Co-reporter:Chunjie Xie, Teng Qiu, Jinglong Li, Heling Zhang, Xiaoyu Li, and Xinlin Tuo
Langmuir August 15, 2017 Volume 33(Issue 32) pp:8043-8043
Publication Date(Web):July 22, 2017
DOI:10.1021/acs.langmuir.7b01915
The direct synthesis of polymer microspheres modified by aramid nanofibers (ANFs) is an interesting challenge. This work describes a simple aqueous process to prepare polystyrene (PS)/ANF composite microspheres, where the specific ANF network was “dressed” on PS. ANF was derived from the copolymerization of terephthaloyl chloride, p-phenylene diamine, and methoxypolyethylene glycol and could be dispersed in water stably. We applied the as-synthesized ANF as a Pickering emulsifier in the o/w emulsion of styrene monomer. Radical polymerization was subsequently initiated in the Pickering emulsion system. The combination of ANF with polymer spheres was revealed by scanning electron microscopy (SEM) and thermal gravity analysis. The role of ANF in the monomer emulsion as well as in the polymerization was studied through SEM, optical microscopy, optical stability analyzer, and pulse nuclear magnetic resonance combined with the polymerization kinetic analysis. Moreover, we investigated the effects of other synthesis parameters, such as monomer type, monomer content, pH value, and salt concentration.
Co-reporter:Jinglong Li;Wenting Tian;Hongchen Yan;Lianyuan He
Journal of Applied Polymer Science 2016 Volume 133( Issue 30) pp:
Publication Date(Web):
DOI:10.1002/app.43623
ABSTRACT
Stable and uniform dispersions of para-aramid nanofibers have been prepared by adding methoxypolyethylene glycol (mPEG) in the polymerization process, followed by strong shear and dispersion. Aramid membranes are fabricated by vacuum-assisted filtration of the nanofiber dispersion and assembled into batteries as separator. The membrane properties and battery performances are characterized in detail and the effect of mPEG content on these properties is explored. It is demonstrated that aramid membranes possess good electrolyte wettability, excellent mechanical properties, and superior thermal stability, which improve the safety of lithium ion batteries. The mPEG is critical to the formation of aramid nanofibers and improves the porosity and ionic conductivity of the membranes. These fascinating characteristics and facile papermaking method endow aramid membrane potential application as separator in lithium ion batteries with superior safety. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43623.
Co-reporter:Yixiang Zhang;Lu Wang;Zhihua Zhang;Yu Zhang
Journal of Polymer Science Part A: Polymer Chemistry 2013 Volume 51( Issue 10) pp:2161-2170
Publication Date(Web):
DOI:10.1002/pola.26619
Abstract
A multiblock fluorinated polyurethane was synthesized using tetraphenylethane-based polyurethane as macroiniferter to free-radically polymerize 1H,1H,3H-trihydro perfluoro-2,4-dimethylpentyl methacrylate (FDPMA). Simultaneous self-assembly occurred in FDPMA polymerization process and various nanostructures, like multicore particles, formed depending on FDPMA concentration. Fluorophobic effect and the cooperation of the fluorinated blocks with polyurethane blocks are demonstrated to be the main contribution. That soluble FDPMA in DMF becomes insoluble after polymerization triggers the self-assembly process and leads to the nanostructure formation, and the polyurethane blocks that are soluble in DMF and immiscible with the fluorinated blocks stabilize the discrete nanostructures. Further, the nanostructures in solutions can evolve into various morphologies, such as disk and fiber, when dried to solid state. All these results not only reveal the feasibility and robustness of the multiblock copolymer on the modulation of self-assembly structure but also represent a facile and efficient approach for novel nanostructure construction. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013
Co-reporter:Jing Wang;Weijuan Xia;Kun Liu
Journal of Applied Polymer Science 2011 Volume 121( Issue 3) pp:1245-1253
Publication Date(Web):
DOI:10.1002/app.33008
Abstract
Polyurethane (PU) has widespread applications in implantable devices because of its excellent mechanical and biocompatible properties, whereas weak biostability limits its long-term implantation. The introduction of silicone rubber (SR) onto the PU surface is an effective method for improving the biostability of PU, but the adhesion of these two polymers is unsatisfactory. In this study, the surface modification of PU via grafting through the introduction of vinyl and SiH groups onto the PU surface was attempted to improve the adhesion of PU to SR. Fourier transform infrared, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy were employed to investigate the graft reaction on the PU surface. The interfacial and surface morphology was characterized with scanning electron microscopy. Different PU/SR interfaces after oscillation and shear were compared as well. The results indicated that the PU surface was activated by diisocyanate, which generated free isocyanate groups for the further grafting of vinyl and SiH groups. When addition-type, room-temperature-vulcanized SR was poured onto the PU surface, the vinyl and SiH groups on the PU surface underwent an addition reaction, which improved the adhesion of PU and SR by connecting them with chemical bonds. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Co-reporter:Weiqiang Qu;Weijuan Xia;Chao Feng;Teng Qiu
Journal of Polymer Science Part A: Polymer Chemistry 2011 Volume 49( Issue 10) pp:2191-2198
Publication Date(Web):
DOI:10.1002/pola.24649
Abstract
Novel radiopaque iodinated poly(ether urethane) (IPEU) was prepared by using iodine-containing diol as chain extender in a normal two-step condensation polymerization process. This new iodine-containing diol was synthesized by iodination of terephthalic acid and then reaction with 3-aminopropanol. The chemical structure of the diol chain extender and IPEU was characterized, and the basic properties of IPEU were measured and compared with PEU. X-ray images showed that 15 wt % iodine-containing IPEUs were highly radiopaque, and radiopacity did not decrease after 6-week oxidative degradation treatment. Experimental results showed that IPEUs possessed good thermal stability, favorable mechanical properties, and noncytotoxicity. These results reveal that it is an effective route for the synthesis of biological polyurethane with radiopacity by using iodine-containing diol as chain extender. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Co-reporter:Guichang Jiang, Xinlin Tuo, Dongrui Wang, Junpeng Liu
Reactive and Functional Polymers 2010 70(3) pp: 175-181
Publication Date(Web):March 2010
DOI:10.1016/j.reactfunctpolym.2009.11.010
Co-reporter:Ting Zhang, Jun Qian, Xinlin Tuo, Jun Yuan, Xiaogong Wang
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2009 Volume 335(1–3) pp:202-206
Publication Date(Web):5 March 2009
DOI:10.1016/j.colsurfa.2008.11.022
Both of the PSMA colloidal monolayer and multilayer were transformed to ordered porous monolayers in large-scale through selective solvent treatment. The pore formation is an in situ structure inversion process and the core–shell-like structure of PSMA colloid plays a critical role in pore formation and stabilization. The ordered porous polymer films, prepared by this method, can be used as a template for fabricating metal dot-arrays with large areas.
Co-reporter:Luoxin Wang, Xinlin Tuo, Changhai Yi, Hantao Zou, Jie Xu, Weilin Xu
Journal of Molecular Graphics and Modelling 2009 Volume 28(Issue 2) pp:81-87
Publication Date(Web):September 2009
DOI:10.1016/j.jmgm.2009.04.007
In this work, we carried out the hybrid density functional theory (DFT) calculations in order to understand the thermal trans–cis isomerization and initial thermal decomposition of 3,3′-diamino-4,4′-azofurazan (DAAzF), 3,3′-diamino-4,4′-azoxyfurazan (DAAF), 3,3′-dinitro-4,4′-azofurazan (DAAF) and 3,3′-dinitro-4,4′-azoxyfurazan (DAAzF). The relative energy between the trans- and cis-isomer was also calculated at the B3LYP/6-311++G(d,p)//B3LYP/6-31G(d) level of theory. We found that a negative correlation existed between the relative energy and the sensitivity for these energetic azofurazan and azoxyfurazan compounds, where the higher relative energy means the lower the sensitivity. It was also found that the oxidation of azo-group could cause the decreasing in the relative energy between the trans- and cis-isomer, as well as the alteration of the isomerization mechanism. An inversion mechanism operates for azofurazan compounds (DAAzF and DNAF) while a rotation mechanism works for azoxyfurazan compounds (DAAF and DNOAF). Compared with the thermal trans–cis isomerization, the homolytic cleavage of C–N bond needs to overcome a much higher energy barrier, which indicates that the energy of the external stimulus should firstly trigger the trans–cis isomerization, rather than the breakage of C–N bond. A self-desensitization effect caused by the reversible thermal trans–cis isomerization process was firstly proposed to explain that the azofurazan and azoxyfurazan compounds are class of energetic materials with lower sensitivity. This new concept (self-desensitization effect) is expected to be useful to design the novel high density, insensitive energetic material.
Co-reporter:Xinyang Li;Pengwei Fan
Frontiers of Chemical Science and Engineering 2008 Volume 2( Issue 3) pp:286-290
Publication Date(Web):2008 September
DOI:10.1007/s11705-008-0058-4
Acidized single-wall carbon nanotubes (SWNTs) were fabricated into multilayers with a hyperbranched azobenzene-containing polymeric diazonium salt (PDAS) using the layer-by-layer adsorption technique. The fabrication process, multilayer thickness variation, multilayer surface morphology and the interaction between SWNTs and PDAS were monitored by UV-Vis absorption spectroscopy, optical ellipsometry, Atomic Force Microscopy, Scanning Electron Microscopy and Raman spectroscopy. Moreover, the nanomechanical properties of the multilayer films were measured by nanoindentation. All results show that SWNTs and PDAS can be fabricated into multilayers based on the cooperation of electrostatic absorption and chemical cross-linkage between SWNTs and PDAS. Further, this cooperation endows the SWNT/PDAS multilayer films with outstanding nanomechanical properties. The hardness and modulus are about 2.0GPa and 10.0GPa, respectively. Finally, the SWNT/PDAS multilayer film can be peeled off to be a free-standing film.
Co-reporter:Luoxin Wang, Xinlin Tuo, Changhai Yi, Xiaogong Wang
Journal of Molecular Graphics and Modelling 2008 Volume 27(Issue 3) pp:388-393
Publication Date(Web):October 2008
DOI:10.1016/j.jmgm.2008.06.007
In this work, the effects of H+ and NH4+ on the initial decomposition of HMX were investigated on the basis of the B3P86/6-31G** and B3LYP/6-31G* calculations. Three initial decomposition pathways including the N–NO2 bond fission, HONO elimination and C–N bond dissociation were considered for the complexes formed by HMX with H+ (PHMX1 and PHMX2) or with NH4+ (AHMX). We found that H+ and NH4+ did not evidently induce the HMX to trigger the N–NO2 heterolysis because the energy barrier of N–NO2 heterolysis was found to be higher than the bond dissociation energy of N–NO2 homolytic cleavage. Meanwhile, the transition state barriers of the HONO elimination from the complexes were found to be similar to that from the isolated HMX, which means that the HONO elimination reaction of HMX was not affected by the H+ and NH4+. As for the ring-opening reaction of HMX due to the C–N bond dissociation, the calculated potential energy profile showed that the energy of the complex (AHMX) went uphill along the C–N bond length and no transition state existed on the curve. However, the transition state energy barriers of C–N bond dissociation were calculated to be only 5.0 kcal/mol and 5.5 kcal/mol for the PHMX1 and PHMX2 complexes, respectively, which were much lower than the C–N bond dissociation energy of isolated HMX. Moreover, among the three initial decomposition reactions, the C–N bond dissociation was also the most energetically favorable pathway for the PHMX1 and PHMX2. Our calculation results showed that the H+ can significantly promote the initial thermal decomposition of C–N bond of HMX, which, however, is influenced by NH4+ slightly.
Co-reporter:Luoxin Wang, Xinlin Tuo, Xiaogong Wang
Journal of Molecular Structure: THEOCHEM 2008 Volume 868(1–3) pp:50-54
Publication Date(Web):15 November 2008
DOI:10.1016/j.theochem.2008.07.039
The (U)MP2/6-311+G∗//(U)HF/6-31G∗ strategy was used to study the thermal decomposition mechanism of azobenzene and its complex with two NO2 radicals. The calculated results showed that the initial thermal decomposition of azobenzene mainly involved the homolytic fission of the CN bond. There existed an interaction between azobenzene and NO2. The geometry of the azobenzene in the complex changed significantly. Comparison of the activation energies indicated that the nitrobenzene and N2 should be the pyrolytic products of the complex. The bond dissociation energy of CNO2 bond for nitrobenzene was higher than that of NNO2, CNO2, and ONO2 bonds for some traditional nitro explosives. The pyrolysis characteristic of azobenzene in the NO2 environment can be used to modify the exothermic redox reaction pathways of NO2 radicals in the thermal decomposition of explosives and propellants.
