Mechanistic aspects on molecular structure formation of polymeric networks from diisocyanates with amidine compounds. Issue 9 (9th February 2018)

• Record Type: Journal Article
• Authors: Laue, Andreas; Uhlig, Daniel; Fiedler, Benjamin; Friedrich, Joachim; Mende, Carola; Kroll, Lothar; Spange, Stefan
• Is Part Of: Journal of polymer science. Volume 56:Issue 9(2018)
• Page Start: 977
• Page End: 985
• Publication Date: 2018-02-09
• Subjects: addition polymerization -- amidine -- blocked isocyanate -- differential scanning calorimetry (DSC) -- isocyanate -- polymer network -- step‐growth polymerization -- theory and modeling, resins; 547
• DOI: 10.1002/pola.28975
• Languages: English
• ISSNs: 0887-624X

Abstract

ABSTRACT: Polymeric networks are produced by step‐growth polyaddition and co‐polyaddition reactions of 1‐ethylimidazoline in combination with various diisocyanates. Five aromatic, two aliphatic diisocyanates and a polyurethane prepolymer are used as particular reactant in N, N ‐dimethylformamide as solvent at room temperature. Obviously, 1‐ethylimidazoline can serve as trifunctional monomer, which enables a crosslinking reaction with diisocyanates. Molecular structure elements of the polymeric networks were studied by solid state 13C‐NMR spectroscopy revealing that detailed molecular structure formations are determined whether aromatic or aliphatic diisocyanates are used. Quantum chemical calculations were used as supporting method to elucidate the complex reaction cascades. Hence, it can be shown that beside 3:1 stoichiometric structures 2:1 based structures are formed as well. These structures are observed as kinetically controlled products only when aromatic diisocyanate monomers are used. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem.2018, 56, 977–985 Abstract : The reaction of 1‐ethylimidazoline with aliphatic and aromatic diisocyanates provides novel polymeric networks formed via step‐growth polymerization. Materials obtained by this reaction include thermal stable as well as sensitive structures, especially when aromatic diisocyanates are used. These new materials are of special interest for polyurethane or poly urea formulations. In this work, the structural and thermal properties of these compounds are presented.