All articles starting with P
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Polyhydroxyalkanoates
Polyhydroxyalkanoates (PHAs) are biodegradable polyesters of hydroxy fatty acids that many bacteria and archaea store as granules, and that serve as thermoplastic, biocompatible materials for packaging, medicine, and agriculture.
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.
Polyimide aerogel thermal insulation
Polyimide aerogel thermal insulation is a flexible polymer aerogel developed at NASA's Glenn Research Center for hypersonic heat shields and commercialized as AeroZero by Blueshift Materials.
Polyimide separator
A polyimide separator is a porous polyimide membrane that keeps lithium battery electrodes apart, offering far greater heat resistance and dimensional stability than conventional polyolefin separators.
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.
PolyJet (3D printing)
PolyJet is a material jetting 3D printing process, owned by Stratasys, that jets liquid photopolymer droplets cured with UV light to build smooth, accurate, multi-material parts.
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.
Polyketide
A polyketide is a natural product biosynthesized by polyketide synthases from acyl-CoA units, produced by bacteria, fungi, and plants, and including medicines such as erythromycin and lovastatin.
Polyketide synthase
Polyketide synthase (PKS), types I, II, III multidomain enzymes assembling antibiotics like erythromycin from acyl-CoA precursors via modular or iterative condensation, parallel to fatty acid biosynthesis.
Polyketide synthase dimerisation element domain
Polyketide synthase dimerisation element domain (DE, InterPro IPR041618): a ~55-residue motif N-terminal to KR in about half of PKS β-modules; novel fold, 19.9 μM dimerization constant, PDB 4IMP, preserved in KR domain swaps.
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.
Polylactic acid recycling
Polylactic acid recycling (PLA recycling) recovers the biobased polyester PLA from waste by mechanical, chemical, and biological means, such as depolymerizing it back to lactic acid.
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.
Polymarket
Polymarket is a prediction market platform founded in 2020 by Shayne Coplan on which users buy and sell shares in outcomes of events such as elections and sports.
Polymath
Polymath: a person with deep expertise and contributions across several distinct fields, from Greek polys (many) and mathema (learning). Covers the term's 1603 Latin origin, Islamic and Renaissance traditions, breadth–depth–integration research, and interdisciplinary performance evidence.
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 aerogel insulation
Polymer aerogel insulation is thermal insulation made from aerogels whose solid skeleton is an organic polymer rather than silica, combining very low thermal conductivity with the toughness and flexibility of plastics.
Polymer banknote
A polymer banknote, also called plastic money, is a banknote printed on a plastic substrate rather than paper, pioneered by Australia in 1988 to combat counterfeiting.
Polymer blend
A polymer blend is a physical mixture of two or more polymers that combines their properties in one material; most blends are immiscible and need compatibilizers.
Polymer brushes
A polymer brush is a layer of polymer chains tethered by one end to a surface at a density so high that the chains stretch away from it.
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 clay
Polymer clay is an oven-hardening modeling material made of PVC particles in a liquid plasticizer; it never dries in air and is used for jewelry, beads, miniatures, and sculpture.
Polymer crystallinity
Polymer crystallinity is the fraction of a polymer existing in ordered crystals rather than the disordered amorphous phase. Semicrystalline polymers form thin lamellar platelets, often arranged as spherulites.
Polymer degradation
Polymer degradation is the change in a polymer's chemical structure, molecular weight, or properties caused by heat, oxygen, UV radiation, moisture, mechanical stress, chemicals, or microorganisms.