Mechanical properties, compositional effects

Folydlacetylenes offer a unique opportunity of studying structure/property relationships in polymers. This paper is concerned with structural factors which control mechanical properties. The effect of the size of side-groups upon the Young s moduli of different polydiacetylenes is discussed briefly. The effect of internal and surface defects upon the strengths of individual fibres is also described. Examples are given of how Raman spectroscopy can be used to follow the deformation of fibres and it is shown how this can be extended to fibres in composites. The general mechanical properties of the composites are also described. 

Knowles J.C. and Bonfield W. 1993. Development of a glass reinforced hydroxyapatite with enhanced mechanical properties, the effect of glass composition on mechanical properties and its relationship to phase changes. /. Biomed. Mater. Res. 27 1591-1598. 

BK Larson, LT Drzal. Glass fibre sizing/malrix interphase formation in liquid composite moulding effects on fibre/malrix adhesion and mechanical properties. Composites 25 711-721, 1994. 

Fig. 7). For the composites, however, the PP scattering and MMT scattering were discrete on the surface of the rod, but inside the nanocomposite rods only discrete scattering of the MMT was observed. This led to a fascinating discussion about the evolution of primary and secondary crystalline domains and concluded that the PP matrix of the composite must exhibit deteriorated mechanical properties. In effect, the work presents an interesting approach using SAXS to make predictions about the mechanical properties of semicrystalline composites.

Kevlar fibers can be used as reinforcement for wood-flour/high-density-polyethylene matrices to improve their mechanical properties. The study of Ou et al. [112] demonstrates that the addition of a small amount (23%) of Kevlar short fibers can cause an improvement in the tensile, flexural and impact properties of HDPE/wood composites. As expected, additional surface modification of the Kevlar fiber with organosilanes and halides resulted in a further improvement on the composites mechanical properties. This effect was ascribed to the increased interfacial compatibility between the aramid fibers and HDPE, evidenced by SEM, XPS and FTIR methods. 

Carli, L.N., Crespo, J.S., Mauler, R.S., 2011. PHBV nanocomposites based on organomodified montmorillonite and haUoysite the effect of clay t5fpe on the morphology and thermal and mechanical properties. Composites Part A Applied Science and Manufacturing 42, 1601-1608. 

Keywords smart materials, magnetic fillers, magnetorheological composites, elastomers, magnetic properties, mechanical properties, magnetorheological effect... 

With respect to mechanical properties, the effect of any mineral filler is firstly related to particle size and particle size distribution. For instance, the impact resistance of a PP-talc composite strongly depends on those two filler characteristics, and it is easily understood that particles with excessive dimensions are likely to be fracture initiation sites. For mineral fillers which are extracted from lodes, grinding and sorting are thus key preparation steps, with obviously processing costs that dramatically increase as the targeted (average) particle size decreases. The balance between the benefits in mechanical or physical properties and the extra-cost of filler addition is therefore the bottleneck of all applications for filled thermoplastics. 

Density. Density is the most important variable in determining mechanical properties of a foamed plastic of given composition. Its effect has been recognized since foamed plastics were first made and has been extensively studied. 

The effects of variations in composition, cleanliness, stmcture, and mechanical properties of electroslag remelted (ESR) 35NiCrMoV12.5 steel have been reported. This steel which ties between Grades 2 and 3 of ASTM specification A723 is widely used in Europe (145). 

The water hberated during the cure has no apparent effect on the composite properties. Glass-filled composites prepared in this manner retain mechanical properties at elevated temperatures as well as solvent and flammabiUty resistance (88). PhenoHc-graphite-fiber composites that exhibit superior mechanical properties have also been prepared by this process. 

The physical and mechanical properties of steel depend on its microstmcture, that is, the nature, distribution, and amounts of its metaHographic constituents as distinct from its chemical composition. The amount and distribution of iron and iron carbide determine most of the properties, although most plain carbon steels also contain manganese, siUcon, phosphoms, sulfur, oxygen, and traces of nitrogen, hydrogen, and other chemical elements such as aluminum and copper. These elements may modify, to a certain extent, the main effects of iron and iron carbide, but the influence of iron carbide always predominates. This is tme even of medium alloy steels, which may contain considerable amounts of nickel, chromium, and molybdenum. 

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