Advances in three-dimensional nanofibrous macrostructures via electrospinning

Compared with other nanofiber fabrication processes, electrospinning is versatile and superior in production and construction of ordered or more complex nanofibrous assemblies. Besides traditional two-dimensional (2D) nanofibrous structures, electrospinning is powerful in fabrication of three-dimensional (3D) fibrous macrostructures, especially for tissue engineering applications. This article summarizes and reviews recent advances in various promising and cutting-edge electrospinning techniques, including multilayering electrospinning, post-processing after electrospinning, liquid-assisted collection, template-assisted collection, porogen-added electrospinning, and self-assembly. And their formation mechanisms, features, and the challenges of electrospinning have also been discussed. Furthermore, these 3D nanofibrous macrostructures have been demonstrated to have potential applications in tissue engineering, energy harvesting and storage, and filtration.     

交联改性PAMPS质子交换膜的制备与性能

制备了聚2-丙烯酰胺-2-甲基丙磺酸（PAMPS）质子交换膜并对其进行交联改性,研究了膜的含水率、溶胀率、拉伸强度、高温保水率、质子电导率等性能.结果表明,PAMPS均质膜的质子导电率很高（0.32 S/cm）,但溶胀率过高、机械强度差.交联改性后,膜保持高的导电率（3% MBA,0.076 S/cm）和高温保水性能,且膜的溶胀率大幅度降低,机械强度显著提高（3% MBA,23.6 MPa）.     

微波等离子体引发接枝凝胶型智能棉针织品

用Ar微波等离子体引发接枝聚合法,将2-丙烯酰胺-2-甲基丙磺酸(AMPS)接枝聚合到棉针织物上,使PAMPS凝胶与纺织品相结合。通过正交设计及数理统计方法对接枝工艺进行了筛选和优化;用红外光谱法证明了AMPS被接枝到了棉针织物上;对接枝前后织物的表面状态、静水压、透湿性、顶破强力等性能进行了探讨。结果表明,棉针织物接枝PAMPS后,湿态织物静水压大幅度增加,织物对湿环境具有智能响应性;同时干态织物透湿性和顶破强力有所下降。     

Telechelic polymers by living and controlled/living polymerization methods

Telechelic polymers, defined as macromolecules that contain two reactive end groups, are used as cross-linkers, chain extenders, and important building blocks for various macromolecular structures, including block and graft copolymers, star, hyperbranched or dendritic polymers. This review article describes the general techniques for the preparation of telechelic polymers by living and controlled/living polymerization methods; namely atom transfer radical polymerization, nitroxide mediated radical polymerization, reversible addition-fragmentation chain transfer polymerization, iniferters, iodine transfer polymerization, cobalt mediated radical polymerization, organotellurium-, organostibine-, organobismuthine-mediated living radical polymerization, living anionic polymerization, living cationic polymerization, and ring opening metathesis polymerization. The efficient click reactions for the synthesis of telechelic polymers are also presented.     

An investigation of lithium ion conductivity of copolymers based on P(AMPS-co-PEGMA)

In this work, a series of novel lithium ion-conducting copolymer electrolytes based on 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS) and poly(ethyleneglycol) methacrylate (PEGMA) were produced and characterized. The copolymers were synthesized by free-radical polymerization of the corresponding monomers with three different feed ratios to form P(AMPS-co-PEGMA)-based electrolytes. After the polymerization, AMPS units of the copolymers were lithiated via ion exchange. The characterization of the electrolytes was done by ¹H-NMR, FTIR, differential scanning calorimetry (DSC), thermogravimetric analysis, X-ray diffraction, scanning electron microscopy (SEM), and impedance analyzer. The copolymers were thermal stable approximately to 200 °C. Single T_g transitions in DSC curves verified the homogeneity as well as amorphous characteristics. SEM further confirmed the homogeneity of the electrolytes. The lithium ion conductivity of these new polymer electrolytes was studied by impedance dielectric impedance analyzer and the effect of PEGMA contents onto the ionic conductivity of these copolymer electrolytes were investigated. It was observed that the temperature dependence of ionic conductivity was interpreted over Vogel Tammann Fulcher model. The Li ion conductivity increased by PEGMA content and S3 has maximum conductivity of 3 × 10⁻³ mS cm⁻¹ at 100 °C. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47798.     

纳米银/PAMPS复合物的微波合成及表征

在不加还原剂的条件下,微波辐射双原位合成纳米银/2-丙烯酰胺基-2-甲基丙磺酸均聚物[PAMPS]复合材料。并通过UV-Vis、XRD、FTIR、TEM、XPS和TG等分析方法对其进行表征。结果表明:纳米银粒子具有面心立方结构,且较均匀地分散在聚合物基体中;微波辐射时间不影响纳米银粒子的形态;纳米银与基体PAMPS中的氮原子和羰基氧原子存在相互作用,而且对基体PAMPS的热学性能有很大影响。     

Conducting polymer gel: formation of a novel semi-IPN from polyaniline and crosslinked poly(2-acrylamido-2-methyl propanesulphonicacid)

In the present article, a simple two-step technique for synthesis of electrically conducting hydrogel is described. The synthesized hydrogel is originally a semi-interpenetrating polymer network (IPN) in which conducting polyaniline (linear) is entrapped within a crosslinked polyelectrolyte gel viz. poly(2-acrylamido-2-methyl propane sulphonic acid) (PAMPS). A conventional photo-polymerization technique was followed for synthesis of the PAMPS gel while aniline is in situ polymerized within the gel, giving rise to the desired semi-IPN. For comparison, a neutral gel based semi-IPN PAn-PAAm (polyaniline-polyacrylamide) was also prepared following the similar route. PAn imparts appreciable electrical conductivity to both PAMPS and PAAm based gels without hampering their existing properties that indicates the success of the work. Synthesis of the gel was studied in detail and different experimental conditions were optimized. Different physical properties of the gel viz. its degree of swelling, electrical conductivity, mechanical strength, etc were also studied. The resultant semi-IPN or the composite hydrogel was found to possess appreciable electrical conductivity, good swellability and mechanical strength. The electro-driven volume contraction of the composite gel was found to occur at sufficiently lower voltage compared to the pure PAMPS gel, which indicates its promising application aspect in fabrication of chemomechanical devices.     

Laser-induced anchoring of WO3 nanoparticles on reduced graphene oxide sheets for photocatalytic water decontamination and energy storage

In this work, the synthesis of tungsten oxide/reduced graphene oxide (WO₃-rGO) nanocomposite, using a simple method of pulsed laser ablation in liquids (PLAL) is reported. The pulsed laser beam of 355 nm wavelength carries out two simultaneous processes: the reduction of graphene oxide and at the same time the anchoring of nanostructured WO₃ on reduced graphene oxide. In the photo-catalytic application, WO₃-rGO shows much better visible light absorption and less photo-generated charge recombination than pure WO₃, as indicated by optical absorption and photoluminescence spectra. These improved features in WO₃-rGO significantly enhanced the photo-catalytic decontamination of methylene blue (MB) dye in the water, compared to the use of pure WO₃ as a photocatalyst. A Poly 2-acrylamido-2-methyl-1-propanesulfonic acid (PAMPS) based electrolyte together with the high electrical conductance and porosity of rGO which were produced after anchoring WO₃ on the graphene oxide, were harnessed for the energy storage application using this material for a supercapacitor. The specific capacitance for WO₃-rGO based device is achieved to be 577 F g⁻¹ measured by the galvanostatic charge-discharge (GCD) method. Also, at a power density of 1000 W kg⁻¹, the as-synthesized WO₃-rGO demonstrated a large energy density value of 76.3 Wh Kg⁻¹ that is much larger than obtained, using WO₃ alone. Besides these photocatalytic and energy storage performance evaluation of WO₃-rGO, the optical, morphological and elemental characteristics of synthesized WO₃-rGO were also investigated to study the improved performance of the nanocomposite in these two applications.     

PAMPS高吸水性树脂吸附性能

用溶液聚合法合成了聚(2-丙烯酰胺-2-甲基丙磺酸)高吸水性树脂(PAMPS树脂),研究了树脂在Pb(NO3)2、Cu(NO3)2、Zn(NO3)2溶液中的吸附性能,结果表明,在单一金属离子溶液中,实验范围内PAMPS树脂吸附量随溶液浓度增加而增大,对Pb2 的吸附量还随交联剂浓度和单体中和度增加而增大;在二元和三元混合金属离子溶液中,PAMPS树脂对Pb2 有很好的选择吸附性。     

纳米银/PAMPS复合材料的微波合成及表征

在不加还原剂的条件下,采用微波辐射双原位聚合方法合成了纳米银/2-丙烯酰胺基-2-甲基丙磺酸均聚物(PAMPS)复合材料,并通过UV-Vis、XRD、FTIR、TEM、XPS和TG分析方法对其进行分析和表征。结果表明:纳米银粒子具有面心立方结构,且均匀地分散在聚合物基体中;微波辐射时间不影响纳米银粒子的形态;纳米银与基体PAMPS中的氮原子和羰基氧原子存在相互作用,降低了基体PAMPS的热稳定性。