Preparation of polymer brushes on attapulgite surfaces via a combination of CROP and click reaction

<正>In this work,by a combination of controlled ring-opening polymerization(CROP) and click reaction,we reported a facile and useful method to synthesize linear poly(ε-caprolactone) at attapulgite nanocomposites with well-defined structures.For this,first, the chlorine terminated attapulgite was prepared by the self-assembly of 3-chloropropyltrimethoxysiIane from the surfaces of attapulgite.And then,the terminal chlorines of modified attapulgite were substituted with azido groups.As the second step,linear propargyl-terminated poly(ε-caprolactone)(PCLs) with different molecular weights were synthesized by the CROP ofε-CL monomer in toluene with Sn(Oct)_2 as a catalyst and propargyl alcohol as an initiator.Finally,the azido-terminated attapulgites were reacted with propargyl-terminated PCLs via the click reactions.     

Synthesis of a new aromatic diacid containing pyridine ring and related polybenzimidazole

<正>A new aromatic diacid monomer containing pyridine unit,4-phenyl-2,6-bis[4-(4-carboxyphenoxy) phenyl]pyridine 3,was successfully synthesized in three steps,starting from 4-hydroxyacetophenone.The corresponding pyridine-containing polybenzimidazole was prepared via polycondensation of 3 with tetraaminodiphenyl ether(TADE) in poly(phosphoric acid)(PPA).The resulting polybenzimidazole exhibits excellent solubility,good thermal stabilities and high thermal resistance.     

Asymptotic Behaviors of the Solutions to Scalar Viscous Conservation Laws on Bounded Interval

Abstract This paper concerns the asymptotic behaviors of the solutions to the initial-boundary value prob-lem for scalar viscous conservations laws u_t+f(u)_x=u_(xx) on[0,1],with the boundary condition u(0,t) =u_,u(1,t)=u_+ and the initial data u(x,0)=u_0(x,0)=u_0(x),where u_≠u_+ and f is a given function satisfyingf'(u)>0 for u under consideration.By means of energy estimates method and under some more regular condi-tions on the initial data,both the global existence and the asymptotic behavior are obtained.When u_u_+, which corresponds to shock waves in inviscid conservation laws, it is established for weak shockwaves,which means that │u_-u_+│is small.Moreover,exponential decay rates are both given.     

Fabrication of polydiacetylene nanowires by associated self-polymerization and self-assembly processes for efficient field emission properties

The paper described here concerns a challenge of general interest for producing a novel structure of a polymer aggregate, the achievement of nanowires with controlled diameters. We provide a strategy for fabricating a supramolecular polymer, in which ordered polydiacetylene nanowires can be obtained by associated self-polymerization and self-assembly processes. The polymer nanowire film shows excellent field emission properties with the turn-on field of 8.2 V/mum at 10 muA/cm2 and the maximum current density of 5 mA/cm2 at an applied field of 15 V/mum.     

A facile synthesis of 2,3-dihydro-2-aryl-4（1H）-quinazolinones catalyzed by scandium（Ⅲ） triflate

2,3-Dihydro-2-aryl-4(1H)-quinazolinones were prepared in good yields via condensation of o-aminobenzamide with aldehydes promoted by a catalytic amount of Sc(OTf)_3 under mild conditions.     

Polypyrrole–multi-walled carbon nanotube nanocomposites synthesized in oil–water microemulsion

An oil–water microemulsion system, having been successfully used for synthesizing polypyrrole (PPy) nanoparticles, is introduced for preparing PPy–multi-walled carbon nanotube (MWCNT) nanocomposites via in situ chemical oxidative polymerization. The structures and the physical properties of the PPy–MWCNT nanocomposites are also investigated. The studies show that PPy can coat MWCNTs to form core–shell structure. The backbone structure of PPy is not damaged by the introduction of MWCNTs, and the PPy in the PPy–MWCNT nanocomposites is still amorphous as pure PPy. The conductivities of PPy–MWCNT nanocomposites are higher than that of pure PPy and are enhanced with the increase in the MWCNT–monomer mass ratio. Furthermore, a model is supposed to be used for illustrating the mechanism for PPy–MWCNT nanocomposite formation via in situ microemulsion synthesis.     

Combinatorial method for the study of new co-fluorescence enhancement system

The new co-fluorescence enhancement system was found in polymer matrix and studied with a combinatorial approach based on Re(DBM)3phen (Re3+: Tb3+, La3+, Gd3+, Y3+; dbm: dibenzoylmethane; phen: phenanthroline) and Sm3+ complex co-doped poly(methyl methacrylate)(PMMA). We have presents a new methodology for the rapid optimization of the luminescence conditions of thin-film sample in arrays of microwells. Two libraries were generated in order to study the effect of the species and content of enhancing ions on the luminescence enhancing efficiency, respectively. At the optimal content of 20 wt.% Sm(DBM)3phen, the maximum sensitization efficiency of Tb(DBM)3phen is about nine times. The intramolecular and intermolecular energy transfer processes in rare-earth complex-doped PMMA are discussed. The energy transfer processes make the co-fluorescence effect come true. Although, the methodology described here was implemented for optimization of co-fluorescence conditions, it is can be further implemented for a variety of applications in which optimization of parameters can be studied in situ using spectroscopic tool.     

Sm(DBM)3Phen-doped poly(methyl methacrylate) for three-dimensional multilayered optical memory

We report on the formation of submicrometer voids within Sm(DBM)3Phen-doped poly(methyl methacrylate) (PMMA) under multiphoton absorption excited by an infrared laser beam. An ultrashort-pulsed laser beam with a pulse width of 200 fs at a wavelength of 800 nm is focused into doped PMMA. The large changes in refractive index and the fluorescence associated with a void allow conventional optical microscopy and reflection-type confocal microscopy to be used as detection methods. Voids can be arranged in a three-dimensional multilayered structure for high-density optical data storage.     

苯并三氮唑及其衍生物在菜籽油中的摩擦学性能研究

利用四球试验机考察了苯并三氮唑及其衍生物在菜籽油中的摩擦学性能,并用X射线光电子能谱和扫描电子显微镜分析观察磨斑表面的化学组成和形貌。结果表明,苯并三氮唑在菜籽油中有良好的抗磨作用,在其分子中引入长链烷基虽然提高了其在菜籽油中的溶解度,但却降低了其抗磨减摩性能,这主要是由于苯并三氮唑有效成分的减少以及添加剂和基础油之间的竞争吸附所致。