Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From carboxylic acid or derivative thereof
Patent
1994-09-12
1999-06-29
Truong, Duc
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From carboxylic acid or derivative thereof
528331, 525535, 526 89, 526210, 526217, 526222, C08G 6908
Patent
active
059170034
DESCRIPTION:
BRIEF SUMMARY
A process for producing polymers of .alpha.,.omega.-unsaturated conjugated compounds, and high molecular weight conjugated polymers thus obtainable
The present invention relates to a process for producing polymers of .alpha.,.omega.-unsaturated conjugated compounds, in particular of compounds which contain aromatic ring systems. It also relates to high molecular weight polymers obtainable by said process, to high molecular weight conjugated polymers and to electroluminescent devices comprising such polymers. There is an urgent industrial need for large-area solid-state light sources, for a wide range of applications mostly related to display technologies, and there is no fully satisfactory technology at present. Polymer-based electroluminescent devices are very promising and they offer several advantages over conventional, inorganic light-emitting diodes and liquid-crystal displays. These advantages include the availability of the whole color spectrum, the ability to make large area electroluminescent devices, the ability to make flexible displays, and the high brightness of the luminescence. This is combined with simple processing technology and low fabrication costs. Furthermore, displays of this type do not need backlighting, in contrast to liquid-crystal displays.
Polymer-based electroluminescent devices are described, e.g., in WO 90/13 148 and EP-A 0 443 861.
A typical device as described in WO 90/13 148 is made up of a semiconductor layer in the form of a thin dense polymer film comprising at least one conjugated polymer, a first contact layer in contact with a first surface of the semiconductor layer, and a second contact layer in contact with a second surface of the semiconductor layer, wherein the polymer film of the semiconductor layer has a sufficiently low concentration of extrinsic charge carriers that on applying an electric field between the first and second contact layers across the semiconductor layer so as to render the second contact layer positive relative to the first contact layer charge carriers are injected into the semiconductor layer and radiation is emitted from the semiconductor layer.
The polymer employed as a semiconductor layer in these devices is conjugated.
By conjugated polymer is meant a polymer which possesses a delocalized .pi.-electron system along the polymer backbone; the delocalized .pi.-electron system confers semiconducting properties to the polymer and gives it the ability to support positive and/or negative charge carriers with high mobilities. Such polymers are discussed, for example, by R. H. Friend in J. Mol. Elec. 4, (1988) 37. in WO 90/13 148, and it is suggested in this document to have substituents on the phenylene ring or to replace phenylene with a fused carbocyclic system or a heterocyclic system. Conductive layers made of poly(aniline) 861.
Highly conjugated polymers, such as PPV or PTV, are generally insoluble and infusible because of the stiffness of their backbone. Consequently they are difficult to process. A solution to this problem is their synthesis via soluble precursor polymers or the use of specifically substituted monomers which lead to soluble, specifically sidechain-substituted conjugated polymers.
The synthesis via precursor polymers proceeds, for example, according to the so-called Wessling bis-(sulphonium salt) precursor route (R. A. Wessling, J. Polym. Sci., Polym. Symp. 72, (1985) 55.). For example, PPV precursor polymers can be prepared by treating an .alpha.,.alpha.'-bis(sulfonium chloride)-p-xylene, e.g., .alpha.,.alpha.'-bis(tetrahydrothiophenium chloride)-p-xylene, with NaOH in water or alcohols as a solvent to yield a sulphonium polyelectrolyte. This precursor polymer is soluble and can be processed, e.g. by spin-coating or film-casting. On heating the precursor polymer, PPV is formed by elimination of tetrahydrothiophene and HCl. Although this is a versatile method for the preparation of a wide range of poly(arylene vinylenes) there are two major drawbacks. Firstly, the polyelectrolyte nature of the precursor makes filtration
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patent: 4808681 (1989-02-01), Harper et al.
patent: 5364522 (1994-11-01), Wang
Journal of Polymer Science, pp. 55-66, 1985 entitled "The Polymerization of Xylyene Bisdialkyl Sulfonium Salts" by R.A. Wessling.
Journal of Polymer Science: Part A-1: vol. 4, 1337-1349, 1966 entitled Polymerization of .alpha.-Halogenated p-Xylenes with Base by Gilch et al.
Journal of Polymer Science: Part A: Polymer Chemistry, vol. 26, 3241-3249, 1988 entitled "Preparation of Polyphenylene Vinylene) from Cycloalkylene Sulfonium Salt Monomers and Polymers" by Lenz et al.
Polymer, 1993, vol. 34, No. 6, pp. 1282-1288 entitled "Reactions proceeding via the reactive intermediate .alpha.-vinyl-p-xylylene. Contrasting orientations in the formation of cyclic dimers and polymer" by Brooke et al.
Die Makromolekulare Chemie 131 (1970) pp. 105-132 (No. 3096), entitled "Poly-p-xylyliden" by Horhold et al.
Polymer, 1992, vol. 33, No. 15 entitled "Highly conductive cyrstalline poly (2-methoxy-p-phenylene vinylene)" by Liang et al.
Gelan Joanes
Louwet Frank
Vanderzande Dirk
Hoechst Aktiengesellschaft
Truong Duc
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