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We are presenting a clay (montmorillonite) based method of reintroducing plastics back into the market without subjecting them to extended processing methods. We have prepared montmorillonite/recycled polymer materials with recycled polystyrene (R-PS) and recycled polyethylene (R-PE). R-PS was melt mixed with as-received organomodified montmorillonite or blowing agent treated organomodified montmorillonite which led to intercalated/exfoliated clay/polymer nanocomposites. Similarly, R-PE was melt compounded, with or without the addition of a compatibiliser with the above mentioned organomodified clay minerals which resulted in conventional composite formation. In the case of R-PS, the thermal degradation temperature of the materials increased with the presence of clay minerals, whereas for R-PE based materials it was observed that the thermal degradation temperatures decreased with the presence of clay minerals. Overall it was observed that the presence of clay minerals improved the stiffness of the materials. The use of blowing agent treated organomodified clay minerals in R-PS led to nearly doubled impact strength compared to organomodified clay/R-PS nanocomposites. [ABSTRACT FROM AUTHOR]

Chitosan/kaolin composite porous membranes were successfully prepared by solvent casting and evaporation process. The suspensions with different concentration of kaolin and chitosan showed a Newtonian behaviour. Strong interaction between chitosan and kaolin was revealed by FTIR and thermogravimetric analysis. The effect of kaolin content on the morphology and properties of the obtained membranes was studied. It was found by SEM observation that the kaolin particles were well dispersed in the chitosan matrix generating a porous microstructure. Incorporation of kaolin particles also improved the mechanical and thermal properties of the membranes and reduced drastically the water washout of chitosan in moderate acidic medium. Owing to their porous structure, the water permeability of the composite chitosan/kaolin membrane was significantly enhanced. The better formulation of the dope suspension in the range studied was 4% chitosan and 5% kaolin in acetic acid. These membranes made from naturally occurring materials might play an important role in advanced research in water treatment and environmental science. [ABSTRACT FROM AUTHOR]

A commercial organically modified montmorillonite Cloisite ® 15A was modified via a new silanization route by two different silane coupling agents: 3-Aminopropyltriethoxysilane and 3-Glycidyloxypropyltrimethoxysilane. This method enables the use of very high concentration of silanes for functionalization of clay minerals. The ratio of weight of silane coupling agent to that of weight of clay mineral (X) was varied from 0.1 to 6. Small angle X- ray scattering and thermogravimetric analysis were carried out on silane modified clay minerals to quantify the grafting of silanes as a function of ratio of weight of silane agent to that of clay mineral. Fiber reinforced epoxy nanocomposites containing silylated clay minerals were manufactured using vacuum assisted resin infusion molding method. Also, curing studies were carried out on fiber reinforced epoxy nanocomposites containing Cloisite ® 15A at different cure temperatures, e.g. 70 °C, 80 °C, 85 °C, 95 °C and for two different curing time periods, e.g. 7 h and 10 h. Significant improvements in mechanical properties of fiber reinforced nanocomposites were obtained with incorporation of clay minerals silanized using high concentration of silanes in solvent and chosen curing schedule. The tensile modulus, tensile strength, flexural modulus and bending strength increased by 30%, 37%, 139% and 146% respectively, in nanocomposites containing clay mineral modified using 4X aminopropyltriethoxysilane. An attempt has been made to correlate the results with the morphology of nanocomposites by transmission electron microscopy and that of fractured surfaces by scanning electron microscopy. [ABSTRACT FROM AUTHOR]

Palygorskite (Pal) and modified Pal (OPal) by a silane coupling agent are used to improve the mechanical and thermal properties of poly(butylene succinate) (PBS) and the nanocomposites are prepared by melt blending. The synthesized palygorskite PBS nanocomposites are characterized by thermo-gravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The mechanical properties and dynamic mechanical and crystallization behavior have been studied. Surface modification improves the dispersion of Pal in the PBS matrix and 16% improvement in the tensile strength is observed from palygorskite PBS nanocomposites with 3 wt.% of OPal compared to pure PBS. The flexural properties and thermal stability of the palygorskite PBS nanocomposites are also enhanced significantly in the presence of OPal. Incorporation of OPal increases the storage modulus and decreases tan δ demonstrating the reinforcing effects of clay on the PBS matrix. Thermal analysis reveals that the Pal nanoparticles are effective nucleating agents accelerating crystallization. The glass transition temperature increases slightly in the presence of palygorskite except the sample with 2 wt.% clay. [ABSTRACT FROM AUTHOR]

In this work, the capability of organo-bentonite (OBent)/recycled polypropylene (PP) and mineral oil blends to form gel-like dispersions potentially applicable as lubricating greases was explored. Specifically, the effect of both thickener concentration ratios on the rheology, thermal and some lubricant performance properties of the resulting gel-like dispersions was studied. The rheological response was qualitatively similar for all the samples studied and also similar to that found in standard lubricating greases. The plateau modulus G°N, of OBent/PP dispersions in mineral oil showed negative deviation from the additivity line and minimum values were observed for intermediate OBent/PP concentration ratios, excepting at the highest temperature studied (150°C), where a continuous increase of this viscoelastic parameter with OBent content was found. The degree of crystallinity of recycled PP in the sample was influenced by the presence of OBent. Samples formulated with lower values of OBent/PP concentration ratio yield gel-like formulations with appropriate mechanical stabilities to be used as lubricating greases. The friction coefficient evaluated in a ball-on-plate tribological contact decreased with OBent content. [ABSTRACT FROM AUTHOR]

Abstract: Completely exfoliated epoxy/organo-montmorillonite nanocomposites with high-performance were successfully prepared using Nano-disassembling method. Nano-SiO2 particles were added into the organo-montmorillonite and epoxy mixture system as a disassembler to interact with organo-montmorillonite (o-MMT). By means of the strong interaction between nanoscale particles, the MMT layers were completely disassembled into elemental nanoscale mono-platelets. These mono-platelets and the disassembler particles dispersed in the resultant nanocomposites taking an interlacing arrangement. Mechanical testing and thermal analysis results indicated that the nanocomposites prepared by Nano-disassembling method displayed dramatic improvements in mechanical and thermal properties compared with traditional epoxy/o-MMT nanocomposites. Tensile modulus and tensile strength increased by 63.0% and 53.0%, respectively. Flexural modulus enhanced by 6.0%, flexural strength by 13.2% and notch impact strength by 36.1%. Glass transition temperature and thermal decomposition temperature moved to high temperatures by 9.0°C and 5.0°C. [Copyright &y& Elsevier]

Abstract: The effect of organically modified montmorillonite (OMMT) on polyamide nanocomposites was studied. OMMT/polyamide nanocomposites were prepared through direct melt compounding on a conventional twin screw extruder. With increasing the loading of OMMT, the Young modulus, elongation at break and tensile strength increased. 1mass% loading of OMMT/polyamide resulted in 11% increase of the elongation at break compared to virgin polymer, while 4% loading showed 13%. Rheological data like torque, fusion time, viscosity and shear rate were also recorded on Brabender Plasticorder and were correlated with M = CS a and τ = K(γ) n . The value n <1 indicated pseudo-plastic nature of the polyamide/OMMT. The torque decreased with increased loading due to soft nature of OMMT, which acts as a lubricating agent. This improvement in mechanical properties with increase in amount of OMMT loading was also indicated by the reduction in shear viscosity and torque. [Copyright &y& Elsevier]

Ethylene vinyl acetate (EVA) nanocomposites containing hydrophobic organo-clays were prepared by a solution blending method to investigate the role of organic modifiers stabilized in the interlayer space of host clays on the thermal stability and mechanical strength of EVA. The smectite clays such as Mt. (Na-montmorillonite), Mica (Na‑fluorine mica), and Ht (Na-hectorite) were used as the host with different particle sizes, but hydrophobically modified by intercalating the long chained alkylammonium surfactants like cetyltrimethylammonium (CTA) bromide, and dimethyldistearylammonium (DMDSA) bromide to form organo-clays. Thus, prepared organo-clays were dispersed homogeneously in a toluene solution of EVA, and then the toluene was evaporated to obtain the organo-clay/EVA nanocomposites. According to the powder XRD analyses for all the nanocomposites, the CTA-clays were better exfoliated and dispersed in EVA matrix than the DMDSA-ones. Among three CTA-clay/EVA nanocomposites, the CTA-Mica/EVA one was determined to be the best in terms of thermal stability compared to the other two nanocomposites, CTA-Mt/EVA and CTA-Ht/EVA. The thermal stability of the CTA-Mica/EVA nanocomposite was significantly improved by ~38 °C, compared to that of the pristine EVA. Upon increasing the CTA-Mica loading concentration up to 12 wt% in EVA matrix, the Young's modulus and tensile strength of the EVA nanocomposites were increased up to 54% in maximum. It is, therefore, suggested that the CTA-Mica is a potential nanofiller for enhancing the thermal stability and mechanical properties of EVA. Unlabelled Image • Three smectite clays were hybridized with CTA and DMDSA. • From six organo-clays, we found that CTA-clays were better exfoliated and dispersed in EVA matrix than DMDSA-ones, resulting in the improvement of thermal stability of the EVA nanocomposites. • The CTA-Mica/EVA was evaluated as the best sample based on thermal and mechanical properties. [ABSTRACT FROM AUTHOR]

In the recent years, halloysite (Hal) nanotube has emerged as promising naturally occurring filler for the development of commercially viable advanced rubber composites. The present review is an attempt to present the relevant information from past and recent developments in Hal nanotube based natural and synthetic rubber composites. The potential of Hal nanotube as reinforcing filler in rubber composites is critically explored in terms of mechanical, dynamic mechanical, morphological and thermal properties. The homogeneous dispersion of Hal within the rubber matrix is the key parameter for the preparation of highly reinforced Hal nanotube filled rubber composites. The last section of the review will emphasize the major challenges regarding the practical application of Hal nanotube as reinforcing filler in rubber industry. This study will be the part of huge interest of modern rubber researchers regarding the progress of non-petroleum based sustainable rubber technology by the suitable application of clay science and technology. • Past and recent applications of Hal nanotube in rubber composites • Potential of Hal nanotube as efficient reinforcing filler in rubber industry • Mechanistic study of interaction between rubber chain and Hal nanotube • Challenges regarding the practical application of Hal nanotube in rubber industry [ABSTRACT FROM AUTHOR]