SCRATCH HARDNESS TESTS OF CERAMIC MATERIALS1

Three sets of standards were prepared: (1) a set of minerals according to Mohs'Scale, (2) a set of steel samples, and (3) a set of Carboloy (tungsten carbide alloy) samples. The sets of standards were compared with each other according to their scratch hardness. Specimens of ceramic materials were then measured for scratch hardness with each set of standards. The results are compared.     

SCRATCH RESISTANT POLYIMIDE COATINGS FOR ALUMINOSILICATE GLASS SURFACES

Several polyimide resins were tested as possible scratch resistant coatings for aluminosilicate glass centrifuge tubes. Tubes with siloxane pretreatments provided the best adhesion between the polyimide and glass surface. Resins synthesized with an alkoxysilane group incorporated into the polyimide chain also showed improved adhesion, but the results were not as significant as when the pretreatment was used. Elastic recovery and effective Young's modulus of the polyimide coatings were calculated from nano-scratching. The results indicate that polyimides with a lower modulus, and higher elastic recovery, protected the glass surface best, exhibiting compression of the coating layer. An example was poly-4-4'-oxydiphenylene pyromellitimide (PMDA-ODA), whereas the coatings with a high effective Young's modulus and low elastic recovery ruptured. An example of a failed coating was poly-4,4'-carbonyldiphenylene 3,3',4,4'-biphenylenetetracarboximide (BPDA-DABP) which had low amount of elastic recovery, high effective Young's modulus and a large amount of flaking during macroscratch testing.     

耐划伤车用聚丙烯材料的研制及应用

研究了耐划伤剂、滑石粉粒径对聚丙烯(PP)材料耐划伤效果与力学性能的影响,通过测试划伤前后的色差来评价耐划伤剂对材料的耐划伤效果.结果表明,耐划伤剂增加了材料的表面润滑性;采用小粒径滑石粉改性材料的耐划伤性能优于采用大粒径滑石粉改性的材料.利用耐划伤PP开发出的汽车内饰件被成熟应用于通用NGS308车型.     

二氧化碳压缩机叶轮刮伤事故分析

介绍二氧化碳压缩机在试开车过程中遇到的问题和发生的事故,分析事故发生的过程、现象、原因,提出预防措施。     

车用聚丙烯内饰材料耐划伤性能研究

采用衰减全反射红外光谱(ATR)研究酰胺类耐划伤剂在车用聚丙烯(PP)耐划伤内饰材料表面和内部的含量分布.ATR及十字划格实验结果表明,酰胺耐划伤剂能有效地迁移到材料表面,降低表面摩擦系数,且酰胺耐划伤剂在材料表面和内部的分布有所差异.ATR及扫描电子显微镜(SEM)证明车用PP耐划伤内饰材料呈皮芯结构,未加入耐划伤剂...     

II, Cold-Setting Properties

Experimental data indicate that cold-setting bonds may be farmed from oxide-phosphoric acid reactions, from phosphate-phosphoric acid reactions, or by direct addition of liquid phosphate bond. In all cases acid phosphates are responsible for the bonding action. For optimum bonding, a weakly basic or amphoteric cation having a moderately small ionic radius is required so that a nonordered structure can be formed. The solidification process for a liquid phosphate bond has been determined. No weak temperature zone appears on heating these bonds because of the gradual loss of "combined" water and the gradual crystallization of the dehydration products.     

Copolymerization of UV-absorbers,II

Polymerizable UV-absorbers, such as 4-allyloxy-2-hydroxy-4'-methylbenzophenone and 4-allyloxy-2-hydroxy-4'-methoxybenzophenone were copolymerized with styrene to give copolymers containing 2–8% of UV-stabilizer. The copolymer films were subjected to UV-irradiation, and the carbonyl index, hydroxy index, tensile strength, elongation at break and evaporation loss were examined to evaluate the efficiency of the new stabilizers.     

MECHANICS OF ENAMEL ADHERENCE, II

The effect on adherence of the variation in the amount of cobalt oxide, nickel oxide, and manganese oxide, and the effect of atmosphere, air, oxygen, and nitrogen on ad- herence were studied. Enamels of same base but with varying amounts of the special oxides were made up, fired in the various atmospheres, and tested for adherence by drop- hammer impact methods and by flexure methods. A number of photographs of metallographic sections showing contact line between enamel and metal are given. General conclusions are (1) that adherence is not a function of the roughness of contact line, (2) that the adherence promoting effect of cobalt oxide is higher at 1.25% than at 2.5% or 5.0%, and (3) that the effect of oxygen and nitrogen in general is to decrease the adherence as measured by impact strength.     

EXTRACTION BY N,N'-TETRAALKYLMALONAMIDES II.

Suitable N.N'-tetraalkylmalonamldes for Am(III) extraction from concentrated HNO₃ aqueous liquors have been selected. Extraction mechanisms of Eu(III) and Am(III) by NN'-dlmethyldioctylmalonamide (DMDOMA) have been investigated. The distributions ratios of Am(III) and Eu(III) between 1M DMDOMA in t-butylbenzene and per chloric acid are higher than those obtained In nitrate media. Extraction data for Pu)IV), U(VI), Fe(III), Zr(IV) are reported. From these results It can be concluded that the NN'-dlmethyldlal-kylmalonamldes are good extractants for the actinides contained in the radioactive wastes.     

Viscoelastic-Elastic Composites: II, Sandwich Seal

The viscoelastic analysis of the sandwich seal is compared with experimental results. Agreement is good for cooling, heating, and isothermal holds. The importance of accounting for the effect of structural relaxation on glass properties is demonstrated. Based on the observation that the average relaxation time of the seal at the setting temperature is constant, two simple and accurate procedures are presented for estimating the setting temperature of a seal using minimal experimental data.     

Polymerization initiated with polymeric compounds,II

The polymerization of methyl methacrylate initiated by the copolymers methacrylaldehyde — styrene — divinylbenzene and acrylaldehyde — ethylene dimethacrylate in the absence of usual initiators was investigated. The polymerization was found to proceed fairly readily and fast. Acceleration can be achieved by adding glycerylaldehyde. An increase in the surface of the initiating copolymer favourably influences the reaction rate; at the same time, however, physical trapping of ungraft poly(methyl methacrylate) molecules in the macroporous initiator seems likely to occur. It was also found that only copolymers containing aldehyde groups could be used for initiation and that besides MMA some other monomers could be polymerized in this way, such as glycidyl methacrylate, acrylic and methacrylic acid, acrylonitrile, and alkyl acrylate.     

BERYLLIUM GLASS,II POTASSIUM-BERYLLIUM SERIES1

This paper includes a triaxial diagram for the potash series, containing two good glass areas in contrast with a single area in the soda series. ³ 3 J C. F. Lai and A. Silverman, “Reryllium Glass,” Jour. Amer. Ceram. SOL, 11, 535 (1928).
One area is in the region of low beryllia and high silica; the other in the region of high beryllia and low silica. The latter contains the better glasses. Areas are also shown in which the tendency to increase silica produces opalescence while that toward an increase of beryllis promotes divitrification. Great difficulty has been experienced in obtaining pure beryllium oxide. Material that was supposedly pure contained as much as 20° of moisture. Difficulty has been encountered also through such impurities as the oxides of iron and manganese. One sample of supposedly C.P. beryllium oxide contained over 90° alumina. Optical data are not yet available. As was the case with the sodium beryllium silicates. so here again the announcement is the first of the potassium-beryllium glasses, t o the best knowledge of the authors.     

Sintering of High-Purity Nickel Oxide, II

The effects of particle size, compacting pressure, additives, and mode of preparation on the sintering of nickel oxide are presented. A low calcining temperature results in a high bulk density of a sintered compact. No appreciable change in the rate of sintering is found above 1000 kg. per sq. cm., whereas the unheated density increases with increasing pressures. Additions of CaO promote sintering, additions of Na₂O, Fe₂O₃, and Al₂O₃ retard sintering, and CeO₂ and Ag₂O have no effect; B₂O₃ accelerates grain growth but retards densification. Nickel oxide from oxalate has a small rate of sintering as compared with nickel oxides from hydroxide, nitrate, and carbonate. The effects of the mode of preparation of nickel oxide are discussed in view of the activation energy of electronic conductivity and particle size.     

Properties of Aluminoborate Glasses of Group II Metal Oxides: II, Electrical Properties

The dc resistivities and dielectric properties at 0.060 to 100 kc and temperatures of 100° to 500° C have been determined for the Group II aluminoborate glasses. These glasses have resistivities as high as 10^11.5 ohm-cm at 450°C and activation energies ranging from 26 to 42 kcal per mole. The covalent character of the Group II-B aluminoborates is demonstrated.     

Synthesis, characterization, and properties of polychelates of poly(maleic acid-co-olefin) with Cu(II), Co(II), Ni(II), and Zn(II)

SUMMARY Polychelates of poly(maleic acid-co-olefin) with Cu(II), Co(II), Ni(II), and Zn(II) metal ions are synthesized. These compounds are characterized by FT IR, UV-vis spectroscopy, and thermal analysis. The electrical conductivity measurements are carried out. These demonstrate that at temperature close to 130°C the electrical conductivity increased to values near to the semiconductor range. The PM3 calculations are also carried to study the geometry of the polychelates. Received: 1 November 2000/Revised version: 20 March 2001/Accepted: 21 March 2001     

Selective Transport of Copper(I,II), Cadmium(II), and Zinc(II) Ions through a Supported Liquid Membrane Containing Bathocuproine,Neocuproine, or Bathophenanthroline

Abstract

Some selective transport systems for heavy metallic ions through a supported liquid membrane (SLM) containing a 2,2′-dipyridyl derivative ligand, 4,7-diphenyl-2,9-dimethyl-1,10-phenanthroline (bathocuproine), 2,9-dimethyl-1,10-phenanthro-line (neocuproine), or 4,7-diphenyl-1,10-phenanthroline (bathophenanthroline), were investigated. The transport of copper(I, II), cadmium(II), zinc(II), lead(II), and cobalt(II) ions was accomplished with a halogen ion such as chloride, bromide, or iodide ion as a pairing ion species for any SLM. The ranking of the permeability of the metallic ions was Cu^+,2+, Zn²⁺, Cd²⁺ ? Pb²⁺, Co²⁺. When the oxidation-reduction potential gradient was used as a driving force for metallic ions, the transport of Cu⁺ ion was higher than those of Cd²⁺ and Zn²⁺ ions for any SLM containing bathocuproine, neocuproine, or bathophenanthroline. On the other hand, in the transport system which used the concentration gradient of pairing ion species, the permeability of the Cu²⁺ ion decreased whereas that of the Cd²⁺ ion increased. Moreover, it was found that the different selectivity for the transport of metallic ions is produced by using various pairing ion species.     

Bio active mixed ligand complexes of Cu(II), Ni(II) and Zn(II): Synthesis,spectral, XRD,DNA binding and cleavage properties

The paper presents the synthesis of complex combinations of Cu(II), Zn(II) and Ni(II) with Schiff bases obtained by the condensation reaction of diphenylglyoxal with 1-amino-4-nitrobenzene (L¹)/1-amino-4-chlorobenzene (L²)/p-anisidine (L³) as the main ligand and 1,10-phenanthroline as the co-ligand respectively. The characterization of newly formed complexes has been done by spectral and molar conductivity studies. The bioefficacy of the ligands and their complexes have been examined against the growth of bacteria and fungi in vitro to evaluate their antimicrobial potential. The in vitro antibacterial and antifungal assay indicates that these complexes are good antimicrobial agents against various pathogens. X-ray powder diffraction illustrates that the complexes have crystalline nature. The effect of the metal complexes on DNA is carried out by pUC19 DNA agarose gel electrophoresis at 50 V for 2 h. The results indicate that the complexes bind to DNA through intercalation and act as efficient cleaving agents.     

Synthesis, Crystal Structure, Fluorescence and Thermostability of Ni(II), Zn(II), Cd(II) Complexes with Schiff Base 2-Acetylpyridine-d-tryptophan

Three novel transition metal coordination polymers, [Ni(C₁₈H₁₆N₃O₂)₂·2CH₃OH] _n (1), [Zn(C₁₈H₁₆N₃O₂)₂·4CH₃OH] _n (2) and [Cd(C₁₈H₁₆N₃O₂)₂·2CH₃OH] _n (3) (C₁₈H₁₆N₃O₂=2-acetylpyridine-d-tryptophan) were synthesized and characterized by elemental analysis, IR, UV, ¹H NMR and X-ray diffraction single crystal analysis. The analyses of the structures indicate that all three materials crystallize in the tetragonal crystal system, space group P4₁2₁2. They have similar structures; i.e., the Schiff base coordinates in its deprotonated form and behaves as a hexadentate (4N+2O) coordinated ligand to form a distorted octahedron geometry. On the other hand, as a result of the alternate arrangement of chains through N–H···O intermolecular hydrogen bonds interactions, 2-D layers are formed for the three complexes. Furthermore, the luminescent properties and thermal stabilities of the three complexes were investigated.