Polymer composites nano-sized fillers

The mechanical properties of polymer composites having a nano-sized filler whose dimensions are no larger than that of one polymer molecule differ from those of composites with micro-sized filler particles much larger than a polymer molecule because most of the polymer molecules interface with a nano-sized filler but not with a micro-sized filler (2). 

Finally, starting from the opinion [5] that today we cannot be happy with the mechanical performance of polymer composites reinforced with nano-sized fillers of various origins, new routes to create polymeric materials with improved properties have to be researched in addition to attempts to overcome the disadvantages. An attractive alternative in this respect seems to be the preparation of polymers themselves as nano-sized materials, as, for example, electrospinning does. 

Recentiy, a new class of organic-inorganic hybrid materials based on the ultra incorporation of nano-sized fillers (nanofillers) into a polymer matrix has been investigated. Nanotechnology is the aptitude to work on a scale of about 1-100 nm in order to understand, create, characterize and use material structure, devices, and system with unique properties derived from their base on the nanostructures. Nanocomposites could exhibit exclusive modifications in their properties, compared with conventional composites in terms of physical properties, including gas barrier, flammability resistance, thermal and environmental stability, solvent uptake, and rate of biodegradability of biodegradable (Chivrac et al. 2009). 

The dispersion of nano-sized fillers into polymer matrix creates a tortuous path for the diffusant in comparison to neat polymer having straight diffusive path perpendicular to the film (Figure 3). In case of intercalated and exfoliated nanocomposites, path travelled by diffusant molecule would be greater than that of aggregate micro composite. 

As it is known [13, 14], the scale effects are often found at the study of different materials mechanical properties. The dependence of failure stress on grain size for metals (Holl-Petsch formula) [15] or of effective filling degree on filler particles size in case of polymer composites [16] are examples of such effect. The strong dependence of elasticity modulus on nanofiller particles diameter is observed for particulate-filled elastomeric nanocomposites [5], Therefore, it is necessary to elucidate the physical grounds of nano- and micromechanical behavior scale effect for polymer nanocomposites. 

Kim, M., Lee, L., Jung, Y., Kim, S. (2013). Study on ion conductivity and crystallinity of composite polymer electrolytes based on poly(ethylene oxide)/poly(acrylonitrile) containing nano-sized AI2O3 Fillers, Ngng gi lfjmgteclmgl., 13(12), 7865-7869. 

Jaj Jajam, K. C., Tippur, H. V. Quasi-static and dynamic fi-acture behavior of particulate polymer composites A study of nano- vs. micro-size filler and loading-rate effects. Compos. Part B -... 

The PVA (Mw 1,25,000, Aldrich), Orthophosphoric acid (H PO ) (Ranbaxy, India) and nano particles of AEj03 (50 mn. Sigma) were used for the preparation of NCPE films. The films of Solid Polymer Electrolyte (PVA + HjPO ) and Nano Composite Polymer Electrolyte (PVA + H3PO + Al Oj) in different filler wt% ratios were prepared by solution cast technique. Grantdes of PVA were dissolved in triply distilled water and stirred magnetically for 10-12 hr to obtain a clear and homogeneous solution. A known amount of H3PO was added to it and stirred continuously until a viscous solution was obtained. A part of solution was poured into the Teflon Petri dishes to get SPE thin film and in another part of the solution, nano-sized Al Oj was added in different wt % to get NCPE thin films. The prepared thin films were rinsed with benzene/methanol to remove any volatile impurities present in it. 

Abstract Smart composites based on carbonyl iron powder, micro and nano size Fe304 in ethylene - propylene and acrylonitrile - butadiene rubber were manufactured and studied. Elastomer samples with various volume fractions of magnetic particles were tested. To improve dispersion of applied fillers in polymer matrix, ionic liquids were added during the process of composites preparation. To align particles in elastomer, cross-linking process took place in magnetic field. 

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