t‐Butyl‐Oxycarbonylated Diamines as Building Blocks for Isocyanate‐Free Polyurethane/Urea Dispersions and Coatings
Shuang Ma; Huiyi Zhang; Rafaël J. Sablong; Cor E. Koning; Rolf A. T. M. van Benthem
Index: 10.1002/marc.201800004
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Abstract
t‐Butyl‐oxycarbonylated diamines (“di‐Boc‐carbamates”) are investigated as dicarbamate monomers for diamine/dicarbamate polymerizations. Polyureas (PUs) and polyurethanes (PURs) with high molecular weights are prepared from stoichiometric polymerizations of diamines or diols with N‐N′‐di‐t‐butyl‐oxycarbonyl isophorone diamine (DiBoc‐IPDC) using KOt‐Bu as a catalyst, while gelation is observed when an excess of DiBoc‐IPDC is used with respect to the diamines or diols. Stable dispersions are obtained from PUs and PURs with 3,3′‐diamino‐N‐methyldipropylamine (DMDPA) as internal dispersing agent. The corresponding PU‐based coatings exhibit superior mechanical properties and solvent resistances compared to the polyurethane urea coatings synthesized from diols, DiBoc‐IPDC, and DMDPA.