Properties of Segmented Polyether Poly(urethaneureas) Based of 2,4-Toluene Diisocyanate. 2. Infrared and Mechanical Studies

Sung, Cynthia; Smith, Thomas W.; Sung, N. H.

doi:10.1021/ma60073a023

Cited by 187 publications

(28 citation statements)

References 3 publications

(3 reference statements)

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“…Ai, 11 and Ai, 1 region. On the other hand, the soft segments keep positive orientation over the whole range of the fatigue time and the variation of the orientation factors is less compared with those of the hard segments for both TM-1 and TM-3.…”

Section: Infrared Studiesmentioning

confidence: 99%

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Structure and Properties of Fatigued Segmented Poly(urethaneurea) I. Segment Orientation Mechanism due to Fatigue

Shibayama

Kawauchi

Kotani

et al. 1986

Polym J

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ABSTRACT:Changes of structure and properties of segmented poly(urethaneura)s (SPUU) subjected to a sinusoidal strain were studied as a function of the duration of the load (the fatigue time). Mechanical experiments as well as infrared dichroism experiments indicate that destruction of hard segment domains and phase mixing between hard and soft segment domains proceed with increasing fatigue time. Infrared dichroism shows that the hard segments orient negatively, then positively, with increasing elongation. Negative orientation results from the behavior of the hard segment domain as a filler having an anisotropic shape ("domain orientation"). Subsequent positive orientation is explained by the hard segment orientation coupled with fragmentation of the hard segment domains ("segment orientation"). In the fatigue process, on the other hand, proceeding of phase mixing is dominant followed by phase demixing related to rearrangement and reorientation of the hard segments, which would finally lead to fracture. It is found that the fatigue process consists of three stages; the domain orientation stage, the phase-mixing stage, and the segment orientation stage.KEY WORDS Poly(urethaneurea) I Fatigue Mechanism I Infrared Dichroism I Spherulite Deformation I Segmented poly(urethaneurea) (SPUU) block copolymers are thermoplastic copolymers which have mechanical properties similar to those of conventional crosslinked rubbers. These materials belong to a class of (A-B)n type multiblock copolymers 1 -u consisting of alternately joined blocks of two chemically dissimilar segments along the polymer backbone, which are called hard and soft segments.Physical crosslinks are provided by the hard segments, which are generally formed from an extension of an aromatic diisocyanate with a low molecular weight diol or diamine. Elastomeric properties are imparted by the soft segments, usually formed from an aliphatic polyether or polyester macroglycol. Such SPUU is extensively hydrogen bonded. 3 -10 In all cases, the NH and C=O groups of each urethane or urea linkage can act as a proton donor and a proton acceptor. Although hydrogen bonding is an important structural feature of these materials, its influence on their properties and morphologies is not clear. In addition, two-phase microdomain structure 7 -10 • 12 • 13 has not been well understood due predominantly to the chemical complexity of the materials themselves. Charactensttc mechanical properties of SPUU, such as, high extensibility, and resiliency,

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Section: Infrared Studiesmentioning

confidence: 99%

“…Proposed Fatigue Mechanism Figure 16 shows the fatigue time dependence of the Young's modulus, the orientation factor ., 1 10,1986 fatigue process can be divided into three stages as indicated at the bottom of the figure. In Stage I, the system keeps more or less the original structure.…”

Section: Infrared Studiesmentioning

confidence: 99%

Structure and Properties of Fatigued Segmented Poly(urethaneurea) I. Segment Orientation Mechanism due to Fatigue

Shibayama

Kawauchi

Kotani

et al. 1986

Polym J

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“…According to Smith [22], high TS for TPE-U was observed as the hard domains were of isolated type. Paik-Sung [23,24] found that connected domains in TPE-U led to higher hysteresis and lower strain at break. Bonart [25] showed that interpenetrating domains were favored for plastic deformation of hard segments.…”

Section: General Characteristics Of Polyurethanesmentioning

confidence: 99%

“…The unsaturated polyurethane structure is shown in Figure 9.24. [24,172], DSC [99,173À185], DMTA [21,186,187], DEA [188], SALS [189À193], and optical [187,193À198], electron [30,195,199À212], or atomic force microscopy [99,213À221] studies were used to follow phase separation in different types of polyurethanes. It was established that in amorphous, soluble TPU the nanodomains are fundamental entities of morphology (Figure 9.25).…”

Section: Carbodiimide the Way Of Reaction Trimerization Of Isocyanatesmentioning

confidence: 99%

Polyurethanes

Janik¹,

Sienkiewicz²,

Kucińska-Lipka³

2014

Handbook of Thermoset Plastics

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“…The band at 1,730 cm −1 is assigned to the stretching of free urethane carbonyl groups, and the peak at 1,708 cm −1 corresponds to the stretching of the hydrogenbonded urethane carbonyl groups [7]. Table 1 shows the fraction of free urethane carbonyl groups and hydrogenbonded urethane carbonyl groups.…”

Section: Ft-ir Measurementmentioning

confidence: 99%

The effect of hard segment content on ionic conductivity of poly(ether urethane)-based solid polymer electrolytes

Kim

2011

Ionics

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To investigate the effect of hard segment content on ionic conductivities of poly(ether urethane) (PEU)-based solid polymer electrolytes (SPEs), PEUs containing 20, 40, 60, 80, and 100 wt.% of hard segment content were synthesized. Also we introduced polymer-in-salt system with ion-hopping mechanism contrary to traditional salt-inpolymer system with segmental motion mechanism and investigated the effect of hard segment of PEU on ionic conductivities by A.C. impedance, FT-IR, DSC, and SEM. And it could be known that hydrogen bonding of urethane group influenced the ionic conductivities of PEU-based SPE. PEU-based SPE containing 70 wt.% of salt and 20 wt. % of hard segment showed the highest ionic conductivity of 2.95×10 −5 S/cm at room temperature.

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Properties of Segmented Polyether Poly(urethaneureas) Based of 2,4-Toluene Diisocyanate. 2. Infrared and Mechanical Studies

Cited by 187 publications

References 3 publications

Structure and Properties of Fatigued Segmented Poly(urethaneurea) I. Segment Orientation Mechanism due to Fatigue

Structure and Properties of Fatigued Segmented Poly(urethaneurea) I. Segment Orientation Mechanism due to Fatigue

Polyurethanes

The effect of hard segment content on ionic conductivity of poly(ether urethane)-based solid polymer electrolytes

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