多元助剂改性羰基铁粉雷达波低频吸波性能研究

采用三种处理剂对羰基铁粉样品进行表面复合改性,研究了多元助剂对羰基铁粉样品表面改性后的微观结构及电磁参量的影响。结果表明,多元助剂的使用使羰基铁粉表面形成了一层致密的有机绝缘薄膜,能有效降低羰基铁粉的复介电常数,增加复磁导率虚部,提高吸波材料的电磁匹配性能,改善吸收剂的低频吸收效果。根据传输线理论计算吸波材料的反射损耗(Reflection loss,RL),在厚度为2mm时,三元助剂改性羰基铁粉的反射损耗峰值在2GHz附近达到-15dB,在RL-10dB的有效吸收频宽为1GHz(1.6~2.6GHz),具有较好的雷达波低频吸波性能。     

MgAlZnFeCe类水滑石水热合成、表征及其FCC硫转移性能的研究

分别以MgO为镁源,拟薄水铝石为铝源,以Zn、Fe、Ce的氯化盐为助剂,水热法合成了MgAlZnFeCe类水滑石前驱体,经过700℃焙烧6h后,制得新型FCC硫转移剂MgAlZnFeCe复合氧化物.运用XRD、TG-DTA等对硫转移剂及其前驱体的结构和物化性能进行了表征;在模拟FCC反应再生条件下,采用改装的WRP-3热重天平评价了硫转移剂的氧化吸硫和还原脱硫的性能.结果表明,采用水热法合成的前驱体材料具有典型的类水滑石结构,但MgO不能完全进入水滑石相,以Mg(OH)2的形式存在;类水滑石材料经过焙烧后得到复合氧化物MgAlZnFeCe-LDOs,在FCC再生烟气硫转移中具有良好的饱和吸附硫容量和氧化吸硫速率,10min可达到1.16g/g的饱和吸附能力,同时具有较强的还原脱硫能力.     

硫铝酸钙改性硅酸盐水泥应用研究进展

硫铝酸钙改性硅酸盐水泥熟料兼具硅酸盐水泥熟料和硫铝酸盐水泥熟料的优良性能,同时该种水泥熟料对粉煤灰等火山灰类材料具有超强的活性激发效果,这使得硫铝酸钙改性硅酸盐水泥具有广阔的应用前景。主要概括了硫铝酸盐改性硅酸盐水泥的性能及水化特性,综述了该种水泥与不同矿物掺合料的复合性能以及与化学外加剂的适应性,提出了硫铝酸钙改性硅酸盐水泥存在的问题及改善措施。     

丙三醇缩水甘油醚改性脱细胞猪真皮基质的研究

研究了丙三醇缩水甘油醚（GPE）改性脱细胞猪真皮基质材料（pADM）的基本性能．通过考察不同温度、pH值、用量和反应时间对改性材料（GPE-pADM）性能的影响，初步探讨了改性条件与改性材料性能之间的关系．实验结果表明：反应温度37～42℃，pH值10．0～10．5，反应时间48-72h，用量8％时综合性能较好．交联后材料的接触角明显降低，且随着GPE用量的增加，接触角降低程度增大，表明交联提高了材料的亲水性能．     

包装废聚丙烯复合改性沥青防水材料研究

利用回收的包装废弃聚丙烯、废胶粉代替普通聚合物改性剂，采用复合改性的技术方法，对普通沥青进行改性，提高基质沥青的防水性能。结果表明，改性后沥青的软化点、5℃延度提高，针入度降低，不透水性得到明显提高；不同混合比改性效果显示复合改性沥青综合性能优于单一改性剂直接改性。通过FT-IRF、微观结构分析，对复合改性沥青的高、低温性能，抗变形能力进行了研究，表明改性剂的溶胀及其与沥青形成的空间网络结构、银纹支化、应力剪切作用是产生改性效果的重要原因。     

PP/EPDM反应挤出共混制备高熔体黏度PP的研究

采用反应型双螺杆挤出机,用过氧化物(BPO)为交联剂、不饱和烯烃为交联助剂,对PP/EPDM体系进行反应增容,一步实现聚丙烯(PP)与少量EPDM的共混、接枝与交联,制备出了具有高熔体黏度的发泡用聚丙烯.对改性材料熔体流动性能、力学性能和发泡性能研究结果表明:当交联剂、交联助剂的质量比约为0.78 :1时,可以获得最佳的改性效果,改性后体系的熔体流动速率(MFR)下降92.9%;改性PP的多项力学性能都有显著改善,其中拉伸强度提高12.9%,缺口冲击强度提高93%;改性使材料的发泡性能得到显著提高,采用反应共混改性PP可获得泡孔大小约100μm,泡沫密度在0.44g/cm3左右,且分布均匀,闭孔率高的发泡材料.     

硫掺杂炭材料在钠离子电池负极中的研究进展

钠离子电池因资源丰富及成本低等优势，在大规模储能领域备受关注。炭材料作为钠离子电池实用化进程中的关键负极材料，具有高容量、低嵌钠平台、易调控且稳定性好等特点，引起了研究者的广泛关注。掺杂原子可改善炭材料的微观与电子结构，是提升储钠性能的有效途径。常见的杂原子包括N、S、O、P、B等，其中硫原子因其较大的半径能显著扩大层间距、增加缺陷与活性位点，被广泛用于炭负极材料的掺杂改性。本文综述了近年来硫掺杂炭材料的设计制备及在钠离子电池负极中的研究进展，分析了硫掺杂对碳结构的调控机理与改善电池性能的作用机制，最后针对目前面临的挑战和可能的解决方案进行了总结和展望，以期推动硫掺杂炭负极材料在钠离子电池中的实用化进程。     

包装废EPS改性沥青研究

以回收的包装废聚苯乙烯发泡塑料(EPS)代替普通聚合物改性剂,对基质沥青进行改性,并对改性后沥青性能进行了研究.结果表明,改性后沥青软化点、5℃延度升高,针入度降低,基质沥青综合性能得到明显改善,并通过实验结果以及改性沥青微观结构的分析对包装废EPS改性机理进行了研究.     

阻尼橡胶的改性研究

采用复合助剂Ａ作改性剂来改善阻尼橡胶的焦烧性能和溶解性能，研究结果表明，复合助剂Ａ的含量为０．６％时所改性的阻尼橡胶具有较好的焦烧性能，能溶解的时间提高了４倍，同时，其改性阻尼橡胶的吸声效果提高了５０５，改性阻尼橡胶的粘着强度有所下降，但能满足雷达的使用要求。     

环氧灌注材料的改性对比研究

采用聚氨酯、中空玻璃微球和纳米材料3种方式对环氧电子灌注材料进行了改性，研究了改性方式对密度、冲击韧性和压缩性能的影响。结果表明：中空玻璃微球改性对密度降低最大，比纯环氧降低了20％左右，密度达到近1.0g／cm^3，聚氨酯改性的冲击韧性最高，纳米材料改性能显著提高压缩性能。     

中空ZSM-5分子筛微球及其吸附与催化性能

首先利用聚乙二醇作为软模板合成出具有一定介孔结构的ZSM-5分子筛微球, 再通过快速可控碱刻蚀的方法, 成功制备出尺寸均一的中空分子筛微球。利用X射线衍射(XRD)、氮气吸附等温线分析(N₂ isotherm)、扫描和透射电子显微镜(SEM, TEM)对所制备的中空分子筛微球进行了表征, 并研究了中空分子筛微球对有机物废水的吸附性能和对大分子的催化裂解性能。结果表明, 刻蚀后分子筛结晶度略有下降, 但是介孔度和孔体积明显提升。中空分子筛微球外径在600 nm, 壳层厚度在100 nm左右。此外, 该中空结构不仅对苯等有机分子具有吸附富集作用, 其饱和吸附量几乎达到了常规分子筛微球的3倍, 并且六次循环使用后的吸附容量依然保持基本不变, 显示出较高的吸附容量和循环使用稳定性。在异丙苯和三异丙苯裂解反应中中空分子筛微球也显示出较高的催化活性。     

Synthesis of nano-sized NaY zeolite composite from metakaolin by ionothermal method with microwave assisted

Nano-sized NaY zeolite had been synthesized from metakaolin by ionothermal method with microwave assisted. Its structure had been characterized by XRD, SEM, HREM, and its physicochemical properties and catalytic characteristics were studied. The results showed that the size of the product was 150–250 nm, relative crystallinity 69.16%, Si/Al ratio 5.02. Compared with conventional NaY zeolite, nano-sized zeolite composite had larger surface area and mesopore volume, better thermal stability, higher cracking activity, higher gasoline selectivity, lower coke and gas selectivity. So it has good industry application prospects.     

络合剂对溶胶凝胶制备纳米铜及其催化性能影响

为研究络合剂对纳米铜粉体的制备及其催化性能的影响,分别以柠檬酸、葡萄糖为络合剂,采用溶胶-凝胶法制备纳米铜.考察了两种络合剂对制备过程以及产物结构的影响,通过催化苯氧化合成苯酚的反应考察制得的纳米铜粉的催化性能.研究表明:葡萄糖为络合剂制得的纳米铜(G-Cu)平均粒径较小(30 nm),比表面积为5.203 m2/g,在催化苯制苯酚反应时,具有较高的苯转化率(50.30%),但对苯酚的选择性较差;而柠檬酸为络合剂制得的纳米铜(C-Cu)平均粒径为55 nm,比表面积19.517 m2/g,催化苯转化率为21.95%,选择性为38.46%.此外,通过对溶胶凝胶法制备机理分析可知,在形成的胶体结构中,柠檬酸和葡萄糖中的羧基和羟基分别与铜离子进行配位.     

静态胀裂剂(SCA)的研究进展

根据收集的资料,介绍了一种在静态胀裂剂的基础上发展起来的特种破碎技术。就目前应用的静态胀裂剂,主要从破碎原理、配方组成及施工方法等方面进行了综述,评述了静态胀裂剂的研究进展和发展方向。     

静态胀裂剂(SCA)的研究进展

根据收集的资料,介绍了一种在静态胀裂剂的基础上发展起来的特种破碎技术。就目前应用的静态胀裂剂,主要从破碎原理、配方组成及施工方法等方面进行了综述,评述了静态胀裂剂的研究进展和发展方向。     

Catalytic conversion of waste particle board to bio-oil using nanoporous catalyst

The catalytic pyrolysis of waste wood including the particle board was examined by pyrolysis gas chromatography/mass spectrometry (Py-GC/MS) to produce bio-oil. Three different catalysts with a nanoporous structure, Al-MCM-48, Meso-MFI, and Pt-Meso-MFI, were used and their performances were compared. When MCM-48 was used, the quality of the bio-oil product was better than that prepared by non-catalytic pyrolysis but the improvement was limited due to its weak acid sites. On the other hand, Meso-MFI, which has both an MFI structure and strong acid sites, exhibited much better cracking ability and higher selectivity for aromatics. Moreover, Pt-impregnation on Meso-MFI resulted in an even higher selectivity for aromatics and phenolics, which are important raw materials in various petroleum chemical processes. Keywords: Catalytic Pyrolysis, Py-GC/MS, Waste Particle Board, AI-MCM-48, Meso-MFI,     

Efficient photocatalysis and sustainable degradation of methylene blue by titanium dioxide and zinc oxide supported on spent FCC catalyst

Journal of Materials Science: Materials in Electronics - Zinc oxide (ZnO) and titanium dioxide (TiO2) are loaded on the spent fluid catalytic cracking catalyst (FCC) via an impregnation method to...     

Study on the structural formation of new useful multiporous material ‘nano–meso ZSM-5’ and its application in producing biofuel

New ‘nano–meso ZSM-5’ (NM-ZSM-5) material was successfully synthesised by hydrothermal treatment using silica derived from rice husk. The synthesis of the material involves two steps of crystallisation, including the formation of ZSM-5 zeolite seed and mesoporous structure. The effect of crystallisation time on the formation of mesoporous structure was studied in the range 0–40?h. Samples were characterised by X-ray diffraction, infrared spectroscopy, transmission electron microscopy, Brunauer–Emmett–Teller and ²⁷Al-NMR methods. The results show that the best time for crystallisation is 14?h. The synthesised material has a multiporous structure, including micropore system of ZSM-5 zeolite, mesopore system of MCM-41 and another pore system which has a diameter in the range 10–50?nm (mesoporous system) due to the burning of organic compounds that remain in the material during the calcination process. In addition, the synthesised NM-ZSM-5 achieves crystallinity of approximately 100%. The catalytic performance of NM-ZSM-5 material was evaluated by the catalytic cracking reaction to produce biofuel from vegetable oil sludge. The research proved that NM-ZSM-5 is one of the most suitable catalysts for this process. The catalytic cracking reaction over NM-ZSM-5 yields products that are similar to those of the petroleum cracking process, such as dry gases, liquefied petroleum gas, gasoline, light cycle oil and heavy cycle oil.     

Numerical investigation of influence of treatment of the coke component on hydrodynamic and catalytic cracking reactions in an industrial riser

A three dimensional gas-solid reactive flow model based on the Eulerian-Eulerian approach was used to simulate the hydrodynamic, heat transfer and catalytic cracking reaction within in a conventional Fluid Catalytic cracking (FCC) riser. A 12-lump kinetic model was used to represent the catalytic cracking reaction network. It was proposed a catalyst deactivation model as a function of the weight percentage of coke amount on the catalyst to replace the deactivation model dependent of the residence time. It was compared the effects of novel treatment for coke component (coke produced in the solid phase) with common treatment (coke produced in the gas phase) on the fluid dynamic and catalytic cracking. The results showed that the treatment for coke component affects radial distribution of coke mass flow. It also showed that the treatment for coke plays an important role in simulation with catalyst deactivation as a function of coke amount on catalyst.     

Relationship between acidity and catalytic activity of high-silica zeolites in cracking

The catalytic activity of mordenite and pentasil-type zeolites in cracking of n-octane is correlated with their acidity, determined from the measurement of the adsorption heats using ammonia as the probe molecule. The method of regional analysis is applied to calculate the specific activity of the sites with different strength of acidity.