环氧树脂/纳米介孔分子筛复合材料的制备及性能研究

通过溶液共混法制备出环氧树脂（EP）／纳米介孔分子筛MCM-41（with template）（以下简称MCM-41）复合材料。研究了不同的MCM-41粒子含量对其在EP中的分散性和EP／MCM-41复合材料拉伸性能的影响。结果表明,这种具有独特的有机-无机复合结构的MCM-41直接用作填料时,能与EP形成新型网络复合结构,当MCM-41粒子的用量为1．5～2．5份时,它能均匀地分散在EP基体中,有效地提高EP／MCM-41复合材料的拉伸性能。     

介孔分子筛的添加对PE基复合材料性能的影响

用熔融共混法制备出聚乙烯基纳米复合材料.研究了填充介孔分子筛MCM-41(带模板和无模板)颗粒以及不同的填充颗粒含量对复合材料拉伸性能的影响.结果表明,这种具有独特有机-无机复合结构的纳米介孔分子筛MCM-41(带模板)直接作填料,能与基体形成新型网络复合结构.因此,在MCM-41(带模板)的质量分数为2.5%时,复合材料的拉伸强度达到最大值,比基体树脂提高43.5%,弹性模量提高了50%;用MCM-41(无模板)作填料,在其质量分数为2.5%时,复合材料的拉伸强度达到最大值,比基体树脂提高52%,弹性模量提高了106%.     

无机粒子的有机高分子化及其对PVC填充改性的研究

本文研究了几种无机 有机复合粒子与聚氯乙烯共混复合材料力学性能的变化规律。结果表明 :SiO2 /HPMC PMMA(SiO2 经SDS预处理 )和HPMC g PMMA使材料力学性能下降 ,而SiO2 /HPMC PMMA(未经SDS处理 )、TiO2 /HPMC PMMA、ZnO/HPMC PMMA复合粒子使材料的力学性能有所提高。经柔性设计后的SiO2 /HPMC PBA/PMMA和ZnO/HPMC PBA/PMMA使材料的冲击强度提高的幅度更大。SEM提供的证据也表明 :ZnO复合粒子使材料出现较好的塑性变形 ;经柔性设计的SiO2 复合粒子比未经柔性设计的SiO2 复合粒子使材料的塑性变形也更加显著     

包覆型Hβ和MCM-41复合分子筛作载体制备Pt加氢脱硫催化剂的研究

以Hβ为内核、十六烷基三甲基溴化铵为模板剂、偏硅酸钠为硅源,采用附晶生长法在Hβ表面包覆了一层MCM-41介孔相。分别以Hβ、MCM-41、包覆型复合分子筛(βM)以及Hβ和MCM-41机械混合物(β+M)作载体,采用等体积浸渍法制备了Pt催化剂。以二苯并噻吩(DBT)为模型含硫化合物,考察了催化剂的加氢脱硫(HDS)反应性能。结果表明,引入酸性Hβ载体不同程度地提高了催化剂的HDS活性,但也加剧了HDS产物的裂化反应。Pt/βM的HDS活性与Pt/Hβ接近,显著高于Pt/MCM-41和Pt/β+M。DBT在Pt/MCM-41上以直接脱硫路径为主,且不发生裂化反应。Pt/βM兼具很高的HDS活性和较低的裂化选择性,同时预加氢路径选择性也有所提高,说明包覆型βM复合分子筛是一种潜在的优异深度HDS催化剂载体。     

不同孔径介孔分子筛MCM-41的合成及载药释药性能

通过添加辅助剂1,3,5-三甲基苯合成不同孔径的介孔分子筛(mesoporous molecular sieves,MCM-41)。将利尿性氢氯噻嗪引入到MCM-41的孔道内,采用低温N2吸附-脱附、X射线衍射、Fourier红外光谱仪、热重分析等表征MCM-41材料,并测定了氢氯噻嗪在模拟体液中的释放率。结果表明:合成的MCM-41具有均一的介孔结构,孔径在4.0～5.6nm,氢氯噻嗪在MCM-41-B(具有最大的孔径)中的释放速率较快,10h释放了79%,其他材料的需20h,而且氢氯噻嗪的释放速率随着孔径的增加而减小,表明已制得了氢氯噻嗪的缓释体系,并且可以通过控制孔径来调节氢氯噻嗪的释放速率。     

细乳液聚合法TiO_2/PMMA纳米复合粒子的制备及其性能

采用细乳液聚合法制备了二氧化钛/聚甲基丙烯酸甲酯(TiO2/PMMA)纳米复合粒子,研究了引发剂、助乳化剂、乳化剂、单体结构对TiO2/PMMA纳米复合粒子性能的影响。结果表明,十六烷(HD)比十二醇和十六醇更能有效抑制甲基丙烯酸甲酯(MMA)液滴在水相中的Ostwald熟化效应,当MMA占TiO2质量的60%,HD占单体质量的6%,可聚合乳化剂1-烯丙氧基-3-(4-壬基苯酚)-2-丙醇聚氧乙烯(10)醚硫酸铵(DNS-86)占整个体系质量的2%时,制备TiO2/PMMA纳米复合粒子分散体的粒径为185 nm,此时TiO2/PMMA纳米复合粒子与细乳液粒径差距较小;采用TiO2/PMMA纳米复合粒子制备喷墨印花用白色涂料墨水的稳定性和遮盖力明显优于同等条件下TiO2所制备的涂料墨水。     

丙烯酸(AA)-丙烯酰胺(AM)-MCM-41复合高强度吸水性树脂的合成与性能

以丙烯酸(AA),丙烯酰胺(AM)和MCM-41为原料,用反相悬浮聚合法合成了AA-AM-MCM-41复合高吸水性树脂。研究了添加有MCM-41的复合高吸水性树脂合成中分子筛的添加量、单体组成比(AA/AM)、中和度、引发剂用量、交联剂用量等影响树脂性能的主要因素。结果表明,用反相悬浮聚合法合成的AA-AM-MCM-41复合高吸水性树脂后处理容易,树脂的吸水率可达1355 g/g,吸盐率可达82 g/g,凝胶强度为3859 N/Kg,比不添加MCM-41分子筛的吸水树脂提高了2倍左右。用IR研究了复合高吸水性树脂的表面和结构,IR初步表明MCM-41与丙烯酸、丙烯酰胺产生了交联。TGA图表明复合高吸水性树脂具有较好的高温保水性。     

介孔MCM-41对聚丙烯力学性能的影响

将纳米介孔MCM-41配制成悬浮液,采用熔融共混方法将其与聚丙烯共混,制备出综合力学性能较好的PP/MCM-41复合材料.透射电子显微镜(TEM)观测结果显示,MCM-41在悬浮液中呈纳米尺寸分散,无团聚现象;力学测试结果显示,当MCM-41的添加量为0.5%(质量分数)时,复合材料的拉伸、冲击、弯曲综合力学均较纯PP有所提高.     

基于细乳液聚合法TiO2/PMMA纳米复合粒子的制备及其性能

采用细乳液聚合法制备了二氧化钛/聚甲基丙烯酸甲酯（TiO2/PMMA）纳米复合粒子,考察了引发剂、助乳化剂、乳化剂、单体结构和种类对TiO2/PMMA纳米复合粒子性能的影响。结果表明与十二醇和十六醇相比,十六烷（HD）更能抑制甲基丙烯酸甲酯（MMA）液滴的Ostwald熟化效应,当MMA占TiO2质量分数的60%,HD对单体质量分数的6%,可聚合乳化剂1-烯丙氧基-3-(4-壬基苯酚)-2-丙醇聚氧乙烯(10)醚硫酸铵（DNS-86）占整个体系的质量分数为2%时,制备TiO2/PMMA纳米复合粒子分散体的粒径为185nm,此时TiO2/PMMA纳米复合粒子与细乳液粒径差距较小;采用TiO2/PMMA纳米复合粒子制备白色涂料墨水的稳定性和遮盖力明显优于同等条件下TiO2所制备的涂料墨水。     

分子筛固载型Cosalen的制备、表征及其应用研究

分别采用NaY分子筛、γ-氨丙基三乙氧基硅烷修饰的MCM-41分子筛固载双水杨醛缩乙二胺合钴(Cosahn)配合物,制备了固载型Cosahn/NaY、Cosalen/MCM-41催化剂.采用傅里叶变换红外光谱、热重-差热、X射线衍射、比表面积测定等方法对固载型分子筛催化剂的结构进行表征.结果表明,Cosalen已成功地进入分子筛孔道内.在以氧气为氧源的环己烷氧化反应中,Cosalen/MCM-41催化剂具有较好的活性和对环己醇、环己酮的选择性.该催化反应体系产物中环己基过氧化氢(CHHP)的量很少,表明Cosalen/MCM-41催化剂能加速CHHP的分解.在初始氧气压力0.80 MPa、温度130℃、环己烷用量30 g、Cosalen/MCM-41用量0.30 g、叔丁基过氧化氢0.10 g的条件下反应2 h,环己烷的转化率达到5.96%,醇酮选择性87.03%.     

Study on performance of composite polymer films doped with modified molecular sieve for lithium-ion batteries

To improve the tensile strength and ionic conductivity of composite polymer films for lithium-ion batteries, molecular sieves of MCM-41 modified with sulfated zirconia (SO₄²⁻/ZrO₂, SZ), denoted as MCM-41/SZ, were doped into a poly(vinylidene fluoride) (PVdF) matrix to fabricate MCM-41/SZ composite polymer films, denoted as MCM-41/SZ films. Examination by transmission electron microscope (TEM) shows that modified molecular sieves have lower aggregation and a more porous structure. Tensile strength tests were carried out to investigate the mechanical performance of MCM-41/SZ films, and then the electrochemical performance of batteries with MCM-41/SZ films as separators was tested. The results show that the tensile strength (σ_t) of MCM-41/SZ film was up to 7.8 MPa; the ionic conductivity of MCM-41/SZ film was close to 10⁻³ S cm⁻¹ at room temperature; and the coulombic efficiency of the assembled lithium-ion battery was 92% at the first cycle and reached as high as 99.99% after the 20th cycle. Meanwhile, the charge-discharge voltage plateau of the lithium-ion battery presented a stable state. Therefore, MCM-41/SZ films are a good choice as separators for lithium-ion batteries due to their high tensile strength and ionic conductivity.     

A novel self-assembly approach to form tubular poly(diphenylamine) inside the mesoporous silica

MCM-41 materials were synthesized using alkyl(decosane, dodecyl)trimethyl ammonium bromide as structure directing surfactants. X-ray diffraction (XRD) analysis and nitrogen adsorption measurements reveal that the pores are hexagonal with tunable textural properties through the choice of surfactant and experimental condition. Poly(diphenylamine), PDPA was entrapped into the pores of MCM-41 by initial sorption of diphenylamine (DPA, monomer) in a medium (napthalein sulfonic acid) that provides self-assembling of DPA inside the pores and subsequent oxidative of polymerization with peroxydisulphate. Clear presence of an additional peak (around 9-10°) in XRD pattern for the DPA loaded MCM-41 provides evidence for self-assembled structure. Upon polymerization the self-assembly of DPA molecules resulted tubular PDPA inside the pores of MCM-41. PDPA thus formed shows different electronic property than the PDPA prepared by conventional method. XRD and FTIR spectroscopic analysis of PDPA loaded MCM-41 clearly informs that PDPA are entrapped in channels of MCM-41.     

The synergistic cooperation between MCM-41 and azithromycin: a pH responsive system for drug adsorption and release

The capability of MCM-41 silica for accepting and delivering poorly soluble azithromycin (AZT) in water is reported as robust drug delivery system. This property has been evidenced by using two MCM-41 samples with different pore sizes as hosts of AZT. The choice of this macrolide antibiotic is due not only to its low bioavailability but also to its molecular size which lies in the range of pore diameter of MCM-41s. The drug was loaded inside the pore voids of the mesoporous when MCM-41 was stirred at AZT solution, based on XRD, Nitrogen adsorption–desorption isotherms, TGA analysis data and FT-IR spectroscopy. The amount of AZT stored inside the pores of MCM-41 s was between 22 and 25 wt%. The loaded drug was released in different rates from the particles by changing the pH (1.7 and 7.4) to give a smart pH-responsive carrier system. The drug release kinetics was fitted to Korsmeyer–Peppas and Higuchi models which indicated that the rate of drug release was controlled by the diffusion of the drug. The result of the present study confirms that the controlled adsorption and liberation of AZT may improve the oral bioavailability of poor water soluble AZT. This study demonstrates the feasibility of designing reliable drug delivery systems by appropriate choice of the matrix and the organic molecule. In general, MCM-41 is a promising matrix for AZT adsorption with different application from drug delivery to wastewater filtration.     

Characterisation and catalytic properties of MCM-41 and Pd/MCM-41 materials

Pure silica MCM-41 mesoporous molecular sieve material was synthesised and characterised by in situ synchrotron XRD, TEM, TGA/DTA and DRIFTS techniques. In situ energy dispersive XRD (EDXRD) confirmed the exact nature of the pore diameter of MCM-41 and the change in crystal structure on calcination. The IR band at 1057 cm^-1 of as-synthesised MCM-41 was shifted by 14 cm^-1 on heating to 673 K due to increased condensation of silanol groups to form Si-O-Si bridges. Calcined MCM-41 materials were used to support Pd, and the catalytic activities for 1-hexene and benzene selective hydrogenation were investigated. The Pd/MCM-41 catalyst showed high activity in hydrogenation of 1-hexene at an inlet reaction temperature of 298 K, but did not show any activity in hydrogenation for benzene. TEM results for the reduced Pd/MCM-41 catalysts revealed that the average Pd particle size was around 2-2.5 nm and these particles were located in the pores of MCM-41 and showed good distribution. TPR measurements showed that about 70% of palladium oxide (PdO) loading in the calcined catalysts was reduced at sub-ambient temperature. This revised version was published online in July 2006 with corrections to the Cover Date.     

MCM-41的孔径和添加量对环氧树脂力学性能的影响

以1,3,5三甲苯(TMB)为扩孔剂,水热合成了5种不同孔径(2.7～5.9 nm)的介孔二氧化硅MCM-41粉体,采用溶液共混法制备了MCM-41环氧树脂复合材料,研究了MCM-41孔径和添加质量对复合材料力学性能的影响。结果表明,添加1%最大孔径的MCM-41时,复合材料的力学性能达到最佳,拉伸强度、弯曲强度、弯曲模量分别比纯环氧树脂提高了54.6%、30.1%、68.3%。     

Exploring suitable ZSM-5/MCM-41 zeolites for catalytic cracking of n-dodecane: Effect of initial particle size and Si/Al ratio

In this study, various ZSM-5/MCM-41 micro/mesoporous zeolite composites have been prepared by alkalidesilication and surfactant-directed recrystallization of ZSM-5. The effects of particle size and Si/Al ratio of initial ZSM-5 zeolites on the structure and catalytic performance of ZSM-5/MCM-41 composites are studied. The results of XRD, TEM N₂-adsorption-desorption, NH₃-TPD and in situ FT-IR revealed that ordered hexagonal MCM-41 mesopores with 3-4 nm pore size were formed around ZSM-5 crystals, and the specific surface area and mesopore volume of composites increased with increasing the Si/Al ratio of initial ZSM-5. Catalytic cracking of n-dodecane (550 ℃, 4 MPa) showed that the ZSM-5/MCM-41 composites obtained from the high Si/Al ratio and nano-sized initial ZSM-5 zeolites exhibited superior catalytic performance, with the improvement higher than 87% in the catalytic activities and 21% in the deactivation rate compared with untreated zeolites. This could be ascribed to their suitable pore structure, which enhanced the diffusion of reactant molecules in pores of catalysts.     

MCM-41介孔材料的合成条件和特性对吸附镉离子的影响

以气相氧化硅为硅源,十六烷基三甲基溴化铵(cetyl trimethyl ammonium bromide,CTAB)为模板剂,分别在碱性[氢氧化钠(NaOH),四乙基氢氧化铵,tetraethyl ammonium hydroxide,(C2Hs)4NOH(TEAOH)]和酸性介质条件[盐酸(HCl)]T水热合成了MCM-41有序介孔材料MCM-41-N,MCM-41-T和MCM-41-H.用X射线衍射、氮气吸附-脱附等手段对比分析了合成的3种MCM-41介孔材料的物相、比表面积、孔径、孔体积等,发现酸性介质中合成的介孔材料的孔径最大.在此基础上,利用MCM-41介孔材料对比研究了处理含镉离子(Cd2 )废水的效果和机理,确定了不同介孔材料用量、不同初始pH值条件下MCM-41介孔材料对水中Cd2 的吸附率和吸附量.结果表明:介孔材料用量相同时,溶液pH值的增大有利于提高3种MCM-41介孔材料对水中Cd2 的处理效果.在pH值从7.0到8.0的过程中,其吸附率有1个突变,MCM-41-T的Cd2 吸附率从35.65%提高到62.15%;MCM-41-N的从38.80%提高到69.40%;MCM-41-H的从50.22%提高到73.47%.孔径最大的MCM-41-H对Cd2 的吸附效果最佳,最大吸附率为89.56%,最大吸附容量为8.57 mg/g.吸附溶液pH值的大小和介孔材料的孔径尺寸是决定吸附量大小的关键因素,因此,重点应通过优化合成工艺提高介孔材料的孔径.     

聚噻吩/MCM-41的合成与表征

文章以FeCl3为氧化剂,采用原位化学聚合的方法制备了聚噻吩/MCM-41新型复合材料,并对其结构和性能进行了表征。结果表明:小角X射线衍射和氮气吸附与脱附说明复合材料具有规则的介孔结构并且孔径明显小于分子筛MCM-41的孔径,红外光谱分析进一步证明PT进入了MCM-41的介孔孔道内,热重分析表明,聚噻吩进入孔道之后热稳定性得到了提高。