Physical properties and dielectric behavior of the poly(urethane‐urea) based on o‐dianisidine and renewable cross‐linkers

Abstract

The novelty of the poly(urethane-urea) series consists in inclusion of odianisidine units in the main chain and cross-linking with renewable biomaterials, unused compounds so far in the synthesis of the poly(urethane-urea) (Tween 20, Span 20, Phloroglucinol). The effects of these components on the structure, surface, thermo-mechanical properties and dielectric behavior of the obtained poly(urethane-urea) were investigated by Fourier transform infrared (FTIR) spectroscopy, thermo-gravimetric analysis, static contact angles, broadband dielectric spectroscopy, and mechanical testing. The FTIR spectra showed that the urethane hydrogen bonds decreased with the increase of odianisidine content. Such that, at the increase of the o-dianisidine content, decreased the thermo-mechanical properties, and increased strongly the water contact angle from 83 to 108. By dielectric relaxation spectroscopy was studied the molecular dynamics within the polymeric matrices with identical soft segments but different structure of the hard domains. These poly(urethane-urea) materials exhibit two secondary relaxations (β and γ) and a relaxation process α, corresponding to the segmental movements in the soft phase, which occurs around the temperature of −50 C independent of the measurement frequency. o-Dianisidine prevents the formation of all the urethane hydrogen bonds and so increases the chains mobility and dipoles polarization of polymer matrix, thus increasing the dielectric constants.

An insight on the effect of the hard segment domain on the thermo‐mechanical and surface properties of new piperazine‐based polyurethanes

“…These have not been widely used in the synthesis of the polyurethanes as cross‐linkers. This study is a continuation of our previous work when we used these renewable resources to increase the dielectric properties of the synthesized polyurethanes 42 . In this paper we have done some preliminary study to establish the influence of the hard segment structure on the microstructure and properties of the formed polyurethanes.…”

“…The structures of the hard segments have a great influence on the properties of the polyurethanes due to their physical crosslinking that acts as a polymer reinforcement matrix influencing in a significant way the performance of the obtained materials. Thus, the morphology and structural rearrangement of segmented copolymers have been widely studied 8–12 …”

“…This study is a continuation of our previous work when we used these renewable resources to increase the dielectric properties of the synthesized polyurethanes. 42 In this paper we have done some preliminary study to establish the influence of the hard segment structure on the microstructure and properties of the formed polyurethanes. In a future work, we will study the dielectric behavior of these new polyurethane materials.…”

Synthesis and properties of water‐dispersible polyurethanes based on various diisocyanates and PEG as the hard segment

“…Polyurethanes were prepared by the conventional pre‐polymer process 39 . All polyurethanes were prepared by the reaction of equivalent amounts of isocyanate groups and hydroxyl groups.…”

Synthesis and application of aminosiloxane‐modified cationic waterborne polyurethane as fixing agent for nylon fabric

“…Hydrophilic chain extenders are introduced to give it a certain water solubility, so it can be directly emulsified and dispersed in water without emulsifier. WPU, a very promising environmental material, has broad applications in industries 12–15 . The isocyanate group is the terminal group of WPU and is usually protected by a blocking agent.…”