Mechanical properties organoclays

In the matrix of PLA/ polycaprilactone (PCL)/OMMT nano-composites, the silicate layers of the organoclay were intercalated and randomly distributed (Zhenyang et at, 2007). The PLA/PCL blend significantly improved the tensile and other mechanical properties by addition of OMMT. Thermal stability of PLA/PCL blends was also explicitly improved when the OMMT content is less than 5%wt. Preparation of PLA/thermoplastic starch/MMT nano-composites have been investigated and the products have been characterized using X-Ray diffraction, transmission electron microscopy and tensile measurements. The results show improvement in the tensile and modulus, and reduction in fracture toughness (Arroyo et ah, 2010). 

It is also interesting to look into the chemical interactions of organoclay (QUAT-modified MMT) with functionally polar rubbers like XNBR, CR, and their mutual blend. The role of layered silicate on the curing process of CR/XNBR blends was investigated through the study of curing kinetics, mechanical properties, WAXS, and DMA [74]. 

Morgan, A.B. Harris, J.D. Effects of organoclay soxhlet extraction on mechanical properties, flammability properties and organoclay dispersion of polypropylene nanocomposites. Polymer 2003, 44, 2313-2320. 

Lan and Pinnavaia [6] showed that hybrid organic-inorganic composites exhibited mechanical properties superior to those for their separate composites. Dependence of tensile strength and modulus of epoxy nano-clay composites on the chain length of the clay-intercalated alkylammonium ions is shown in Fig. 28. The presence of the organoclay substantially increased both the tensile strength and modulus relative to the pristine polymer. The mechanical properties increased with any exfoliation in the order ... 

Tanoue, S., Utracki, L. A., Garcia-Rejon, A., Tatibouet, J., and Kamal, M. R., Melt compounding of different grades of polystyrene with organoclay Part 3. Mechanical properties, Polym. Eng. ScL, 45, 827-837 (2005). 

Using data of the Table 2, we explain the improvement in the mechanical properties of the nanocomposites with added organoclay up to 3 wt% by the good degree of distribution of the organoclay within the polymeric matrix. The degree of the improvement also depends on the interaction between the polymeric chain and clay layers. 

The study of the influence of the degree of the extract of fibers on the mechanical properties has shown that the limit of strength and the rigidity modulus both increase in PBT whereas they decrease in nanocomposites (Table 5). This can be explained by the breaking of the bonds between the organoclay and PBT at greater degree of extract. Sirch phenomena have been observed in numerous polymeric composites [73-75]. 

V. Tanrattanakul and P. Saithai, Mechanical properties of bioplastics and bio-plastic-organoclay nanocomposites prepared from epoxidized soybean oil with different epoxide contents , /AppZ Polym Sci, 2009,114, iC61 (n. 

The mechanical properties showed an increase of 0.9 GPa for the storage modulus at 30°C when 5% of exfoliated clay nanoplatelets were added. In contrast, the glass transition temperature, decreases with the addition of the organoclay nanoplatelets (45). 

Chow, W. S., Mohd Ishak, Z. A., Karger-Kocsis, J., Apostolov, A. A., and Ishiaku, U. S. 2003. Compatibilizing effect of maleated pol5 ropylene on the mechanical properties and morphology of injection molded polyamide 6/pol5 ropylene/organoclay nanocomposites. 44 7427-7440. 

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