Adhesion between polymer surface modified by graft polymerization and tissue during surgery using an ultrasonically activated scalpel device

In the field of surgery, achieving adhesion between a polymer implant and tissue poses a challenge considering that suturing is not appropriate for the stability of such implants. An ultrasonically activated scalpel that generates heat by mechanical vibration and promotes adhesion between a polymer implant and native tissue by pressing the two materials together has very good potential for application in the field. To determine the type of polymer that is suitable for the purpose, we investigated polyethylene (PE) and polystyrene (PS) films, the surfaces of which were activated by corona discharge. Graft polymerization was then performed on the corona‐treated surfaces to vary their properties. The corona‐treated PE and PS films grafted with poly(acrylic acid), poly(methacrylic acid), poly(vinyl benzylacrylic acid), and poly(hydroxylethyl acrylate), respectively, adhered to the tissue when the ultrasonically activated scalpel was applied. The heat generated by the mechanical vibration and the applied pressure enabled the carboxyl or hydroxyl groups to bond with the proteins in the extracellular matrix. We therefore concluded that it was possible to integrate this technique in the development of new types of polymer devices that could be stably implanted in a living body. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40885.     

Electrohydrostatics of capillary switches

A capillary switch is a system of two liquid drops, one sessile and the other pendant, obtained by overfilling a hole of radius R in a plate. When surface tension dominates gravity, the equilibrium shapes of the drops are spherical sections of equal radii. If the combined volume of the top V_T and bottom V_B drops exceeds , the system has three equilibrium states of which two are stable. This bistability is exploited in applications by toggling the system between its two stable states. Here, we examine the effectiveness of using an electric field for toggling. Bifurcation diagrams are obtained that depict how the system's response varies with applied field strength E, and show loss of stability at turning points and the possibility of hysteresis. A phase diagram in space is presented to readily infer when an electric field is an effective means for toggling. © 2014 American Institute of Chemical Engineers AIChE J, 60: 1451–1459, 2014     

过程装备与控制工程创新发展探讨——迈向数字化、网络化、智能化

发展过程装备与控制工程是建设制造强国的重要环节。文章通过分析过程装备与控制工程领域新的发展机遇,发现数字化、网络化、智能化是其重要的发展趋势,并给出了发展的内涵和进展,在此基础上从战略研究、专业建设、合作交流等方面提出了发展建议,以期为相关部门及人员提供参考。     

Superhydrophobic PES/PDA/ODTS fibrous mat prepared by electrospinning and silanization modification for oil/water separation

With polydopamine (PDA) acting as interlayer, combined with electrospinning technology and a silanization method, here a versatile method for fabricating a superhydrophobic PES/PDA/ODTS fibrous mat is reported. Scanning electron microscopy, attenuated total reflection Fourier transform infrared spectroscopy, and contact angle measurements were applied to characterize the morphologies and chemical composition changes of the prepared fibrous mats. Their separation ability for oil/water mixtures was measured by self‐made instruments. The results show that the fabricated PES/PDA/ODTS fibrous mat displays a water contact angle too large to be assessed by the ordinary amount of water applied in a conventional measurement. In other words, a water drop of less than 10 μL adheres to the syringe needle and leaves with it during the measurement. The prepared PES/PDA/ODTS fibrous mat also shows a threshold sliding angle no more than 2.5°. At the same time, this kind of material exhibits superoleophilicity for organic solvents, such as n‐hexane, gasoline, toluene, and chloroform. The experimental contact angles were also analyzed using the Cassie–Baxter model to gain insights into the fundamental microstructure–wetting property relationship. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45923.     

Resorcinol formaldehyde xerogels modified with mercapto functional groups as mercury adsorbent

Resorcinol formaldehyde xerogels are modified by mercaptopropyl‐trimethoxysilane during the sol–gel process used to produce the xerogel. The chemical modification is confirmed by Fourier‐transform infrared spectroscopy. The xerogel is then used to adsorb mercury ions from aqueous solutions. The effects of the molar ratios of the precursors as well as the catalyst and the modifier are studied on the textural properties of the xerogel and the adsorption efficiency. It is shown that the chemical modification of the resorcinol formaldehyde xerogels creates the chemical sites on the structure of the xerogel to adsorb more mercury ions and increase the adsorption efficiency. At the same time, chemical modification decreases the xerogel surface area which results in a reduction of the mercury adsorption. Therefore, there exists an optimum value for the chemical modification of the xerogel to achieve the highest adsorption efficiency. Adsorption kinetics as well as equilibrium isotherm of xerogels were examined using pseudo‐first‐ and second‐order kinetic equations, and Freundlich and Langmuir isotherm models. The adsorption kinetics was found to follow the pseudo‐second‐order kinetic equations. The experimental data was also fitted into the Longmuir model more precisely comparing the Freundlich model. Finally, a series of mercury adsorption–desorption tests proved that the optimized mercapto‐modified resorcinol formaldehyde xerogel was an efficient reusable adsorbent for mercury ions. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42543.     

Preparation and characterization of P(AN‐co‐VA‐co‐DEMA) fibers coated with multiwalled carbon nanotubes by electrostatic interactions

P(AN‐co‐VA‐co‐DEMA) terpolymers were synthesized by aqueous precipitation copolymerization of acrylonitrile (AN), vinyl acetate (VA), and 2‐dimethylamino ethyl methacrylate (DEMA) with an Na₂S₂O₅–NaClO₃ redox initiating system and fibers from these terpolymers were thus prepared by a wet spinning method. Functionalized multiwalled carbon nanotube (F‐MWNT) networks were created on the surface of P(AN‐co‐VA‐co‐DEMA) fibers by a simple dipping method. The morphology and interfacial interactions of the obtained F‐MWNTs‐coated fibers were characterized by scanning electron microscope, Raman spectroscopy, and Fourier transform infrared spectroscopy. The results showed that F‐MWNTs were assembled on the fibers and the density of F‐MWNTs can be controlled by adjusting the F‐MWNTs content in the dipping solution. The assembly process was driven by electrostatic interactions between the negative charges on the nanotube sidewalls and the positive charges of the fibers. The F‐MWNTs‐coated fibers had a good conductivity. The volume resistivity of the fibers coated with 1.18 wt % F‐MWNTs reached 0.27 Ω·cm, while the original mechanical properties were preserved. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42545.     

LaPO4添加量对粗晶ZrO2陶瓷抗热震性能的影响

以空气为淬冷介质,用淬冷-强度法研究了LaPO4添加量对粗晶ZrO2(4Y)陶瓷抗热震性能的影响。结果表明,原料粒度为1.5μm的ZrO2陶瓷,其抗热震性能随LaPO4添加量的增加逐渐提高。LaPO4添加量为20 vol%时,陶瓷的临界抗热震温差达1300℃,比单一ZrO2陶瓷提高了400℃。ZrO2-LaPO4复相陶瓷抗热震性能的提高主要是由于LaPO4晶体的层间解理以及弱界面开裂分散了热应力,耗散了热震裂纹扩展的能量。     

Interphasial viscoelastic behavior of CNT reinforced nanocomposites studied by means of the concept of the hybrid viscoelastic interphase

In this study the effect of carbon nanotubes content as well as of the tensile stress level applied upon the linear viscoelastic creep response of carbon nanotube polymer nanocomposites was investigated. Experimental findings were modeled by means of the newly developed hybrid viscoelastic interphase model, which constitutes an extension of the previously developed hybrid interphase model. According to this model, the viscoelastic interphase thickness has not of constant value but is dependent upon the property considered at the time as well as on the creep time. In addition, the parameter of imperfect bonding is introduced through the degree of adhesion. Experimental findings combined with analytical results gave a better understanding of the viscoelastic response of epoxy resin carbon nanotubes nanocomposites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Controllable layer-by-layer assembly based on brucite and alginates with the assistance of spray drying and flame retardancy influenced by gradients of alginates

With the aim of tailoring and controlling surface assembly, multifunctional flame retardants (FRs) were obtained based on depositing alginates and silane coupling agents on brucite via the spray-drying-assisted layer-by-layer assembly technique. The assembly was controllable in both structure and gradient mass. Two series of FRs were named CuFR1-3 and NiFR1-3 based on the assembly content of metal alginates. With the assistance of spray drying, good compatibility between FRs and ethylene-vinyl acetate (EVA) was obtained, resulting in better mechanical properties. Meanwhile, the FRs improved flame retardancy and smoke suppression when used in EVA composites. With 55 wt % loading, composites with CuFR3 and NiFR1 passed UL 94 V-0 rating, while those with brucite were not rated. The peak of heat release rate decreased by 51.7 and 49.3% while the residue increased by 9.8 and 11.9%, respectively. The FRs also reduced the smoke and CO production rates. For the two series of FRs, the relationship between FR efficiency and alginate contents is different. The CuFRs assembled more copper alginates and exerted better flame retardancy caused by lower catalytic graphitization. NiFRs exerted a higher catalyzing efficiency at low assembly content. However, at high assembly content, the catalytic graphitization effect would decrease by thermally oxidized degradation leading to excess nickel alginates. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 47570.