Effect of surface treatment of nanoclay on the mechanical properties of epoxy/glass fiber/clay nanocomposites

A new method of silane treatment of nanoclays is reported where in the clay is nanodispersed in hydrolyzed silanes. The surface functionalization of Cloisite^® 15A nanoclay has been carried out using two different silane coupling agents: 3-aminopropyltriethoxy silane and 3-glycidyloxypropyltrimethoxy silane using varied amounts of silane coupling agents, e.g. 10, 50, 200, and 400 wt% of clay. The surface modification of Cloisite^® 15A has been confirmed by Fourier transform infrared spectroscopy. The modified clays were then dispersed in epoxy resin, and glass fiber-reinforced epoxy clay laminates were manufactured using vacuum bagging technique. The fiber-reinforced epoxy clay nanocomposites containing silane modified clays have been characterized using small angle X-ray scattering, transmission electron spectroscopy and differential scanning calorimetry. The results indicate that the silane treatment of nanoclay aided the exfoliation of nanoclay and also led to an increase in mechanical properties. The optimized amount of silane coupling agents was 200 wt%. The nanocomposites containing clay modified in 200 wt% of silanes exhibited an exfoliated morphology, improved tensile strength, flexural modulus, and flexural strength. The improved interfacial bonding between silane modified nanoclays and epoxy matrix was also evident from significant increase in elongation at break.     

β-羟基丁酸与β-羟基戊酸酯共聚物/有机化蒙脱土纳米复合材料热性能、结晶性能与生物降解性能的研究

采用溶液插层法制备了β-羟基丁酸与β-羟基戊酸酯共聚物(PHBV)有机化蒙脱土(OMMT)的纳米复合材料．用示差热分析(DSC)，热重分析(TG)和偏光显微镜(POM)研究了材料的热性能和结晶行为．通过土壤悬浊降解培养法研究了材料的生物降解性．结果表明，材料的熔点和熔融焓随OMMT含量的增加而降低．OMMT在纳米复合材料中的均匀分散，使材料形成了小尺寸的结晶，并有效降低了PHBV的结晶度，提高了结晶速率．在土壤悬浊液中该材料的生物降解性随着OMMT含量的增加而降低．     

Hybrid Nanocomposite Prepared by Graft Copolymerization of 4-Acryloyl morpholine onto Chitosan in the Presence of Organophilic Montmorillonite

Organophilic montmorillonite (OMMT) was synthesized by cationic exchange between Na-MMT and Vinyl benzyl triphenyl phosphonium chloride in an aqueous solution. A new nanocomposite consisting of 4-acryloyl morpholine-chitosan and OMMT was prepared by γ -ray irradiation polymerization. The intercalation spacing of these nanocomposites was investigated with X-ray diffraction and its thermal stabilities by adding nanocomposites were characterized by thermal gravimetric analysis. The nanocomposites showed improved resistance to water absorption. The most interesting application of the nanocomposite is its ability for adsorption purification of waste water containing acid dyes. One of the objectives in this study was to develop new and active prepared copolymers which can be examined for their antimicrobial activities. It was found that the copolymer nanocomposite based on phosphonium group and some heavy metal ions in its structure having broad spectrum against pathogenic bacteria such as Staphylococcus aurius, Escherichia coli and Aspergillus flavus fungi.     

Flammability, structure and mechanical properties of PP/OMMT nanocomposites

Polypropylene/organoclay (PP/OMMT) nanocomposites were prepared in a twin-screw corotating extruder using two methods. The first method was the dilution of commercial (PP/50% Nanofil SE3000) masterbatch in PP (or PP with commercial flame retardant). The second method consists of two stages was the extrusion of maleic anhydride grafted polypropylene (PP-g-MAH) with commercially available organobentonite masterbatch in first stage and dilution of the masterbatch in PP (or PP with commercial flame retardant) in second stage. XRD results showed no intercalation in composites obtained from commercial masterbatch without compatibilizer and semi - delamination for compatibilized systems. Tensile tests revealed that nanocomposites with 5% of organoclay have a slightly higher tensile modulus and tensile strength than pristine PP, however addition of the commercial flame retardant (FR) reduces mechanical parameters to roughly the level of those for neat PP. PP/OMMT composites have approx. 25% higher oxygen index than pristine PP, and this changes slightly after the addition of FR. The cone calorimeter tests showed a decrease of a heat release rate (HRR) and a mass loss rate (MLR) after the addition of FR.     

Preparation,Characterization, and Properties of Polyamide 66/Maleic Anhydride -grafted-polypropylene/Clay Ternary Nanocomposites

Polyamide (PA) 66/PP-g-MA/Organic-modified MMT (OMMT) ternary composites were prepared by direct melt compounding. The FESEM results showed that the PP-g-MA phase dispersed homogeneously in the PA matrix due to the interfacial chemical reactions between the two phases. The mechanical properties of the composites were evaluated. The tensile and bending properties decreased and the notched impact strength increased with the increase of PP-g-MA. The tribological behaviors of the ternary composites were studied by means of a ball-on-disk apparatus. The ternary composites exhibited better tribological properties compared with the PA/OMMT system. This was probably due to the fact that the PP has good flexibility and a transferring film could be formed easily on the counterpart. Combining the results of the mechanical and tribological properties, the optimal mass fraction of PP-g-MA was 10 wt. %.     

Preparation and Properties of Organically Modified Montmorillonite/Nitrile Rubber Nanocomposites

A series of organically modified montmorillonite (OMMT)/nitrile rubber (NBR) nanocomposites were prepared by a simple mechanical-mixing method. The structures of OMMT and the dispersion of OMMT in the rubber matrix were detected by X-ray diffraction (XRD). The mechanical properties of the NBR/OMMT nanocomposites were characterized, and the tribological behaviors of the nanocomposites were evaluated on a ring-block (MRH-3) wear tester. The results showed that the OMMT was homogeneously dispersed in the NBR matrix. The tensile strength of the OMMT/NBR nanocomposites increased with increasing OMMT contents. Both the coefficient of friction (COF) and wear of the nanocomposites decreased remarkably with increasing OMMT content. In addition, the influence of the applied load on the tribological properties of the nanocomposites is discussed. It is expected that the research may be of aid in the rational design and use of solid, self-lubricating nanocomposites under different loading states.     

界面作用对PMMA/MCM-41/OMMT复合材料性能的影响

通过单体插层原位本体聚合的方法, 制备了多种不同含量的聚甲基丙烯酸甲酯(PMMA)/蒙脱土/介孔分子筛(无模板剂)复合材料. 研究了不同结构填料与基体间的界面作用, 以及不同结构填料的比例变化对复合材料性能的影响. 研究结果表明: 有机蒙脱土(OMMT)与介孔分子筛MCM-41(无模板剂)共同作为填料, 与基体发生较强的界面效应, 形成新型网络复合结构, 两种粒子起到了协同增强作用|当有机蒙脱土(OMMT)/介孔分子筛(MCM-41)混合填料(比例为1∶1)含量为0.5%时, PMMA基纳米复合材料的拉伸强度达到最大值49.0 MPa, 比PMMA提高了15%|同时添加OMMT和MCM-41的PMMA基纳米复合材料的热稳定性高于单独添加OMMT或MCM-41的PMMA基复合材料.     

Preparation and characterization of an asphalt-modifying agent with waste packaging polyethylene and organic montmorillonite

In this paper, waste packaging polyethylene (WPE)/organic montmorillonite (OMMT) nanocomposites were prepared and used as an asphalt-modifying agent. The structure and morphology of the nanocomposites and the effects of OMMT on the thermal properties of WPE were investigated. The influence of the microcosmic effects and physical properties of the composite agents on the base asphalt were also studied. The results show that the WPE/OMMT asphalt-modifying agents are exfoliated nanocomposites. When compared with WPE, the melting range of the composites decreases and the thermal stability is improved. In addition, the composite agents not only promote good dispersion of WPE in asphalt, but also improve the low temperature properties of WPE-modified asphalt without adversely affecting its excellent high temperature properties. Therefore, from an environmental and economic standpoint, it is a novel and significant attempt at dealing with waste plastics packaging.