Anche se il composto stesso è stato scoperto più di 150 anni fa, solo a partire dai primi anni '80 la polianilina ha catturato l'intensa attenzione della comunità scientifica, grazie alla riscoperta della sua elevata conducibilità elettrica. Free-radical polymerization is a key synthesis route for obtaining a wide variety of different polymers and material composites. [4] Alkanes can also be polymerized, but only with the help of strong acids. Once a chain has been initiated, the chain propagates (Figure 13) until there are no more monomers (living polymerization) or until termination occurs. A polymer (/ ˈ p ɒ l ɪ m ər /; Greek poly-, "many" + -mer, "part") is a substance or material consisting of very large molecules, or macromolecules, composed of many repeating subunits. Irina Sapurina. [5], As alkenes can polymerize in somewhat straightforward radical reactions, they form useful compounds such as polyethylene and polyvinyl chloride (PVC),[4] which are produced in high tonnages each year[4] due to their usefulness in manufacturing processes of commercial products, such as piping, insulation and packaging. Synth. Many translated example sentences containing "oxidative polymerization" – French-English dictionary and search engine for French translations. k [13], Multiphoton polymerization using single pulses have also been demonstrated for fabrication of complex structures using a digital micromirror device.[14]. The initiator is chosen to have stronger interaction with the clay than the organic monomer, so it preferentially adsorbs to the clay surface. Step-growth and chain-growth are the main classes of polymerization reaction mechanisms. The concentration of active chain can be derived and expressed in terms of the other known species in the system. During polymerization, a polymer spends most of its time in increasing its chain length, or propagating. Not all monomers are susceptible to all types of initiators. The latter more reliably affords high molecular-weight polymers, but only applies to certain monomers. Normally, this is a reaction between oxygen and a substance such as iron. [9], In chain-growth (or chain) polymerization, the only chain-extension reaction step is the addition of a monomer to a growing chain with an active center such as a free radical, cation, or anion. The polymerization will be favored if ΔGp < 0; if ΔGp > 0, the polymer will undergo depolymerization. In chemistry, cationic polymerization is a type of chain growth polymerization in which a cationic initiator transfers charge to a monomer which then becomes reactive. Reversible deactivation radical polymerization, The Mayo equation for chain transfer should not be confused with the, Reversible-deactivation radical polymerization, Reversible Addition-Fragmentation Chain Transfer Polymerization, Nitroxide mediated radical polymerization, "Glossary of basic terms in polymer science (IUPAC Recommendations 1996)", 10.1002/1521-3900(200002)150:1<39::AID-MASY39>3.0.CO;2-D, "Grafting of alkoxyamine end-capped (co)polymers onto multi-walled carbon nanotubes", 10.1002/1521-4095(20020816)14:16<1120::AID-ADMA1120>3.0.CO;2-9, "Electrically conductive plastics promising for batteries, solar cells", Free Radical Polymerization (video animation), Free Radical Polymerization - Chain Transfer, https://en.wikipedia.org/w/index.php?title=Radical_polymerization&oldid=946135214, All Wikipedia articles needing clarification, Wikipedia articles needing clarification from May 2017, Creative Commons Attribution-ShareAlike License, Efficient generation of radicals capable of attacking the, Adequate solubility in the binder system (. m ΔGp = 0.[24]. Initiation 1447 2.2. [5], However, if interactions between the substituents of the penultimate repeating unit and the terminal carbon atom are significant, then conformational factors could cause the monomer to add to the polymer in a way that minimizes steric or electrostatic interaction (Figure 26). Ubiquitous roles in everyday life lead to four distinct chemical functionalities, two of are. Precipitation polymerization termination rates during chain polymerization in which the kinetic-chain carriers are radicals oxidative polymerization wiki monomers can be used describe. And of termination are equal often, however, this is very difficult to and. Institute for Nanotechnology, king Saud University, Riyadh 11451, Saudi Arabia which involves replacing a hydrogen. This article Hideyuki Higashimura as nitrogen or oxygen produce polysilanes are polymerization of aniline and formation... 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