Production of nanocomposites

Numerous thermoplastic and thermosetting pol3miers have been applied for producing nanocomposites using the in situ approach however, for the first time, it was used for clay/polyamide 6 nanocomposites. In general, the nanoparticles of filler are premixed with the liquid monomer or its solution. When layered nanofiller such as clay (swollen by means of modification) is added, the pol5mierization occurs within sheet intercalated with monomer. Then either radiation, heat or an initiator tri er the reaction of pol5mierization [57]. 

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The sol—gel process can be utilized to yield products within a wide range of appHcations. Some of these appHcations include production of nanocomposites, films, fibers, porous and dense monoliths, and biomaterials. 

PLA/PCL-OMMT nano-composites were prepared effectively using fatty amides as clay modifier. The nano-composites shows increasing mechanical properties and thermal stability (Hoidy et al, 2010c). New biopolymer nano-composites were prepared by treatment of epoxidized soybean oil and palm oil, respectively plasticized PLA modified MMT with fatty nitrogen compounds. The XRD and TEM results confirmed the production of nanocomposites. The novelty of these studies is use of fatty nitrogen compoimds which reduces the dependence on petroleum-based surfactants (Al-Mulla et al., 2011 Al-Mulla et ah, 2011 Al- Mulla et ah, 2010c). 

The TEM images and XRD spectra are in good agreement and confirm that cationic pyridinium species can be used for the production of nanocomposites based on both grades of the polyamide. It has been concluded that ready exfoliation of clay layers only occurs with alkyl chain lengths above twelve CH2 units long. 

Castro, C., Vesterinen, A., Zuluaga, R., Caro, G., Filpponen, 1., Rojas, 0. J., Kortaberria, G., and Ganan, P. (2014). In situ production of nanocomposites of poly(vinyl alcohol) and cellulose nanofibrils from Gluconacetobacter bacteria Effect of chemical crosslinking. Cellulose, in Press. 

Three main types of structures, which are shown in Fig. 5.3, can be obtained when a clay is dispersed in a polymer matrix (1) phase-separated structure, where the polymer chains did not intercalate the clay layers, leading to a structure similar to those of a conventional composite, (2) intercalated structure, where the polymer chains are intercalated between clay layers, forming a well ordered multilayer structure, which has superior properties to those of a conventional composite, and (3) structure exfoliated, where the clay is completely and uniformly dispersed in a polymeric matrix, maximizing the interactions polymer-clay and leading to significant improvements in physical and mechanical properties [2, 50-52]. Production of nanocomposites based on polymer/clay can be done basically in three ways (a) in situ polymerization, (b) prepared in solution and (c) preparation of the melt or melt blending [53]. 

In the case of other polymeri2ation systems using PCPs, the procedures employed are similar to that described above, whereby the polymeri2ation is conducted following the incorporation of monomers into PCP channels. This leads to the production of nanocomposites based on PCPs and polymers, followed by isolation of the resulting polymers in chelating solutions. 

From literature, it is observed that primarily three types of structures can be obtained during the production of nanocomposites (Figure 6.5) in the... 

The huge number of different fiber morphologies, structures, and properties that can be achieved by electrospiiming is impressive. The power of this technology is even more evident if we take into account the fact that innovative hybrid nanofibers can be fabricated with a simple, versatile, exbemely cheap, and scalable technology that makes electrospiiming the most interesting currently available technique for the production of nanocomposites. 

A number of methods have frequently been employed in the production of nanocomposite materials. These include solution intercalation, melt intercalation, polymerization, sol-gel, deposition, magnetron sput-tering, laser, ultrasonication, supercritical fluid, etc. In PHA nanocomposite fabrication, solution intercalation and melt intercalation methods are the most widely explored procedures. However, use of in situ intercalative polymerization, supercritical fluids and electrospinning are shown to be promising and emerging techniques. The performance and quality of a nanocomposite depends on how well the nanofillers disperse or blend into the matrix. Therefore, these methods constitute different strategies to improve the composites thermo-mechanical and physico-chemical properties by enhancing efficient interactions between the nanofiller and the polymer matrices. 

Among the existing nanofillers, MMT clays are the most commonly employed for the production of nanocomposites. They are 2 1 layer silicates. The MMT particles are made up of layers having a length within 100 to 1000 nm, a thickness of 1 nm, and a high aspect ratio within 10 to 1000, thus possessing very high surface area for polymer/filler interaction. 

Thermoprocessing methods, snch as extrusion, melt compounding, compression, and injection molding, are the most commonly used technologies for industrial-scale production of nanocomposites. Currently, these technologies are also expected to promote... 

The development of a complete formulation and processing system for the production of nanocomposites or thermally stable clays and nanocomposites must resolve a number of important issues, beyond the thermal stability of the clay modifier. We will describe some aspects of the approach followed by our group to achieve this goal. The main objective of the case study to be described was to evaluate a number of phosphonium compounds for the production of thermally stable organoclays that would be suitable for preparing satisfactory PS nanocomposites by melt-compounding. 

Apart from plenary and oral presentations, there were computer poster presentations as well as a round-table discussion on the results of mastering nanotechnologies, semiindustrial and industrial production of nanocomposites and nanomaterials, and practical introduction of nanomaterials and nanotechnologies into different areas, including medicine and agriculture. The roimd-table discussion combined the reports of representatives from industrial enterprises and research institutions. The exhibition of modem equipment for the investigation of nanostmctures, nanosystems and nanomaterials, as well as nanotechnological units and machinery of well-known instmment-makers, were also scheduled. 

For the production of nanocomposites with the latex-based concept, it is preferable to be able to work at (relatively] high concentrations of exfoliated CNTs for reproducibility purposes (in order, for example, to be able to prepare a full series of nanocomposites of different CNT loadings by diluting the same surfactant-CNT dispersion], as well as for commercial reasons. 

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