Poly condensation polymerization

Solution poly condensation polymerization is used when the temperatures needed to melt the monomer are too high or when bulk (mass) polymerization is too exothermic and hazardous. With solution polymerization, monomers and polymerization initiators are dissolved in a nonmonomeric liquid solvent at the start of polymerization. The solvent is usually a solvent for the polymer and copolymer product. 

The second category of polymerization reactions does not involve a chain reaction and is divided into two groups poly addition and poly condensation [4]. In botli reactions, tire growth of a polymer chains proceeds by reactions between molecules of all degrees of polymerization. In polycondensations a low-molecular-weight product L is eliminated, while polyadditions occur witliout elimination ... 

Among the polymeric stabilizers may be listed poly-condensed polymers based on alkyl phenols, aldehydes, and ketones of the aliphatic series, where = 1 - 8 and R,R means alkyl [24], Na, K, Ca phenolates of poly-condensed polymers [25], and also products of epichlor-ide with one or more aliphatic amines C3—C30 [26]. 

The sulfonium precursor route may also be applied to alkoxy-substituted PPVs, but a dehydrohalogenation-condensation polymerization route, pioneered by Gilch, is favored 37]. The polymerization again proceeds via a quinomethide intermediate, but die syndicsis of the conjugated polymer requires only two steps and proceeds often in improved yields. The synthesis of the much-studied poly 2-methoxy-5-(2-ethylhexyloxy)-l,4-phenylene vinylene], MEH-PPV 15 is outlined in Scheme 1-5 33, 35]. The solubility of MEH-PPV is believed to be enhanced by the branched nature of its side-chain. 

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-... 

Horhold et al. and Lenz et al. [94,95]. The polycondensation provides the cyano-PPVs as insoluble, intractable powders. Holmes et al. [96], and later on Rikken et al. [97], described a new family of soluble, well-characterized 2,5-dialkyl- and 2,5-dialkoxy-substituted poly(pflrfl-phenylene-cyanovinylene)s (74b) synthesized by Knoevenagel condensation-polymerization of the corresponding alkyl-or alkoxy-substituted aromatic monomers. Careful control of the reaction conditions (tetra-n-butyl ammonium hydroxide as base) is required to avoid Michael-type addition. 

The ring structures undergo further (poly)condensation reactions. These polymerization reactions proceed rapidly until particles with diameters of typically 1-2 nm are formed. Schematically, the process can be summarized as shown in Figure 3.15. 

We report here the results of our recent studies of poly(alkyl/arylphosphazenes) with particular emphasis on the following areas (1) the overall scope of, and recent improvements in, the condensation polymerization method (2) the characterization of a representative series of these polymers by dilute solution techniques (viscosity, membrane osmometry, light scattering, and size exclusion chromatography), thermal analysis (TGA and DSC), NMR spectroscopy, and X-ray diffraction (3) the preparation and preliminary thermolysis reactions of new, functionalized phosphoranimine monomers and (4) the mechanism of the polymerization reaction. 

Material produced by the reaction of relatively simple molecules with functional groups that allow their combination to proceed to high-molecular weights under suitable conditions formed by polymerization or poly condensation. 

In order to keep polyamides soluble in relatively apolar solvents, the use of flexible (macro)monomers such as a, co-(diaminopropyl)polydimethylsiloxane [52] or oligoethyleneglycol-based diamines [53, 54] has been proven to be a successful approach (Fig. 10). Poly condensations of dimethyl adipate with a variety of diamines were successful in bulk and at moderate temperatures between 60 and 100 °C (reaction A in Fig. 10). The low temperatures (60-100 °C) that suffice in these polymerizations also allow the use of monomers that are thermally instable, such as diethyl fumarate [53]. Moreover, multifunctional amines could be regioselectively polymerized up to molecular weights of 9 kDa, making lipase catalysts a valuable tool for the preparation of well-defined polyamides that can be further functionalized with active groups. 

Investigation of template poly condensation kinetics has only been studied within a very narrow scope. Polymerization of dimethyl tartrate with hexamethylene diamine was found to be enhanced by using as a template poly(vinyl pyrrolidone), poly(2-vinyl pyridine), or polysaccharides and poly(vinyl alcohol), poly(4-vinyl pyridine). In this case, the template can be treated as a catalyst. No information exists on the influence of the template on the order of reaction. The increase in molecular weight of the polymerization product by the template can be induced by a shift of equilibrium or by an increase in the reaction rate. A similar increase in the reaction rate was observed when poly(4-vi-nyl pyridine) was used in the synthesis of poly(terephtalamides) activated by triphenyl phosphite.The authors suggested that a high molecular weight template was involved in the increase of the local concentration of the substrate (terephthalic acid) by adsorption and activation via N-phosphonium salt of poly(4- vinyl pyridine). 

Observations Condensation polymerization was used to prepare poly(ester-amides)... 

While dicarboxylic acid-functional pyrroles have received only cursory attention in condensation polymerizations, other derivatives have been studied extensively. Pyrrole itself has been electrooxidatively polymerized (81CS145) to give a flexible conductive film, presumably containing poly(2,5-pyrrolediyl) units (23) as the main structural feature. The blue-black polymer obviously contains other functionality, as evidenced by elemental analysis and by the fact that it carries a partial positive charge, and it exhibits p-type conductivities approaching the metallic range (e.g. 100 fi-1 cm-1). The main utility of poly(pyrrole) (23) has been for the modification of electrode surfaces, although numerous other applications can be envisioned. 

Synthesis, The first Fully alkyl/aryl-subsiiluted polymers were reported in 1980 via a condensation-polymerization route. In addition lo providing fully alkyl/aryl-Mihsiiuiled poly pliospha/enes. the versatility of ihe process has allowed the preparation of various functionalized polymers and copolymers. 

Nafion-H has also been used as a catalyst for the oligomerization of styrene. The reaction was studied by Higashimura and co-workers.933,934 Hydroxy-terminated poly (alkylene)oxides were prepared by condensation-polymerization of 1,8-octanediol and 1,10-decanediol in the presence of Nafion-H.935 It showed higher activity than sulfuric acid consequently, polymerization could be carried out at lower temperature. 

Both electrochemical and chemical oxidative routes are most often utilized for the synthesis of PANI. In an interesting departure from the oxidative route, poly(phenylene amine imine) was prepared via a conventional condensation polymerization, as illustrated in Scheme 63 [302, 303]. Comparison of this structurally well-characterized polymer with oxidatively prepared PANI allowed confirmation of the PANI structure. However, the structure of PANI produced by electrochemical means is less understood. 

Condensation Polymerizations That Yield Poly(dichlorophosphazene)... 

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