Investigating the Properties and Structure of Polyurethane Elastomers with Monoethylene Glycol Chain Extender

Abstract

The effect of monoethylene glycol (mEG) acting as chain extender in polypropylene glycol (PPG-4000) and 4,4ʹ-diphenylmethane diisocyanate (MDI) reaction was investigated. Polyurethane elastomers (PUR) were changed from flexible to rigid materials by varying the mEG content. Results show that Shore A and D hardness values trend to increase with increasing mEG content. It appears that increasing the chain extender content increases the hard segment content in the polyurethane structure. Moreover, increasing the mEG content increases Young’s modulus and the tensile strength of PUR, while elongation at break decreases. The chemical structure of the hard segment of PUR was characterized by Infrared (IR) spectroscopy. IR spectra exhibited the bands typical for PUR consisting of –NH, CH2– and C=O groups. The spectra reveal a few interactions between the polymeric chains that appear to be responsible for the shift of transmittance peak and decrease of some peak intensity. This may be due to the hard segment aggregating more to form domains in the PUR when mEG content was increased.

Synthesis of Mono Ethylene Glycol (MEG)-Based Polyurethane and Effect of Chain Extender on Its Associated Properties

“…The Figure evidently depicts the impact of the extender on the polymer [ 46 ]. The amine groups (–NH), attached with hydrogen bonding, stretched at 3309, 3323, 3323, and 3315 cm −1 , in Figure 1 B–E, respectively [ 35 , 47 ]. The polyurethane carbonyl (C=O) stretched at 1720, 1722, and 1726 cm −1 , showing the presence of free hydrogen bonded carbonyl groups ( Figure 1 A–E) [ 48 ].…”

“…Bigger extending molecules result in a bigger elongated domain and improved phase separation in the polymeric elastomers. The concentration of rigid and flexible segments affects phase separation, as well as physical plus mechanical characteristics [ 35 ]. The impact of several novel extenders on the mechanical as well as thermal characteristics of PU was investigated.…”

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

“…Therefore, it is necessary to study the relationship between the chemical structures of the components to improve their properties and obtain new materials with specific applications. [1][2][3][4][5] The physical characteristics necessary in the specific application of the polymeric material must be provided by the components used for the synthesis of the polyurethanes. The structures of the soft segment and especially of the hard segment affect the properties because they act together on the degree of phase separation, crystallization, morphology and hydrogen bonds.…”

“…Polyurethane materials are widely used due to the diversity of their properties, which ensure the possibility of developing high‐quality products. Therefore, it is necessary to study the relationship between the chemical structures of the components to improve their properties and obtain new materials with specific applications 1–5 . The physical characteristics necessary in the specific application of the polymeric material must be provided by the components used for the synthesis of the polyurethanes.…”