Polycondensation products

Polyimides (PI) are polycondensation products (1) prepared from derivatives of tetracarboxylic acids and primary diamines (1—5). Descriptions of self-polycondensation polymers (2) based on aminodicarboxylic acid derivatives are also found in the literature (6—9). 

Enamines containing one -hydrogen atom react with the lactone dimer of dimethylketene to form aminocyclohexanediones 116). Polycondensation of acetone diethyl ketal takes place by treating it with morpholine and a catalytic amount of p-toluenesulfonic acid while distilling off the ethanol formed 117-119). The resulting spiran, bicyclo, and cyclooctadienone products differ from the known polycondensation products of acetone, and hence their formation probably involves enamine intermediates 119). 

M. Hofinger and H. Schellenberg. Process for the preparation of polycondensation products from alkoxylated fatty amines, diols and aliphatic dicarboxylic acids (Verfahren zur Herstellung von Polykon-densationsverbindungen aus oxalkylierten Fettaminen, Diolen und Aliphatischen Dicarbonsauren). Patent EP 299348,1989. 

Polycarbonates have also been studied recently with regard to chemical heterogeneity. Polycarbonates are polycondensation products of phosgene and aliphatic or aromatic dihydroxy compounds. 

The washing-off of prints is best carried out with anionic polycondensation products of arylsulphonic acids [29] since these can improve the wet fastness of anionic dyes. 

There has in the past been some confusion in the use of the term alkyd, which is said to have been derived from alcohol plus acid. The definition offered by Kienle [1], discussed later, is broad enough to include all polyesters derived essentially from diols and dicarboxylic acids, and consequently linear polyesters were initially included in this class of polymer. On the other hand, Bjorksten et al. [2], in their 1956 compilation of published information about polyesters, restrict the term polyester to the polycondensation products of dicarboxylic acids with dihydroxy alcohols, and say that this definition does not include materials commonly known as alkyds . At the present time, there are still problems of nomenclature in the fibre field arising from the use of polyester as a generic term to cover fibres containing only a very restricted range of chemical groups. 

These are the polycondensation products of dlcarboxylic acids and diols. Dacron or terylene Is the best known example of polyesters. It is manufactured by heating a mixture of ethylene glycol and terephthallc acid at 420 to 460 K In the presence of zinc acetate-antimony trioxlde catalyst as per the reaction given earlier. Dacron fibre (terylene) is crease resistant and is used In blending with cotton and wool fibres and also as glass reinforcing materials in safety helmets, etc. 

Special type of template polycondensation product was obtained by Papisov at al Polycondensation of urea with formaldehyde in the presence of polyCacrylic acid) gives polycomplexes or polycomplex composites with various structures and properties. The... 

The formation of copolymer by polycondensation reaction was proved by IR analysis. The spectra show absorption band at 1470, 1640, 2990, and 3100 cm-1 characteristic of—C—O—NH— groups, at 3300 cm-1 for imine groups and at 920 cm-1 for primary amine groups. From the point of view of chemical composition, the polycondensation products are composed by a fraction insoluble in... 

Unlike the poly[2]catenanes 48 and 49, the poly[2]catenand 51b, containing catenane segments prepared from large macrocycles (45 atoms) represents the other extreme in view of the high mobility of the macrocycles of die catenane units (Scheme 17) [53, 58], From a synthetic viewpoint, the large mobility of the dihydroxy[2]catenand 50b has a dramatic influence on the resulting polycondensation products (Scheme 18). 

Carbon subsulfide and 2-aminopyridine gave polycondensed products instead of the dithio derivative of 63 (R = H).125... 

To obtain some indication of the structure of the thermostable residue (undecomposed at 900°C) obtained in these reactions, its IR absorption was determined. Absorption maxima appear at 810 cm-1 and 1190 cm-1, corresponding to =C—, NH—, and =C—N = bonds. The IR spectrum of the control sample lacks these bands, testifying to the existence of a reactions having occurred either between the final polycondensation products and the active centers of the inorganic mass, or between the two compounds (polymer and diamine) and the active centers of the inorganic mass. The first of these possibilities is the more probable one. 

As with the products of polycondensation, the products of mechanochemical complexation were characterized by analysis of chemically linked nitrogen by ligand synthesis (Kjeldahl method), elementary analysis, and IR spectroscopy. The nitrogen variance for different working conditions is discussed elsewhere in this paper results of the elementary analysis are in Table III. IR spectra confirm that the ligand has the same structure as the polycondensation products, obeying the rule that for short durations, the band for ester carbonyl remains unaltered. For longer times, this band disappears. 

In addition, such a method of synthesis can be generated by making use of another destructive means for ligand synthesis. In that sense, the method was verified by achieving some polycondensation products of polyethylene terephthalate and ethylenediamine and their complexation with different metals by irradiating the system with cobalt-60 (gamma rays). These results also make up the subject of other studies. 

The presence of these cyclic esters in the crude polycondensation reaction product was found to be unavoidable indeed some evidence was developed that the polycondensation at least in part proceeds via these cyclic esters. Considerable effort was expended to find means for eliminating these cyclic five-membered esters from our polycondensation products. The cyclic esters can be eliminated by either inducing them to polymerize by use of Lewis acid catalysts such as stannous octoate, or by subjecting them to ring opening by means of an alcohol or water (7). 

One embodiment of this general reaction led to a product which was commercially produced for several years by Stauffer as Fyrol 76 (9), a copolycondensation product of dimethyl methyl-phosphonate with bis(2-chloroethyl) vinylphosphonate. The features of Fyrol 76 were high phosphorus content (20%), water solubility, and ability to be polymerized by means of a radical initiator to a crosslinked polymer. A related polycondensation product was developed from tris(2-chloroethyl) phosphate and dimethyl methylphosphonate. By control of the reagents and procedure used for neutralization, these oligomeric products were produced with primary alcohol functional groups (7). 

One of the major problems in the chemistry of three-coordinated boron-nitrogen compounds is their relative instability towards hydrolysis 79>8°). This feature reduces their possible applications in many areas such as in the medicinal field or utilization for polycondensation-products. However, steric hindrance by bulky substituents on the borazine ring leads to compounds with enhanced hydrolytic stability, particularly when no solvent is present in which they may dissolve. This observation has resulted in extensive research on sterically hindered boron-nitrogen ring compounds. 

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