Mechanical
Formation of spherulites affects many properties of the polymer material; in particular, crystallinity, density, tensile strength and Young's modulus of polymers increase during spherulization. This increase is due to the lamellae fraction within the spherulites, where the molecules are more densely packed than in the amorphous phase. Stronger intermolecular interaction within the lamellae accounts for increased hardness, but also for higher brittleness. On the other hand, the amorphous regions between the lamellae within the spherulites give the material certain elasticity and impact resistance.
Changes in mechanical properties of polymers upon formation of spherulites however strongly depend on the size and density of the spherulites. A representative example is shown in the figure demonstrating that the strain at failure rapidly decreases with the increase in the spherulite size and thus with the decrease in their number in isotactic polypropylene. Similar trends are observed for tensile strength, yield stress and toughness. Increase in the total volume of the spherulites results in their interaction as well as shrinkage of the polymer, which becomes brittle and easily cracks under load along the boundaries between the spherulites.
Read more about this topic: Spherulite (polymer Physics), Properties
Other articles related to "mechanical":
... In physics, mechanical energy is the sum of potential energy and kinetic energy and present in the components of a mechanical system ... system that is only subject to conservative forces, like the gravitational force, the mechanical energy is constant ... like frictional forces, will be present, but often they are of negligible values and the mechanical energy's being constant can therefore be a useful approximation ...
... mirror and eyelevel pentaprism viewfinder) into one superbly integrated package with bulletproof mechanical durability and reliability, plus topnotch optical quality ... With the 35 mm SLR optical and mechanical format perfected, the industry turned to advancements in electronic convenience features ... the Nikkormat F-series was its high quality mechanical shutter ...
... Although mechanical contact-based switches are most commonly used for general purpose electrical switching, switches that have no moving parts are generally longer-lived ... Piezo and capacitive switches are the two most popular non-mechanical switch types currently available ... One advantage they have over mechanical contact-based switches is that they have no moving parts to wear out ...
... Mechanical (character), one of several characters in Shakespeare's A Midsummer Night's Dream A kind of typeface in the VOX-ATypI classification ...
Famous quotes containing the word mechanical:
“A man should have a farm or a mechanical craft for his culture. We must have a basis for our higher accomplishments, our delicate entertainments of poetry and philosophy, in the work of our hands.”
—Ralph Waldo Emerson (1803–1882)
“Prejudices are so to speak the mechanical instincts of men: through their prejudices they do without any effort many things they would find too difficult to think through to the point of resolving to do them.”
—G.C. (Georg Christoph)
“Industry has operated against the artisan in favor of the idler, and also in favor of capital and against labor. Any mechanical invention whatsoever has been more harmful to humanity than a century of war.”
—Rémy De Gourmont (1858–1915)