Constitutional Regularity in Linear Condensation Polymers

Gentile, Frank T.; Suter, Ulrich W.

doi:10.1016/b978-0-08-096701-1.00148-8

Cited by 15 publications

(12 citation statements)

References 29 publications

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“…This isomerism and its influence on properties of some step-growth polymers have been previously investigated. [9][10][11][12][13][14][15][16][17][18] The effect of this isomerism on the properties of the resulting fibers have been reported for a single case. [19] Full Paper: Fibers of various rigid-rod, fully aromatic polyamides, produced by polycondensation of differently substituted p-phenylenediamines and terephthaloyldichlorides, were spun from nematic solution and analyzed with wide-angle X-ray diffraction (WAXD).…”

Section: Generalitiesmentioning

confidence: 99%

“…This leads to a type of head/tail constitutional isomerism. [11,14,18] The degree of order in this type of isomerism is quantified by the probability lc (0 f lc f 1) of two adjacent non-symmetric units in a chain to point in the same direction. [11,18] For a chain where all units point in the same direction, s = 1 (head-to-tail), and when the orientation of the units is strictly alternating, s = 0 (head-to-head/ tail-to-tail).…”

Section: Constitutionmentioning

confidence: 99%

“…The following considerations apply: [11,14] A difference in the reactivity of the functional groups in a non-symmetric monomer is not sufficient to produce polycondensates with ordered constitution; immediate mixing of the two monomers often only gives a random or near-random polymer. If the symmetric monomer (in the second case above, YccY) or the second non-symmetric monomer is fed very slowly into the reaction mixture containing all of the other monomer (XabX), however, the highest possible head-to-head/tail-to-tail regularity can be achieved.…”

Section: Constitutionmentioning

confidence: 99%

See 2 more Smart Citations

Arrangement of substituted, rigid-rod aramids in the highly-ordered solid state

Glomm

Grob

Neuenschwander³

et al. 2000

Macromol. Chem. Phys.

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Section: Generalitiesmentioning

confidence: 99%

Section: Constitutionmentioning

confidence: 99%

Section: Constitutionmentioning

confidence: 99%

See 1 more Smart Citation

Arrangement of substituted, rigid-rod aramids in the highly-ordered solid state

Glomm

Grob

Neuenschwander³

et al. 2000

Macromol. Chem. Phys.

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“…Secondly, the disorder in our systems is controlled and variable. The constitutional isomerism is determined by the conditions applied during the polymerization process 25,26,37,38,58,[60][61][62][63][64][65][66][67][68][69][70] . The chains spun here are of random constitution 37,38) .…”

Section: Heat Treatment and Fiber Structurementioning

confidence: 99%

An investigation of novel approaches in order to provide crosslinked fully aromatic polyamide chains

Glomm¹,

Oertli²,

Rickert³

et al. 2000

Macromol. Chem. Phys.

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Two different, novel approaches to crosslink fully aromatic, rigid‐rod aramid chains were studied. First, the new rigid‐rod aramid poly[1,4‐phenylen‐2,5‐bis(prop‐2‐ynyloxy)‐terephthalamide] with an inherent viscosity of ηinh = 2.74 dL/g was synthesized by low temperature polycondensation of p‐phenylendiamine and 2,5‐bis(prop‐2‐ynyloxy)‐terephthaloylchloride. The pendant alkinyl moieties allowed thermally induced crosslinking at temperatures higher than 200°C. No weight loss was found due to this treatment, but curing gave rise to the formation of stable radicals. However, no fiber spinning experiments were carried out using this material due to the insufficient stability of the polymer chains against degradation when being dissolved in sulfuric acid. Furthermore, fibers of a rigid rod polyamide containing pyrimidine moieties, produced by polycondensation of bis‐silylated 2,5‐diaminoprimidine and terephthaloyl dichloride, were spun from nematic solutions. Fibers were crosslinked by complexation with nickel(II)‐ions in the swollen state. Both crosslinked and non‐crosslinked, otherwise identically processed samples, were characterized by wide‐angle X‐ray‐diffraction (WAXD) measurements and mechanical tests. A post‐spin heat treatment was employed to improve the low degrees of orientation and crystallinity that the untreated fibers in general showed. The dominating crystal structures of both fiber samples are similar to “Modification II” of the well characterized fibers from poly(p‐phenylene‐terephthalamide) (PPTA). The number and size of the morphological defects in the crosslinked fibers was significantly higher than in the non‐crosslinked samples. The influence of the annealing on the mechanical fiber properties and the molecular order in the fibers was investigated. The values of all mechanical parameters were considerably lower in the case of the crosslinked fibers, probably due to the collapse of the entire supramolecular order and fiber morphology.

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“…Also, previously, Ueda [30] and Gentile and Suter [31] reviewed the constitutional isomerism in polyamide structures regarding constitutional order, theory, and polyamide structure.…”

Section: Aromatic Polyamides With Spherical-like Structuresmentioning

confidence: 99%

Functional Aromatic Polyamides

et al. 2017

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Abstract:We describe herein the state of the art following the last 8 years of research into aromatic polyamides, wholly aromatic polyamides or aramids. These polymers belong to the family of high performance materials because of their exceptional thermal and mechanical behavior. Commercially, they have been transformed into fibers mainly for production of advanced composites, paper, and cut and fire protective garments. Huge research efforts have been carried out to take advantage of the mentioned characteristics in advanced fields related to transport applications, optically active materials, electroactive materials, smart materials, or materials with even better mechanical and thermal behavior.

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Constitutional Regularity in Linear Condensation Polymers

Cited by 15 publications

References 29 publications

Arrangement of substituted, rigid-rod aramids in the highly-ordered solid state

Arrangement of substituted, rigid-rod aramids in the highly-ordered solid state

An investigation of novel approaches in order to provide crosslinked fully aromatic polyamide chains

Functional Aromatic Polyamides

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