Phase modification and polymorphism in two poly(ether-block-amide) copolymers

Hatfield, Galen R.; Bush, Richard W.; Killinger, William E.; Roubicek, Paul M.

doi:10.1016/0032-3861(94)90279-8

Cited by 11 publications

(7 citation statements)

References 33 publications

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“…Now, let us give some attentions on understanding the mechanisms for the dual endotherms shown in curve 3 of Figure 2 for the filled compound. First, it is noteworthy to point out that analogous to PA homopolymer,23–25 the melt‐crystallizable PEBA copolymer shows α‐ and γ‐form polymorphism6, 14, 20, 26 and that the γ ↔ α crystal transformation, namely so‐called Brill transition, could be reversible upon heating or cooling 24. Calorimetrically, the PEBA copolymer may exhibit multiple melting endotherms.…”

Section: Resultsmentioning

confidence: 99%

Radiopaque, barium sulfate‐filled biomedical compounds of a poly(ether‐block‐amide) copolymer

Guo

2008

J of Applied Polymer Sci

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Various radiopaque compounds of a poly (ether‐block‐amide) copolymer resin filled with fine barium sulfate particles were prepared by melt mixing. Material properties of the filled compounds were investigated using various material characterization techniques, including thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic rheometry, uniaxial tensile test, and dynamic mechanical thermal analysis (DMTA). The effects of the filler and its concentration on the measured material properties are evaluated. It has been found that in addition to its well‐known X‐ray radiopacity, the filler is quite effective in reinforcing some mechanical properties of the copolymer, including modulus of elasticity and yield strength. More interestingly, it has been observed that at low loading concentrations near 10 wt %, the filler may also act as a rigid, inorganic toughener for the copolymer by improving the postyield material extensibility of strain hardening against ultimate material fracture. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

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Section: Resultsmentioning

confidence: 99%

Radiopaque, barium sulfate‐filled biomedical compounds of a poly(ether‐block‐amide) copolymer

Guo

2008

J of Applied Polymer Sci

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“…Segmented poly(ether amide)s comprising polyamide-6, polyamide-11, or polyamide-12 hard segments and polytetrahydrofuran, poly(propylene oxide), or poly(ethylene oxide) soft segments are typical examples of segmented thermoplastic elastomers. , Such polymers have a phase-separated morphology depending on the molecular weight of the polyether and polyamide structural units. − In general, the polyamide segments crystallize in a lamellar type structure. The segmented copolymers show typical elastomeric properties if the polyether matrix is the continuous phase in which the crystalline polyamide domains are dispersed.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Morphology, and Properties of Segmented Poly(ether amide)s with Uniform Oxalamide-Based Hard Segments

et al. 2012

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The synthesis, morphology, and properties of segmented poly(ether amide)s based on flexible PTHF segments (M n = 1.1 × 103 g mol–1) and uniform rigid oxalamide segments were investigated. The amount of oxalamide groups in the hard segment and the spacer length of bisoxalamide-based hydrogen bonded arrays were varied systematically. The segmented poly(ether amide) with single oxalamide groups connecting the polyether blocks was a sticky solid with a melting temperature of ∼25 °C. Incorporation of uniform hard segments consisting of two interconnected oxalamide units provided highly phase-separated thermoplastic elastomers with a broad temperature-independent rubber plateau. By decreasing the aliphatic spacer length separating two oxalamide units from 10 to 2 methylene groups, the melting transitions increased from 140 to 200 °C. FT-IR evidenced strongly hydrogen bonded and highly ordered bisoxalamide hard segments with degrees of ordering between 66 and 90%. AFM revealed the presence of fiber-like nanocrystals with lengths up to several hundreds of nanometers randomly dispersed in the soft PTHF matrix. The long dimension of the crystals was found parallel to the direction of the hydrogen bonds. One of the other small dimensions of the crystal approximately equals the length of the oxalamide segment, whereas the other one may correspond to the height of a stack containing ca. 10–20 hydrogen-bonded sheets. Upon heating, the crystalline phase melts over a broad temperature range to give a homogeneous melt according to temperature-dependent FT-IR, SAXS, and rheology data. Increasing the number of oxalamide groups in the hard segment to three afforded a highly phase-separated material with a melting transition above 200 °C. The segmented copolymers with two or three oxalamide groups in the hard segment show a distinct yield point and have an elastic modulus between 121 and 210 MPa, a stress at break ranging from 15 to 27 MPa, and strain at break of 150 up to 900%. The results demonstrate that alternating block copolymers with soft PTHF segments and uniform hard segments containing two or three oxalamide groups are TPEs with good thermal and mechanical properties.

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“…PEBA consists of an aliphatic polyamide as the hard block and a polyether as the soft block and between the two blocks a di-acid serves as the joint. Various tools including wide angle X-ray diffraction [3][4][5], small angle X-ray scattering [6,7], transmission electron microscopy [6], and atomic force microscopy (AFM) [8] had been used to investigate the morphology of PEBA. The segmented copolymer shows microphase separation due to the high polarity difference between the hard and soft segment [2].…”

Section: Introductionmentioning

confidence: 99%

Abnormal Flow and Viscoelastic Behavior of Poly(Ether-Block-Amide)

Yang¹,

Tsai²

2006

AIP Conference Proceedings

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Articles you may be interested inPoly(D-lactic acid) as a rheological modifier of poly(L-lactic acid): Shear and biaxial extensional flow behavior Abstract. The transient and viscoelastic behavior of a segmented block copolymer, poly(ether-b-amide) was carefully studied. Upon a sudden shear the stress of the copolymer melt shows a fluctuation when the shear rate exceeds a critical value. The recoverable strain at the onset of the fluctuation is found approximately at a constant value of 0.6. The fluctuation is independent of materials of shearing apparatus and depends on the roughness of the shearing surfaces. Increasing the roughness of the surface suppresses the stress fluctuation. The copolymer melt also exhibit an abnormal terminal behavior in viscoelasticity. A plateau of storage modulus emerges upon a temperature raise which may relate to the domain structure change induced by the dissociation of hydrogen bonding.

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Phase modification and polymorphism in two poly(ether-block-amide) copolymers

Cited by 11 publications

References 33 publications

Radiopaque, barium sulfate‐filled biomedical compounds of a poly(ether‐block‐amide) copolymer

Radiopaque, barium sulfate‐filled biomedical compounds of a poly(ether‐block‐amide) copolymer

Synthesis, Morphology, and Properties of Segmented Poly(ether amide)s with Uniform Oxalamide-Based Hard Segments

Abnormal Flow and Viscoelastic Behavior of Poly(Ether-Block-Amide)

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