Structure-Property Relationships of Soluble Poly(ester-urea)s containing Naphthyl Groups

Abstract

The preparation of new types of polyureas with good thermal properties and improved solubility was investigated. Two new bulky diamines as new monomers for the preparation of polyurea were synthesized via two steps. First, a nucleophilic reaction of 1-naphthol and 2-naphthol with 3,5-dinitrobenzoyl chloride and then the reduction of the nitro groups by hydrazine hydrate/Pd-C to produce the corresponding diamines (1NA and 2NA). The poly(ester-urea)s were synthesized through the polyaddition reaction of the diamines with various commercially available diisocyanates. The polymers were characterized using IR and 1H NMR spectroscopy, elemental analysis, viscometry, thermal analysis, gel permeation chromatography (GPC), and X-ray diffraction. The copolymers were amorphous and readily soluble in a wide range of organic solvents such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide, N, N-dimethylformamide, and m-cresol. Thermal analysis showed a glass transition temperature between 146 and 178 °C. Their decomposition temperatures were more than 180 °C, and their 10% weight losses were in the range 281—315 ° C in air. The weight average molecular weights ( Mw) of the polymers were about 32 200—40 500 g/mol.