All articles starting with P
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Polyaspartic acid
Polyaspartic acid (PASP) is a synthetic, water-soluble, biodegradable polypeptide of aspartic acid units, produced industrially as a green alternative to polyacrylates and used as a mineral scale inhibitor.
Polyatomic ion
A polyatomic ion is an electrically charged molecule, a group of two or more covalently bonded atoms carrying a net charge and acting as a single unit in reactions and salts.
Polybenzimidazole
Polybenzimidazole (PBI) is a heat-resistant synthetic polymer first synthesized by Carl Marvel in the late 1950s for the U.S. Air Force, known for firefighter turnout gear and fuel cell membranes.
Polybenzoxazine
Polybenzoxazine, also called PBZ, is a thermosetting phenolic resin formed by ring-opening polymerization of benzoxazine monomers, combining phenolic heat resistance and flame retardancy with epoxy-like strength, used in aerospace composites.
Polybia sericea
Polybia sericea is a swarm-founding social wasp (Vespidae, Epiponini) of tropical South America, about 17 mm long, building carton nests, hunting caterpillars, using Richards' gland trail pheromones during swarming.
Polybius (urban legend)
Polybius is an urban legend about a supposedly addictive, harmful 1981 arcade game by "Sinneslöschen" in Portland, Oregon arcades, with men in black. Earliest trace: a 2000 CoinOp.org entry; Snopes and KLOV treat it as a hoax.
Polybius (Πολύβιος)
Polybius (Πολύβιος, c. 204–122 BC), Greek historian of Megalopolis and Achaean League hipparch, deported to Rome and associate of Scipio Aemilianus; author of the forty-book Histories on Rome's rise (264–146 BC), with Book VI anacyclosis and mixed-constitution theory.
Polybius square
The Polybius square, or Polybius checkerboard, is a cipher representing each letter as a row-and-column digit pair in a 5×5 grid, described by Polybius around 150 BC for torch signaling.
Polyborosiloxane
Polyborosiloxane (PBS) is a viscoelastic silicone polymer whose dynamic boron–oxygen bonds let it self-heal at room temperature; first made in 1947 as the main ingredient of Silly Putty.
PolyBot
PolyBot is a chain-type modular self-reconfigurable robot developed at Xerox PARC by Mark Yim, David Duff, and Kimon Roufas, which reconfigured between rolling loop, snake, and four-legged spider forms.
Polybutadiene
Polybutadiene, also known as butadiene rubber, is a synthetic rubber made by polymerizing 1,3-butadiene; it is the second most produced rubber worldwide, used in tire treads and golf ball cores.
Polybutylene
Polybutylene, more precisely polybutene-1 (PB-1), is a semicrystalline thermoplastic polyolefin used for hot and cold water piping since the mid 1960s, though it vanished from North America after 1990s plumbing-failure litigation.
Polybutylene adipate terephthalate
Polybutylene adipate terephthalate (PBAT), formally poly(butylene adipate-co-terephthalate), is a biodegradable copolyester first commercialized by BASF in 1998 as ecoflex, used for compostable packaging and agricultural mulch films.
Polybutylene succinate
Polybutylene succinate, sometimes called poly(tetramethylene succinate), is a biodegradable thermoplastic aliphatic polyester made from succinic acid and 1,4-butanediol, used in compostable packaging and agricultural films.
Polybutylene terephthalate
Polybutylene terephthalate (PBT) is a semicrystalline thermoplastic polyester made from 1,4-butanediol and terephthalic acid or dimethyl terephthalate, marketed from 1970 and used for automotive and electronic parts.
Polycab India
Polycab India Limited is an Indian manufacturer of wires, cables, and fast-moving electrical goods, headquartered in Mumbai and India's largest in the organized wires and cables market.
Polycapillary optics
Polycapillary optics, also known as Kumakhov lenses, are arrays of thousands of hollow glass tubes that collect and focus X-ray and neutron beams by total external reflection.
Polycaprolactone
Polycaprolactone (PCL) is a biodegradable, semicrystalline aliphatic polyester, first synthesized in the 1930s, with a melting point near 60 °C, used in resorbable sutures, drug delivery, and tissue-engineering scaffolds.
Polycarbazole
Polycarbazole is a conducting polymer formed by linking carbazole units through oxidative coupling, valued for chemical stability and used in OLEDs, solar cells, sensors, and corrosion protection coatings.
Polycarbonate
Polycarbonate, sold under brand names such as Lexan, is an amorphous thermoplastic combining high impact strength, optical transparency, and heat resistance, with production over 5 million tons a year.
Polycarbonate e-passport
A polycarbonate e-passport is a biometric passport with a data page of fused polycarbonate layers, where details are laser-engraved and a contactless chip is embedded, first issued by Finland in 1997.
Polycarbonate recycling
Polycarbonate recycling is the recovery of waste polycarbonate, an engineering plastic used in electronics and optics, through mechanical, solvent, or chemical routes back into monomers and chemicals.
Polycarbosilane
Polycarbosilane is an organosilicon preceramic polymer that converts to silicon carbide when heated, used mainly to make SiC ceramic fibers and ceramic matrix composites for aerospace.
Polycarp (Πολύκαρπος)
Polycarp (Πολύκαρπος), also known as Polycarp of Smyrna, was a Greek bishop of Smyrna, a leading second-century Christian figure and Apostolic Father martyred in the city's stadium.
Polycentric four-bar knee
A polycentric four-bar knee is a prosthetic knee joint for above-knee amputees in which a four-bar linkage replaces the single hinge, giving stance stability and better toe clearance.
Polycentropodidae
Polycentropodidae (Ulmer, 1903) is a family of annulipalpian caddisflies whose larvae spin silk snare nets at retreat openings; over 930 species in 23 genera, sister family Ecnomidae, type genus Polycentropus.
Polycephaly
Polycephaly, also called bicephaly, is the condition of having two or more heads on a single body, caused by incomplete embryonic splitting and seen in humans, cattle, and snakes.
Polychaete
Polychaetes (bristle worms, class Polychaeta) are mostly marine segmented annelids whose segments bear paired parapodia with chaetae; over 13,000 described species, external fertilization, trochophore larvae, and a phylogeny in which Clitellata nests within the group.
Polychemotherapy
Polychemotherapy is the treatment of cancer with several chemotherapy drugs given together in a single regimen; regimens like CHOP are named by acronyms built from drug names.
Polychlorinated biphenyl
Polychlorinated biphenyls (PCBs), sold commercially as Aroclors, are stable man-made chemicals with 209 variants, used as insulating fluids from 1929 until international bans as carcinogenic pollutants.