Polymeric condensation

The reaction of gaseous SO2 or SO3 with O2 in a silent electric discharge gives colourless polymeric condensates of composition S03+ t (0 < jc < 1). These materials are derived from yS-SO3 by random substitution of oxo-bridges by peroxo-bridges ... 

Though less prevalent than addition polymerization, condensation polymerization produces important polymers such as polyesters, polyamides (nylons), polycarbonates, polyurethanes, and phenol-formaldehyde resins (Chapter 12). 

How would you explain to a young science student how to decide whether a given compound might be useful as a monomer for addition polymerization Condensation polymerization ... 

The most common form of step growth polymerization is condensation polymerization. Condensation polymers are generally formed from simple reactions involving two different monomers. The monomers are difunctional, having a chemically reactive group on each end of their molecules. Examples of condensation polymerization are the formation of nylon 66, a polyamide, and of poly(ethylene terephthalate), a polyester. Because condensation poly-... 

Lekishvili N.G., Katsitadze M.G., Nakaidze L.I., Khananashvili L.M. Some Kinetically Regularities of Polymerization Condensation Reaction of Organocyclosilazanes with Spacial Groups at Silicon Atoms with Aromatic Dihydroxy compounds. Bulletin of the Academy of Sciences of Georgia. Series of Chemistry. 152, 3 529-531 (1995) (Rus.). 

The basic structure of humic substances involves a backbone composed of alkyl or aromatic units crosslinked mainly by oxygen and nitrogen groups. Major functional groups attached to the backbone are carboxylic acids, phenolic hydroxyls, alcoholic hydroxyls, ketones, and quinones. The molecular structure is variable as it is dependent on the collection of DOM available in seawater to undergo the various polymerization, condensation, and oxidation reactions and reaction conditions involved in humification, as well as the ambient physicochemical reaction conditions, such as temperature and light availability. 

The very great stability of the iron (II) — N=C—C=N— chelate ring provides the driving force for the reaction. This is further illustrated by the formation of monomeric Schiff bases between Qj-diketones and methylamine (Equation 21), for in the absence of the metal ion (Fe+2, Co+2, Ni+2) polymeric condensation products are formed (30, 49). 

It was decided to study the system tetrakis (trifluorophosphine) nickel- (0) -ammonia (23) in some detail a smooth reaction was observed when the complex, condensed on excess ammonia at liquid air temperature, was allowed to warm up gradually. Precipitation of colorless crystals, identified as ammonium fluoride in almost stoichiometric amount, based on complete ammonolysis of the phosphorus-fluorine bonds, was observed at temperatures as low as —90° to —80°. Removal of the ammonium fluoride by filtration at temperatures not higher than —50°, and subsequent slow evaporation of the ammonia from the filtrate invariably led to a brown-yellow solid, although a colorless, crystalline material was formed initially. The product was decomposed almost instantaneously by water with precipitation of elemental nickel. Analysis of the hydrolyzate obtained in aqueous hydrochloric acid revealed a nickel-phosphorus-nitrogen atom ratio close to 1 4 4, corresponding to an apparently polymeric condensation product. 

Mumper R, Wang JJ, Claspell JM et al (1995) Novel polymeric condensing carriers for gene delivery. Proc Inti Sym Control Release Bioact Mater 22 178-179... 

The most likely opportunities for exploitation will come from mass transfer-limited reactions and the combination of unit operations in one device. Examples of reactions mentioned earlier include polymerization, condensation reactions, crystallization, and heterogeneous catalysis. Combined unit operations are illustrated by reactive distillation, polymer devolatilization with pelletization, and the use of heat exchangers (reboilers and condensers) with distillation. 

Cationic Formaldehyde Condensation Resins. An appreciable improvement in wet-fastness properties is obtained by aftertreating the dyeings with polymeric condensation resins containing strongly basic groups. This leads to the formation of insoluble salts from resin cation and dye anion. 

Keywords Chain-growth polymerization Condensation polymers Cyclic polymers jt-Conjugated polymers Polycondensation... 

Domine and Gogos (88-90) considered a very long, very wide, and thin mold being fed by a constant temperature mixture of AA, BB molecules. Both types are bifunctional and the feed has a molecular weight Mq. The polymerization, assumed to be reversible, proceeds by the reaction of A-ends with B-ends, and follows idealized step polymerization (condensation) kinetics without the generation of a small molecule (91). Specifically, we have... 

Polymers are made from the repeating units through two process. One process simply adds each succeeding monomer onto the chain through various methods, called addition polymerization. Condensation polymerization is the second process of adding monomers onto the chain to make large molecules. In condensation polymerization, small molecules like water are removed as the monomer unit is added onto the chain. 

Step polymerization (condensation reactions) polyetheremide, polyesters, polyethylterephthalate (PET), polybutylterephtalate (PBT), polyamide 6.6, polyarylate, polyurethanes, polyamide 6... 

Figure 1. Simulation of the transient response of iron catalysts to the introduction of synthesis gas to the reactor, when the propagation step is rate limiting. Polymerization-condensation model is on the top (Ct + = C, ) and polymerization model (C, = A eCj = keC J, co-insertion model (C, = A eC, = keA ) is on the bottom. The data required for the simulation are taken from the work of...

The chief impurities are the polymeric condensation products of />-aminobenzaldehyde with itself. No satisfactory method for recrystallization has been found. If the melting point is high and a pure product is desired, it is best to extract with boiling water until the filtrate is clear, and extract the monomer from the water with ether. This procedure gives recoveries of 25-30%. 

A polymeric condensation product of aluminium oxide and aspirin which contains about 83% of total salicylates. 

No. Oligomer Initiator Temp. rc) Conversion (%) Polymerization Condensation ... 

The polymeric phosphazenes are treated in chapter (see Polyphosphazenes) A recent monograph covers the chemistry of polyphosphazenes (nomenclature, synthesis of cyclic monomers , ring opening polymerization, condensation polymerization, substitution, polymer properties, and applications more than 1000 literature citations). Other reviews have also been published recently. Sulfur-containing polyphosphazenes have also been described. ... 

From these discoveries branched his work in hydrogenation (both organic and inorganic), isomerization, polymerization, condensation, cyclization, alkylation, and related reactions... 

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