Linear polyurethanes with imidazoquinazoline rings: preparation and properties evaluation

Agnieszka Szyszkowska,Kamil Gancarczyk,Marek Pyda,Iwona Zarzyka,Vladimir Sedlarik,Anna Czerniecka-Kubicka,Łukasz Byczyński

doi:10.1007/s00289-019-02702-5

Abstract

In this work, research concerning the synthesis and properties of linear polyurethanes (PUs) with the imidazoquinazoline rings was represented. Reaction conditions of 2,6-bis(2-hydroxyethyl)-1-phenylimida-zo[1,5-c]quinazoline-3,5-dione (BHPIQ) with 1,6-hexamethylene diisocyanate were determined and optimized. These conditions are adapted to reaction of BHPIQ with 4,4′-diphenylmethane diisocyanate and 2,4-toluene diisocyanate. New PUs with imidazoquinazoline rings were characterized by spectral methods (1H-NMR and IR spectroscopies), which confirm their structures. Their molar masses and dispersity index were measured by size exclusion chromatography method. The wide-angle X-ray scattering and differential scanning calorimetry (DSC) studies have shown that all PUs based on BHPIQ are amorphous. Moreover, thermal properties of PUs were investigated by thermogravimetry analysis, standard DSC, and temperature-modulated DSC methods. During thermogravimetric measurements, the exhaust gases were analyzed by FTIR method. Incorporation of imidazoquinazoline ring into the PU chains escalates their glass transition temperature; thus, their heat resistance was enhanced. Furthermore, their degradation rate and the amount of released degradation products were reduced. The investigated properties of the obtained PUs with imidazoquinazoline rings were compared with those ones of suitable PUs based on 1,4-butanediol.Graphical abstractLinear polyurethanes were obtained in reaction of 1-phenyl-2,6-bis(2-hydroxyethylimidazo[1,5-c]quinazoline-3,5-dione with hexamethylene 1,6-diisocyanate, 4,4′-diphenylmethane diisocyanate and toluene 2,4-diisocyanate. Their composition and structure were confirmed. The phase contents and thermal properties were investigated

Highlights

Polyurethanes (PUs) are one of the most significant industrial polymers
Linear aliphatic PUs may be considered as derivatives of polyamides with the same number of atoms in the main chain in which one methylene group has been replaced by an oxygen atom
It has been observed that BHPIQ had the shortest reaction time with HDI

Summary

Introduction

Polyurethanes (PUs) are one of the most significant industrial polymers. They are applied in the furniture, footwear, textiles, automotive and construction industries as well as in medicine [1,2,3,4,5,6,7,8,9].From a chemical composition perspective, the PUs –NH–(CO)O– can be seen as a hybrid of polyamides –NH–(CO)– and polyesters –(CO)O–. Polyurethanes (PUs) are one of the most significant industrial polymers. They are applied in the furniture, footwear, textiles, automotive and construction industries as well as in medicine [1,2,3,4,5,6,7,8,9]. From a chemical composition perspective, the PUs –NH–(CO)O– can be seen as a hybrid of polyamides –NH–(CO)– and polyesters –(CO)O–. The behavior of PUs is closer to polyamides due to their ability to form hydrogen bonds using the urethane “amide moiety.”. Linear aliphatic PUs may be considered as derivatives of polyamides with the same number of atoms in the main chain in which one methylene group has been replaced by an oxygen atom The behavior of PUs is closer to polyamides due to their ability to form hydrogen bonds using the urethane “amide moiety.” linear aliphatic PUs may be considered as derivatives of polyamides with the same number of atoms in the main chain in which one methylene group has been replaced by an oxygen atom

Methods

Results

Conclusion