Dibenzyl Structures in Macromolecular Chains

The dibenzyl system represents the simplest biaromatic system able for rotational isomerism which allows multiple spatial arrangements, with different reciprocal influences of the functional groups situated in the two rings. The possibility of introducing this system to a macromolecular chain and its influence on some properties of the polymer obtained was studied of the cases of polyurethanes, polyureas, poly(parabanic acids), and poly-imides. In the case of copolyurethanes, made using 4,4′-dibenzyl-diiSocyanate, an unexpected phenomenon was the possibility of disproportionation of some homogeneous systems by two parallel polyaddition processes which progress in parallel in two places, i.e., solution and suspension, leading to different polymers. The process is probably governed by the lower entropy of the crystalline polymer which appears in suspension. Some practical applications of polymers with dibenzyl structures are presented.