Graft copolymerization of styrene and acrylonitrile onto EPDM

Acrylonitrile–EPDM–styrene (AES) graft copolymers were synthesized by solution graft polymerization of styrene (St) and acrylonitrile (AN) onto EPDM in an n‐hexane/benzene solvent with benzoyl peroxide (BPO) as an initiator. The structure changes were studied by an FTIR spectrophotometer. The grafting parameters were calculated gravimetrically. The influence of the polymerization conditions, such as the reaction time, concentration of the initiator, EPDM content, and weight ratio of St/AN, on the structure of the products was investigated. It was found that a proper initiator concentration and EPDM content will give a high grafting ratio of the AES resin. The thermal property of the copolymer was studied using programmed thermogravimetric analysis (TGA). The results showed that the copolymer has a better heat‐resistant property than that of ABS, especially for the initial decomposition temperature (T_in) and the maximum weight loss rate temperature (T_max). Also, the mechanism of the graft reaction was discussed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 428–432, 2002     

Effects of the electrospray ionization parameters on the formation and morphology of colloidal microspheres of polyacrylonitrile

Polyacrylonitrile colloidal microspheres have been successfully prepared with different concentrations of electrospraying polyacrylonitrile solutions. The morphology of the colloidal spheres has two kinds of structures and is strongly affected by electrospray‐ionization parameters, such as the polymer concentration, applied voltage, and distance between the electrodes. The solvent can also affect the morphology of polyacrylonitrile. The optimum conditions for preparing colloidal spheres have been found, and differential scanning calorimetry results indicate that polyacrylonitrile colloid spheres are amorphous. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2889–2893, 2006     

几种无机阴离子对TiO_2催化活性影响的实验研究

以N掺杂TiO2试剂为催化剂,降解偶氮直接耐酸大红4BS溶液,同时外加4种浓度不同的阴离子溶液,探讨了HCO3-,F-,NO3-,H2PO4-等阴离子对N/TiO2化学试剂催化活性的影响。实验表明,HCO3-,F-,NO3-,H2PO4-等阴离子对N/TiO2化学试剂的催化活性有显著影响。因此,可以通过外加不同的离子来提高或降低N/TiO2的活性。     

基于国家电网的财务管理系统的开发与研究

随着社会生产力的不断发展,越来越多的企业认识到了财务工作的重要性。企业要利用现代高效的运作方式来开发和管理组织中最重要、最昂贵的资源,实现财务管理的精细化、自动化,提高财务资源的利用率,促进企业的发展。     

Mn2+、Nb5+共掺BaTiO3陶瓷的制备及压电性能的研究

本文采用改进的固相反应法,制备了施主杂质Nb5 和受主杂质Mn2 共掺的BaTiO3陶瓷。按不同Nb5 、Mn2 的掺杂量,分别在1180℃、1210℃、1250℃、1280℃温度下煅烧。实验结果表明:当烧结温度为1250℃、掺杂量为0.05mol%时,制得的试样性能较好。     

热管省煤器在120 kt/a硫磺制酸系统中的应用

介绍120kt／a硫磺制酸装置转化工段两台热管省煤器的结构特点和应用情况。转化器第三段出口冷换热器后的省煤器为水箱式热管省煤器，锅炉给水在水箱内与热管内工质换热；五段出口省煤器为夹套式热管省煤器，锅炉给水在套管与热管的间隙内被工质加热：两台热管省煤器的蒸发段与放热段之间均由管板隔离，以防止烟气对水侧管壁面的腐蚀，热管省煤器具有运行费用低、操作安全稳定等优点。通过严格控制锅炉给水质量和正确的开停车操作，近两年来热管省煤器运行良好，未发生泄漏故障：     

基于视觉原理的曲线重构算法研究

曲线和曲面的重构是逆向工程中的重要问题,特别是按照计算机图形学中点线面的发展规律,曲线重构更是其中很重要的一步,为后面的曲面重构奠定了研究基础。论文研究和实现了一种曲线重构算法,该算法将人类的视觉具有的接近性和连续性融入到了曲线重构算法中。实验结果表明了该算法的有效性。     

Studies on syntheses and properties of novel CeO2/polyimide nanocomposite films from Ce(Phen)3 complex

A series of cerium dioxide (CeO₂)/polyimide (PI) nanocomposites were successfully prepared from Ce(Phen)₃ and polyamic acid (PAA) via the solution direct-dispersing method, followed by a step thermal imidization process. TGA and XPS studies showed that the cerium complex decomposed to form CeO₂ during the thermal imidization process at 300 °C. SEM observation showed that the formed CeO₂ as nanoparticles was well dispersed in polyimide matrix with a size of about 50-100 nm for samples with different contents of CeO₂. Thermal analysis indicated that the introduction of CeO₂ decreased the thermal stability of nanocomposite films due to the decomposition of Ce(Phen)₃ in the imidization process, while the glass transition temperature (T_g) increased obviously, especially nanocomposite films with high loading of CeO₂ exhibited a trend of disappearance of T_g. DMTA and static tensile measurements showed that the storage modulus of nanocomposite films increased, while the elongation at break decreased with increasing CeO₂ content.     

二苯并噻吩合成方法的改进

对文献报道的由联苯和硫在AlCl3催化下反应合成二苯并噻吩(DBT方法中的提纯过程作了改进，大大简化了提纯步骤，使制备DBT的时间缩短了一半，产率为63．4％，经提纯后的成品含量达99．7％，其纯度、外观、晶相均优于进口试剂，但成本远低于进口试剂。产品用FT-IR、LRS、XRD和^1H NMR表征结果与文献报道完全相符合。     

Thermal and mechanical properties of the polymers synthesized by the sequential polymerization of propylene and 1‐hexadecene

The block copolymer of poly(1‐hexadecene) (PHD) and polypropylene (PP) was effectively synthesized by the sequential polymerization of propylene and 1‐hexadecene by using highly isospecific TiCl₃/Cp₂Ti(CH₃)₂ (Cp = cyclopentadienyl). The block copolymers had two separate melting temperatures of constituent blocks. The modulus of PHD–PP block copolymer was enhanced as the content of sequentially polymerized PP block was increased. The elongation at break showed positive deviation at the intermediate compositions from the simple additive values of constituent homopolymers. Shape memory effect which utilizes the crystalline PHD block as a reversible phase and the crystalline PP block as a fixed structure was examined. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1709–1715, 2002; DOI 10.1002/app.10551