herein, we describe how robust superhydrophobic surfaces on soft poly(dimethylsiloxane) (PDMS) foams can be achieved using an extremely simple, ultrafast, and environmentally friendly flame scanning strategy. The ultrafast flame treatment (1-3 s) of PDMS foams produces microwavy and nanosilica rough structures bonded on the soft skeletons, forming robust superhydrophobic surfaces (i.e., water contact angles (WCAs) > 155° and water sliding angles (WSAs) < 5°). The rough surface can be effectively tailored by simply altering the flame scanning speed (2.5-15.0 cm/s) to adjust the thermal pyrolysis of the PDMS molecules. The optimized surfaces display reliable mechanical robustness and excellent water repellency even after 100 cycles of compression of 60% strain, stretching of 100% strain, and bending of 90° and hostile environmental conditions (including acid/salt/alkali conditions, high/low temperatures, UV aging, and harsh cyclic abrasion). Moreover, such flame-induced superhydrophobic surfaces are easily peeled off from ice and can be healable even after severe abrasion cycles. Clearly, the flame scanning strategy provides a facile and versatile approach for fabricating mechanically robust and surface superhydrophobic PDMS foam materials for applications in complex conditions.

[Oxidative damage of volatile oil from Chenopodium ambrosioides on Vicia faba root tip cells].

Chenopodium ambrosioides is an invasive species, which has strong allelopathic effect on surrounding plants. In this study, the methods of soil culture and filter paper culture were adopted to simulate the eluviation and volatilization of the volatile oil from C. ambrosioides, respectively, and to investigate the allelopathy of the volatile oil on the lipid peroxidation and antioxidant enzyme activities of Vicia faba root tip cells, with the mechanisms of the induced tip cell apoptosis analyzed. At the early stage (24 h) of soil culture and filter paper culture, the superoxide dismutase, peroxidase and catalase activities of the tip cells decreased after an initial increase with the increasing dose of the volatile oil, and the malondialdehyde content of the tip cells increased with the increasing volatile oil dose and treated time. At the midterm (48 h) and later (72 h) stages of soil culture and filter paper culture, a typical DNA ladder strip appeared, suggesting that the volatile oil from C. ambrosioides could induce the apoptosis of the tip cells, and the apoptosis was dose- and time dependent. This study showed that the volatile oil from C. ambrosioides could act on its surrounding plants via eluviation and volatilization, making the lipid peroxidation of acceptor plants aggravated and the antioxidant enzyme activities of the plants inhibited, resulting in the oxidative damage and apoptosis of the plant root tip cells, and accordingly, the inhibition of the plant growth. Under soil culture, the root tip cells of V. faba had higher antioxidant enzyme activities and lesser DNA damage, suggesting that the volatile oil from C. ambrosioides via volatilization had stronger allelopathy on the growth of surrounding plants than via eluviation.

[Treatment of fracture of tibia and fibula with three dimensional diaplasis fixation].

OBJECTIVE: To study the clinical effect of three dimensional diaplasis fixation in fracture of tibia and fibula. METHODS: Twenty-one cases of fracture of tibia and fibula were treated with three dimensions fixation (12 males, 9 females, with an average age of 46 years). There were 5 cases in open fracture, 16 cases in closed fracture, and 4 cases in up-segment fracture, 8 cases in mid-segment fracture, 9 cases in below-segment fracture. Oblique fracture were in 10 cases, thrypsis were in 8 cases, multisegmental fracture were in 3 cases. RESULTS: (1) Conditions of diaplasis fracture: dissected diaplasis were in 11 cases, closely dissected diaplasis in 9 cases, functional diaplasis in 1 case. (2) Clinical healing time: the minimum time was 43 days and maximum time was 85 days with an average of 62 days. (3) Conditions of functional recovery: all the patients were followed up from 4 to 12 months, 13 cases were excellent, 8 cases were good. (4) Time of backouting three dimensional diaplasis fixation: the minimum time was 6 weeks and the maximum 12 weeks with an average time of 8.5 weeks. CONCLUSION: The three dimensional diaplasis fixation and the fracture extremity from such a three dimensional solid that it can satisfy crus biomechanics for treating fracture of tibia and fibula with unstressed barrier and uncentric stress. Moreover, the three dimensional diaplasis fixation is elastic, it's structure is so fixed that it can be favorable for bone union.