What is crystalline and brittle

Specifically, the POM study based on partially crystallized PLLA samples promotes the idea that the spherulitic crystals are mechanically weaker than glassy noncrystalline domains whose cohesive strength stems from the chain networking because of intermolecular uncrossability.

By removing the large spherulitic crystal formation and inducing nanocrystal formation through melt-stretching of PLLA in its amorphous state, we identified a completely transparent crystalline state of PLLA that is extremely tough and resistant against heat. Such files may be downloaded by article for research use if there is a public use license linked to the relevant article, that license may permit other uses.

More by Masoud Razavi. More by Shi-Qing Wang. Cite this: Macromolecules , 52 , 14 , — Article Views Altmetric -. Citations Supporting Information. Cited By. This article is cited by 30 publications. Macromolecules , 54 10 , Gutmann, Larisa A. Macromolecules , 53 19 , Macromolecules , 53 16 , Poly lactic acid Toughening through Chain End Engineering. Haugan, Bongjoon Lee, Michael J. Maher, Aristotelis Zografos, Haley J. Schibur, Seamus D.

Jones, Marc A. Hillmyer, Frank S. Stone breaks in a similar way, it just doesn't flex noticeably, anyway and it takes a lot more stress to get the process of breaking started. Disclaimer: this is all based on about twenty minutes worth of internet research, so if I am wrong about any or all of it hopefully someone who knows more about it will be able to set things straight.

Out of interest, the Destructive Harmonics supernatural ability of the Destrachan lists "wood, stone, metal, or glass" as the materials that the sonic attack can shatter. This isn't decisive in regards to shout , but it may be a little insight into what could be considered brittle materials with regards to sonic attacks. Whatever the case, both shout and great shout do pretty well against objects as sonic energy attacks do full damage to objects and ignore hardness.

Sejs First Post. Quite possibly metal. Ask yourself: is the substance rigid? Felix Explorer. Peanut Brittle. Sejs said:. MerakSpielman said:. Felix said:. All your examples are things that are both brittle and crystalline. Surely the spell would also be able to affect things that are merely brittle or crystalline. I'd say that anything that would shatter into numerous, sharp shards when you hit it with a hammer would qualify as brittle such as a brick, or an old, dry skull.

I'm having trouble coming up with a description of crystalline that doesn't go into modern chemestry, atoms, or molecules. Anybody got any ideas? Doctor Bomb First Post. That includes wood, crystal, ice, and most stone, but excludes earthen walls, living creatures, and most metals.

Interesting that there seems to be no consensus on what might be "brittle or crystalline" - might be worth e-mailing for an 'official' answer Post reply. Insert quotes…. Similar Threads. Replies 40 Views 4K. Aug 17, Wolf All exhibit high thermal and electrical conductivity, metallic luster, and malleability. Many are very hard and quite strong. Because of their malleability the ability to deform under pressure or hammering , they do not shatter and, therefore, make useful construction materials.

The melting points of the metals vary widely. These differences reflect differences in strengths of metallic bonding among the metals. Covalent network solids include crystals of diamond, silicon, some other nonmetals, and some covalent compounds such as silicon dioxide sand and silicon carbide carborundum, the abrasive on sandpaper.

Many minerals have networks of covalent bonds. The atoms in these solids are held together by a network of covalent bonds, as shown in Figure 5. To break or to melt a covalent network solid, covalent bonds must be broken. Because covalent bonds are relatively strong, covalent network solids are typically characterized by hardness, strength, and high melting points. Molecular solids , such as ice, sucrose table sugar , and iodine, as shown in Figure 6 , are composed of neutral molecules.

The strengths of the attractive forces between the units present in different crystals vary widely, as indicated by the melting points of the crystals. Substances consisting of larger, nonpolar molecules have larger attractive forces and melt at higher temperatures. Molecular solids composed of molecules with permanent dipole moments polar molecules melt at still higher temperatures. A crystalline solid, like those listed in Table 7 , has a precise melting temperature because each atom or molecule of the same type is held in place with the same forces or energy.

Thus, the attractions between the units that make up the crystal all have the same strength and all require the same amount of energy to be broken.

The gradual softening of an amorphous material differs dramatically from the distinct melting of a crystalline solid. This results from the structural nonequivalence of the molecules in the amorphous solid. Some forces are weaker than others, and when an amorphous material is heated, the weakest intermolecular attractions break first. As the temperature is increased further, the stronger attractions are broken.

Thus amorphous materials soften over a range of temperatures. Carbon is an essential element in our world. The unique properties of carbon atoms allow the existence of carbon-based life forms such as ourselves. Carbon forms a huge variety of substances that we use on a daily basis, including those shown in Figure 7.

You may be familiar with diamond and graphite, the two most common allotropes of carbon. Allotropes are different structural forms of the same element. Diamond is one of the hardest-known substances, whereas graphite is soft enough to be used as pencil lead.

These very different properties stem from the different arrangements of the carbon atoms in the different allotropes. You may be less familiar with a recently discovered form of carbon: graphene. Graphene was first isolated in by using tape to peel off thinner and thinner layers from graphite.