The utilization of Cyclophosphazenes as polymer modifiers is reviewed, with particular concern to their exploitation as versatile chain extenders, possibly for recycle problems, crosslinkers, to enhance mechanical properties of polymeric materials, branchers, to selectively introduce ramifications in linear polymers, and compatibilizers, to favor the formation of blends between originally incompatible organic macromolecules. The great versatility of the synthetic methods put forward for these substrates, together with the ease of controlling their modification, functionalization and reactivity are important parameters for the evaluation of which type of use is more feasible for these trimers. The importance of cyclophosphazenes bearing organic polymeric chains, azide groups, 2‐oxazoline derivatives and oxirane rings in connection with organic conventional macromolecules is critically highlighted.

Kinetic and catalytic aspects of the formation of poly(ethylene terephthalate) (PET) have been studied in this work using model molecules such as 2-hydroxyethyl 4-methylbenzoate (MP), 2-hydroxyethyl 4-benzoate (MB), and 2(-hydroxyethyl 4-methylbenzoate) 4-methylbenzoate (DP), synthesized and purified in our laboratories. The methods to obtain these molecules have been described in detail. Many kinetic runs have been performed using different catalysts, such as compounds of Sb, Ti, Zr, Al, Mo (VI), Mn, Zn, Sn (IV), and Ge. We have made kinetic runs on some catalysts under different operative conditions to evaluate the effect of catalyst concentration and temperature on the reaction rate. We have observed that a second-order kinetic law is suitable for both condensation and reverse reaction. All kinetic runs have been interpreted and kinetic parameters determined. Activity can depend on catalyst concentration in a different way for each type of catalyst. Bivalent metals activity is affected by the presence of a substituent in the aromatic ring, unlike tri-and tetravalent metals. Suggestions on the reaction mechanisms conclude the work.

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A new class of poly(ester-amide)s was prepared by reacting bis(2-oxazoline)s, carboxylic anhydrides, and diols of different structures. The polymerization proceeds through the formation of a dicarboxy ester by reaction of two anhydride molecules with one diol molecule and subsequent 2-oxazoline ring opening by attack of the dicarboxy ester. The whole process leads to linear poly(ester-amide)s, whose structures were established by carbon and proton NMR analysis. The thermal characteristics of the prepared polymers were studied by differential scanning calorimetry. Transition temperatures were found to increase with an increase in the polymer chain stiffness. Poly(ether-ester-amidels were also prepared by employing polyethylene glycol) as a comonomer, alone, or in a mixture with ethylene glycol, thus obtaining block segmented polymers.

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