Chemistry of Engineering Materials - Metals, Polymers, and Nanoengineered Materials

Vocabulary flashcards covering key definitions and facts from all five provided lecture sources on metals, polymers, polyolefins, biopolymers, and nanoengineered materials.

Metal (in Chemistry)

An element that creates positive ions (cations) readily and has metallic bonds, often represented by a cloud of delocalized electrons and a lattice of positive ions.

Metallurgy

The study of metals.

Alkali Metals (Group IA)

Group IA elements characterized by lower densities than other metals, one loosely bound valence electron, the largest atomic radii in their periods, low ionization energies, low electronegativities, and high reactivity.

Alkaline Metals (Group IIA)

Group IIA elements that have low electron affinities, low electronegativities, two outer shell electrons, and smaller atomic radii than alkali metals that readily lose two electrons to form divalent cations.

Transition Metals (Group IB-VIIIB)

Group IB-VIIIB elements characterized as very hard with high melting and boiling points, high electrical and thermal conductivity, malleability, low ionization energies, and positive oxidation states.

Lanthanides and Actinides

Rare earth metals that are silver, silvery-white, or gray with a high luster, high electrical conductivity, and tarnish readily in air.

Tungsten

The hardest metal with the highest tensile strength, which is brittle and appears to break down on contact.

Cesium

Considered to be the softest metal, followed by Rubidium, Potassium, and Sodium.

Mercury

A liquid metal at room temperature that does not form a strong metallic bond, resulting in a low melting point of $-38.8\,^\circ\text{C}$.

Gallium

A metal with a melting point of $29.7\,^\circ\text{C}$, making it solid at room temperature ($20\text{--}25\,^\circ\text{C}$) but liquid at body temperature ($37\,^\circ\text{C}$).

Malleability

The physical property of a metal that allows it to be hammered or rolled into thin sheets without breaking.

Ductility

The physical property of a metal that allows it to be drawn or stretched into wires.

Sonority

The physical property of a metal to produce a ringing sound when struck.

Ferrous Metals

Metals that contain iron, such as steel, stainless steel, carbon steel, cast iron, and wrought iron.

Nonferrous Metals

Metals that contain no iron, such as copper, aluminum, lead, and zinc.

Polymer

A substance or material consisting of very large molecules (macromolecules) constituted by many repeating subunits derived from monomer molecules.

Monomer

A molecule that can react together with other monomer molecules to form a larger polymer chain or three-dimensional network in a process called polymerization.

Polynucleotides

Long natural polymers of nucleotides, such as RNA and DNA.

Polypeptides

Natural polymers that include proteins and shorter chains of amino acids, such as collagen, actin, and fibrin.

Polysaccharides

Linear or branched chains of sugar carbohydrates, such as starch, cellulose, and alginate.

Hemoglycin

A space polymer (previously termed hemolithin) that is the first polymer of amino acids found in meteorites.

Chitosan

A biopolymer used for water purification as a flocculant that purifies water through chelation by binding metal ions along its polymer chain.

High-density Polyethylene (HDPE)

A polyolefin consisting of straight carbon chains used in applications such as milk jugs and cutting boards.

Low-density Polyethylene (LDPE)

A polyolefin consisting of branched carbon chains used in products like Ziplock bags.

Polytetrafluoroethylene (PTFE)

Also known as Teflon, a halogenated polymer used in PTFE hotend tubing and space applications that releases acid gas ($\text{HCl}$ or $\text{HF}$) upon combustion.

Polymer Backbone

The continuously linked backbone of a polymer, consisting mainly of carbon atoms in plastics, silicon in silicones, or oxygen in polyethylene glycol, polysaccharides, and DNA.

Nanoengineered Materials

Materials designed, manipulated, or structured at the nanometer scale ($1\text{--}100\,\text{nm}$) that exhibit special properties not seen in bulk form.

Nanometer

A length equal to one millionth of a millimeter ($10^{-6}\,\text{mm}$), approximately $100{,}000$ times smaller than the diameter of a human hair.

Nanoparticles

Metal-based nanomaterials with tiny particles between $1\text{--}100\,\text{nm}$, such as gold nanoparticles used in medicine and titanium dioxide nanoparticles used in sunscreens.

Carbon Nanotubes (CNTs)

Long, thin cylindrical nanoengineered structures exhibiting extraordinary strength, high electrical conductivity, and a high strength-to-weight ratio.

Graphene

A 2D nanomaterial consisting of a single layer of carbon atoms that is $200\times$ stronger than steel.

Nanocomposites

Conventional materials like polymers or ceramics reinforced with nanoparticles, such as car parts reinforced with nanoclays for lightness and strength.