Relationship between dielectric behaviors and conversion of MMA during polymerization process

Poly(methyl methacrylate), which is prepared by polymerization of methyl methacrylate (MMA), is widely used in the fabrication of polymer optical fiber and devices. In this article, a dielectric measurement method was proposed to monitor the polymerization process. The measurement result is compared with that obtained by the traditional Abbe's refractometer method. By monitoring the dielectric behaviors of polymerization system, the correlation between dielectric properties of reacting bulk and conversion of MMA was established. The influence of reactive temperature, reactive time, conversion rate of prepolymerization, and oxygen environment was discussed. It was shown that the gel effect occurred at 2 h at the reactive temperature of 50°C when the conversion of prepolymer was about 24% with the absence of oxygen. The conversion rate obtained by Abbe's refractometer method was larger than that measured by dielectric method in the reaction metaphase. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

《计算机在化工中的应用》课程建设与教学

介绍了武汉科技大学化学工程与技术学院《计算机在化工中的应用》课程建设与教学实施情况,总结了该门课程的教学心得。教学实践表明,该课程内容实用,深受学生欢迎。     

强化化工专业本科生计算机应用能力培养

以武汉科技大学化学工程与技术学院化学工程与工艺专业为例,介绍了优化培养计划、在专业理论教学中融入计算机应用和在实践教学强中融入计算机应用等强化化工专业本科生计算机应用能力培养的具体措施。指出化工专业本科生计算机应用能力的培养是一项系统工程,光靠低年级开设的那几门计算机课程是不够的,在高年级阶段还要继续强化计算机应用能力的培养。     

KOH活化焦油渣制备活性炭的研究

以武钢焦化公司焦油渣为原料,KOH为活化剂,采用正交实验研究了活化温度、活化时间、碱炭比（氢氧化钾与焦化除尘灰的质量比）和炭化温度对所制活性炭吸附性能的影响,得出制备焦油渣基活性炭影响因素主次顺序为活化温度、活化时间、碱炭比、炭化温度,最佳活化条件为活化温度为800℃,活化时间为100min,碱炭比为4：1,炭化温度为400℃。在此条件下制备活性炭的碘吸附值为1300．765mg／g。     

环境监测课程的教学改革与教学研究

环境监测是环境工程专业学生的基础课之一,社会对环境类人才的环境监测能力提出了越来越高的要求,结合本院环境监测教学的现状,对环境监测课程进行教学改革。在明确专业培养目标和规格的情况下,确定了教改的基本思路,通过合理构建教学体系、规范教学、改革教材课程体系、加强实践教学体系建设、加强课程评价体系建设等一系列措施,全面提升环境监测理论和实验的地位,培养学生的创新能力、操作能力、综合能力和科研能力。使本专业的教学适应了培养目标的要求,保障了人才培养质量。     

造纸系统中杀菌剂与胶黏物控制剂的协同杀菌作用研究

造纸系统中不可避免的会有微生物的存在和污染,对造纸生产过程和成品纸质量产生不良影响。评价了杀菌剂纸保308和两种胶黏物控制剂胶控物I和胶控物Ⅱ单独使用及复配使用的抑菌效果,研究结果显示三种试剂单独使用时,纸保308的抑菌效果最好,而纸保308和胶控物I按照2：l的比例复配,抑菌效果比各试剂单独及纸保308和胶控物Ⅱ复配的抑菌效果都好,为筛选造纸工业中杀菌和胶黏物控制俱佳的复配物提供实验数据。     

1,2,3,3,3-五氟丙烯的合成

介绍了1,2,3,3,3-五氟丙烯的性质和应用,综述了1,2,3,3,3-五氟丙烯的合成方法,分析了各合成工艺的优缺点,认为以HFP或卤代甲烷和卤代乙烯为原料合成1,2,3,3,3-五氟丙烯具有工业化前景,并指出加快1,2,3,3,3-五氟丙烯的应用研究对丰富我国ODS替代品的种类有重要意义。     

Pt promotional effects on Pd–Pt alloy catalysts for hydrogen peroxide synthesis directly from hydrogen and oxygen

H₂O₂ synthesis directly from H₂ and O₂ over supported Pd–Pt alloy catalysts was carried out using a semibatch reactor under ambient conditions. As compared to pure Pd, the performance of Pd–Pt catalysts was enhanced significantly. The promotional role of Pt was studied systematically by using in situ diffuse reflectance infrared Fourier transform spectroscopy of CO adsorption (DRIFTS), quantitative powder X-ray diffraction (XRD), X-rays photoelectron spectroscopy (XPS), and temperature-programmed desorption of H₂/O₂ (H₂/O₂-TPD). The spectra of DRIFT, XPS, and XRD demonstrate the formation of Pd–Pt alloy particles, which surfaces are enriched by Pt accompanying with possible electron transfer from Pd to Pt. The addition of Pt into Pd phase was proposed to impact on reactants adsorption, stabilization of intermediates such as OOH and OH radicals, and the formation and decomposition of H₂O₂.     

Preparation,Structural Characterization,and Enhanced Electrical Conductivity of Pyrochlore‐type (Sm1–xEux)2Zr2O7 Ceramics

(Sm_1–xEu_x)₂Zr₂O₇ (0 ≤ x ≤ 1.0) samples are prepared by solid state reaction method using Sm₂O₃, Eu₂O₃, and ZrO₂ as starting materials. The phase composition and microstructure of (Sm_1–xEu_x)₂Zr₂O₇ ceramics are investigated by X‐ray diffraction (XRD), scanning electron microscopy, high‐resolution transmission electron microscopy (HRTEM) coupled with selected area electron diffraction and Raman spectroscopy. XRD and TEM show that all the samples exhibit a single pyrochlore‐type structure. HRTEM observation indicates that the whole grain interior of Sm₂Zr₂O₇ ceramic is a perfect crystal free of any dislocation. Raman spectroscopy reveals that the degree of structural disorder of (Sm_1–xEu_x)₂Zr₂O₇ ceramics increases gradually with increasing Eu content. The electrical conductivity of (Sm_1–xEu_x)₂Zr₂O₇ ceramics is investigated by impedance spectroscopy in the air and hydrogen atmospheres, respectively. The electrical conductivity of (Sm_1–xEu_x)₂Zr₂O₇ ceramics increases with increasing Eu content at identical temperature levels. Both the activation energy E_g and the pre‐exponential factor σ_0g for the grain conductivity gradually increase with increasing Eu content. As the ionic conductivity shows no obvious change in both air and hydrogen atmospheres, the conduction of (Sm_1–xEu_x)₂Zr₂O₇ is purely ionic with negligible electronic conduction.     

Super‐Tough,Self‐Healing Polyurethane Based on Diels‐Alder Bonds and Dynamic Zinc–Ligand Interactions

Self‐healing polymer materials have attracted extensive attention and have been explored due to their ability of crack repairing in materials. This paper aims to develop a novel polyurethane‐based material with high self‐healing efficiency and excellent mechanical properties under 80 °C on the basis of reversible Diels–Alder bonds as well as zinc–ligand structure (DA‐ZN‐PU). By integrating DA bonds and zinc–ligand structure, as‐prepared DA‐ZN‐PU samples reach the maximum tensile strength as much as 28.45 MPa. After self‐healing, the tensile strength is 25.85 MPa, leading to the high self‐healing efficiency of 90.8%. In addition, by introducing carbonyl iron powder (CIP), a new polyurethane containing carbonyl iron powder (DA‐ZN‐CIP‐PU) can be achieved, exhibiting microwave‐assisted self‐healing property. And the self‐healing efficiency can be reached to 92.6% in 3 min. Due to high self‐healing efficiency and excellent mechanical properties of the prepared novel polyurethane, it has application attributes in crack repair of functional composite materials.