Correlations between chemical structure, stress‐induced crystallization, and deformation behavior of polyurethane elastomers

Morbitzer, L.; Hespe, H.

doi:10.1002/app.1972.070161022

Cited by 41 publications

(14 citation statements)

References 10 publications

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“…The stress softening in the ascending curve in the 1st cycle can be caused by a rearrangement in the crystalline microphase, formed during the film casting. 28 The hysteresis area decreased in the 2nd cycle, and a much smaller additional set was observed. The difference between the ascending curve of the first cycle and the ascending curve of the 2nd cycle can probably be explained by a reorientation of macromolecules combined with the crystallization during straining.…”

Section: Dmamentioning

confidence: 95%

Resilient Bioresorbable Copolymers Based on Trimethylene Carbonate, l-Lactide, and 1,5-Dioxepan-2-one

2006

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The new combinations of monomers presented in this work were evaluated in order to create an elastic material for potential application in soft tissue engineering. Thermoplastic elastomers (TPE) of trimethylene carbonate (TMC) with L-lactide (LLA) and 1,5-dioxepan-2-one (DXO) have been synthesized using a cyclic five-membered tin alkoxide initiator. The block copolymers were designed in such a way that poly(trimethylene carbonate-co-1,5-dioxepan-2-one) formed an amorphous middle block and the poly(L-lactide) (PLLA) formed semicrystalline terminal blocks. The amorphous middle block consisted of relatively randomly distributed TMC and DXO monomer units, and the defined block structure of the PLLA terminal segments was confirmed by 13C NMR. The properties of the TMC-DXO-LLA copolymers were compared with those of triblock copolymers based either on LLA-TMC or on LLA-DXO. Differential scanning calorimetry and dynamic mechanical analysis data confirmed the micro-phase separation in the copolymers. The mechanical properties of the copolymers were evaluated using tensile testing and cycling loading. All of the copolymers synthesized showed a highly elastic behavior. The properties of copolymers could be tailored by altering the proportions of the different monomers.

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Section: Dmamentioning

confidence: 95%

Resilient Bioresorbable Copolymers Based on Trimethylene Carbonate, l-Lactide, and 1,5-Dioxepan-2-one

2006

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“…In uniaxial stress, the onset of crystallization occurs at about 150% strain, and the amount of crystallization increases with strain. 17 The two most distinct indications of crystallization in the infrared spectra of PTMO are a new band at 996 cm −1 and a sharp increase and shift in the 1370 cm −1 band. 12 Crystallization in biaxially stressed PEUU was detected by the presence of the 996 cm −1 band in the transmission infrared spectrum of a tube stretched over a potassium bromide mandrel.…”

Section: Molecular Orientationmentioning

confidence: 99%

The effect of strain state on the biostability of a poly(etherurethane urea) elastomer

Schubert

Wiggins

Anderson

et al. 1997

J. Biomed. Mater. Res.

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The effect of deformation state on degradation of a PEUU without added stabilizers was examined in an oxidative environment that simulates the in vivo biodegradation of the polymer. Polymer tubes were stressed uniaxially and biaxially over glass mandrels and treated in 20% hydrogen peroxide/0.1 M cobalt chloride solution for 12 days at 37 degrees C. The amount of degradation was determined from the ATR-FTIR peak height of the amorphous aliphatic ether absorbance at 1110 cm-1. If a uniaxial stress was applied, degradation was inhibited and the amount of surface ether remaining after treatment increased linearly with strain. If the stress was biaxial, the amount of degradation was not reduced unless the strain was greater than 200%. Decreased degradation correlated with the amount of soft-segment orientation. The decreased degradation rate was attributed to compaction of the polyether phase by orientation, which resulted in lower permeability to oxidative agents, particularly oxygen. Macroscopic damage was confined to a thin peeling surface layer if the stress was uniaxial. In comparison, biaxially stressed PEUU ruptured.

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“…Higher tensile strength of PTMG based polymer over PPG is due to the facilitated strain-induced crystallization of PTMG units. [36,37] …”

Section: Stress-strain Measurementsmentioning

confidence: 99%

Comparative studies on short-chain and long-chain crosslinking in polyurethane networks

Sriram

Mahesh

Jeevan

et al. 2000

Macromol. Chem. Phys.

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Isocyanate terminated prepolymers were synthesised using poly(tetramethylene oxide) glycol of molecular weight 1 000 (PTMG1000) and poly(propylene oxide) glycol of molecular weight 1 000 (PPG1000) with tolylene‐2,4‐diisocyanate (TDI). The prepolymers were chain extended with N,N‐bis(2‐hydroxyethyl)isonicotinamide to form polyurethanes containing pyridine moieties. These polyurethanes were converted to cationomers by crosslinking with (a) 1,4‐dibromobutane to form short‐chain crosslinked polymers (SCCPs) and (b) bromine‐terminated prepolymers to form long‐chain crosslinked polymers (LCCPs). The cationomers were characterised by Fourier transform infrared spectroscopy, thermal and mechanical analysis. FTIR spectral results of SCCPs and LCCPs confirmed the quaternisation of heterocyclic nitrogen leading to crosslinking. Dynamic mechanical analysis showed better damping properties for LCCPs than SCCPs. The stress‐strain measurements showed higher elongation and lower tensile strength for LCCPs.

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Correlations between chemical structure, stress‐induced crystallization, and deformation behavior of polyurethane elastomers

Cited by 41 publications

References 10 publications

Resilient Bioresorbable Copolymers Based on Trimethylene Carbonate, l-Lactide, and 1,5-Dioxepan-2-one

Resilient Bioresorbable Copolymers Based on Trimethylene Carbonate, l-Lactide, and 1,5-Dioxepan-2-one

The effect of strain state on the biostability of a poly(etherurethane urea) elastomer

Comparative studies on short-chain and long-chain crosslinking in polyurethane networks

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