Relationship between modulus and structure of annealed thermoplastic polyurethane

Yu, Yang; Osaka, Noboru; Iimori, Sohgo; Murayama, Satoshi; Saito, Hiromu

doi:10.1016/j.mtcomm.2014.10.001

Cited by 31 publications

(29 citation statements)

References 31 publications

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“…Comparison with the above mentioned studies shows that the microstructure changes depend on the chemical composition and the type of PUs (polyester or polyether). Furthermore, the increase in the degree of phase mixing and the decrease in the number density of hard domains in Estane induced by γ-irradiation would result in the deterioration of mechanical properties due to the reduction of the number density of reinforce fillers (hard domains), as was shown in a recent study [31].…”

Section: Estane + Hoh + Estane Estane Estane Ohmentioning

confidence: 78%

Study on the Microstructure of Polyester Polyurethane Irradiated in Air and Water

et al. 2015

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The gamma irradiation induced aging of thermoplastic polymer Estane 5703 in air and water environments was studied by small-angle neutron scattering (SANS), Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), and X-ray diffraction (XRD). The degree of phase mixing was increased after irradiation, accompanied by the increase of domain distance and decrease of domain size. The hard domain distance increased from 9.8 to 11.2 nm and 14.4 nm for the samples irradiated in air and water with a dose up to 500 kGy, respectively. The GPC results indicated progressive formation of larger linked structures with very high molar mass with increasing absorbed doses. The samples irradiated in water exhibited a stronger aging effect than those irradiated in air. The FTIR results suggested that the cross-linking occurred among the secondary alkyl radicals, and the interactions in hard domains weakened because of the loss of inter-urethane H-bonds. The volume fraction of well-ordered soft segments in Estane increased upon irradiation.

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Section: Estane + Hoh + Estane Estane Estane Ohmentioning

confidence: 78%

Study on the Microstructure of Polyester Polyurethane Irradiated in Air and Water

et al. 2015

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“…Crystallizations of two domains can occur simultaneously when the two domains obtained well‐separated T c s or separately if their T c s are close . By application of different thermal treatments, the final morphology of semi‐crystalline block copolymers can be altered, and in this way changes their mechanical properties, degradation rate, or shape‐memory properties . For example, a two stage crystallization took place when the segregated diblock copolymer polyethylene‐poly( L ‐lactide) was slowly cooled from the melt state to temperatures below than the T c s of both crystallizable domains, but when a rapid cooling process was applied coincident crystallization occurred …”

Section: Introductionmentioning

confidence: 99%

The influence of thermal treatment on the morphology in differently prepared films of a oligodepsipeptide based multiblock copolymer

Yan

Fang

Weigel

et al. 2016

Polymers for Advanced Techs

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Degradable multiblock copolymers prepared from equal weight amounts of poly(ε‐caprolactone)‐diol (PCL‐diol) and poly[oligo(3S‐iso‐butylmorpholine‐2,5‐dione)]‐diol (PIBMD‐diol), named PCL‐PIBMD, provide a phase‐segregated morphology. It exhibits a low melting temperature from PCL domains (Tm,PCL) of 38 ± 2 °C and a high Tm,PIBMD of 170 ± 2 °C with a glass transition temperature (Tg,PIBMD) at 42 ± 2 °C from PIBMD domains. In this study, we explored the influence of applying different thermal treatments on the resulting morphologies of solution‐cast and spin‐coated PCL‐PIBMD thin films, which showed different initial surface morphologies. Differential scanning calorimetry results and atomic force microscopy images after different thermal treatments indicated that PCL and PIBMD domains showed similar crystallization behaviors in 270 ± 30 µm thick solution‐cast films as well as in 30 ± 2 and 8 ± 1 nm thick spin‐coated PCL‐PIBMD films. Existing PIBMD crystalline domains highly restricted the generation of PCL crystalline domains during cooling when the sample was annealed at 180 °C. By annealing the sample above 120 °C, the PIBMD domains crystallized sufficiently and covered the free surface, which restricted the crystallization of PCL domains during cooling. The PCL domains can crystallize by hindering the crystallization of PIBMD domains via the fast vitrification of PIBMD domains when the sample was cooled/quenched in liquid nitrogen after annealing at 180 °C. These findings contribute to a better fundamental understanding of the crystallization mechanism of multi‐block copolymers containing two crystallizable domains whereby the Tg of the higher melting domain type is in the same temperature range as the Tm of the lower melting domain type. Copyright © 2016 John Wiley & Sons, Ltd.

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“…The TPU film was melted at 200 °C for 2 min and was quenched to room temperature at around 25 °C. The melt‐quenched specimen was stored at 25 °C for over 7 days before the investigation because the crystallization proceeds at 25 °C in the melt‐quenched specimen . The specimen thus obtained is designated as untreated TPU.…”

Section: Methodsmentioning

confidence: 99%

“…Such characteristic mechanical properties are attributed to their microphase separated structure in nanometer scale consisting of chemically linked crystalline hard segment (HS) domain and amorphous soft segment (SS) matrix; that is, the SS provides elastomeric behavior as a spring and the HS acts as a rigid physical cross‐link point. Crystallization and morphological change in TPU can be triggered by thermal annealing which strongly affects their mechanical properties . The HS domain consisting of fringed micelle‐like crystal becomes larger by annealing due to the coarsening of the phase separation .…”

Section: Introductionmentioning

confidence: 99%

“…As competing development of the microphase separated structure, crystalline structure, and spherulite are occurred in TPU during thermal annealing, spherulite in TPUs are generated in a limited condition. Hence, a few reports of spherulite in TPU created via melt‐crystallization have been published yet, although a number of studies have been reported in the microphase separated structure . Chu and coworkers found an experimental condition to obtain large spherulite by melt crystallization of several TPUs consisting of 4,4′‐diphenylmethane diisocyanate (MDI) and 1,4‐butandiol (BD) in a limited annealing temperature range and long period of crystallization time of 48 h .…”

Section: Introductionmentioning

confidence: 99%

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Structure and deformation recovery of the thermoplastic polyurethane spherulite

Akiko

Kondo

et al. 2017

J Polym Sci B Polym Phys

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We investigated the structure and deformation behavior of the thermoplastic polyurethane (TPU) spherulite by optical microscopy, tensile testing, Hv light scattering, and small angle X-ray scattering. The TPU spherulite structure obtained by melt crystallization was coarse consisting of bundle-like structure containing hard segment (HS) lamellar domain in which the HS domains were stacked and the HS chain direction was perpendicular to the longitudinal axis of the HS domain. By stretching, the spherulite was deformed to ellipsoidal one and the stacked HS lamellar domains were tilted in the stretching direction. The deformed spherulite and the tilted HS domain in the spherulite were recovered to the unstretched state by retraction. The recovery of the structure is ascribed to the characteristic spherulite structure consisting of rubbery soft segment matrix physically cross-linked with the stacked HS domain.

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Relationship between modulus and structure of annealed thermoplastic polyurethane

Cited by 31 publications

References 31 publications

Study on the Microstructure of Polyester Polyurethane Irradiated in Air and Water

Study on the Microstructure of Polyester Polyurethane Irradiated in Air and Water

The influence of thermal treatment on the morphology in differently prepared films of a oligodepsipeptide based multiblock copolymer

Structure and deformation recovery of the thermoplastic polyurethane spherulite

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