Synthesis and properties of segmented polyurethanes with hydroquinone ether derivatives as chain extender

Abstract

Two series of 4, 4′-diphenylmethane diisocyanate (MDI) type polyurethanes based on poly(tetramethyleneoxide) glycol (PTMO) and polybutylene adipate glycol (PBA) as soft segments were synthesized by one-step bulk polymerization process. Various hard segments were obtained from hydroquinone ether derivatives with or without ether oxygen structure bonded with the aromatic units in main chain, including hydroquinone (HQE), hydroquinone bis(b-hydroxyethy) ether (HQEE), and 4-hydroxyethyl ethyl oxygen-1-hydroxy ethyl benzene ether (HQEE-L) as chain extenders. The effect of chain extender structure on aggregation structure, thermal and mechanical properties was studied. ATR-FTIR suggested that hydrogen bonding interactions were significantly changed in the presence of flexible ether oxygen structure in hard segment. HQEE-based polyurethanes and HQEE-L-based polyurethanes displayed microphase separation and microphase mixing behavior respectively based on DMA and DSC results. XRD curves confirmed that flexible ether oxygen chain bonded with the rigid aromatic units played a balancing role in the steric effect caused by aromatic chain extender. Thermal properties of polyurethanes were affected mainly by the hard segment packing while mechanical properties were influenced by both phase separation and phase mixing which possess strong hydrogen bonding interactions. The excellent elongation in PTMO/HQEE-L and the high ultimate tensile strength in PBA/HQEE-L can be attributed to the phase mixing with strong hydrogen bonding interactions presented in HQEE-Lbased polyurethanes.

New thermoplastic poly(carbonate-urethane)s based on diphenylethane-derivative chain extenders—the effect of chain extender structure on thermal and mechanical properties

“…However, from among those ''bulky'' diols, aliphatic-aromatic ones give polyurethanes with higher elongation at break and somewhat lower hardness [3,7,8]. Both the aliphatic-aromatic and aromatic diols are also used for the synthesis of polyurethanes with enhanced thermal stability [9,10] or liquid crystalline properties [11]. Additionally, introducing bromine atoms into the structure of these diols results in improved flame retardancy of the resulting materials [12].…”

New thermoplastic poly(carbonate-urethane)s based on diphenylethane derivative chain extender

“…Due to electron delocalization, they are characterized by less reactivity than aliphatic ones [6,7]. The aromatic and aliphatic-aromatic diols are also advantageous when the aim is to prepare materials of higher modulus of elasticity and hardness, enhanced thermal stability or liquid crystalline properties [7,[17][18][19][20][21]. The investigation interests of co-workers and myself include aliphatic-aromatic diols with sulfur atoms, being the derivatives, among others, of diphenylmethane [22][23][24], diphenyl ether [25,26], and diphenyl sulfide [25][26][27][28][29].…”

Shape Memory Polyurethane-Based Smart Polymer Substrates for Physiologically Responsive, Dynamic Pressure (Re)Distribution

“…62−64 The shift of certain bands (N–H, C=O, and C–O stretches of TPU are shifted to lower wavenumbers for SMPu foam) indicates increased hydrogen bonding effects in the hard segments. 65,66 Such differences are caused by the changes made to the parent TPU structure upon mixing with MDI and other components, during the SMPu foam formation process. These structural changes cause modifications of, e.g., modulus, stiffness, etc., and thus facilitate the reversible shape memory properties.…”

“…All expected thermoplastic polyurethane signals were observed in the attenuated total reflectance (ATR)-Fourier transform infrared (FTIR) spectra. Additional assignments (see Figure S3, Supporting Information (SI)) indicate clear differences between the TPU and SMPu foam concerning incidence and intensity of IR bands, due to the partial degradation of TPU as well as the organic reactants used to form the SMPu foam. − The shift of certain bands (N–H, CO, and C–O stretches of TPU are shifted to lower wavenumbers for SMPu foam) indicates increased hydrogen bonding effects in the hard segments. , Such differences are caused by the changes made to the parent TPU structure upon mixing with MDI and other components, during the SMPu foam formation process. These structural changes cause modifications of, e.g., modulus, stiffness, etc., and thus facilitate the reversible shape memory properties.…”