用聚丙烯酸酯乳液提高轮胎帘线储存稳定性

研究了一种自交联型五元共聚聚丙烯酸酯乳液的单体种类和配比、加料顺序、表面活性剂的种类和用量、引发剂用量等合成工艺因素与乳液稳定性及其增粘和防紫外线、臭氧老化的关系。用这种乳液改性的ＲＦＬ浸渍液处理锦纶６６轮胎帘线，可以显著改善帘线的储存稳定性。     

One-Step Synthesis of Luminescent Nanoparticles of Complex Oxide, Strontium Aluminate

An organic aqueous solution of metal acetylacetonate precursors was subjected to spray pyrolysis in order to fabricate SrAl₂O₄:Eu (SAO) nanoparticles. Non-agglomerated luminescent SAO nanoparticles, having a spherical shape with a size of 10–30 nm, were achieved in a single step, while only submicrometer-sized SAO particles were obtained from the conventional ultrasonic pyrolysis of the metal nitrates. Without any post-annealing process, the as-prepared SAO nanoparticles were observed to exhibit a strong photoluminescence, which is comparable with that of the submicrometer-sized SAO particles. A mechanism for the formation of the nanoparticles is also discussed.     

Effect of Microstructure on Material-Removal Mechanisms and Damage Tolerance in Abrasive Machining of Silicon Carbide

Effects of microstructural heterogeneity on material-removal mechanisms and damage-formation processes in the abrasive machining of silicon carbide are investigated. It is shown that the process of material removal in a conventional silicon carbide material with equiaxed-grain micro-structure and strong grain boundaries consists of the formation and propagation of transgranular cracks which results in macroscopic chipping. However, in a silicon carbide material, containing 20 vol% yttrium aluminum garnet (YAG) second phase, with elongated-grain micro-structure and weak grain boundaries, intergranular micro-cracks are formed at the interphase boundaries, leading to dislodgment of individual grains. These different mechanisms of material-removal affect the nature of machining-induced damage. While in the conventional silicon carbide material the machining damage consists of transgranular median/radial cracks, in the heterogeneous silicon carbide material, abrasive machining produces interfacial micro-cracks distributed within a thin surface layer. These two distinct types of machining damage result in a different strength response in the two forms of silicon carbide materials. In the case of the conventional silicon carbide, grinding damage results in a dramatic decrease in strength relative to the as-polished specimens. In contrast, the ground heterogeneous silicon carbide specimens show no strength loss at all.     

利用震动磨超细粉碎天然羟基磷灰石

本文利用震动磨对羟基磷灰石进行超细粉碎,优选出震动磨超细粉碎的最佳工艺条件。利用震动磨研磨可以得到粒度分布单一的粉体样品,D50为2.001μm。     

KC型第三代推动篦冷机的开发设计及其特点

前言 从我国水泥生产技术的发展来看，由于第二代以及不带热端固定床的第三代推动篦式冷却机均存在高温端部容易漏料、篦饭寿命短、篦板结构形式的缺陷使得其冷却效率差、易出现“红河”、二三次风温低、冷却风量偏大、动力消耗大、热回收效率低等一系列不尽人意之处。我院存对同外有关技术的消化吸收和实验研究的基础上，通过不断开发、优化，     

Influence of polymerization conditions on the structure and properties of polyethylene/polypropylene in‐reactor alloy synthesized in the gas phase with a spherical Ziegler–Natta catalyst

A spherical TiCl₄/MgCl₂‐based catalyst was used in the synthesis of in‐reactor polyethylene/polypropylene alloys by polyethylene homopolymerization and subsequent homopolymerization of propylene in the gas phase. Different conditions in the ethylene homopolymerization stage, such as monomer pressure and polymerization temperature, were investigated, and their influences on the structure and properties of in‐reactor alloys were studied. Raising the polymerization temperature is the most effective way of speeding up polymerization and regulating the ethylene content of polyethylene (PE)/polypropylene (PP) alloys, but it will cause a greater increase in the PE‐b‐PP block copolymer fraction (named fraction D) than in the fraction of PP‐block‐PE in which the PP segments have low or medium isotacticity (named fraction A). Although changing ethylene monomer pressure could influence the ethylene content of PE/PP alloys slightly, it is an effective way of regulating the structural distribution. Reducing the monomer pressure will evidently increase fractions A and D. The mechanical properties of the alloys, including impact strength and flexural modulus, can be regulated in a broad range with changes in polymerization conditions. These properties are highly dependent on the amount, distribution, and chain structure of fractions A and D. The impact strength is affected by both fraction A and fraction D in a complicated way, whereas the flexural modulus is mainly determined by the amount of fraction A. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2136–2143, 2006     

Synthesis and properties of polystyrene‐b‐poly(ethylene oxide)‐b‐polystyrene triblock copolymers

A series of well‐defined and property‐controlled polystyrene (PS)‐b‐poly(ethylene oxide) (PEO)‐b‐polystyrene (PS) triblock copolymers were synthesized by atom‐transfer radical polymerization, using 2‐bromo‐propionate‐end‐group PEO 2000 as macroinitiatators. The structure of triblock copolymers was confirmed by ¹H‐NMR and GPC. The relationship between some properties and molecular weight of copolymers was studied. It was found that glass‐transition temperature (T_g) of copolymers gradually rose and crystallinity of copolymers regularly dropped when molecular weight of copolymers increased. The copolymers showed to be amphiphilic. Stable emulsions could form in water layer of copolymer–toluene–water system and the emulsifying abilities of copolymers slightly decreased when molecular weight of copolymers increased. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 727–730, 2006     

A novel method for the preparation of monocarboxyl‐end‐grouped polycaprolactam with an adjustable molecular weight

A novel method was used to synthesize adjustable‐molecular‐weight polycaprolactams with monocarboxyl end groups. The reaction device and conditions are discussed. The products were characterized by Fourier transform infrared spectroscopy, ¹H‐NMR spectroscopy, high‐resolution pyrolysis gas chromatography–mass spectrometry, and wide‐angle X‐ray diffraction. The thermal properties were studied by differential scanning calorimetry and thermogravimetric analysis. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 722–727, 2004     

Capture of gypsy moth,Lymantria dispar (L.), andLymantria mathura (L.) males in traps baited with disparlure enantiomers and olefin precursor in the People's Republic of China

Pheromone traps baited with (+)-disparlure,cis-7,8-epoxy-2methyocta-decane, captured males ofLymantria dispar, L. monacha, andL. mathura in northeastern People's Republic of China.L. dispar responded to the addition of olefin to (+)-disparlure-baited traps in a negative doseresponse manner. Observations on site and seasonal capture ofL. dispar andL. mathura are discussed.Lepidoptera: Lymantriidae.     

有机硫加氢(HDS)催化剂的预硫化

预硫化是HDS、HDN过程中决定催化剂活性的最重要环节。在分析催化剂硫化反应原理、硫化条件、硫化与还原的关系等基础上进一步指出了在工业过程中预硫化的一些原则。