Quantitative Analysis of Zinc Vaporization from Manganese Zinc Ferrites

Zinc vaporization of Mn-Zn ferrites was quantitatively characterized in terms of oxygen partial pressure P _O2, temperature, grain size and sample geometry. The amount of zinc loss was measured as a function of time at various temperatures by a thermogravimetric method. The weight loss due to irreversible zinc vaporization showed a linear behavior with time and increased exponentially with temperature. The observed weight loss due to zinc evaporation at 1100°C was small, whereas a significant weight change was detected at 1200°C. The weight loss was even greater in a reducing atmosphere ( P _O2= 5 × 10⁻⁵). Below 1300°C, the diffusion of elemental zinc was sufficiently fast to compensate the zinc loss at the interface region, resulting in a linear dependence on time. At temperatures ≥1400°C, the weight change no longer followed the linear dependence and showed a rather parabolic behavior with a concave upward slope. The core shape and the gas flow around ferrite cores were important factors that affected the rate of zinc vaporization, but not the grain size.     

POE和T-ZnOw协同改性聚丙烯的研究

以聚丙烯（PP）、热塑性弹性体（POE）、四针状氧化锌晶须（T-ZnOw）为原料，制备了PP／POE／T-ZnOw复合材料；研究了复合材料的结晶结构和力学性能。结果表明：T-ZnOw能诱导β晶型的生成，在快速冷却的条件下POE也能诱导生成β晶型。随着T-ZnOw含量的增加，PP／POE／T-ZnOw复合材料的冲击性能不断提高。T-ZnOw含量为20％时，PP／POE／T-ZnOw的冲击强度比纯PP提高了82.5％；拉伸强度和断裂伸长率先增加后降低。T-ZnOw的加入还能很好地改善复合材料的熔体流动性能。     

Formation of Zinc–Antimony-Based Spinel Phases

Formation of spinel phases in ZnO–Sb₂O₃and ZnO–Sb₂O₃–Bi₂O₃systems is studied by the use of X-ray diffraction. The formation of nonstoichiometric Zn_2.33Sb_0.67O₄phase is observed in both the systems at ∼900°C. However, in these systems, at higher temperatures ( T ≥ 1100°C), formation of the inverse spinel phase Zn₇Sb₂O₁₂is observed. The study has been extended to understand the effect of CrO₃doping on the stability of the different spinel phases in the previously mentioned systems. Interestingly, in both the systems, samples doped with CrO₃, displayed the presence of Zn_2.33Sb_0.67O₄phase <1200°C, indicating the stabilization of the spinel phase by CrO₃.     

机械力化学湿法一步制备表面修饰磷酸锌微粉

以氧化锌和磷酸为原料,以硅烷偶联剂为改性剂,采用机械力化学湿法制备微细磷酸锌并进行表面改性.用XRD、润湿角、活化指数、沉降时间等手段对产物进行表征,用FT-IR对改性粉末的结构进行分析,初步探讨了偶联剂与磷酸锌的作用机理.结果表明产物为二水和四水磷酸锌混合物;在红外区域2 800～3 000 cm-1和1 400 cm-1有偶联剂的特征吸收峰,说明偶联剂与磷酸锌之间发生了化学反应;当硅烷偶联剂添加质量分数由0增加到2%,改性产品的活化指数由0增加到98.71%,对水的润湿角由0°增加到93.21°,沉降时间由0.5 h增加到176 h,在涂料中的分散性和贮存稳定性得到改进.     

甲基丙烯酸锌在NBR／木质素中的应用

研究了α－甲基丙烯酸锌（ＭＡＡ－Ｚｎ）对ＮＢＲ／木质素（１００／１００，质量比）硫化胶性能的影响。结果表明，加入１．５～５．０份ＭＡＡ－Ｚｎ，可提高硫化胺的１００％的定伸应力，硬度和抗压缩永久变形能力，但对其他力学性能影响甚微，经分析可知，ＭＡＡ－Ｚｎ还可以降低硫化反应活化能，提高硫化胶的交联密度和耐热老化性能。     

模数对无机富锌涂料和涂层性能的影响

硅酸钾富锌涂料是目前广泛使用的钢铁防腐蚀涂料。作为涂料粘结剂的高模数硅酸钾溶液对涂料和涂层的性能有重要影响。本研究考察了硅酸钾粘结剂的模数变化对涂料及涂层性能产生的影响。实验结果表明：粘结剂模数的提高可以提高固化后涂层的耐水性能，当粘结剂模数在5.0左右时，所得富锌涂层具有最佳的耐磨性能，但当粘结剂模数超过5.5时会造成涂料施工性能和贮存稳定性下降，涂层柔韧性降低，从而降低涂层的耐磨性能。     

以SnO/ZnO为催化剂合成油酸正丁酯

研究了以SnO／ZnO为催化剂合成油酸正丁酯，优化的工艺条件为：催化剂中ZnO含量为0．04～0．05，催化剂用量为1．0％（占总投料量质量分数），酸醇投料比n油酸：n丁醇为1：1．6，反应温度140～145℃，反应时间1．0h，产品收率达95％以上，催化剂可重复使用4次，再生容易。     

以氧化镁和氧化锌为主稳定剂的PVC的热稳定性和力学性能

用HAAKE流变仪研究了氧化镁／氧化锌稳定体系对聚氯乙烯的动态热稳定性能。结果发现，在氧化镁／氧化锌质量比为2／3的条件下，配合环氧大豆油、硬脂酸钙、无毒亚磷酸酯和有机稳定剂作为辅助稳定剂，其初期着色和热稳定效果都超过了市售钙锌稳定体系，流变性能和动态热稳定特性接近铅盐稳定体系。用这种稳定体系稳定的PVC的力学性能与市售钙锌稳定体系稳定的相当。     

Effect of Microstructural Control on Thermoelectric Properties of Hot-Pressed Aluminum-Doped Zinc Oxide

The thermal conductivity of polycrystalline Al-doped ZnO was controlled through the fabrication of nanostructured polycrystalline materials, by hot-pressing nanosized Zn_{1– x} Al _x O ( x = 0.01, 0.02) particles, which were synthesized by a coprecipitation and spray-drying method. This process resulted in an improved thermoelectric power factor because of the nanosized Zn_0.99Al_0.01O particles of the polycrystalline products. The thermal conductivity also was decreased as a result of the formation of nanocrystalline Zn_0.99Al_0.01O.     

Influence of ZnO nanoparticles on the cure characteristics and mechanical properties of carboxylated nitrile rubber

Zinc oxide (ZnO) nanoparticles assembled in one dimension to give rod‐shaped morphology were synthesized. The effect of these ZnO nanoparticles (average particle size ～ 50 nm) as the curing agent for carboxylated nitrile rubber was studied with special attention to cure characteristics, mechanical properties, dynamic mechanical properties, and swelling. These results were compared with those of the conventional rubber grade ZnO. The study confirmed that the ZnO nanoparticles gave a better state of cure and higher maximum torque with a marginal decrease in optimum cure time and scorch time. The mechanical properties also showed an improvement. There was an increase in tensile strength by ～ 120%, elongation at break by ～ 20%, and modulus at 300% elongation by ～ 30% for the vulcanizate cured with ZnO nanoparticles, as compared with the one containing rubber grade ZnO. Dynamic mechanical analysis revealed that the vulcanizates exhibited two transitions—one occurring at lower temperature due to the T_g of the polymer, while the second at higher temperature corresponding to the hard phase arising due to the ionic structures. The second transition showed a peak broadening because of an increase in the points of interaction of ZnO nanoparticles with the matrix. The tan δ peak showed a shift towards higher T_g in the case of ZnO nanoparticle‐cured vulcanizate, indicating higher crosslinking density. This was further confirmed by volume fraction of rubber in the swollen gel and infrared spectroscopic studies. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007