PA-1010/ABS合金的性能研究

研究了以自制的马来酸酐 (MAH)接枝改性ABS(MABS)作为PA 10 10 /ABS增容剂所形成的PA 10 10 /ABS合金的性能。研究结果表明 ,随ABS中马来酸酐接枝量的上升 ,PA 10 10 /ABS合金的冲击强度提高 ,保持PA 10 10与ABS用量在某一恰当配比范围内 ,可得到冲击强度高 ,维卡软化温度较高的合金。     

Electrochemical micromachining of nitinol by confined-etchant-layer technique

The confined etchant layer technique has been applied to fabricate complex three-dimensional microstructures on nitinol for the first time. HF and HNO₃ were locally and simultaneously electrogenerated at the mold surface to etch a nitinol workpiece. NaOH was used as an efficient scavenger to confine the etchant close to the mold. Cyclic voltammetry was employed to study the electrochemical behavior of a Pt electrode in the etching solution in order to choose an appropriate potential for etchant generation on the mold. The thickness of the confined etchant layer was estimated to be several micrometers by inspecting the deviation of the sizes of the etched spots from the sizes of those on the microelectrode. Thus, the composition of the electrolyte could be optimized for better etching precision. By optimizing the composition of the electrolyte, complex microstructures on a Pt-Ir mold bearing the logo “XMU” of Xiamen University were successfully fabricated on nitinol. The etched patterns were approximately negative copies of the mold, and the precision of duplication could easily reach the micrometer scale.     

Performance and stability of Pt-based ternary alloy catalysts for PEMFC

Carbon-supported Pt-based ternary alloy electrocatalysts were prepared by incipient wetness method in order to elucidate the origin of the enhanced activity of oxygen reduction reaction in PEMFC. To measure the catalytic activity and stability of the cathode alloy catalysts (electrodes containing Pt loading of 0.3 mg/cm², 20 wt.% Pt/C, E-TEK), the I-V polarization curves were obtained. All alloy catalysts showed higher performances than Pt/C. It can be concluded that as platinum formed alloys with transition metals, the electronic state of Pt and the nearest neighbor Pt-Pt distance changes, which significantly influence the electrocatalytic activity for oxygen reduction.Long-term stability test was performed with the Pt₆Co₁Cr₁/C alloy catalyst for 500 h. According to XPS analysis, the lower oxide component with Pt₆Co₁Cr₁/C electrocatalyst provides a large portion of platinum in metallic species in the electrocatalyst and it seems to be mainly responsible for its enhanced activity towards oxygen reduction.     

PPO/PA合金的研制

比较了三条技术路线、PPO／PA质量比、各种抗冲击剂对PPO／PA合金性能的影响。应用FTIR．Molau实验、DSC曲线证实了改性反应原理及增容作用。结果表明：在双螺杆挤出机中，聚苯醚(PPO)与马来酸酐(MAH)接枝反应，然后与聚酰胺(PA66)、SEBS挤出共混，制成的PPO／PA合金，抗冲击性能高。     

EVA／EPDM／PVC三元聚合物合金软质泡沫体的制备及其在复合衬垫中的应用

采用物理共混以及化学交联模压发泡成型工艺制备聚乙烯－醋酸乙烯酯（ＥＶＡ）／乙丙橡胶（ＥＰＤＭ）／聚氯乙烯（ＰＶＣ）三元聚合物合金软泡沫体，并制成贴布复合衬垫。讨论了该体系的相容性，动态共交联与发泡的适配，以及贴布复合，造型等问题，结果表明，该衬垫可完合替代国外同类先进产品。     

PPO/PP及PPO/PA合金

PPO与PA,PP是不相容的,制造PPO PA及PPO PP合金需要提高合金中两组分的相容性。本文叙述改善相容性的原理和途径、两种合金的特点及其重要性能。     

相容剂对PS／PP共混合金混容形态和性能的影响

研制了马来酸酯接枝聚丙烯相容剂，并将其用于聚苯乙烯／聚丙烯的共混改性；通过力学性能测试、透射电镜分析、差示扫描量热分析等方法研究了相容剂对ＰＳ／ＰＰ合金的混容形态和力学性能的影响。结果表明：相容剂的加入，使ＰＳ／ＰＰ由不相容的独立聚集的两相变为相畴很小的细分散相，共混高分子的链段运动也表现为趋于均相结构的运动方式。加入相容剂后共混材料的冲击强度有明显提高，拉伸强度也有所上升。相容剂的含量对性能也有较大影响，相容剂用量为８％时，力学性能最好，从ＤＳＣ测试中可以看到此时共混物趋向均相体系；继续增大相容剂用量，合金的力学性能反而下降。     

PA66/UHMWPE合金的力学性能和微观结构研究

制备了PA66／uHMwPE／HDPE-g-MAH共混合金，并对其力学性能和微观结构进行了研究。结果表明，随着UHMWPE质量分数的增加，共混合金常温和低温下的缺口冲击强度都显著提高，拉伸强度和拉伸模量下降，但仍能保持较高的力学性能；添加了UHMWPE的PA66合金的断裂面有大量的空穴产生和应力发白现象。     

《铁碳合金相图》的教学探究

本文对Fe-Fe3C相图和它的教学设计进行了全面分析,特别用简而易懂的5单7双3线9点方法对铁碳合金相图进行了详细的分析,使得原本枯燥难懂的理论变得形象生动。     

Electrodeposition of Ni, Co and Ni-Co alloy powders

In this paper the polarization characteristics of the processes of Ni and Co powders and Ni-Co alloy powders electrodeposition from ammonium sulfate containing supporting electrolyte are investigated as a function of Ni²⁺ and Co²⁺ ions concentrations. It is shown that the correct polarization curves for Ni and Co powders and Ni-Co alloy powders electrodeposition could be obtained only after IR drop correction, since the total current density of electrodeposition at the most negative potential of −1.4 V versus Ag|AgCl is extremely high (up to about 3-6 A cm⁻²) as a consequence of simultaneous hydrogen evolution which starts immediately after the beginning of metals (alloys) deposition. After determining the current density for hydrogen evolution and its subtraction from the total current density, correct polarization curves for Ni and Co powders and Ni-Co alloy powders electrodeposition are obtained. They are found to be different for each ratio of Ni²⁺/Co²⁺ ions concentration. It is also concluded that the shape of the polarization curves in all cases is practically defined by the shape of the polarization curve for hydrogen evolution. The morphology and composition of electrodeposited powders were also found to be sensitive to the ratio of Ni²⁺/Co²⁺ ions concentration.