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％。     

环氧丙烯酸酯/蒙脱土纳米复合材料的合成及性能研究

采用十八烷基胺蒙脱土和环氧树脂进行浸润插层,与丙烯酸反应,合成了环氧丙烯酸酯/蒙脱土预聚体,光固化反应制备涂膜,利用X-射线衍射进行了表征;对环氧丙烯酸酯的固化漆膜进行了冲击强度、收缩率等性能测试.结果表明,蒙脱土的含量为1.0%～2.0%的环氧丙烯酸酯/蒙脱土复合材料冲击强度比较好,含量越多收缩率越低.     

聚氨酯/蒙脱土纳米复合弹性体材料--(Ⅱ)结构及性能的表征

借助锥体磨的研磨剪切外力，将聚醚多元醇插层进入蒙脱土片层中，使其片层间距扩大并发生部分剥离，从而利用本体插层聚合法制备了综合性能优异的聚氨酯／蒙脱土纳米复合弹性体材料。当有机蒙脱土添加量仅为1％时，其拉伸强度比纯聚氨酯弹性体高30％．达到30．2MPa，断裂伸长率也略有增加。TGA及吸水实验分析表明聚氨酯／蒙脱土纳米复合材料有更高的热失重温度和更低的吸水率．研究了蒙脱土含量对聚氨酯／蒙脱土纳米复合材料各项性能的影响。     

苯乙烯-丙烯酸丁酯/蒙脱土纳米复合材料的阻燃性

以乳液插层聚合法合成苯乙烯-丙烯酸丁酯／蒙脱土纳米复合材料。X射线衍射结果表明，聚合物能够有效地插层到经过有机化处理的蒙脱土层间，且蒙脱土片层可以均匀地分散在苯乙烯-丙烯酸丁酯共聚物中。TGA分析表明，苯乙烯-丙烯酸丁酯／有机蒙脱土纳米复合材料的热稳定性有所提高．锥形量热仪测试和研究表明。复合材料的燃烧性能，包括热释放速率和质量损失，在蒙脱土含量为2％时，效果最好。     

PP/蒙脱土纳米复合材料的制备及剪切粘度

应用双螺杆挤出机熔融插层制备出PP／蒙脱土纳米复合材料，X射线衍射表明，PP高分子链已插层进入有机蒙脱土片层之间。应用两种不同缝隙厚度的窄缝流变仪对PP及PP／蒙脱土纳米复合材料的剪切粘度及影响因素进行了研究。结果表明，PP／蒙脱土纳米复合材料为剪切变稀性流体。在190℃和210℃温度下，PP／蒙脱土纳米复合材料呈现类固体的非牛顿流体行为，剪切粘度随着剪切速率的升高逐渐降低。在230℃和剪切速率小于80s^-1的情况下，PP／蒙脱土纳米复合材料呈现类牛顿性流体行为。温度较高时,蒙脱土的含量对复合材料的剪切粘度的影响较为明显。     

环氧树脂/粘土纳米复合材料的制备与性能研究

研究了有机蒙脱土在环氧树脂中的插层和剥离行为,制备了两种环氧树脂/蒙脱土纳米复合材料并测试了其力学性能。实验结果表明,环氧树脂与有机土的相容性好,二者混合时环氧树脂很容易插入到粘土层间。使用经不同有机阳离子处理的两种有机蒙脱土,分别制得插层型和剥离型环氧/粘土纳米复合材料,力学性能结果表明,剥离型纳米复合材料的性能优于同组成的插层型纳米复合材料。     

UP/Na-MMT纳米复合材料的制备与性能

研究了UP／Na-MMT纳米复合材料的制备与性能，并考察了插层剂种类、有机蒙脱土加入量及离子交换量对复合材料性能的影响。结果表明，UP／Na-MMT纳米复合材料的XRD曲线中蒙脱土晶体结构的布拉格衍射峰已经消失，说明其晶层已被树脂撑开，达到纳米级分散；复合材料的耐热性能得到明显改善，其冲击强度和拉伸强度均有较大提高。     

PP-g-MAH/蒙脱土纳米复合材料的制备和性能

采用熔融插层法成功制备了接枝物(PP—g—MAH)／有机蒙脱土(Org—MMT)纳米复合材料，用X射线衍射法检测了复合材料的层间距、微晶尺寸和晶胞参数的变化，并考察了纳米复合材料的力学性能。结果发现，对于PP—g—MAH／Org—MMT=100：20的复合材料，接枝物大分子链难以插层进入有机蒙脱土片层间。增大PP—g—MAH／Org—MMT比例，接枝物大分子链能插层进入有机蒙脱土片层，形成插层型纳米复合材料。PP—g—MAH／Org—MMT=100：10时，PP—g—MAH／Org—MMT复合材料110、040、041等晶面垂直于反射方向的微晶尺寸出现最小值．且可获得较好的力学性能．说明选择适当的接枝物／有机蒙脱土比例可降低聚丙烯的微晶尺寸，改善力学性能．但对复合材料晶胞参数的影响较小。     

天然橡胶/蒙脱土原土纳米复合材料的制备与性能

用机械混炼反应插层法,通过引入第三组分RH,制备了天然橡胶／蒙脱土原土纳米复合材料,实现了对天然橡胶的补强,在这种复合材料中,蒙脱土原土的层间距显著增大,蒙脱土无机片层在橡胶基体中达到了纳米级分散．蒙脱土原土与天然胶纳米复合保持了较低的滚动阻力,显著地提高了天然胶的抗湿滑性．     

共插层剂改性蒙脱土制备尼龙1010/蒙脱土纳米复合材料

以间甲酚(MC)、尼龙66盐(NS)分别与十六烷基三甲基溴化铵(CTAB)共插层改性蒙脱土，制备了尼龙1010／蒙脱土纳米复合材料。TG和WAXD实验结果表明，采用共插层剂改性的蒙脱土的片层间距显著增大，且热分解温度较高；蒙脱土的引入改善了尼龙1010的拉伸性能、弯曲性能和热变形温度，冲击韧性基本保持；蒙脱土的加入可能改变了尼龙1010的结晶结构，且使尼龙1010的结晶温度升高。共插层剂两组分所起的作用不同，CTAB的插入有利于蒙脱土片层间距的扩开，MC和NS则起到了界面相容剂的作用．有利于基体树脂与蒙脱土片层的复合。     

马来酸酐接枝聚丙烯对聚丙烯/蒙脱土纳米复合材料的影响

研究了相容剂马来酸酐接枝聚丙烯对聚丙烯/蒙脱土纳米复合材料(PP/MM T)的影响,它不仅显著改善了PP与蒙脱土的界面相容性,使复合材料力学性能显著提高,而且改善了复合材料的加工流动性。PP的断裂方式属典型的脆性断裂,含有马来酸酐接枝聚丙烯的PP/MM T断裂方式属韧性断裂。蒙脱土在聚丙烯结晶时起成核剂的作用,提高了PP/MM T纳米复合材料的结晶速率。相容剂使得有机蒙脱土对PP的成核作用更加明显。     

聚丙烯/蒙脱土纳米复合包装材料的制备与力学性能研究

采用熔融插层法在双螺杆挤出机中制备了聚丙烯(PP)/蒙脱土(MMT)纳米复合材料,纳米复合材料机械性能测试结果表明,当有机蒙脱土(MMT)质量比为2%时,复合材料的综合力学性能明显优于聚丙烯(PP).扫描电镜观测不到纳米复合材料中明显的有机-无机相畴,表明蒙脱土(MMT)片层分散均匀,分散尺度已基本达到纳米级.     

熔融挤出插层制备聚丙烯/蒙脱土纳米复合材料的探讨(Ⅰ)

通过双螺杆挤出机熔融挤出法制备出插层型聚丙烯/蒙脱土纳米复合材料。利用有机蒙脱土的预凝胶测试,复合材料的透射电子显微镜(TEM)观察,熔体流动指数测试(M I),力学性能测试,耐热性测试等方法进行了表征。结果表明,通过本方法制备的聚丙烯/蒙脱土复合材料是典型的插层型纳米复合材料。该复合材料在有机蒙脱土质量分数仅为4.0%时缺口冲击强度提高了103%,耐热性有所提高,而屈服强度、刚性基本不变,为研制PPR管等同时具有高韧性和高耐热性的聚丙烯产品开辟了一条崭新的途径。     

Study on fracture behavior of surface treated montmorillonite/epoxy nanocomposites

It is known that the mechanical properties of clay-reinforced nanocomposites are significantly affected by the dispersion of clay particles in the matrix. In this study, the effect of surface-treatment of Montmorillonite (MMT) on the fracture behavior of MMT/epoxy nanocomposite was investigated. For this purpose, fracture tests were performed using samples with three different clay concentration level. After fracture tests, SEM analysis was made on the fracture surfaces to examine the fracture mechanism. It was found that the MMT treatment using 3-aminopropyltriethoxysilane enhanced the fracture toughness increased of the MMT/epoxy nanocomposite. This is due to the improved intercalation effect and interfacial strength between MMT and epoxy matrix.     

球磨分散法制备新型改性粘土/环氧纳米复合材料的结构与性能

采用十二烷基二甲基卞基氯化铵(DBDA) 和间苯二甲胺(MXDA) 设计并制备了一种新型有机化改性蒙脱土(MMT Ⅱ), 通过球磨法来促进其在环氧树脂中的细化与分散, 制备出具有良好解离结构的MMT Ⅱ/ 环氧纳米复合材料。利用红外光谱(FTIR) 、X-射线衍射(XRD) 和透射电镜( TEM) 表征了新型MMT Ⅱ及其纳米复合材料的结构, 测试了力学性能。结构表征与分析表明, 大颗粒粘土聚集体并不能在搅拌混合过程中分散开, 在固化过程中很难充分解离, 而通过球磨过程中产生的剪切力可促进其分散与细化, 从而获得良好解离结构。MMTⅡ中MXDA 的引入, 减少了季铵盐分子链所产生的悬键, 增加了MMT Ⅱ片层的界面反应性, 大大提高了纳米复合材料的力学性能, 冲击强度由3211kJ / m2 提高到4811 kJ / m2, 提高近50 %, 弯曲强度提高近8 %。     

Improving the mechanical properties of thermoplastic starch/poly(vinyl alcohol)/clay nanocomposites

Thermoplastic starch/poly(vinyl alcohol) (PVOH)/clay nanocomposites, exhibiting the intercalated and exfoliated structures, were prepared via melt extrusion method. The effects of clay cation, water, PVOH and clay contents on clay intercalation and mechanical properties of nanocomposites were investigated. The experiments were carried out according to the Taguchi experimental design method. Montmorillonite (MMT) with three types of cation or modifier (Na⁺, alkyl ammonium ion, and citric acid) was examined. The prepared nanocomposites with modified montmorillonite indicated a mechanical improvement in the properties in comparison with pristine MMT. It was also observed that increases in tensile strength and modulus would be attained for nanocomposite samples with 10%, 5% and 4% (by weight) of water, PVOH and clay loading, respectively. The clay intercalation was examined by X-ray diffraction (XRD) patterns. The chemical structure and morphology of the optimum sample was also probed by FTIR spectroscopy and transmission electron microscopy (TEM).     

Controlled release formulation of ranitidine-containing montmorillonite and Eudragit® E-100

Aim: The objective of this work was to illustrate the suitability of montmorillonite (MMT) as a drug delivery carrier, by developing a new clay–drug composite of ranitidine hydrochloride (RT) intercalated in MMT. Methods: The MMT–RT composite was prepared by ion-exchange process. X-ray diffraction and Fourier transform infrared spectra were employed to confirm the intercalation of RT in the MMT interlayers. The prepared MMT–RT hybrid was coated with cationic polymer Eudragit® E-100 by oil-in-water solvent evaporation method. The release processes of RT from MMT–RT and MMT–RT/Eudragit® E-100 were monitored under in vitro condition in the gastric fluid. Results: X-ray diffraction and Fourier transform infrared spectra analysis indicated the intercalation of RT molecules within the clay lattice. The in vitro release studies showed that MMT–RT released RT in a controlled manner. In the case of MMT–RT/Eudragit® E-100, both the release rate and the release percentages noticeably increased in the presence of Eudragit® E-100, because of its effective exchange with intercalated RT molecules. The release kinetics followed parabolic diffusion mechanism. Conclusion: MMT has great potential as a drug delivery carrier with various scenarios. The dosage of the MMT–RT/Eudragit® E-100 can be in the tablet form. The hybrid material and polymer-coated hybrids are microparticles.     

蒙脱土/聚丙烯复合材料结晶形态及耐电树枝化特性

为了改善聚丙烯(PP)的耐电树枝性能,以有机化蒙脱土(MMT)作为纳米填充相,马来酸酐接枝聚丙烯(PP-g-MAH)作为相容剂,采用熔融插层一步法和二步法制备了MMT/PP复合材料。分别利用偏光显微镜(PLM)及差示扫描量热(DSC)曲线观测了PP及MMT/PP复合材料的结晶形态及结晶过程,采用SEM考察了MMT在复合材料中的分散状态。通过电树枝引发实验,探究了制备方法及结晶形态对复合材料耐电树枝化性能的影响。实验结果表明:采用熔融插层二步法制备的MMT/PP复合材料,其无机相分散较均匀,结晶尺寸减小,结晶结构由球晶转变为片晶的堆叠,结晶度提高了约2.7%;在PP试样中,电树枝长度较长且分枝较少,而MMT/PP试样中电树枝转变为长度较小且分枝较多的稠密结构。     

Chlorinated polyethylene nanocomposites: thermal and mechanical behavior

Chlorinated polyethylene (CPE) nanocomposites prepared with natural and organically treated montmorillonite (MMT) clays by solution intercalation method were investigated. X-ray diffraction and transmission electron microscopy techniques showed separation of organically modified clay MMT layers and indicated formation of exfoliated nanocomposites. Fourier transform infrared spectroscopy results showed interaction between the CPE matrix and the clay intercalants of Cloisite^® 30B and Cloisite^® 15A (natural MMT modified with quaternary ammonium salts). Organically treated MMT clays were found to be better dispersed in CPE in comparison to natural MMT clay. Mechanical testing showed enhanced tensile strength, Young’s modulus, and storage modulus of chlorinated-polymers/organically treated MMT clay nanocomposites. Significant improvements in the above properties were obtained with Cloisite^® 15A nanoclay. The temperature, at which maximum degradation occurred, was higher for the nanocomposite having 5 wt% Cloisite 15A than that of neat CPE. Differential scanning calorimetric results revealed that the same composition also absorbed more heat during the heating, indicating better thermal stability. CPE rubber nanocomposite could be a promising heat resistant polymeric material.