CR/SBS/CEVA-g-MMA/n-BMA胶粘剂的研制

以ＣＲ、苯乙烯丁二烯苯乙烯嵌段共聚物（ＳＢＳ）和氯化乙烯乙酸乙烯酯共聚物（ＣＥＶＡ）３种固体物料为接枝母体,以甲基丙烯酸甲酯（ＭＭＡ）和甲基丙烯酸正丁酯（ｎＢＭＡ）为接枝单体,在溶剂回流温度下,空气氛围中,以过氧化二苯甲酰（ＢＰＯ）为引发剂进行接枝共聚,制得了共混接枝共聚胶粘剂。此种胶粘剂的单体转化率、接枝率、初粘强度都有较大的提高,其广谱性能也有所改善。     

PP/POE/PE/CaCO3/PP-g-MAH复合材料力学性能的研究

采用熔融共混法制备聚丙烯/聚烯烃弹性体/聚乙烯/马来酸酐接枝聚丙烯（PP/POE/PE/CaCO3/PP-g-MAH）复合材料,并研究其力学性能。结果表明：PP-g-MAH可提高PP与CaCO3的相容性,使复合材料的韧性和拉伸性能得到提高,PE可提高PP与POE的相容性,并有效提高复合材料的韧性,经POE、PE、CaCO3和PP-g-MAH之间的相互协同改性作用可制得综合性能优良的PP复合材料。     

Structure and superconducting properties of layered perovskite-like compounds Y1 ? 2xCaxPrxBa2Cu3Oy and Y1 ? xBa2PrxCu3 ? xZnxOy

The conditions of preparation of Y_{1 − x} Pr _x Ba₂Cu_{3 − x} Zn _x O _y and Y_{1 − 2x} Ca _x Pr _x Ba₂Cu₃O _y solid solutions with an Y-123-type structure in the orthorhombic crystal system by the method of solid-phase chemical reactions have been determined. The concentration dependences of the unit cell parameters for these solid solutions have been established. The temperature dependences of the resistivity of the synthesized compounds have been investigated, the critical temperatures of the superconducting transition have been determined, and their variation as a function of the type and content of the introduced dopants has been analyzed. It has been demonstrated that, in the Y_{1 − x} Pr _x Ba₂Cu_{3 − x} Zn _x O _y samples, individual dopants have a combined effect on the suppression of the superconducting properties, whereas in the Y_{1 − 2x} Ca _x Pr _x Ba₂Cu₃O _y samples, calcium and praseodymium ions interact with each other when they are simultaneously introduced into the yttrium sublattice.     

POE/POE-g-MAH/PP-g-MAH增韧PP/滑石粉研究

以聚丙烯(PP)/滑石粉复合体系为基料,马来酸酐接枝聚乙烯辛烯弹性体(POE-g-MAH)、聚乙烯辛烯弹性体(POE)以及聚丙烯接枝马来酸酐(PP-g-MAH)作为增韧剂,利用双螺杆挤出机进行熔融共混,研究了不同增韧剂对共混体系的力学性能、流变性能和结晶性能,并通过XRD、红外光谱和DSC进行综合测试。实验结果表明:三种增韧剂对PP/滑石粉复合体系的性能有显著影响,综合增韧效果以PP-g-MAH为最佳。红外表征、XRD和DSC分析表明:三种增韧剂对PP/滑石粉复合体系中的PP分子链有一定相互作用。     

催化剂MnyCezOx/Al2O3催化氧化乙酸乙酯的性能

采用浸渍法制备了Mn基负载型催化剂,测定了它们催化氧化乙酸乙酯的活性以及水蒸气对其催化性能的影响,研究结果表明所制备的催化剂对乙酸乙酯都具有明显的催化活性,其中催化剂Mn0.8Ce0.2Ox/Al2O3催化氧化乙酸乙酯的活性最高,其T90仅为225℃。催化剂Mn0.8Ce0.2Ox/Al2O3的抗水蒸气影响的能力也要高于催化剂MnOx/Al2O3。     

NiO/Co/Cu/Co/NiFe自旋阀多层膜研究

采用射频磁控溅射方法制备了一系列自旋阀多层膜。在Cu/NiFe界面处插入适当厚度的Co薄层,可增强界面处的自旋相关散射,增大自旋阀的MR值。用绝缘材料NiO作钉扎层,在大磁场中淀积了NiO/Co/Cu/Co/NiFe底自旋阀,其最大MR值达6％。     

Wet Milling of Fe/Al/Al2O3 and Fe2O3/Al/Al2O3 Powder Mixtures

Wet milling of Al₂O₃-aluminide alloy (3A) precursor powders in acetone has been investigated by milling Fe/Al/Al₂O₃ and Fe₂O₃/Al/Al₂O₃ powder mixtures. The influence of the milling process on the physical and chemical properties of the milled powders has been studied. Particle refinement and homogenization were found not to play a dominant role, whereas plastic deformation of the metal particles leads to the formation of dislocations and a highly disarranged polycrystalline structure. Although no chemical reactions among the powder components in Fe₂O₃/Al/Al₂O₃ powder mixtures were observed, the formation of a nanocrystalline, ordered intermetallic FeAl phase in Fe/Al/Al₂O₃ powder mixtures caused by mechanical alloying was detected. Chemical reactions of Fe and Al particle surfaces with the atmosphere and the milling media lead to the formation of highly porous hydroxides on the particle surfaces. Hence the specific surface area of the powders increases, while the powder density decreases during milling. The fraction of Fe oxidized during milling was determined to be 0.13. The fraction of Al oxidized during milling strongly depends on the metal content of the powder mixture. It ranges between 0.4 and 0.8.     

Preparation and properties of poly(Nε,Nε-dicarboxymethyl-l-lysine)

A new ampholytic homopolypeptide, $\text{poly}\text{(N}{}^{\mathrm{\epsilon }}\text{,N}{}^{\mathrm{\epsilon }}\text{-}\text{dicarboxy-methyl-}\text{l}\text{-lysine}\text{)}$, which has one tertiary amino and two carboxyl groups in the side chain has been derived from a hydrochloride salt of poly(L-lysine). The polymer in aqueous solution seems to be in the coil form with locally extended structure (LES) at neutral pH. In both the acidic and alkaline regions, the molar ellipticity of the polymer changes as a result of change in net charge on the side chain. The conformational changes may be from the coil with LES to other coiled forms. 5–7 M NaClO₄ and 80% aqueous methanol induce the α-helix in the polymer at neutral pH. Divalent cations, Cu²⁺ and Ca²⁺, do not induce any remarkably ordered structures such as α-helix or β-structure in the polymer in aqueous solution at any pH. Ultraviolet absorption studies show an absorption peak of the polymer-Cu²⁺ complex near 240 nm. Dependence of the peak intensity on pH at various q values ($\text{q =}\text{[}\text{Cu}{}^{\mathrm{2+}}\text{]}\text{[}\text{residue}\text{]}$) indicates the two steps of the complex formation. At q less than 0.64, the formation is described only with the first step. An average coordination number for Cu²⁺ at the first step was calculated to be about 2 by the method of Mandel and Leyte. The association constant of Cu²⁺ with the residue at the step was determined from the absorption data to be far smaller than that for the Cu²⁺-EDTA complex. The second step of the formation occurs in the case of large q but the absorption data for the second step cannot be obtained exactly due to precipitation.     

Participation of lewis base on vinyl chloride polymerization with Al(C2H5)3CCl4 catalyst system

The polymerization of vinyl chloride has been investigated using an $\text{Al}\text{(}\text{C}{}_2\text{H}{}_5\text{)}{}_3\text{CCl}{}_4$ catalyst system in the presence of various Lewis bases. Effective Lewis bases are γ-butyrolactone, diglyme and diethylenetriamine which are multidentate. The rate of polymerization is dependent not only on the basicity of the Lewis base used but also on a coordination number of one. The latter is the predominant factor. For the effect of polymeric amines, a tentative hypothesis is discussed.     

Ag2O-Doped Bi2Sr2Ca1Cu2Ox Superconductors Prepared via Melt-Quenching

Ag₂O-doped superconducting Bi₂Sr₂Ca₁Cu₂O _x ceramics were prepared by a melt-quenching–reheating method. It is found that the Ag₂O-doped, as-cast specimens exhibit superconductivity ( T _c= around 80 K) by heat treatment at temperatures around 800°C even in an evacuated and sealed silica glass tube, while the undoped specimens do not and vaporize by the corresponding heat treatment. Conversion of the Ag₂O-doped, as-cast specimens into superconducting ceramics when heated in an evacuated vessel is explained in terms of the oxygen donor of Ag₂O in the specimen. This finding enables us to fabricate a desired shape of superconducting Bi₂Sr₂Ca₁Cu₂O _x ceramics sealed in metals or glasses. The addition of Ag₂O to Bi₂Sr₂Ca₁Cu₂O _x melt, however, had deleterious influences on the superconducting properties ( T _c and J _c) of the resultant ceramics when obtained by heat treatment in air.     

Synthesis and Characterization of Ti0.33Ta0.33Nb0.33C and Ti0.33Ta0.33Nb0.33CxN1-x Whiskers

Ta_0.33Ti_0.33Nb_0.33C and Ta_0.33Ti_0.33Nb_0.33C _x N_{1− x} whiskers were synthesized via a carbothermal vapor-liquid-solid growth mechanism in the temperature range 900°-1450°C in Ar or N₂. The optimum temperature was 1250°C. Whiskers were obtained in a yield of 70-90 vol%. The whiskers were 0.5–1 µm in diameter and 10–30 µm in length. The starting materials that produced the highest whisker yield were: TiO₂, Ta₂O₅, Nb₂O₅, C, Ni, and NaCl. C was added to reduce the oxides, and Ni to catalyze whisker growth. NaCl was used as a source of Cl for vapor-phase transportation of Ta and Nb oxochlorides and Ti chlorides to the catalyst. The catalyst metal was recycled several times during the synthesis and was transported as NiCl₂( g ) according to thermodynamic calculations. The rate of formation and the chemical composition of the whiskers depended on the synthesis temperature, the choice of catalyst, and the atmosphere. At low temperatures, the whiskers were enriched in Nb and Ta, whereas the Ti content increased with increased synthesis temperature.