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Polygon
A polygon, also called an N-gon, is a closed plane figure bounded by straight segments called sides; the interior angles of an n-sided polygon sum to (n-2) × 180 degrees.
Polygon mesh
A polygon mesh is a collection of vertices, edges, and faces that defines the surface of a 3D object, the standard representation in computer graphics and games.
Polygon triangulation
Polygon triangulation, also known as polygon division, is the decomposition of a simple polygon into triangles with non-intersecting interiors, a basic primitive in computer graphics and computational geometry.
Polyhalite
Polyhalite is a hydrated sulfate mineral containing potassium, calcium, magnesium, and sulfur, first described in 1817 in Austria and now mined in North Yorkshire, England, as a low-chloride fertilizer.
Polyhedron
A polyhedron (plural: polyhedra) is a three-dimensional solid bounded by flat polygonal faces joined along straight edges, with corners called vertices; examples include the cube, pyramid, and prism.
Polyhexahydrotriazine
Polyhexahydrotriazine (PHT) is a stiff, solvent-resistant crosslinked thermoset polymer, first reported as recyclable by IBM researchers in 2014 and depolymerized back to amine monomers by acid.
Polyhexanide
Polyhexanide, formally polyhexamethylene biguanide hydrochloride and commonly abbreviated PHMB, is a synthetic cationic polymer used as a broad-spectrum antiseptic, disinfectant, and preservative against bacteria, fungi, parasites, and certain viruses.
Polyhydric phenols
Polyhydric phenols, also called polyhydroxybenzenes, are phenols carrying two or more hydroxyl groups on the aromatic ring; their di- and trihydric members are commonly known as polyphenols.
Polyimide
A polyimide is a step-growth polymer whose backbone contains cyclic dicarboximide groups, formed from a dianhydride and a diamine; aromatic grades such as Kapton serve at up to 316 °C.
Polyisobutylene
Polyisobutylene (PIB) is a saturated homopolymer of isobutylene, first developed by BASF in 1931 and used mainly as a fuel and lubricant additive and in adhesives and sealants.
Polyisocyanurate
Polyisocyanurate (PIR), also known as polyiso, is a polymer whose backbone contains isocyanurate rings; in practice it means rigid polyurethane-modified foam used as wall, roof, and pipe insulation with better fire performance than polyurethane.
Polykarp Kusch
Polykarp Kusch (1911–1993) was a German-born American physicist at Columbia University who shared the 1955 Nobel Prize in Physics for his precision measurement of the electron's magnetic moment.
Polyketone
Polyketone, sold under trade names such as Carilon and POKETONE, is a semi-crystalline engineering thermoplastic formed by the perfectly alternating copolymerization of carbon monoxide with ethylene or other alpha-olefins.
Polylactic acid
Polylactic acid, also called polylactide or PLA, is a bio-based thermoplastic polyester made from fermented plant sugars and used in packaging, fibers, and medical devices.
Polylactide recycling
Polylactide recycling is the set of processes that reprocesses waste poly(lactic acid) (PLA), a compostable bio-based polyester, through mechanical, chemical, solvent-based, and enzymatic routes instead of disposal.
Polylogarithm
The polylogarithm, also called Jonquière's function, is a special function defined by the series Li_s(z) = sum z^n/n^s, generalizing the logarithm and Riemann zeta function.
Polymake
Polymake is open source software for research in polyhedral geometry, developed since 1997 at TU Berlin by Ewgenij Gawrilow and Michael Joswig, handling polytopes, fans, matroids, and tropical hypersurfaces.
Polymath Project
The Polymath Project, whose papers are signed D. H. J. Polymath, is a series of online collaborative mathematics projects launched by Timothy Gowers in January 2009 through blog comments.
Polymatroid
A polymatroid is a combinatorial structure in matroid theory, defined either as a polytope or by a monotone, submodular rank function; Jack Edmonds introduced it in 1970 as a generalization of the matroid.
Polymer
A polymer is a substance made of very large molecules built from repeated units called monomers, including natural ones like DNA and synthetic plastics like polyethylene.
Polymer chemistry
Polymer chemistry is the branch of chemistry concerned with the synthesis, mechanisms, and structure of polymers, large molecules built from repeating monomer units; synthetic polymers are over half the chemical industry's output.
Polymer mechanochemistry
Polymer mechanochemistry is the study of chemical reactions in polymers driven by mechanical force, using embedded force-responsive molecules called mechanophores for sensing, strengthening, and recycling.
Polymer of styrene and acrylamide
Polymer of styrene and acrylamide (styrene/acrylamide copolymer, CAS 24981-13-3) is a synthetic copolymer used as an opacifier in cosmetics and detergents, not approved as an EU pesticide, and studied for mercury adsorption and drag reduction.
Polymer precipitation
Polymer precipitation, also known as nanoprecipitation or solvent displacement, is a method that forms polymer particles by adding a nonsolvent to a dissolved polymer, used mainly for drug delivery.
Polymer synthesis in supercritical carbon dioxide
Polymer synthesis in supercritical carbon dioxide carries out polymerization in CO₂ above 31.1 °C and 73.8 bar, a tunable green solvent; depressurization leaves dry polymer with no solvent waste.
Polymer translocation through nanopores
Polymer translocation through nanopores is the process by which a polymer chain, such as DNA or a protein, crosses a membrane through a pore only a few nanometers wide.
Polymer-derived SiBCN ceramics
Polymer-derived SiBCN ceramics are quaternary non-oxide ceramics of silicon, boron, carbon, and nitrogen, made by pyrolyzing polyborosilazane precursors, with oxidation resistance exceeding that of SiC and Si₃N₄.
Polymer-dispersed liquid crystal
A polymer-dispersed liquid crystal (PDLC) is a composite film of liquid crystal droplets in a solid polymer matrix that switches electrically between a milky, light-scattering state and a transparent state.
Polymerase chain reaction
Polymerase chain reaction (PCR), invented by Kary Mullis in 1983 at Cetus, is a lab method amplifying specific DNA segments via denaturation, primer annealing, and Taq polymerase extension cycles; Nobel Prize 1993; basis of qPCR and digital PCR.
Polymeric carbon dioxide
Polymeric carbon dioxide, best known as phase V (CO₂-V), is a superhard crystalline form of solid CO₂ in which molecules become a covalent network, formed above about 40 GPa.