Novel polyurea polymers with enhanced mechanical properties

The present work describes the preparation of a set of new polyurea polymers suitable for ballistic protection applications by employing different aromatic diamines derivatives with different flexibility degrees. This modification would allow the synthesis of polymers with both enhanced and controllable mechanical properties through the combination of aliphatic and aromatic molecules. Besides the classical methylene diphenyl diisocyanate and polypropylene glycol bis(2-aminopropyl ether) (PPG), benzidine, 4,4'-diaminodiphenylmethane and 3,6-diamino carbazole were chosen as the third monomer and used in different ratios toward PPG, in order to optimize the polymer properties. The proportions between the polyurea components were selected as such to achieve the total consumption of the monomers. The different types of polyurea obtained have been characterized by Fourier transform infrared spectroscopy, thermal measurements (differential scanning calorimetry and thermogravimetric analysis), tensile tests, and scanning electron microscope. (C) 2016 Wiley Periodicals, Inc.