PP/PP-g-MAH与铝板粘接界面相的XPS研究

用X射线光电子能谱(XPS)研究铝板/聚丙烯层状复合材料的粘接界面相，提出了粘接界面的化学反应机制.研究发现,聚丙烯(PP)中加入马来酸酐接枝聚丙烯(PP-g-MAH)时，铝板面上Al 2p、O 1s谱线明显向高结合能端移动，表明PP-g-MAH与铝板表面发生了化学反应，形成Al－O－C配位键.配位键的形成使界面粘接强度明显提高. PP中不含PP-g-MAH时，铝板面上Al 2p、O 1s谱线处于低结合能端，聚丙烯未与铝板表面形成化学配位作用.     

Terpolymerization of maleic anhydride, trans-stilbene and acrylic monomers

The results of radical terpolymerization of maleic anhydride (MA), trans-stilbene (Stb) and acrylic monomers (n-butyl methacrylate (BMA) and acrylonitrile (AN)) as acceptor-donor-acceptor monomer systems are discussed. The structure and composition of terpolymers are determined by chemical (acid number for MA units) and elemental (content of N for AN units and O for BMA units) analyses, as well as by FTIR spectroscopy through recorded analytical absorption bands for MA (1770 and 1845 cm⁻¹), Stb (864 cm⁻¹) and BMA (1730 cm⁻¹) units, respectively. The considerable change in the terpolymer compositions is observed when a strong acceptor MA is substituted with BMA (or AN), having comparatively low acceptor character in the system studied. Copolymerization constants for the MA ? Stb complex and acrylic comonomers pairs are determined according to the modified Kelen-Tüdös equation. Obtained results show that at the chosen ratios of comonomers, radical terpolymerization proceeded mainly by a true “complex” mechanism in the stage of near binary copolymerization of MA ? Stb complexed monomers with free BMA (or AN). The kinetics of terpolymerization and terpolymer compositions are studied in the low and high conversion stages. It is shown that for the MA-Stb-BMA system the dependence of R_p on the concentration of individual comonomers has extreme character, while for BMA-Stb-AN this dependence does not have similar character. This fact indicated that terpolymerization in the BMA-Stb-AN system proceeds according to a classical statistical copolymerization mechanism. The terpolymer composition-thermal behaviour relationships are also studied by differential scanning calorimetry and thermogravimetric analysis methods.     

Reactive surfactants in heterophase polymerization: Colloidal properties,film‐water absorption,and surfactant exudation

In this article the results obtained with latexes prepared by emulsion polymerization with a conventional surfactant and a polymerizable surfactant (surfmer) are presented. For this study, well‐defined styrene‐butylacrylate latexes with a conventional nonreactive surfactant (sodium dodecyl sulfate) and a maleate diester surfmer, of which films can be easily cast, were used. The latex with the surfmer was prepared following a surfmer addition strategy to maximize the amount of surfmer bound to the particle surface, and not buried in the particle interior. The latex properties in terms of mechanical stability, film‐water absorption, and film‐surfactant exudation were assessed and compared. The mechanical stability and water‐absorption properties of the latex prepared with surfmer were better than those of the latex with sodium dodecyl sulfate. Additionally, by using a surfmer the surfactant migration to the film‐substrate and film‐air interfaces can be inhibited. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2994–3000, 2002     

Effect of divalent cations on the volume of a maleic acid copolymer gel examined by incorporating lysozyme

An ionic gel of poly(maleic acid-alt-methyl vinyl ether) cross-linked by 1,6-hexanediol was prepared with molar ratio of 1/0.5 at 50 °C. The gels with different molar ratios at different temperatures were also prepared for comparison. Their swelling-shrinkage profiles were examined by measuring the ratio of initial to final weights at various pHs and CaCl₂ concentrations in buffer solution. The gel squeezed remarkably in the presence of Ca²⁺ for pH>6.3, corresponding to the solution properties of maleic acid copolymer. No appreciable change was observed below pH 6.3. To estimate free space in the gel in more detail, lysozyme was incorporated into the free space, and its release rate was measured under several CaCl₂ concentrations. The time course of the release was either simple or complicated, depending on pH and CaCl₂ concentration. The control mechanism of the release of lysozyme from the gel network may be widely applicable to the drug delivery system.     

A direct link between the Passerini reaction and α-lactams

α-Lactams (aziridinones) can function to replace two of the three reactants, the oxo-compound and the isonitrile, in the Passerini reaction. Four α-lactams (5a-d) were reacted with mono- and dicarboxylic acids of positive pK_a values to give 2-acyloxycarboxamides (4) and bis-2-acyloxycarboxamide products 12 and 13, respectively. The same compounds were also prepared via the Passerini reaction. Acids with a negative pK_a decarbonylate α-lactams to give immonium salts. The main path of the reaction depends on the pK_a of the acid component, the reactivity of the α-lactam, and the reaction conditions.     

乳化剂在双重乳液合成含胰岛素纳米胶囊中的作用

Insulin entrapped nanocapsules to use polylactide （PLA） as the encapsulating material were prepared through a modified water-in-oil-in-water （W/O/W） emulsification and solvent evaporation method, The average particle size of PLA nanocapsules obtained was decreased to （181.5 ± 8.4） nm, and capably adjusted from 180 to 370 nm by using different types and content of nonionic emulsifiers. The influence of emulsifiers on property of nanocapsules was discussed in detail. The effects of spans and tweens to modify the size of the nanocapsules were different, which can be due to the distribution of the surfactants on the inner interface between the inner water and oil of the double emulsion. The encapsulation efficiency and drug release of nanocapsules were affected obviously by the content and type of emulsifiers.     

Determination of antimony in waste water by micelle solubilization spectrophotometry

A simple, sensitive and selective micelle solubilization spectro-photometric method is described for the determination of micro amounts of antimony(III) in waste water with 2-(3,5-dibromo-2-pyri-dylazo)-5-diethylaminophenol (3,5-dibromo-PADAP) as colour reagent and emulsifier OP as solubilizing and sensitizing agent. In 0.15M HCl, antimony forms a blue-green ternary complex with the above-mentioned reagents. The complex exhibits maximum absorption at 630nm, and the value of the apparent molar absorption coefficient is found to be 5.2 × 10⁴1 mol^–1 cm^–1. The complex is stable up to 7 days at room temperature. The system obeys Beer's Law in the range 0–25 g Sb(III) per 10 ml. Most metal ions do not interfere with the determination of antimony.     

Extraction of maleic hydrazide residues from potato crisps and their determination using high-performance liquid chromatography with UV and atmospheric pressure chemical ionisation mass spectrometric detection

A method was required for the determination of maleic hydrazide residues in potato crisps. A published method for the extraction of the analyte from onions and potatoes was evaluated and found to be inappropriate due to the inability of the extracting solvent to penetrate the oily matrix. A method was developed to overcome this problem; the resulting recovery data (mean=92.9%. R.S.D.=8.3%, N=16) confirmed its efficiency, and was used to analyse 48 retail potato crisp samples. To confirm possible residues identified by screening with HPLC-UV, and HPLC-atmospheric pressure chemical ionization MS method was developed. There was good agreement between the data obtained from the detection techniques (R²=0.978, slope=1.11).     

POLYMERIC IONIC CONDUCTORS MODIFIED WITH POLAR GROUPS: PART Ⅱ. STRUCTURE-IONIC CONDUCTION RELATION IN LI-COMPLEX BASED ON MALEIC ANHYDRID E-COPOLYMERIZED METHACRYLATES

Ringlike polar monomer maleic, anhydride (MAn) was copolymerized with oligo (oxyethylene) methacrylate (MEO_n), and its effect on ion conduction property of the corresponding polymer-salt complexes was studied. As a consequence the introduction of MAn onto polymer chain retards crystallization of the ether pendants considerably, and improves the ion conductivity to a larger degree compared with other polar groups once investigated (σ_(max),25℃=8.5×10~(-5) S/cm). The structure-ion conduction relation in the polymer-salt matrix is also analyzed macroscopically through the correspondence between composition-dependences of polymerization conversion and isothermal ion conductivity, and microscopically through the measurements of cross polarized light and electron transmission.