Topochemical polymerization of monomers with conjugated triple bonds

Wegner, Gerhard

doi:10.1002/macp.1972.021540103

Cited by 520 publications

(213 citation statements)

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“…Examples of the former polymerization have included oxacyclobutanes such as 1,3,5-trioxane, 2,3 diolefins undergoing four-center type photopolymerization 4,5 and monomers with conjugated triple bonds such as substituted diacetylenes. 6,7 On the other hand, the first polymer whisker was obtained by the cationic ring-opening polymerization of 1,3,5-trioxane. [8][9][10] The obtained polyoxymethylene whiskers were 1-2 mm in width and 10-50 mm in length.…”

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confidence: 99%

Morphology Control of Aromatic Polymers in Concert with Polymerization

Kimura

Kohama

Yamazaki

2006

Polym J

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ABSTRACT:Morphology control methods of aromatic polymers in concert with polymerization reaction are described in this review. Many attractive methods have been developed including reaction-induced phase separation of oligomers, epitaxial polymerization, shear-induced chain orientation during gelation, template-based polymerization, suspension polycondensation, solid-state polycondensation and liquid-liquid interfacial precipitation and so on. Among them, the reaction-induced phase separation of oligomers, in which there are two modes of crystallization and liquidliquid phase separation, possess practically high potentiality to create novel polymer materials since it can control not only the morphology but also the molecular chain orientation. Ultimate goal is the embodiment of the nature system in a flask, that is, the control of the materials from primary structures to super structures. The morphology control methods by using polymerization reaction afford the valuable methodology for the three-dimensional structure architecture.[doi:10.1295/polymj.PJ2006083] KEY WORDS Morphology / Phase Separation / Oligomer / Whisker / Microsphere / Epitaxy / Aromatic Polymer / Morphology of polymer materials is of great importance as well as the molecular chain orientation for the creation of new functional and high-performance materials possessing essential properties predicted from their molecular structures. From the both aspects of molecular chain orientation and morphology, one of the ideal materials is a needle-like single crystal of extended molecular chains called polymer whisker. Especially, wide variety of polymeric nanomaterials is required for supporting nanotechnology and the more precise controls are rapidly necessitated in these days. Hence, the demand for the morphology control method increases significantly. Usually, extended molecular chain crystals are difficult to obtain by conventional processing methods and the special processing techniques have been developed thus far.1 There exists another stream for the development of extended molecular chain crystals by means of crystallization during polymerization. The needle-like crystals of both flexible and rigid polymers have been obtained by the solid-state polymerization of the monomers and the polymerization in the solution. Examples of the former polymerization have included oxacyclobutanes such as 1,3,5-trioxane, 2,3 diolefins undergoing four-center type photopolymerization 4,5 and monomers with conjugated triple bonds such as substituted diacetylenes.6,7 On the other hand, the first polymer whisker was obtained by the cationic ring-opening polymerization of 1,3,5-trioxane. [8][9][10] The obtained polyoxymethylene whiskers were 1-2 mm in width and 10-50 mm in length. The molecular chains aligned along the long axis of the whisker. They were brought into practical uses with its unique morphology and good mechanical properties.11,12 However, the polyoxymethylene whisker has a melting temperature at 180 C and the low melting temperature limits the broader c...

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Morphology Control of Aromatic Polymers in Concert with Polymerization

Kimura

Kohama

Yamazaki

2006

Polym J

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“…* Discussion. Wegner (1969Wegner ( , 1972 has shown that large and almost defect-free monocrystalline polymers can be obtained via solid-state polymerization of diacetylenes…”

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Poly[1,6-di(N-carbazolyl)-2,4-hexadiyne]

Apgar¹,

Yee²

1978

Acta Crystallogr Sect B

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Abstract. (C30H20N2)n, monoclinic, P2Jc, a = 12.865 (5), b = 4.907 (4), c = 17.403 (5) .h, fl = I08.3 (4) ° , Z = 2/n, M r = n(408.5), Dob s = 1.30, Dealt = 1.301 g cm -3. Intensity data collected on a twocircle diffractometer using graphite-monochromated Cu K~t radiation were refined by full-matrix least squares to an R factor of 0-086. Single-crystal structure analyses show that the polymer backbone has the alternating double-single-triple-single bonding pattern and is a planar conjugated system. The carbazolyl groups are planar and make angles of 43.3 and 81° with the b axis and the plane of the polymer backbone, respectively.Introduction. Intensity data were collected on a HewlettPackard-Canberra controlled Supper diffractometer of Weissenberg geometry, using graphite-monochromated Cu K~t (2 = 1.54178 ,~) radiation and a pulseheight analyser. A fixed-counter moving-crystal technique with variable step scans was used (Hanson & Nordman, 1975) (scan range = 9 to 12°; rate = 2 to 8 ° min-~; sin 20ma× = 1.0). 880 reflections were measured;

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“…1 (Wegner, 1969(Wegner, , 1972(Wegner, , 1977. Polymerization may be initiated by thermal, photochemical or mechanical techniques.…”

Section: Introduction Many Diacetylenes (General Formulamentioning

confidence: 99%