Orientational crystallization and orientational drawing as strengthening methods for polyethylene

This paper reports on the theoretical and experimental studies of structure formation and strengthening (stiffening) of flexible-chain polymers. Two techniques of strengthening relying on the melt extrusion, i.e., orientational crystallization (crystallization initiated by melt extension) and drawing (uniaxial stretching of a crystallized polymer) are analysed by theory. The experiments involved preparation and study of melt extruded films and film fibers of linear polyethylene formed by the two techniques mentioned above. The effect of the degree of orientation and other parameters of the formation processes on the mechanical characteristics and the factors limiting the ultimate values of these characteristics are discussed. It is shown that multistage drawing succeeds in achieving a higher tensile strength and elastic modulus (1.2 and 35 GPa, respectively) than the orientational crystallization, which gives 0.8 and 15 GPa. The strengthening by drawing is accompanied by microcrack formation. In contrast, no discontinuities are observed in orientationally crystallized samples up to their ultimate extension.     

超长余辉蓄能发光涂料的制备

通过选用透明度高、太阳能吸收率高的丙烯酸树脂和高亮度、长余辉时间的镝和铕稀土离子共掺杂的稀土硅酸盐光致发光粉末材料aCaO·bZnO·cBaO·dMgO·nSiO2:Eu,Dy,制备出了具有较强的蓄光能力和较长发光时间的夜光涂料,并论述了其制备方法和特性。     

Preparation of fluoroacrylate nanocopolymer by miniemulsion polymerization used in textile finishing

Latex based on fluoroacrylate (TAN) and other comonomers was prepared via miniemulsion polymerization in the presence of stearyl trimethyl ammonium chloride (STAC) and 2, 2′‐azobis (2‐amidinopropane) dihydrochloride (ABAP) as a water soluble initiator. Light transmittance studies demonstrated that the light transmittance of prepared emulsions increases with the amount of TAN, STAC, cosolvent DPM, and hydrophobe DM. Given suitable reaction temperature and quantities of TAN, STAC, DPM, and DM, a copolymer emulsion of fluoroacylate with a particle size of 50 nm was produced. The water repellency tested on polyester fabrics displayed greater effectiveness than that of commercial products with higher fluorine content. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1466–1472, 2004     

Synthesis and Characterization of 2-(Dimethylamino)ethyl Methacrylate Homopolymers via aqueous RAFT Polymerization and Their Application in Miniemulsion Polymerization

Summary Homopolymers of 2-(dimethylamino)ethyl methacrylate (DMAEMA) have been synthesized directly in aqueous media by reversible addition-fragmentation chain transfer polymerization (RAFT) using 4,4-azobis(4-cyanopentanoic acid) (V501) as a water-soluble azo initiator and 4-cyanopentanoic acid dithiobenzoate (CPADB) as a chain transfer agent. The resulting polymers were controlled in the range of narrow molecular weight distributions, with lower than 1.3. Using the produced dithioester-capped DMAEMA homopolymer as a macro chain transfer agent, miniemulsion RAFT polymerization of methyl methacrylate and styrene were carried out, respectively. ¹H NMR analysis showed that the diblock copolymer PDMAEMA-b-PMMA in the form of stable latices was obtained as expected. This revised version was published online at the end of November 2004. Unfortunately, the received date was incorrect due to a technical problem.     

饲料级磷酸氢钙标准样品的研制

简述了饲料级磷酸氢钙标准样品的研制过程，并对样品作了稳定性试验，对搅拌设备的搅拌均匀性和物料的均匀性进行了测定，并由国家认可实验室进行了定值数据的监测。通过对比实验证明了国家实验室之间的无差异性。实验数据表明了所测定的饲料级磷酸氢钙产品是稳定和均匀的，同时简要介绍标准样品的研制程序，为开发其他化工行业标准样品奠定了基础。     

聚碳酸酯的生产及市场

介绍了聚碳酸酯生产工艺技术的进展，综述了国内外聚碳酸酯的生产及市场情况，对我国聚碳酸酯的市场发展趋势进行了分析和预测，并对我国聚碳酸酯工业的发展提出了几点建议。     

掺杂改性对聚苯乙烯性能影响的研究

文章阐述了掺杂烷氧金属的聚苯乙烯的制备以及用红外光谱、扫描电镜和热分析分析其微观结构和热性能的部分研究结果。     

Phosphate-bonded refractory coatings

Conclusions A study of the adhesion and cohesion strength of refractory coatings based on oxides of titanium, zirconium, hafnium, silicon; nitrides of hafnium, boron, silicon; mullite, magnesia spinel, zirconates of calcium, barium, strontium; disulfide and disilicide of molybdenum, and calcium titanate, using phosphate bonds, established the optimum compositions for the coatings for the following alloys: 1Kh18N9T, Él-703, ÉP-99, VT-9, OT-4, ÉI-961, Br.Kh08 bronzes, molybdenum and graphite.Results are given for the working temperatures, shear strengths, and thermal-shock resistance of the coatings and also the electric conductivity and temperature conductivity of some compositions. The refractory coatings with phosphate bonds that were developed are recommended for use in high-temperature installations in the temperature range 1000–1800°C.Translated from Ogneupory, No. 4, pp. 50–54, April, 1973.     

多孔β-TCP陶瓷药物载体的制备与体外释药速率的研究

本文用注浆成形的方法制备了以β-TCP为主晶相的多孔药物载体，体外测定了利福平的释药速率。实验结果表明，利福平在模拟体液中能够达到稳定的释放，可以作为骨结核手术后的辅助治疗。多孔β-TCP药物载体有望成为一种理想的药物缓释载体。