International. One research paper concerns the synthesis of phenalamines and their use as curing agents for polyisocyanates blocked to produce high-performance polyurea coatings.
Several phenalamines were synthesized by the conventional Mannich reaction; selecting various structural amines such as hexamethylendiamine (HMDA), isophoron diamine (IPDA), diaminodiphenylmethane (DDM), Jeffamine D-400 and Jeffamine T-403. The structures of these phenacylamines were confirmed by FTIR, 1H NMR spectroscopy and amine value assessment.
The curing agents were mixed with blocked polyisocyanates based on HDI and IPDI to obtain polyurea coatings that were subsequently characterized by mechanical, chemical, optical, thermal and anticorrosive properties. In addition, the structure-property relationship of all systems was studied and compared with commercial phenalamine (AG-141).
Anticorrosive properties evaluated by salt spray test and electrochemical impedance spectroscopy (EIS) revealed a significant improvement in anticorrosive behavior compared to commercial phenalamine. All polyurea coatings exhibited excellent performance properties regardless of the isocyanates used.
Source: www.sciencedirect.com.
