Structure and properties of segmented polyamides

Bornschlegl, E.; Goldbach, G.; Meyer, K.-P.

doi:10.1007/bfb0114023

Cited by 25 publications

(3 citation statements)

References 6 publications

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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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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 observed glass transition temperature (T g1 ) in the low-temperature region averages -60°C and is constant for the entire copolymer series, while the T g of the PTMO homopolymer is -90°C. It is assumed that the stiffening of the ends of the flexible block chain by the chemical bonding of the rigid block raises the glass transition temperature by about 10°C, and interactions between the continuous phase and the dispersed phase can further increase this temperature by another 5°C [1,[53][54][55]. Therefore, such a significant increase in T g cannot be explained solely by the mentioned phenomena.…”

Section: Thermal Properties and Phase Distribution Of Tpeeamentioning

confidence: 99%

Wpływ stopnia polimeryzacji bloku estrowego na strukturę oraz właściwości blokowych terpolimerów estrowo-eterowo-amidowych

Rokicka,

Janik,

Schmidt

et al. 2024

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Otrzymano nowe multiblokowe elastomery termoplastyczne (TPEEA) składające się z krystalicznego bloku amidowego, amorficznego bloku eterowego oraz pełniącego rolę kompatybilizatora bloku estrowego o zmiennym stopniu polimeryzacji. Wykazano, że rozdział fazowy zachodzi w fazie twardej. TPEEA posiadające krótkie łańcuchy estrowe składają się z eterowej ciągłej matrycy i rozproszonych w niej krystalicznych domen poliamidowych. Na granicy faz znajduje się duży obszar międzyfazowy. Wzrost długości bloków estrowych powoduje oddzielenie się fazy krystalicznej estru.

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“…The Pebax® series of poly(ether‐ block ‐amide) materials produced by Arkema are among the most thoroughly‐characterized block copolymers. Reports of their mechanical and thermal properties have been augmented with studies of their transport properties in membrane separations and in drug delivery systems . The Pebax® grades of present interest have soft blocks comprised of poly(tetramethylene oxide) (PTMO) that provide a glass transition (T g ) near –70 O C and melting temperatures (T m ) less than 25 O C (Fig.…”

Section: Introductionmentioning

confidence: 99%

Block copolymers as sequestering phases in two‐phase biotransformations: effect of constituent homopolymer properties on solute affinity

Dafoe

Parent

2014

J of Chemical Tech & Biotech

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BACKGROUND: Block copolymers can be effective extractants in solid-liquid two-phase partitioning bioreactors (TPPBs) when selected on the basis of their partition coefficient toward target solutes, and their thermo-mechanical properties. A series of Pebax ® block copolymers, containing varying proportions of soft poly(tetramethylene oxide) and hard poly(amide-12), was evaluated to determine the effect of hard segment proportion on solute affinity toward two biotransformation target molecules, carveol and carvone. Subsequently, representative homopolymers comprising the copolymers' soft segment were examined individually for the effects of molecular weight, crystallinity, and polymer end group polarity on affinity. RESULTS: Partition coefficients decreased with greater proportions of copolymer hard segments and homopolymer crystallinity, both of which act as non-absorptive domains, but which impart mechanical strength to the polymer. Partition coefficients increased with decreasing homopolymer molecular weight, which was ascribed to increased entropy of mixing. Hydroxyl vs. ether end group functionality had a variable effect on the partitioning of polar and non-polar solutes, providing a basis for the rational design of selective oligomeric absorbents.CONCLUSION: Block copolymers can provide an attractive, low-cost option for polymeric sequestering phases in TPPBs, but commercial grades of these materials are not optimized for these applications. TPPB performance can be improved by selecting/fabricating polymers that minimize the molecular weight of the soft component, the proportion of hard segment, and by considering the effects of end group composition.

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Structure and properties of segmented polyamides

Cited by 25 publications

References 6 publications

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

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

Wpływ stopnia polimeryzacji bloku estrowego na strukturę oraz właściwości blokowych terpolimerów estrowo-eterowo-amidowych

Block copolymers as sequestering phases in two‐phase biotransformations: effect of constituent homopolymer properties on solute affinity

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