不同水环境条件下马拉硫磷的降解规律

[目的]研究马拉硫磷在不同水环境条件下的降解规律。[方法]在不同pH值、不同温度及不同水样条件下,采用高效液相色谱法检测水环境中马拉硫磷剩余浓度随时间的变化情况。[结果]马拉硫磷降解活化能EA为73.10 kJ/mol,降解速率随pH值增大而加快,随温度升高而加快,湿地原水中降解最快、灭菌湿地原水次之、灭菌超纯水中最慢,准一级反应动力学方程可以描述其在水环境中的降解规律。[结论]马拉硫磷的降解速率受pH值、温度和水样条件的影响,自然水体中马拉硫磷降解速率较快。     

Comparison of Construction Method for DEM Simulation of Ellipsoidal Particles

Discrete element model was developed to simulate the ellipsoidal particles moving in the moving bed. Multi-element model was used to describe a ellipsoidal particle, the contact detection algorithm of ellipsoidal particle was developed, and both contact force and gravity force were considered in the models. The simulation results were validated by our experiment. Three algorithms for representing an ellipsoidal particle were compared in macro and micro aspects. The results show that there exists big difference in the microscopic parameters such as kinetic energy, rotational kinetic energy, deformation, contact force and collision number which leads to the difference of macroscopic parameters. The relative error in the discharge rate and tracer particle position is the largest between 3-tangent-element representation and experimental results. The flow pattern is similar for the 5-element and 3-intersection representations. The only difference is the discharge rate of 5-element representation is larger than the experimental value and that of the 3-intersection representation has the contrary result. Finally the 3-intersection- element representation is chosen in the simulation due to less computing time than that of the 5-element representation.     

聚碳酸酯在不同湿热自然环境下的老化行为

对聚碳酸酯(PC)在我国海南琼海及三亚2个典型湿热地区的自然曝露试验结果进行了研究,并利用红外特征指数对PC的老化机理进行了探讨。结果表明:在琼海湿热内陆地区曝晒的PC试样同时发生了氟利斯重排反应和光氧化反应,而在三亚湿热沿海地区曝晒的试样则可能发生了光氧化反应和盐致水解反应。     

受阻酚改性聚酯/聚醚胺型PU/P(MMA-St)IPN阻尼性能的研究

用一步法制备了受阻酚AO-80改性的聚酯/聚醚胺型聚氨酯/聚(甲基丙烯酸甲酯-苯乙烯)互穿聚合物网络(PU/P(MMA-St)IPN)。通过热失重分析仪、动态力学分析以及扫描电子显微镜对IPN材料的热稳定性、阻尼性能和微观结构形态进行了表征。研究结果表明:AO-80可以提高PU与P(MMA-St)的相容性,从而有效拓宽阻尼温域;当聚氨酯中聚酯/聚醚胺=80/20,w(AO-80)=20phr,PU/P(MMA-St)=70/30时,所得IPN材料的阻尼性能最佳。     

塑料基纳/介孔电介质的制备方法与研究进展

超大规模集成电路（ULSI）的发展需要新型低介电常数电介质材料,对材料进行纳/介孔化是一种降低其介电常数的有效方法。对利用再沉积法、溶胶-凝胶法（包括无序和有序孔材料）、热分解法、超临界发泡法、电化学刻蚀法制备纳/介孔低介电常数塑料基电介质材料的原理及典型产物的性能进行了简略介绍,并对该领域中近十余年来的进展作了综述。认为,今后应针对ULSI领域的应用需求对新的致孔机理进行研究并开发新的致孔方法,同时进一步提高材料的耐热性并降低吸水性。     

高铁酸钾的制备工艺研究与表征

高铁酸钾是一种新型绿色高效的水处理剂,为了探索经济、高效的制备高铁酸钾的工艺,以次氯酸钙为主要原料通过氧化反应制备高铁酸钾,考察反应时间、反应温度、次氯酸钙用量、重结晶温度和碱度等因素对产率的影响,并采用红外光谱对产物高铁酸钾进行表征。实验结果如下：当反应温度为25 ℃,次氯酸钙的用量为理论值的1.2倍,反应时间为40 min,在冰水浴中重结晶时,反应产率可达75%以上;红外光谱（FT-IR） 对产物的结构表征证明合成产物为高铁酸钾。结果表明以次氯酸钙代替次氯酸钠制备高铁酸钾的工艺是可行的。     

改性PVA/天然胶乳胶粘剂的研究

将改性聚乙烯醇(PVA)作为天然胶乳胶粘剂的改性剂,研究其对天然胶乳胶粘剂的粘度、剥离强度及耐水性能的影响。研究结果表明:改性PVA的加入,显著地提高了天然胶乳的硫化速率,延长了胶粘剂的贮存时间,改善了其粘度、剥离强度及耐水性能。     

In-situ Polymerization-modification Process and Foaming of Poly（ethylene terephthalate）

Most of traditional linear poly（ethylene terephthalate）（PET） resins of relatively low molecular mass and narrow molecular mass distribution have low melt strength at foaming temperatures, which are not enough to support and keep cells. An in-situ polymerization-modification process with esterification and polycondensation stages was performed in a 2 L batch stirred reactor using pyromellitic dianhydride（PMDA） or pentaerythritol（PENTA） as modifying monomers to obtain PETs with high melt strength. The influence of amounts of modifying monomers on the properties of modified PET was investigated. It was found that the selected modifying monomers could effectively introduce branched structures into the modified PETs and improve their melt strength. With increasing the amount of the modifying monomer, the melt strength of the modified PET increased. But when the amount of PENTA reached 0.35% or PMDA reached 0.9%, crosslinking phenomenon was observed in the modified PET. Supercritical carbon dioxide（ScCO2） was employed as physical foaming agent to evaluate the foaming ability of modified PETs. The modified PETs had good foaming properties at 14 MPa of CO2 pressure with foaming temperature ranging from 265 °C to 280 °C. SEM micrographs demonstrated that both modified PET foams had homogeneous cellular structures, with cell diameter ranging from 35 μm to 49 μm for PENTA modified PETs and 38 μm to 57 μm for PMDA modified ones. Correspondingly, the cell density had a range of 3.5×107cells·cm 3to 7×106 cells·cm 3for the former and 2.8×107cells·cm 3to 5.8×106cells·cm 3for the latter.     

生物降解树脂PBAT的共混改性研究进展

聚己二酸对苯二甲酸丁二酯(PBAT)是一种新型的完全生物降解脂肪-芳香族共聚酯。与其它聚合物进行共混改性是改善PBAT基材综合性能的有效手段。本报告从PBAT的性能特点和应用出发,综述了近年来PBAT与可降解聚合物、天然高分子、非降解聚合物、无机粒子等进行熔融共混改性的研究进展;并对PBAT将来的发展作了展望。     

阳极氧化参数对TiO2薄膜结晶行为影响的研究进展

阳极氧化技术制备的功能性TiO2薄膜材料因其良好的耐腐蚀性、光催化活性及生物相容性,被广泛应用于腐蚀防护、光催化、太阳能电池及生物工程等领域。钛表面阳极氧化膜的应用性能与其结构密切相关,相较于无定形结构的TiO2,结晶的TiO2具有更高的光催化活性和更好的生物相容性。本文综述了氧化电位、电解液、氧化方式及时间等阳极氧化参数对钛表面氧化物薄膜结晶行为的影响,并分别讨论了各种因素对TiO2结晶的影响机理。在钛阳极氧化过程中,氧化电位的增加、温度的升高、氧化时间的延长以及电解液浓度的增加都有利于TiO2薄膜的结晶,而杂质离子的侵入及氧化膜生长速率的提高则不利于钛氧化物的结晶。