平顶山市区大气中TSP来源

用聚类分析———最小二乘拟合方法,采用迭代的、分裂的、不加权的、非交迭的成聚方法(IDDN),从实测数据阵中求解实际存在的源特征谱及源贡献量,为平顶山市区大气污染总量控制,大气污染综合防治与管理,提供科学依据。

Synthesis of poly[methyl(3,3,3-trifluoropropyl)siloxane]-b-poly(ethylene oxide) block copolymers

A series of new amphiphilic poly[methyl（3,3,3-trifluoropropyl）siloxane]-b-poly（ethylene oxide） （PMTFPS-b-PEO） diblock copolymers with different ratios of hydrophobic segment to hydrophilic segment were prepared by coupling reactions of end-functlonal PMTFPS and PEO homopolymers. Copolymers were shown to be well defined and narrow molecular weight distribution （MWD） （1.07-1.3） by characterizations such as gel permeation chromatography （GPC） and ^1H-nudear magnetic resonance （^1H-NMR）.

One-step synthesis of hydrophobic magnesium hydroxide nanoparticles and their application in flame-retardant polypropylene composites

Hydrophobic magnesium hydroxide(MH) nanoparticles were prepared by a one-step synthesis method in a high-gravity environment generated by a novel impinging stream–rotating packed bed(IS-RPB) reactor. The reactant solutions were simultaneously and continuously pumped into the IS-RPB reactor, and then Tween80 was added as a surface modifier. The morphology, structure, and properties of blank and hydrophobic MH were characterized. The effects of MH nanoparticles on the flame retardancy, thermal stability, and mechanical properties of PP/MH composites were also studied. We found that the obtained MH nanoparticles exhibited hexagonal lamella with a mean size of 30 nm, excellent hydrophobic properties(e.g., high water contact angle of 112°), and improved thermal stability of MH. The limiting oxygen index(LOI) further showed that increased MH loading can significantly improve flame-retardant performance, which reached 29.3% for PP/MH composites with 30 wt% hydrophobic samples. The thermal stability and mechanical properties of the PP/MH composites with hydrophobic samples were also much higher than those of PP/MH composites with blank MH. Results showed that the one-step synthesis had high potential application in the large-scale production of hydrophobic MH nanoparticles.

Structure and Properties of Polyurethane/Polyvinylidene Difluoride Blending Hollow Fiber

Utilization of polyvinylidene difluoride, PVDF, as the disperse phase and thermal plastic polyurethane, PU, as the continuous phase, the PU/PVDF blend hollow fiber membranes with the property of pressure-responsibility, PR, was prepared by melt.spinning. For these hollow fibers, the formation of the interracial micro-voids, IFM, and the spinablllty of the blend were analyzed. The pressm-e-responslblllty was studied by measuring the changing of pure water flux, PWF, with the pressure, and the influence of drawing and heat-setting on the structure and pressure-responsibility of the membranes were also discussed.

Study of Synthesis of Copoly (lactic acid/glycolic acid) by Direct Melt Polycondensation

A two steps direct copolymerisation process was developed. The first step is to produce oligomer and then the oligomer of lactic acid/glycolic acid (90/10) is polymerized with binary catalyst tin chloride dihydrate/p-toluenesulfonic acid. In this way, the direct synthesis of copoly (lactic acid/glycolic acid) without any organic solvent was investigated. The properties and structures of products were characterized by nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), X-ray diffraction and so on. The results show that comparatively high molecular weight copolymer of lactic acid and glycolic acid can be prepared by direct processing under appropriate technological conditions.

Synthesis and Solution Properties of Hydrophobic Associating Polymers

Acrylamide/2-acrylamido alkane sulfonic acid hydrophobic associating copolymers were synthesized by micellar copolymerization. Effects of hydrophobe content, polymer concentration, salinity and surfactant on rheological behavior of copolymers were investigated and the conformation of polymers in solution was studied by means of environmental scanning electronic microscopy and dynamic light scattering. The experimental results showed that in the dilute regime the hydrophobic parts could interact intramolecularly, while in the regime where the polymer concentration was higher than the critical association concentration, intermolecular hydrophobic association became predominant. Within the limit of the solubility, the critical association concentration of the polymer decreased with the increase of the salinity. The experimental results of the solution conformation indicated the presence of the three-dimensional network structure in deionized water and the size of the mesh in the network varied with the polymer concentration. In NaCl solution, above the critical association concentration, an increase in polymer concentration enhanced the intermolecular association and also enlarged the hydrodynamic radius. It would result in the improvement of the thickening power of polymers.

A new multifunctional polymer:Synthesis and characterization of mPEG-b-PAA-grafted chitosan copolymer

A new multifunctional mPEG-b-PAA-grafted chitosan copolymer possessing amino and carboxyl groups,mPEG-b-PAA-g-CHI(compound 6) ,was designed for a potential application in gene/drug delivery and synthesized by the methods of reversible addition-fragmentation chain transfer(RAFT) polymerization of acrylic acid(AA) and grafting reaction of a biodegradable chitosan(CHI) derivative.Completion of the reactions and characterization of the resulting compounds were demonstrated by 1 H NMR,FTIR and gel permeation chtomatography(GPC) studies.The results show that the molar ratio of amino groups to carboxyl groups in the copolymer(compound 6) is 0.41-0.59.

Self-assembly of Polyaniline： Mechanism Study

Anisotropic polyaniline （PAni） plates decorated with self-aligned nanofiber arrays were synthesized under the hydrothermaI conditions. The formation mechanism of the self-assembled structures was investigated by studying the effect on PAni micro-structure with additive electrolyte in reaction system, and numerical simulation for dependence of systematic electrostatic energy on cross angles of self-assembled nanofiber arrays in grid textured PAni plates. It is proposed that the electrostatic interaction based on ionic doping charges plays an important role in the formation of the self-assembled PAni structures.

SYNTHESIS AND CHARACTERIZATION OF HETEROAROMATIC POLYMERS CONTAINING PYRIDINE MOIETIES

The progress on the molecular design, synthesis and characterizations of some kinds of pyridine-containing heteroaromatic polymers in main chain were reviewed in this paper, they would include polyimides （Pls）, polypyrrolones （PPYs）, poly（pyrrolane-imide）s （PPIs）, and poly（pyrrolane-benzimidazone）s （PPBs） containing pyridine moieties. The pyridine-cantaining polymers reported all exhibit good processability, excellent thermal properties and mechanical properties. However, the contribution of pyridine ring to polymers properties is still need to research further, the heteroaromatic polymers containing pyridine moieties have focused by more and more researchers.

Synthesis of Amphiphilic Polyelectrolyte and Study of Their Association Behavior in Hydroalcoholic Media

The objective of the work involves the synthesis of comb-like amphiphilic cationic polymers with repeating units methacylamides laterally substituted by a group containing a quaternary ammonium site and a hydrophobic n-alkyl side chain with 8-10 carbon atoms. Two synthesis methods were developed successfully. The first method is consisted to synthesizing first amphiphilic cationic methacrylamide monomers. In the second method the tertiary amine groups of polymers precursors were quaternised with various n-alkyl bromides. All the polymers obtained in this way were characterized by spectroscopic methods： 1^H NMR and by viscometry. The reduced viscosity of hydro-alcoholic polymer solution decreases with polymer concentration. Viscometry study showed that these polymers display typical polysoap behavior in hydro-alcoholic mixtures.

A review of polymer-derived hard carbon materials as an anode material in sodium-ion batteries

This paper describes the sodium storage mechanism of hard carbon,including the insertion-adsorption model,adsorption-insertion model,adsorption-filling model,and adsorption-insertion-filling model.The research progress of hard carbon prepared by synthetic polymers in recent years is reviewed.The modification strategies of morphology and structure regulation,surface engineering,defect engineering,heteroatom doping,and pretreatment are proposed to improve the electrochemical performance of hard carbon materials and promote the research and development of hard carbon as anode materials for sodium-ion batteries.

Synthesis and characterization of amphiphilic centipede-like copolymer PS-PS-PMAA

A well-defined amphiphilic centipede-like copolymer of styrene and methacrylic acid (PS-PS-PMAA) was synthesized by the combination of living anionic polymerization and atom transfer radical polymerization (ATRP). The synthetic approach involves the first coupling reaction of polystyrene (PS) backbone bearing 1,1-diphenylethene (DPE) pendant groups with living polystyryllithium (PSLi), and sequential anionic polymerization of t-butyl methacrylate (tBMA) initiated by resulting 1,1-diphenylmethyl anion, and final hydrolysis of obtained PS-PS-PtBMA. The centipede-like copolymer PS-PS-PMAA was characterized by 1H NMR, IR, GPC, and SLS measurements. The critical micelle concentration (CMC) of PS-PS-PMAA in water was determined by fluorescence probe technique. The self-assembly behavior of PS-PS-PMAA in water-THF mixture was observed by TEM. The results showed that the micellar morphology can be varied, such as vesicle, sphere, and agglomerate, depending on the THF content. These phenomena are worthy of further research in polymer physics field.

Progress in side-chain thiophene-containing polymers: synthesis, properties and applications

In contrast to conventional main-chain conjugated polymers, incorporation of electronically active conjugated oligomers into non-conjugated polymer backbones as pendant groups represents a promising alternative strategy to developing novel electroactive polymer materials that are desirable for potential applications in organic electronics. This review focuses on polymers with thiophene in the side chain and summarizes the most important synthetic approaches to these polymers, including direct controlled polymerization techniques(e.g., ATRP, ROMP, and RAFT) as well as post-polymerization modifications. Additionally, various properties and applications of these polymers are discussed.