Study on wear,cutting and chipping behaviors of hydrogenated nitrile butadiene rubber reinforced by carbon black and in‐situ prepared zinc dimethacrylate

In this study, the wear (Akron and DIN) and the cutting and chipping (C&C) behaviors of hydrogenated nitrile butadiene rubber (HNBR) reinforced by carbon black (N115) and in‐situ prepared zinc dimethacrylate (ZDMA) were investigated. It was validated that ZDMA was more effective than N115 to enhance the wear and C&C resistance of HNBR composites. The Akron wear resistance of the HNBR/N115 composites increased with the content of ZDMA, and the Schallamach ridges observed on the abraded surfaces became less and less clear. With increasing content of ZDMA, the failure mode of the DIN abraded surface underwent the transition from craters to Schallamach ridges, and finally to scratches. The HNBR/N115 composite reinforced by 10 phr ZDMA had the best DIN wear resistance when Schallamach ridges were the dominant failure mode. The use of 30 phr ZDMA can dramatically enhance the C&C resistance of the HNBR/N115 composites. The C&C resistance was suggested to be related to both the variation of the morphology of the C&C ridges and the direction of crack propagation as a function of the content of ZDMA. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Amino functionalization of multiwalled carbon nanotubes by gamma ray irradiation and its epoxy composites

In this paper, γ‐ray radiation technique was utilized to simply functionalize multi‐walled carbon nanotube (MWCNT) with amino groups. The successful amino functionalization of MWCNTs (MWCNTs‐Am) was proven and the physicochemical properties of MWCNTs before and after radiation grafting modifications were characterized using FT‐IR, X‐ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The results indicated that the γ‐ray radiation had the visible effects on the surface properties of MWCNTs. The effects of various functionalized MWCNTs on morphological, thermal, and mechanical properties of an epoxy‐based nanocomposite system were investigated. Utilizing in situ polymerization, 1 wt% loading of MWCNT was used to prepare epoxy‐based nanocomposites. Compared to the neat epoxy system, nanocomposites prepared with MWCNT‐Am showed 13.0% increase in tensile strength, 20.0% increase in tensile modulus, and 24.1% increase in thermal decomposition temperature. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers     

Tertiary‐amine‐free,non‐planar,sulfone‐containing,tetrafunctional epoxy and its application as a high temperature matrix

Non‐amine‐derived tetrafunctional epoxies have several advantages over the amine‐derived N,N,N′,N′‐tetraglycidyl‐4,4′‐diaminodiphenyl methane (TGDDM) in high temperature applications. Although two non‐amine‐derived tetrafunctional epoxies were developed in our laboratory, further improvements in toughness using less loading amount is still desirable. Thus, a tertiary‐amine‐free, non‐planar and triphenylmethane‐containing tetrafunctional epoxy (STFE) with a sulfone spacer was synthesized. When it was mixed with diglycidyl ether of bisphenol A (DGEBA) and cured with 4,4′‐diaminodiphenylsulfone (DDS), both thermal and mechanical performances outperformed TGDDM. Moreover, STFE modified system shows the highest toughness (35.7 kJ m^–2) among three amine‐free and triphenylmethane‐containing epoxies at merely 5 wt% loading. Molecular simulation and thermomechanical analysis results suggest that the improved mechanical properties could be related to the geometry of the molecule and larger free volume. Despite a marginal drop in T_g, the thermal degradation temperature is better than that of TGDDM/DDS. In addition, the moisture resistance of STFE/DGEBA/DDS is much better than that of TGDDM/DDS. Thus, STFE modified DGEBA could be a potential replacement for TGDDM in some high temperature applications. © 2020 Society of Chemical Industry     

质子化氮化碳的制备及其复合材料的光催化性能

分别采用硫酸、盐酸和硝酸对尿素热解得到的体相块状石墨相氮化碳(g-C_3N_4)进行质子化改性,超声剥离得到氮化碳纳米片,考察3种质子化氮化碳纳米片对亚甲基蓝染料的光催化降解性能,利用XRD、FT-IR、SEM、BET、UV-DRS、UV-VIS等对其结构、形貌、比表面积、禁带宽度进行分析。结果表明,硫酸改性后的g-C_3N_4比表面积最大(60. 9 m~2·g~(-1)),亚甲基蓝降解效果最好,降解率为46. 7%,相比于体相块状g-C_3N_4的29. 2%提高了17. 5个百分点。以硫酸质子化改性的g-C_3N_4为前驱体,采用搅拌法制备得到质子化g-C_3N_4/石墨烯复合材料,其光催化降解亚甲基蓝的降解率为81. 7%,较硫酸质子化g-C_3N_4提高了35. 0个百分点。     

OMS-2催化剂成型工艺研究及其在印染废水处理中的应用

以OMS-2粉体催化剂为基础,对催化剂进行挤出成型,考察粘结剂种类、粘结剂用量、润滑剂和孔结构改进剂用量、焙烧温度对成型催化剂机械强度的影响。得到最佳成型工艺条件为,粘结剂硅溶胶用量为OMS-2粉体催化剂质量的105%～110%、辅助粘结剂纳米ZrO_2用量为OMS-2粉体催化剂质量的30%～35%、润滑剂田菁粉用量为OMS-2粉体催化剂质量的2. 5%～3. 0%、孔结构改进剂柠檬酸用量为OMS-2粉体催化剂质量的5%～6%,焙烧温度450℃。成型后催化剂机械强度可达150 N·cm~(-1),满足工业化应用对催化剂强度的要求。将成型催化剂应用于催化湿式氧化印染废水处理,经过432 h活性评价时间,COD平均去除率约91. 6%,反应结束后催化剂结构完整,平均机械强度约144 N·cm~(-1),表现出良好的水热稳定性。     

基于斯特林制冷机的文物恒湿展柜设计及实验研究

博物馆文物保存过程中相对湿度对文物的影响尤其重要,因此针对目前小型展柜广泛采用的半导体制冷存在制冷量小的缺点,结合斯特林制冷机制冷量大、寿命长、安全可靠等优点,设计并搭建了一台基于斯特林制冷的文物恒湿展柜装置,实现对微环境中相对湿度的精确调节。将斯特林制冷机的冷头置于优化设计的水槽中用于控制水温,采用空气与水直接接触的方式控制展柜内空气湿度。结果表明：使用散热片以及小型循环水泵可以大幅提升冷头与水之间的换热效率;合理的风机控制策略可以有效提升展柜湿度调节速度,维持湿度稳定,降低系统能耗;展柜内的相对湿度在45.0%～65.0%之间连续可调,并能保持稳定。     

基于计算机的镀液温度智能控制系统设计

为提高镀液温度的控制精度,以计算机为平台设计了一种镀液温度智能控制系统。设计了一种模糊PID温度控制器,可实现PID控制器参数的实时在线调整。利用动态矩阵,统计过去和当前时刻的偏差,预测未来偏差,进而得到最佳输入。最后,进行了实验研究。结果表明:镀液温度智能控制系统的收敛速率快、精度高、稳定性好,能满足电镀行业的需求,具有广阔的应用前景。     

Study on surface magnetization recover ilmenite from titanaugite using surfactant sodium oleate

ABSTRACT

Separation of ilmenite from titanaugite was investigated by magnetic coating. By enlarging magnetic difference between ilmenite and titanaugite, ilmenite was efficiently recovered. Scanning electron microscope and vibrating sample magnetometer results indicated that magnetite selectively coated onto ilmenite surface and increased its magnetism, which resulted in different magnetic separation behavior between ilmenite and titanaugite. FTIR and contact angle measurements confirmed that the adsorption difference of sodium oleate resulted in a stronger hydrophobicity on magnetite and ilmenite than titanaugite. Interaction energy analysis illustrated that hydrophobic association interaction on ilmenite was stronger than that on titanaugite, and which led to the selective coating of magnetite onto ilmenite.     

硫酸盐腐蚀对混凝土微观结构特征的影响研究

为了研究硫酸盐溶液侵蚀作用对混凝土微观结构的损伤规律,对试样进行0次、10次、20次、30次和50次硫酸盐溶液的腐蚀试验,获取了试样外观破坏特征、质量变化曲线、矿物成分、微观形态以及核磁共振T2分布曲线与NMRI图像,在此基础上分析了混凝土腐蚀损伤的微观机理.研究结果表明,随着硫酸盐腐蚀次数的增加,混凝土的质量损失率呈幂指数函数上升规律,材料外观破坏程度逐渐增加;对混凝土微观结构进行SEM和XRD分析,发现硫酸盐腐蚀作用使得钙矾石晶体的含量随腐蚀次数增加而上升;由T2分布谱线的变化趋势表明硫酸盐腐蚀作用使得材料内部小孔隙、中孔隙逐渐扩张成相互连通裂隙;不同损伤程度的混凝土NMRI扫描图像与T2分布曲线变化规律较为同步,说明扫描结果较为准确地反应了试样内部结构;硫酸盐溶液的化学腐蚀与渗透力是导致混凝土微观结构损伤的内在机理.