磁性四氧化三铁纳米粒子的超声波辅助水热合成及表征

以六水三氯化铁、四水二氯化铁和氨水为原料，在超声波辅助下，水热法制备了磁性四氧化三铁纳米粒子。借助X射线衍射仪（XRD）、透射电镜（TEM）及振动样品磁强计（VSM）对产物四氧化三铁进行分析。结果表明，当反应物三价铁离子与二价铁离子物质的量比为1．75，pH为13，控制水热合成温度在140～160℃、水热处理时间在3～5h时，可制备出纯相的反尖晶石结构的四氧化三铁纳米微粒。随着水热合成温度的升高和时间的延长，晶体发育更完整，平均粒径增大。磁性测量表明，饱和磁化强度和矫顽力也随着四氧化三铁纳米微粒平均粒径的增大而增大，控制水热合成温度140～150℃、水热处理时间4h能够制备出平均粒径小于20nm、具有超顺磁性的四氧化三铁纳米微粒。     

纳米SiO2-x改性PP／云母复合材料的研究

采用纳米SiO2-x（0≤x≤0．5）对PP／云母复合材料进行改性，系统地研究了纳米SiO2-x（0≤x≤0．5），对pp／云母综合性能的影响，确定了工业配方并且已应用于生产。结果表明：当纳米SiO2-x（0≤x≤0．5）用量为1％，云母用量为30％时的复合材料的缺口冲击达到了9．6kJ／m^2，维卡软化点达到了110℃，比纯PP（5．50kJ／m^2，86℃）和30％PP／云母复合材料（6．20kJ／m^2，109℃）均有了较大的提高。     

A Study on the Friction and Wear Behavior of PTFE Filled with Acid Treated Nano‐Attapulgite

Summary: A solid lubricant composite material was prepared by compression molding PTFE and acid treated nano‐attapulgite. The friction and wear tests were performed on a block‐on‐ring wear tester. Scanning electron microscopy (SEM), energy‐dispersive X‐ray spectrometer (EDS) and DSC were utilized to investigate material microstructures and examine modes of failure. Experimental results showed that there was no significant change in coefficient of friction, but the wear rate of the PTFE composite was orders of magnitude less than that of pure PTFE. Acid treated nano‐attapulgite was superior to untreated nano‐attapulgite in enhancing the wear resistance of PTFE. Moreover, the wear resistance of the composite increased monotonically with increasing treated attapulgite concentration. Investigation of transfer film and analysis of debris for PTFE and its composite showed that acid treated nano‐attapulgite filled to PTFE could facilitate formation of transfer film on the steel ring surface and inhibit breakage of PTFE molecular chain. The PTFE composite with higher heat absorption capacity exhibited improved wear resistance. Furthermore, the steel ring counterface abrasion was not found.

Effect of load on the wear rate of PTFE and its composites.     

纳米TiO2的分散及在水性涂料中的应用研究

研究了各因素对纳米TiO2水悬浮液稳定性的影响,通过正交试验筛选出了最佳的分散工艺,解决了纳米TiO2在水性介质中的团聚问题.将分散后的纳米TiO2浆料加入到普通的水性苯丙乳液涂料中,加入各种助剂配制出了性能优异的水性纳米TiO2涂料,并对涂料的性能进行了测试.     

含纳米ATO聚氨酯弹性抗静电涂料

以脂肪族聚氨酯弹性树脂为基体，透明纳米ATO导电粉为导电介质，添加超分散剂，采用物理与化学相结合的分散方法对纳米ATO进行预处理。主要解决纳米粒子的分散与团聚的难题，制备出可常温固化、颜色可调的含纳米ATO聚氨酯弹性抗静电涂料。讨论了基体树脂、纳米ATO含量、超分散剂种类与加量、研磨时间以及助剂等因素对抗静电涂料的表面电阻、耐候性、弹性、强度以及稳定性等性能的影响。同时对涂料的性能进行了测试与表征。     

Preparation and characterization of calcium carbonate/low‐density‐polyethylene nanocomposites

Calcium carbonate/low‐density‐polyethylene (LDPE) nanocomposites have been prepared by melting blend with twin‐screw extruder. The mechanical properties of composites and the dispersion of the nanoparticles were studied. The reinforcement mechanism was discussed. The results show that not only the tensile property but also the flexural modulus of the system have been evidently increased by the addition of calcium carbonate. The calcium carbonate particles have been dispersed in the matrix in the nanometer scale. The reinforcement mechanism of the calcium carbonate lies on that the calcium carbonate particles, acting as hetero‐nuclei, can induce higher crystallinity at the matrix‐particle interface compared to regions away from the interface. Consequently, in the process of the tensile test, the nanocomposites have better tensile yield strength. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

纳米TiO2对铅镉离子的吸附性能研究

研究了纳米TiO2吸附和解吸附铅镉离子的条件。吸附条件为pH为7-8,超声波振荡3-5 min,解吸附条件为0．12 mol/LHCl进行洗脱,温度50℃,此时吸附率和解吸附率均高于98％。结果表明:吸附存在可逆吸附和不可逆吸附过程,吸附等温线类于朗格缪尔吸附,经线性回归计算出吸附方程、吸附平衡常数、最大吸附容量;不可逆吸附容量与纳米TiO2 表面氧原子有关;可逆吸附与表面羟基有关,而两者均受晶体结构影响,比表面积不是影响吸附容量大小的主要因素。在试验的基础上推断了两种吸附过程的模型。     

撞击流制备高纯纳米氢氧化镁技术研究

采用撞击流反应结晶方法，以青海盐湖水氯镁石为原料，制备了高纯纳米氢氧化镁。研究了各种操作条件对氢氧化镁纯度的影响，并确定了控制因素。并采用X射线衍射（XRD）、透射电镜（TEM）对颗粒形态进行表征。结果表明：可以制备出纯度大于99％、平均粒径为13．5nm的氢氧化镁。适宜条件：镁离子浓度0．25mol／L，镁离子与氢氧根浓度比1：2，反应温度40℃，搅拌时间30min，搅拌转速400r／min，撞击流率100mL／min。     

纳米材料复合改性阻燃聚丙烯的研究进展

综述了近年来纳米无机阻燃剂及其复合阻燃体系对聚丙烯的阻燃性能研究进展。重点介绍了氢氧化铝、氢氧化镁和蒙脱土及其复合卤系、磷系、膨胀型阻燃剂对阻燃聚丙烯材料的阻燃性能及力学性能的影响。并指出纳米复合改性阻燃聚丙烯不仅能提高阻燃性能，还具有增强、增韧作用，是实现阻燃聚丙烯高性能化及低成本的一个重要方向。     

纳米SiO_2改性外墙涂料的研究

介绍了纳米材料改性高性能建筑外墙涂料的配方及研制,着重讨论了纳米SiO2添加量对涂料性能的影响:掺入4%的纳米SiO2能明显改善涂膜的附着力、光泽度、耐水、耐碱、耐洗刷性和涂料的抗沾污性、触变性能、稳定性。