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.     

纳米凹凸棒土改性聚氨酯纤维的结构与性能

以物理共混的方法制备了纳米凹凸棒土(AT)/聚氨酯(PU)共混纤维。通过红外测试表明:AT与PU的硬段发生相互作用,增强了PU链段之间的氢键作用。动态力学性能分析的结果表明:AT可视作为物理交联点,限制了PU分子链的运动。相对于纯PU纤维,纳米AT/PU共混纤维的拉伸力学性能有了明显的提高,热稳定性能也有一定改善。     

原位乳液聚合制备聚苯乙烯丁二烯橡胶/凹凸棒石纳米复合材料

采用原位乳液聚合制备了聚苯乙烯丁二烯橡胶(SBR)/凹凸棒石(AT)纳米复合材料。凹凸棒石的存在一定程度上降低了乳液聚合速率,但对最终聚合产物的分子质量及分子质量分布影响不大。凹凸棒石以长0.5～5μm、直径为20～50nm的棒状纤维均匀的分散在SBR基体中。在硫化过程中,凹凸棒石纤维与橡胶形成互穿网络结构,增加了橡胶的交联密度。随着凹凸棒石的填充量增加,纳米复合材料的300%定伸应力和拉伸强度与纯SBR相比均提高了20%～100%,其补强效果明显高于等量的炭黑N330,还表现出良好的耐磨性能。     

改性凹凸棒土净化含铬废水的研究

将凹凸棒土进行改性处理，用于对含铬废水中铬离子的吸附。本文研究了改性方式、凹凸棒土用量、吸附时间、pH值对含铬废水中铬离子净化率的影响。     

凹凸棒石粘土悬浮液的悬浮性研究

研究了凹凸棒石粘土尺寸、悬浮液浓度、分散时间等因素对凹凸棒石粘土水和乙醇悬浮液悬浮性的影响,试验结果表明:凹凸棒石粘土水悬浮液的悬浮性显著高于乙醇悬浮液的悬浮性;水悬浮液中凹凸棒石粘土长度在38μm和71μm之间对悬浮性影响不大;使用50 W功率的超声波发生器分别分散10 min和15 min可以使凹凸棒石粘土分别在水和乙醇介质中充分分散;悬浮剂浓度为5 g/150 mL时水悬浮液的悬浮性最好。     

凹土/PVA多孔载体生物流化床的挂膜启动研究

通过聚乙烯醇(PVA)缩甲醛交联反应制备的凹土/PVA多孔载体,具有比表面积大、孔隙丰富、挂膜启动速度快、附着生物量大等特点,应用于生物流化床处理有机废水可取得较好的处理效果。20d挂膜启动试验表明,在凹土/PVA多孔载体投加量(堆积体积)为曝气区容积20%的条件下,模拟废水进水COD1000~3000 mg/l,进水COD负荷不超过8.7kg·m-3·d-1时,COD去除率可保持90%以上。对氨氮也有较高的去除能力,进水氨氮浓度100 mg/l以内,停留时间为12 h时,稳定运行时氨氮去除率可保持在90%以上。     

凹凸棒粘土对铸型涂料触变行为影响的研究

通过多种测试手段，分析了安微嘉山凹凸棒粘土的理化性能及内部结构，利用ＮＸＳ－１１型旋转粘度计测试分析了凹凸棒土悬浮液的触变性及触变机制，以及它对水基铸型涂料触变行为的影响，实验结果表明，在涂料中加入少量的凹凸棒粘土能使触变性大大改善。     

药用级凹凸棒黏土质量指标的初步研究

研究药用级凹凸棒黏土的质量标准。分析比较美国药典(USP)、英国药典(BP)和我国卫生部标准(MOH)中凹凸棒黏土的质量指标,按照美国药典规定的方法,用红外光谱(FT-IR)和X-射线衍射(XRD)对经自然沉降法纯化处理的盱眙凹土进行鉴别,并对其重金属含量、微生物限度、pH值、失重、粉末细度等指标进行检测。检测结果符合药典规定,检测方法简单易行,可用于药用级凹凸棒黏土质量的控制。     

Properties of Magnetic Nanoparticles about Doped Rare Earth and Its Composites

The magnetic liquid was prepared with ferric salt by inorganic gel technology. The effect of the doped rare earth elements on the properties of magnetic particles was analyzed. The magnetic liquid was composed with clay mineral into magnetic mineral composites. The crystal structure and micro-morphology of the nanoparticles were studied by XRD and TEM. The results show that the crystal structure of the magnetic particles doped 0.5 % of lanthanum is more complete, and the magnetic response capability is higher with doping agent. At the same time, the possibility of the clay mineral magnetic composites as the carrier of target drug was probed.     

烃链功能改性剂对三元乙丙橡胶/凹凸棒土复合材料性能的影响

采用机械共混法制备三元乙丙橡胶(EPDM)/凹凸棒土(AT)复合材料,考察了不同结构的烃链功能改性剂对复合材料硫化性能、力学性能和应力松弛行为及相结构的影响,探究3种烃链功能改性剂对凹凸棒土在复合材料中分散作用的机理。结果表明,改性剂锚固在AT表面并与EPDM有良好相容性,使AT在EPDM中有更好分散性。改性剂添加量为AT的1%时,对EPDM/AT复合材料的力学性能改善效果最明显,其中,以胺基为端基,相对分子质量为2000左右的改性剂使EPDM和AT两相的界面结合性最好,复合材料的拉伸强度提高了304.34%,综合性能提高最为显著。