Fourier Transform Infrared Spectroscopy Study on Effects of Temperature on Hydrogen Bonding in Amine-Containing Polyurethanes and Poly(urethane−urea)s

Abstract

Three types of amine-containing polyurethanes and poly(urethane−ureas), N-methyldiethanolamine (MDEA) and/or tetraethylenepentamine (TEPA) as the chain extender and poly(ethylene glycol) of MW 400 as the soft-segment component, have been studied by FTIR. The hydrogen bonding in hard and soft segments was examined for the extent of phase separation, and the microstructure was evidenced by differential scanning calorimetry (DSC). The temperature effects on the hydrogen bonding were also investigated. They show a significant amount of hydrogen bonding between the hard and soft segments. It indicates that there exists a large amount of partial phase mixing of hard and soft segments compared to the conventional polyurethanes. The bulky CH3 groups of MDEA in hard segments restrict the hydrogen bonding within the hard segments, while the TEPA-containing urethane−urea polymers have more distinct phase separation. However, all of the polymers studied are amorphous materials such that the dissolved soft segments in the hard-segment domains may interfere with molecular packing in the domains. It shows that the hydrogen bonding in these polymers persists up to 200 °C. The hydrogen bonding of NH to the ether oxygen decreases significantly at T > 50 °C.

Investigations of hydrogen bonding in the poly(urethane-urea)-based membrane materials by using FTIR spectroscopy

“…As a first approximation, the bands have been assigned to free carbonyls, disordered H-bonds of A and B type in different environments, and the ordered hydrogen bonds as named in an order of decreasing wavenumbers. Similar deconvolution results concerning polyamides and polyurethanes have also been reported in literature 2,8,9 . The curve fitting data concerning the changes in the areas of the particular bands as a function of temperature are plotted in Fig.2 and 3.…”

The Effect of Plant Source on the Properties of Lignin-Based Polyurethanes

“…The majority of isocyanates used such as toluene-2,4-diisocyanate, isophorone diisocyanate, and 4,4-methylene diphenyl diisocyanate are aromatic in structure while aliphatic isocyanates, such as hexamethylene diisocyanate (HMDI), are also used (Teo et al, 1997, Chan-Chan et al, 2010, Prisacariu, 2011, Chung and Washburn, 2012, Zhang et al, 2015. Polyols are usually the more flexible of the two components which allows the formation of flexible PU materials and usually consist of polyesters, polyethers, or glycols such as polyethylene glycol (PEG), 1,4-butanediol, and polypropylene glycol (PPG) (Grassie and Zulfiqar, 1978;Wen et al, 2001;Oprea, 2010;Nozaki et al, 2017).…”

Waterborne polyurethane single-ion electrolyte from aliphatic diisocyanate and various molecular length of polyethylene glycol

“…The central peak (peak 2) is N-H stretching which is affected by hard-soft segment H-bonding (about 3430 cm -1 ). The frequency shift of H-bonded N-H stretching represents the stretching of H-bonding in polyurethane [13,16]. The area of each band was determined by using the Nelder-Mead optimization method.…”