Dibenzyl structure on the macromolecular chain. XII. Polyureas: structure-property relatonships

Abstract

A series of polyureas with dibenzylic structures obtained from 2,2′-, 2,4′- or 4,4′-dibenzyl diamines and diisocyanates has been synthesized. Branched polyureas derived from a tetrafunctional monomer were also obtained. Their properties are strongly influenced by the isomeric structure of dibenzylic monomers. Polyureas containing symmetrical aromatic radicals like 4,4′- or 2,2′-dibenzyl exhibit low solubility in aprotic polar solvents and, their crystallinity lies in the range 20–66%. Polymers with non-symmetrical aromatic radicals, especially those with 2,4′-dibenzyl exhibit, increased solubility in polar solvents; they are amorphous and have film-forming properties. All polymers were characterized by their solubility and inherent viscosity, as well as IR spectra, thermogravimetric analysis, differential scanning calorimetry and X-ray diffraction measurements. © 2000 Society of Chemical Industry