Nanocomposites tensile properties

Effect of different RSF loadings on RSF/PP nanocomposite tensile properties... 

Haq, M., Brngueno, R., Mohanty, A.K., Misra, M., 2009b. Processing techniques for bio-based imsaturated-polyester/clay nanocomposites tensile properties, efficiency, and limits. Composites Part A Applied Science and Manufacturing 40, 394—403. 

They have studied the properties of NR-epoxidized natural rubber (ENR) blend nanocomposites also. Vulcanization kinetics of natural mbber-based nanocomposite was also smdied. The effect of different nanoclays on the properties of NR-based nanocomposite was studied. The tensile properties of different nanocomposites are shown in Figure 2.7 [33]. 

Bandyopadhyay et al. [138] have also studied the distribution of nanoclays such as NA and 30B in NR/ENR (containing 50 mol% epoxy) and NR/BR blends and their effect on the overall properties of the resultant nanocomposite blends. They calculated the preferential distribution of clays at various loadings in the blend compounds from the viscoelastic property studies from DMA. The tensile properties of the 50 50 NR/ENR and 50 50 NR/BR blend nanocomposites are shown in Table 5. It is apparent that in both the blends that the mechanical properties increase with increasing clay concentration up to a certain extent and then decrease. These results have been found to depend on matrix polarity and the viscosity of the blend compounds. 

The effect of the microstructure of acrylic copolymer/terpolymer on the properties of silica-based nanocomposites prepared by the sol-gel technique using TEOS has been further studied by Patel et al. [144]. The composites demonstrate superior tensile strength and tensile modulus with increasing proportion of TEOS up to a certain level. At a particular TEOS concentration, the tensile properties improve with increasing hydrophilicity of the polymer matrix and acrylic acid modification. 

Table 6 Tensile properties of various EVA-based nanocomposites...

For both EPDM-LDH and XNBR-LDH nanocomposites, the various tensile properties are summarized in Table 13 and their typical stress-strain plots are shown in Fig. 58 [104]. In Fig. 58a, the gum vulcanizates of both rubber systems showed typical NR-like stress-strain behavior with a sharp upturn in the stress-strain plot after an apparent plateau region, indicating strain-induced crystallization. With the addition of LDH-C10 in the XNBR matrix, the stress value at all strains increased significantly, indicating that the matrix undergoes further curing (Fig. 58b). 

Y. I. Tien and K. H. Wei, High-tensile-property layered silicates/polyurethane nanocomposites by using reactive silicates as pseudo chain extenders, Macromolecules 34, 9045-9252 (2001). 

Keywords nanocomposites, dispersion, aspect ratio, in-situ, melt, morphology, tensile properties, glass transition temperature, degradation, functionalization, electrical conductivity, resistivity. 

Du et al. (50) reported the synthesis of butadiene styrene rubber nanocomposites with halloysite nanotubes. The tensile properties of the composites containing various amounts of nanotubes are depicted in Table 2.2. The tensile properties were observed to significantly increase as a function of increasing amount of nanotubes in the composites. For the maximum loading of the nanotubes, a tensile modulus of 5.56 MPa was observed as compared to 1.52 MPa for the pure polymer. 

Deng et al. (8) investigated the tensile properties of PEEK/MWCNTs, and found increases in the elastic modulus and yield strength at temperatures above and below Tg at 25°C, the tensile modulus increased by -90% for composites including 15 wt% MWCNTs, and the increment reached -160% at 200°C. According to those results, the improvement of MWCNTs in the mechanical behaviour of the matrix is more effective at higher temperatures. Experimental results do confirm that the overall mechanical performance of PEEK/CNT nanocomposites is well above the required for potential aircraft applications. 

Effect of Structure and Morphology on the Tensile Properties of Polymer/ Carbon Nanotube Nanocomposites... 

Crucially, structure of CNTs and polymers plays a key role on mechanical properties and load-transfer of nanocomposites. Efficient load-transfer is only possible when adequate interfacial bonding strength is available. Interfacial failure may compromise the reinforcement effect and then the full potential of CNTs may not be realized (11). Therefore, it is of great importance to understand the effect of molecular structure, interfacial structure and morphology characteristics on the tensile properties of nanocomposite materials. 

In the last ten years, a great deal of experimental work has been presented about the tensile properties of CNTs/polymer composites in the literature. However, it is difficult to generalize across these studies because of the large number of parameters that can influence the effective properties, including size and structure of the CNT, CNT/ polymer interaction, processing techniques and processing conditions. In this chapter, the effect of structure and morphology on the properties of the nanocomposites will be focused and discussed. 

In one example, the tensile strength of polyamide 6 was increased by 55% and the moduli by 90%, with the addition of only 4wt% of delaminated clay. The enhanced tensile property of PCN suggests that nanocomposite performance is related to the degree of clay delamination, which increases the interaction between the clay layers and the polymers. Several explanations, based on the interfacial properties and the mobility of the polymer chains, have been given for this reinforcement. Kojima et al. reported that the tensile modulus improvement for polyamide 6-clay hybrid originated from a constrained region, where the polymer chains have reduced mobility. The dispersion and delamination of the clay were the key factors for the reinforcement. The delaminated nanocomposite structure produces a substantial increase in modulus. 

In terms of nanocomposite reinforcement of thermoplastic starch polymers there has been many exciting new developments. Dufresne [62] and Angles [63] highlight work on the use of microcrystalline whiskers of starch and cellulose as reinforcement in thermoplastic starch polymer and synthetic polymer nanocomposites. They find excellent enhancement of properties, probably due to transcrystallisation processes at the matrix/fibre interface. McGlashan [64] examine the use of nanoscale montmorillonite into thermoplastic starch/polyester blends and find excellent improvements in film blowability and tensile properties. Perhaps surprisingly McGlashan [64] also found an improvement in the clarity of the thermoplastic starch based blown films with nanocomposite addition which was attributed to disruption of large crystals. 

Montrorillonite (MMT) is the most popular filler used for developing thermoplastic starch (TPS)/clay nanocomposites. Nanocomposites showed a significant improvement in tensile properties compared to the pure matrix [231]. 

The objective of this work was to use rice straw pulp cellulose fiber to prepare environmental-friendly rice straw fibril and fibril aggregates (RSF) and evaluate the fibril and fibril aggregates as a novel reinforcing material to compound polypropylene (PP)/ RSF nanocomposite. The scanning electron microscopy (SEM), wide angle X-ray diffraction (WAXD), laser diameter instrument (LDl) were used to evaluate the characteristics of RSF. The RSF/PP nanocomposite was prepared by novel extrusion process. The interface compatibility and tensile properties of nanocomposite were investigated by FTIR and tensile test, respectively. 

Ahm Ahmadi, M., Moghbeli, M. R., Shokrieh, M. M. Unsaturated polyester-based hybrid nanocomposite fracture behavior and tensile properties. J. Polym. Res. 19 (2012) Article No. 9971. 

Table 12 Tensile properties of the polyethylene-clay nanocomposite and related samples (n = 5). The values in parentheses are the relative values of the nanocomposites and PECC ...

However, there are few reports on chitosan/bentonite nanocomposites (Yang Chen, 2007 Zhang et al., 2009 Wan Ngah et al., 2010). The physical properties and biological response of chitosan strongly depend on the starting materials and nanocomposite preparation conditions. In the present study chitosan/day nanocomposites were prepared using two kinds of clay and different chitosan/day ratios, to evaluate how these variables affect the dispersion of clay particles into the chitosan matrix. The samples obtained were characterized by infrared spectroscopy, x-ray diffraction, and mechanical (tensile) properties. 

It has been established that electrospinning a polymer solution containing well-dispersed carbon nanotubes leads to nanocomposite fibers with the embedded carbon nanotubes oriented parallel to the nanofiber axis due to the large shear forces in a fast fiber-drawing process. Table 1 lists most of the polymer/CNT composite nanofibers produced by electrospining, along with their fiber diameters and tensile properties. 

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