摘要:
A system for precision polymerization is disclosed comprising at least one Michael-type monomer and an aluminum compound AlR 1 R 2 R 3 as sole catalyst and initiator, wherein each of R1, R2, and R3 independently is Cl, F, I, Br, linear, branched or cyclic alkyl, heterocycloalkyl, linear, branched or cyclic alkenyl, heterocycloalkenyl, linear, branched, or cyclic alkenyl, linear, branched, or cyclic alkinyl, heterocycloalkinyl, linear, branched, or cyclic alkoxy, aryl, heteroaryl, aryloxy, silyl, metallocenyl, nitro, nitroso, hydroxy, or carboxyl, wherein each alkyl, alkenyl, alkinyl or alkoxy group independently has up to 12 carbon atoms, wherein each aryl or heteroaryl independently has 5 to 10 ring atoms, wherein any hetero group has at least one hetero atom selected from O, S or N, wherein each alkyl, alkenyl, alkinyl or alkoxy, heterocycloalkyl, heterocycloalkenyl, heterocycloalkinyl, aryl, heteroaryl, aryloxy group can be substituted by 1 up to the highest possible number of halogen atoms, or at least one electron-donating or electron-withdrawing group; with the proviso that not all three groups R 1 , R 2 , and R 3 are halogen, hydroxy, or alkoxy or wherein two of R1, R2, and R3 together with Al form a substituted or unsubstituted cyclic or heterocyclic group having 3 to 6 atoms, wherein a heterocyclic group has at least one hetero atom selected from O, S or N; as well as processes for preparing polymers and the polymers obtained therewith.
摘要:
A process for precision polymerization is described using a system of a Lewis acid, a Lewis base and a Michael-type monomer that can form a frustrated triple, wherein a Michael-type monomer, optionally dissolved in an organic solvent, is reached with a Lewis acid to form at least one zwitterionic type complex, a Lewis base is added to form a frustrated triple with the zwitterionic type complex which initiates the polymerization reaction, and the reaction is continued to form a polymer.
摘要:
Provided are: a flame resistant polymer which is obtained by reacting polyacrylonitrile with amine and nitro compounds, the polyacrylonitrile being polymerized by aqueous suspension polymerization using a redox initiator and containing an S component at an amount of 3,000 µg/g or less; a polymer solution using the polymer; a flame resistant fiber using the polymer solution; a carbon fiber using the flame resistant fiber; and methods for producing the same. A PAN-based polymer in which both yarn producing properties and flame resistance are improved can be realized. Also provided are a polymer solution which is suitable for spinning using the polymer and a method for producing the same, a desirable flame resistant fiber using the polymer solution and a method for producing the same, and a desirable carbon fiber using the flame resistant fiber and a method for producing the same.
摘要:
A method for synthesizing polyacrylonitrile (PAN) polymer with a narrow molecular weight distribution is disclosed. The preferred PAN polymer has a PDI (Mw/Mn) of about 2 or less. Such PAN polymer is synthesized by controlled/living radical polymerization using a special RAFT (Reversible Addition-Fragmentation Chain Transfer) agent. Also disclosed is a method for producing carbon fibers from PAN polymer with low PDI.
摘要:
Polymere, die N-substituierte Formamidstruktureinheiten enthalten, erhältlich durch katalytische Umsetzung von nitrilgruppenhaltigen Polymeren in Gegenwart von Wasserstoff, Kohlenmonoxid und/oder kohlenmonoxidfreisetzenden Verbindungen.
摘要:
There is provided with an admixture for hydraulic cement comprising as an effective component a water-soluble amphoteric polymer obtained by Hofmann degradation reaction of an α,β-unsaturated carbonamide polymer or a copolymer of α,β-unsaturated carbonamide and an anionic monomer having a weight average molecular weight of 1,000 - 1,000,000. A substituent such as a primary amino group produced as a result of the Hofmann degradation reaction provides excellent cement dispersing capabilities.
摘要:
Es wurde eine neue mit Wasser quellbare Zusammensetzung aus einem Geliermittel auf der Basis von hydrolysierten Homo- oder Copolymeren des Acrylnitrils und aus einem inerten Metalloxid hergestellt. Dabei wurden 1 bis 22% der Nitrilgruppen zu Amidgruppen und 99 bis 78% zu Alkalisalzen verseift. Die erhaltene Zusammensetzung hat eine schwammartige Struktur und zeichnet sich durch hohe Werte sowohl bezüglich der Quellkapazität als auch der Quellgeschwindigkeit aus. Daher eignet sie sich insbesondere zur Windelherstellung und zur Flachdachbegründung.
摘要:
Mit Wasser quellbare Substanzen auf Basis vernetzter Polyacrylnitrilhydrolysate, vorzugsweise in Granulatform, und deren Verwendung zur Verbesserung der Wasserretention in sandigen Böden und Pflanzsubstraten.