PMAA/MMT及PMAA/MMT/SiO_2纳米复合材料的结构与性能研究

采用原位插层聚合法制备了聚甲基丙烯酸/蒙脱土(PMAA/MMT)纳米复合材料和聚甲基丙烯酸/蒙脱土/二氧化硅(PMAA/MMT/SiO2)纳米复合材料,并比较两种纳米复合材料的结构与性能。研究结果表明,PMAA/MMT纳米复合材料属于插层与剥离共存型纳米复合材料。PMAA/MMT/SiO2纳米复合材料中蒙脱土的特征衍射峰已经消失,蒙脱土与二氧化硅均匀分散在聚合物基体中。PMAA/MMT及PMAA/MMT/SiO2纳米复合材料均有一定的鞣制性能,但相对而言PMAA/MMT/SiO2纳米复合材料的鞣制效果较好。     

蒙脱土负载引发剂法制备PMAA/MMT纳米复合材料

将引发剂过硫酸钾(KPS)负载在MMT片层上制得负载型引发剂MMT-KPS-1和MMT-KPS-2.进而引发甲基丙烯酸(MAA)聚合制备聚甲基丙烯酸/蒙脱土(PMAA/MMT)纳米复合材料.采用X射线衍射(XRD)、热重分析(TG)、热分析(DTA)分别对负载引发剂和纳米复合材料进行表征.结果表明,KPS进入MMT的片层间,并且负载引发剂(MMT-KPS-1)的引发活性较KPS有所提高;所制备的PMAA/MMT纳米复合材料属于剥离型纳米复合材料,应用于皮革鞣制所得坯革的湿热稳定性、增厚率、抗张强度、撕裂强度都有所提高,鞣后浴液中铬含量显著降低.     

St-PMI-AN/蒙脱土纳米复合材料的制备与性能

采用乳液插层聚合的方法制备了苯乙烯（St）-N-苯基马来酰亚胺（PMI）-丙烯腈（AN）/蒙脱土纳米复合材料,并对复合材料的结构、热性能及力学性能进行了表征.结果表明,与蒙脱土插层复合后,复合材料的综合性能有很大提高.采用未经有机化处理的蒙脱土（MMT）制备St-PMI-AN/MMT纳米复合材料,制备工艺比采用有机化蒙脱土（OMMT）简单,而且得到的复合材料的综合性能与St-PMI-AN/OMMT相当,甚至其冲击强度略高.     

木质纤维素-g-丙烯酸/蒙脱土水凝胶制备及吸附性能研究

以原位插层共聚法合成木质纤维素接枝丙烯酸/蒙脱土三维网络水凝胶(LNC-g-AA/MMT),探讨了丙烯酸与木质纤维素的质量比、丙烯酸单体浓度、中和度、引发剂用量和交联剂用量等因素对三维网络水凝胶吸附亚甲基蓝性能的影响,吸附量高达1994.38mg/g,并对最佳条件下吸附饱和的LNC-g-AA/MMT进行解吸研究,脱附率高达83.4%。用XRD、TEM和TG等方法对三维网络水凝胶的形貌和结构进行了表征。结果表明,木质纤维素接枝丙烯酸三维网络水凝胶(LNC-g-AA)插层进入蒙脱土层间,蒙脱土结晶结构在反应过程中被破坏,形成剥离型纳米复合材料,LNC-g-AA/MMT的热稳定性较LNC-g-AA有所改善。     

原位插层聚合制备纳米复合材料及其在皮革鞣制中应用的研究

通过优化聚二烯丙基二甲基季铵盐（PDMDAAC）的合成工艺,选用二烯丙基二甲基季铵盐（DMDAAC）在不同用量的蒙脱土中原位插层聚合,制备了系列纳米复合材料（PDMDAAC／MMT）。通过单体转化率和聚合物的特性粘度考察不同用量的蒙脱土对单体插层聚合的影响;也进行了采用纳米复合材料应用于皮革预鞣,再用2％标准铬粉鞣制的试验初试。结果表明：蒙脱土的用量为5％时,蒙脱土的层间距、单体转化率、聚合物的特性粘度均达到最大值;蒙脱土用量为4％时,纳米复合材料对坯革的增强效果最明显;同时对坯革透水汽性的负面影响最大。     

固相法改性蒙脱土在聚氯乙烯中的应用

采用插层剂季磷盐和KH-560硅烷偶联剂对钠基蒙脱土进行固相法改性得到有机蒙脱土,并通过熔融插层法制备了聚氯乙烯(PVC)/有机蒙脱土(OMMT)纳米复合材料,通过哈克流变仪、X射线衍射(XRD)和透射电镜(TEM)测试对比了钠基蒙脱土(MMT)和OMMT增强PVC复合材料的结构和性能。研究发现,蒙脱土、季磷盐与KH-560质量份为100∶10∶4时改性效果最佳,OMMT最佳用量为3份,PVC/OMMT3的流变性能明显优于PVC/MMT3,且PVC/OMMT材料中有机蒙脱土的层间距较大、层片分散更均匀。     

取代度和改性MMT对纤维素基高吸水性纳米复合材料性能的影响

以麦秸秆为原料制备羧甲基纤维素(CMC),采用水溶性丙烯酸类单体对其接枝共聚,并添加不同有机季铵盐插层改性的蒙脱土(MMT),通过原位插层聚合制备CMC/丙烯酸类聚合物/OMMT高吸水性纳米复合材料。考察了碱和氯乙酸用量对CMC取代度和增重率的影响,探讨了CMC取代度与产物接枝率、接枝效率、吸水率之间的关系,分析了不同季铵盐改性MMT对材料性能的影响。通过红外光谱、X射线衍射等对纳米复合材料的结构进行表征,结果表明,在OMMT存在的条件下,CMC与丙烯酸类单体成功发生了接枝聚合;随着季铵阳离子碳链取代基的体积增大,改性蒙脱土的层间距越大;所制备的纳米复合材料属于剥离型纳米复合材料。     

MAA-AL/MMT纳米复合材料的制备

采用水溶性聚合单体甲基丙烯酸和丙烯醛在钠基蒙脱土层间直接原位插层聚合制备水溶性MAA-AL/MMT纳米复合材料,通过XRD和TEM对纳米复合材料的结构进行表征,采用TGA、DSC研究了纳米复合材料的热性能,同时考察了甲基丙烯酸与丙烯醛配比及体系pH值对纳米复合材料结构及应用性能的影响.研究结果表明所制备的MAA-AL/MMT纳米复合材料属于剥离型纳米复合材料,纳米复合材料的热性能相对未改性的聚合物有较大提高,应用于皮革鞣制所得坯革的增厚率及湿热稳定性均有一定提高,同时纳米复合材料的使用有利于浴液中铬的吸收.     

非剥离型聚苯胺/蒙脱土碳纳米复合吸附材料的研究

采用原位插层聚合法制备非剥离型聚苯胺/蒙脱土纳米复合吸附材料,研究了过氧化环己酮、异辛酸钴的用量和反应时间,以及碳化温度对复合材料性能的影响。结果表明:引发剂的用量为3%,促进剂的用量为5%,聚合反应时间为1.5h,所得的聚苯胺/蒙脱土复合材料的层间距最大,达21.54;碳化温度为500℃,所得的碳纳米复合材料的比表面积最大,达52.39m2/g。利用XRD、FT-IR、TG和BET等手段对该条件下制备的纳米复合材料进行了表征。     

MC尼龙蒙脱土纳米复合材料的制备与表征

在超声条件下以KH550硅烷偶联剂插层蒙脱土,采用阴离子聚合反应制备MC尼龙蒙脱土纳米复合材料(MMT/PA),并对改性蒙脱土和纳米复合材料的结构进行表征与性能测试。结果表明,在超声分散条件下KH-550硅烷偶联剂进入蒙脱土的片层间,增大层间距;聚合过程中己内酰胺进入蒙脱土的片层间,实现蒙脱土与己内酰胺的键性结合,并使得最终尼龙分子插层进入蒙脱土的片层间形成纳米复合材料。蒙脱土以部分剥离的多片层聚集体均匀地分散在尼龙基体中,起到增强增韧作用,当蒙脱土含量在3%左右时纳米复合材料的力学性能达到最优。     

Preparation of the acidic PVA/MMT nanocomposite polymer membrane for the direct methanol fuel cell (DMFC)

A novel nanocomposite polymer electrolyte membrane composed of PVA polymer matrix and nanosized Montmorillonite (MMT) filler, was prepared by a solution casting method. The characteristic properties of the PVA/MMT nanocomposite polymer membrane were investigated using thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), atomic force microscopy (AFM), micro-Raman spectroscopy, and the AC impedance method. The PVA polymer directly blended with nanosized MMT filler (2-20 wt.%) showed good ionic conductivity, thermal, and mechanical properties. The highest ionic conductivity value for the acidic PVA/10 wt.%MMT nanocomposite polymer membrane was around 0.0368 S cm^− 1 at 30 °C. The methanol permeability (P) value was 3-4 × 10^− 6 cm² s^− 1. It was revealed that the addition of nanosized MMT fillers into the PVA matrix could markedly improve the electrochemical properties of the PVA/MMT nanocomposite membrane. In fact, the PVA/MMT nanocomposite polymer membrane appears to be a good candidate for the DMFC applications.     

Study on PVP/C-MMT Nanocomposite Material via Polymer Solution-Intercalation Method

The vinyl polymer/montmorillonite nanocomposite (PVP/C-MMT) was prepared successfully using the way of polymer intercalation from solution. Gel permeation chromatography (GPC) result of PVP showed that polydispersity of PVP was 3.24 with broadly molecule distribution. The results of scan electron microscope (SEM) and thermogravimetry analysis (TGA) showed that the surface of MMT have changed hydrophility into lipophilic and the crystal layer of MMT broken down easily after modified MMT. The result of X-ray diffraction (XRD) and transmission electron microscope (TEM) showed that intercalated nanocomposite was prepared. The pickled sheepskins was tanned with 6% PVP/C-MMT associated with 2% chromate. The application result showed that it is an effective way to decrease use chromate for using nanocomposite.     

蒙脱土/聚丙烯酸高吸水性树脂的合成

用烷基季铵盐对钠基蒙脱土进行插层处理, 使其成为有机蒙脱土(OMMT) , 采用插层法制备蒙脱土/ 聚丙烯酸高吸水性树脂。通过傅立叶变换红外( FTIR) 和X 射线衍射(XRD) 等手段表征其结构。研究了有机蒙脱土、引发剂、交联剂用量以及材料粒径对复合材料吸(盐) 水率的影响。结果表明, 通过插层可使丙烯酸插入蒙脱土片层中发生聚合, 使蒙脱土片层剥离, 达到纳米级分散。所制备树脂的吸水率较聚丙烯酸树脂有很大提高, 其吸蒸馏水和生理盐水( wNaCl = 0. 009) 能力分别达到1200 g·g-1和121 g·g-1 。      

纳米蒙脱土的制备及在超高分子量聚乙烯中的应用

采用插层聚合的方法对蒙脱土进行了层间改性,通过X射线衍射仪、转矩流变仪等,对改性蒙脱土的层间结构进行了表征,随着单体插层、层间聚合、熔融共混的进行,蒙脱土的层间距不断增大,表明蒙脱土发生了层间剥离,与高分子聚合物形成了纳米复合材料。同时比较了不同改性的蒙脱土对聚合物扭矩的影响,苯乙烯单体插层聚合改性的蒙脱土对聚合物体系扭矩影响最大。     

Facile fabrication of CdTe/montmorillonite nanocomposite films with stable photoluminescence properties

We report herein the facile synthesis of CdTe/montmorillonite (MMT) nanocomposite films via charge-charge interactions between the CdTe quantum dots (QDs) and MMT platelets. Firstly, negatively charged CdTe QDs were prepared with the use of thioglycolic acid (TGA) as ligand. Then hybrid of the as-prepared TGA-stabilized CdTe QDs with sodium montmorillonite (Na-MMT) and cetyltrimethylammonium-modified montmorillonite (CTA-MMT), respectively, afforded novel CdTe/MMT nanocomposite films. The structure and optical properties of CdTe/MMT nanocomposite films were thoroughly investigated by scanning electron microscope (SEM), ultraviolet transmittance reflection and photoluminescence (PL) measurements. Results showed that CdTe/(CTA-MMT) nanocomposite films exhibited highly enhanced PL intensity compared with CdTe/(Na-MMT) nanocomposite films. More importantly, CdTe QDs in CdTe/(CTA-MMT) nanocomposite films well maintained PL properties even after thermal annealing at 100 °C for 10 h.     

紫外光固化聚氨酯丙烯酸酯/蒙脱土纳米复合材料的制备与表征

采用原位聚合方法合成了可紫外光固化的插层型聚氨酯丙烯酸酯／蒙脱土复合材料,通过紫外光固化后制备了聚氨酯丙烯酸酯／蒙脱土纳米复合材料。利用FT-IR、XRD等对材料的结构、蒙脱土的插层和剥离行为进行了表征,采用TGA和应力-应变方法对复合材料的热学及力学性能进行了测试。结果表明,当蒙脱土含量为4％～5％时,聚氨酯丙烯酸酯／蒙脱土纳米复合材料的耐热性能有了明显提高,而拉伸强度和撕裂强度比纯聚氨酯丙烯酸酯分别提高了100％和50％。     

Carbamazepine Modified Release Dosage Forms

The preparation of sustained release dosage forms of Carbamazepine (anti-epileptic drug characterized by a very low water solubility and by a short half life on chronique dosing) was carried out.

These formulations were obtained in two different steps:

a) modified release granules were prepared by the loading of cross-linked sodium carboxymethylcellulose (swellable polymer), with the drug and an enteric polymer. Cellulose acetate phthalate, methacrylic acid - methacrylic acid methyl ester copolymer (usually employed as enteric coating agents) and cellulose acetate trimellitate (a new enteric polymer) were used in different weight ratios.

b) some sustained release dosage forms were prepared tabletting physical mixtures of the modified release granules with different weight ratios of hydroxypropylmethylcellulose.

In vitro dissolution tests of modified release granules in gastric fluid (USP XXI) showed a modulation of the drug release, while in intestinal fluid (USP XXI) a quick drug dissolution was observed.

In vitro dissolution tests of sustained release dosage forms, performed varying during the test, the pH of the dissolution medium, (hydrochloric acid pH 1 from 0 to 2 hours and phosphate buffer pH 6.8 from 2 to 18 hours) showed that the determining factors in the controlling release of the drug are: the type and amount of enteric polymer constituting the granules and the amount of hydroxy-propylmethylcellulose mixed with them.     

溶液剥离-吸附法制备高分子纳米复合材料

采用溶液剥离-吸附法制备了乙烯基聚合物/改性蒙脱土(VP/C-MM T)高分子纳米复合材料。X射线衍射检测结果表明,十六烷基三甲基溴化铵(CTAB)改性蒙脱土的层间距由1.2916 nm增加到1.9620 nm,与乙烯基聚合物(VP)复合后,蒙脱土的d(001)峰消失;透射电镜对纳米复合材料成膜物的检测结果表明,蒙脱土在VP基体中以片层形式分散,说明VP/C-MM T为剥离型纳米复合材料。示差扫描量热检测结果表明,蒙脱土的存在可以较好地提高聚合物的热稳定性。通过建立CTAB与蒙脱土插层的理论模型,解释了VP与C-MM T未发生相分离的原因。     

聚乳酸/蒙脱土纳米复合材料的微波辅助制备与性能研究

采用微波辐照酸活化法制备了酸性蒙脱土(H-MMT),并采用BET、NH3-TPD、热重等分析手段对其结构和性质进行表征。结果表明,改性后蒙脱土的比表面积和孔径增大,表面出现超强酸点位,热力学稳定性增强。将H-MMT与SnCl2进行复配后用于微波辅助原位熔融缩聚制备聚乳酸/蒙脱土(PLA/MMT)纳米复合材料,结果表明,H-MMT同时具备了较好的酸催化及纳米增强作用,以剥离形态存在于高分子基体中,PLA/MMT纳米复合材料的力学、热力学性能得到显著提升。     

A pH-sensitive nanocomposite microsphere based on chitosan and montmorillonite with in vitro reduction of the burst release effect

Objective: The aim of this study was to prepare pH-sensitive ofloxacin (OFL)/montmorillonite (MMT)/chitosan (CTS) nanocomposite microspheres that improve the burst release effect of the drug by the solution intercalation technique and emulsification cross-linking techniques. Methods: First, OFL/MMT hybrids were prepared through the solution intercalation technique. Then, OFL/MMT-intercalated OFL/MMT/CTS nanocomposite microspheres were obtained through emulsification cross-linking technology. The intercalated nanocomposite was confirmed by Fourier-transform infrared spectroscopy and X-ray diffraction. Finally, in vitro release of OFL from the microspheres was performed in simulated gastric fluids and simulated intestinal fluids. The effect of MMT content on drug encapsulation efficiency and the drug release of the nanocomposite microspheres were investigated. Results: The results showed that the release rate of OFL from the nanocomposite microspheres at pH 7.4 was higher than that at pH 1.2. Compared with pure CTS microspheres, the incorporation of certain amount of MMT in the nanocomposite microspheres can enhance the drug encapsulation efficiency and reduce the burst release. Conclusion: A sustained release particulate system can be obtained by incorporating MMT into the nanocomposite microspheres and can improve the burst release effect of the drug.