Compositional effects on mechanical properties

Molecular weight (kDa) Modulus (MPa) Ultimate tensile strength (MPa) Ultimate elongation (%) 

6-diisocyanatohexane (HDI), and 1,4-diisocyanatobutane (BDI) exhibit higher mechanical properties dne to symmetry when compared to asymmetrical diisocyanates that inhibit crystallization [14,17,94-96]. One such asymmetrical diisocyanate that has gained popularity is lysine methyl ester diisocyanate (LDI), which is used because of its amino add-based structure. In terms of mechanical properties, LDI has been shown to have reduced tensile properties compared to current aliphatic diisocyanates such as BDI and HDI. This decrease in mechanical properties was attributed to reduced registry and the associated loss of hard segment cohesion [32,49-51,96]. 

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Haraguchi K, Farnworth R, Ohbayashi A, Takehisa T (2003) Compositional effects on mechanical properties of nanocomposite hydrogels composed of poly(N,N -dimethylacrylamide) and clay. Macromolecules 36 5732-5741... 

Martin AR, Manolache S, Mattoso LHC et al (2000) Plasma modification of sisal and high-density polyethylene composite, effect on mechanical properties. In Natural polymers and composites, pp 431-436... 

Reference No. (BS 3468 1974) Typical composition (%) Heat resistance Effect on mechanical properties Overall... 

In order to prepare ENR/silica nanoscale organic-inorganic hybrid composites, nanosilica has been generated by the sol-gel technique using TEOS as a precursor. Their effect on mechanical properties of the resultant nanocomposites have been... 

J.M. Felix, P. Gatenholm, and H.P. Schreiber. Controlled interactions in cellulose-polymer composites. 1 effect on mechanical properties. Polym. Composites, 1993, 14(6), 449-457. 

Recently, some other non- conventional ways have been used to prepare zirconia-mullite ceramics [12-17]. In our previous work, nano-zirconia/mullite composite ceramics were prepared by in-situ controlled crystallization from the Si-Al-Zr-0 amorphous bulk, the crystallization kinetics and the general view on the performance were discussed for the first time. In this article, the detail crystallization behavior, structure changes and their effect on mechanical properties for this new nano composite ceramics with high performance have been evaluated. 

On the other hand, the mechanical properties of thermoplastic vulcanizates containing ground tire rubber have been investigated with the aim of increasing use of recycled rubber. The compositions tested included passenger car combined with EPDM, SBR rubber, isoprene rubber, and butadiene rubber. It was found that the particle size of the ground tire rubber had small effect on mechanical properties, but that the choice of the sulfur accelerator was significant [26]. 

The microstructural factors that have the greatest effect on mechanical properties are the per cent crystallinity and the preferred orientation of the crystals (if any). Composite mechanics concepts will be needed to explain the mechanical properties of spherulitic polymers hence we return to them at the end of the next chapter. 

Thermal cycling of SiC/RBSN in nitrogen had no effect on mechanical properties, but in oxygen environment, composite properties degraded due to internal oxidation (discussed in Section 1.2d) and swelling as shown in Table 11. 

R.T. Bhatt and JT). Kiser, Matrix Density Effects on Mechanical Properties of SiC/RBSN Composites, NASA-TM 103733, 1990. 

A. Hahnel, E. Pippel and J. Woltersdorf, Nanostructure of Interlayers in Different Nicalon Fibre/Glass Matrix Composites and their Effect on Mechanical Properties, J. Microscopy 177, 264-271 (1995). 

Couto E et al (2002) Oxygen plasma treatment of sisal fibers and polypropylene effects on mechanical properties of composites. Polym Eng Sci 42(4) 790-797... 

The results of research described above prove univocally that the presence of lignocellulosic material in polymeric composites influences the crystallization process, altering the kinetic parameters, such as induction time, degree of crystallinity, conversion degree, etc., and characteristic temperatures. Using modification of the filler is not without the effect on crystallization of the matrix. An interesting phenomenon that has not been explained completely so far is the transcrystallization. Both the formation of transcrystallization and its effect on mechanical properties remain a disputable question among researchers. 

The research results confirm that the application of silica-organic compounds for modification of cellulose fiber surface considerably improves strength properties of composites [50, 51, 72-75]. Raj et al. [72] found that the modification of cellulose fibers with silanes as well as with isocyanate caused improvement of mechanical properties of composites based on polypropylene matrix. However, studies conducted by Hornsby et al. [76] do not confirm that. His results prove that processing flax fibers with silanes has no effect on mechanical properties of composites based on polypropylene matrix. These contradictory conclusions are probably the effect of a complex anatomical structure of cellulose fiber and/or application of suitable conditions of modification reaction. 

Weathering audits Effect on Mechanical Properties of Sisal RPP Composites... 

A.J. Pyzik, D. R. Beaman, Al-B-C Phase Development and Effects on Mechanical Properties of B4C/AI Derived Composites , Journal American Ceramic Society, 78, (2), pp.305-12,1995. 

To mimic the mechanical behavior of the native tissue is a basic assumption to facilitate the biointegration and function of the substitute. Incorporation of fibers to the biomaterial matrix opens the way to inhomogeneity, anisotropy, nonlinearity, and viscoelasticity features. Provided that interfacial binding between matrix and fibers in the composite goes on, mechanical properties could be tailored by varying the amount and orientation of fibers embedded, to suit the purpose applications, whether it s related to hard or soft tissue substimtes. Individual fibers, no matter how small and isolated compared to fibrous structure, could affect mechanical properties. To be effective, fibers principal direction should be considered and controlled. 

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