Showing papers on "Polytetrahydrofuran published in 2004"
TL;DR: In this article, the ultrasonic cleavage of high-molecular-weight linear coordination polymers of phosphane telechelic polytetrahydrofuran and palladium dichloride in dilute solution is a reversible process.
Abstract: Breaking up and making up: The ultrasonic cleavage of high-molecular-weight linear coordination polymers of phosphane telechelic polytetrahydrofuran and palladium dichloride in dilute solution is a reversible process (see picture). Sonication for 1 h led to a decrease in the weight-averaged molecular weight of the polymer from 1.7×105 to 1.0×105 g mol−1. Upon leaving the sample to stand for 24 h, the original molecular weight was completely restored.
145 citations
TL;DR: Poly-THF is a medium polarity polymer, and was found to be effective in carrying out simultaneous extraction of both polar and nonpolar analytes, in the first report on the use of a poly-THf based sol-gel material in analytical microextraction.
57 citations
15 Jul 2004
TL;DR: In this article, the authors present an overview of the materials commonly used in solid-supported chemistry and their evolution, starting with polystyrene-divinyl benzene based resins, including reference to microgel and nanoparticles, and moving onto poly(ethylene glycol) (PEG)-grafted resins.
Abstract: This article presents an overview of the materials commonly used in solid-supported chemistry and their evolution. It begins with polystyrene–divinyl benzene based resins, includes reference to microgel and nanoparticles, and moves onto poly(ethylene glycol) (PEG)-grafted resins. A review of alternative types of cross-linker for polystyrene resins such as those based on polytetrahydrofuran and PEG is provided and alternative formats for polystyrene-based resins such as plugs, discs, and films are discussed films. The final section covers aspects of alternative nonpolystyrene matrixes such as polyacrylamide–PEG-based resins and cellulose.
Keywords:
gel;
macroporous;
microgel;
nanoparticles;
PEG;
polymerization;
resins
13 citations
Patent•
06 Jul 2004TL;DR: In this paper, a method of producing a comb polymer comprising the steps of: (a) Providing: (i) a plurality of monomers which are linear, branched or star-shaped, substituted or non-substituted, and have an olefinically unsaturated moiety.
Abstract: The application provides a method of producing a comb polymer comprising the steps of: (a) Providing: (i) a plurality of monomers which are linear, branched or star-shaped, substituted or non-substituted, and have an olefinically unsaturated moiety, the olefinically unsaturated moiety being capable of undergoing addition polymerisation; (ii) an initiator compound; the initiator compound comprising a homolytically cleavable bond. (iii) a catalyst capable of catalysing the polymerisation of the monomer; and (b) Causing the catalyst to catalyse, in combination with the initiator, the polymerisation of a plurality of the monomers to produce the comb polymer. Catalysts and polymers obtainable by the process are also provided. Preferably, the comb polymer is capable of binding proteins and may be produced from monomers which are alkoxy polyethers, such as poly(alkyleneglycol) or polytetrahydrofuran.
10 citations
Patent•
22 Sep 2004
TL;DR: A low temp-resistant high-strength universal pouring material of polyurethane elastomer laid on the ground surface is disclosed in this paper, where the new monomers, polytetrahydrofuran diol and tetrafuran-epoxy propane copolymer diol, are used to react on diisocyanate.
Abstract: A low temp-resistant high-strength universal pouring material of polyurethane elastomer laid on the ground surface is disclosed. During its preparing process, the new monomers, polytetrahydrofuran diol and tetrafuran-epoxy propane copolymer diol, are used to react on diisocyanate, and the cross-linking agent, filler and catalyst are newly designed. Its advantages are high versatility, high strength and high resistance to low temp.
10 citations
TL;DR: In this paper, the thermal degradation processes of p-toluene sulfonate (PTS) doped polypyrrole (PPY) grown from the pyrrole moiety located at both the ends of polytetrahydrofuran (PTHF) have been studied by direct pyrolysis mass spectrometry (DPMS) to gain structural information.
9 citations
Patent•
10 Mar 2004
TL;DR: In this paper, a low-hardness, high-smelting point and high-performance thermoplastic polyether ester containing the hard short-chain polyester segment consisting of bicarboxylic acid and binary alcohol was synthesized.
Abstract: A low-hardness, high-smelting-point and high-performance thermoplastic polyether ester contains the hard short-chain polyester segment consisting of bicarboxylic acid and binary alcohol and the soft polyether ester segment consisting of bicarboxylic acid and oplyalkyleneether diol. In its synthesis the polytetrahydrofuran ether diol and composite antoxidizing agent are used.
7 citations
Patent•
10 Jan 2004
TL;DR: In this paper, a process for working up an at least partially deactivated hydrogenation catalyst for the color number hydrogenation of PTHF and/or pTHF esters, in which the catalyst is purified by treatment with steam at from 100 to 250° C. and a gauge pressure of from 0 to 40 bar.
Abstract: Process for working up an at least partially deactivated hydrogenation catalyst for the color number hydrogenation of PTHF and/or PTHF esters, in which the hydrogenation catalyst is purified by treatment with steam at from 100 to 250° C. and a gauge pressure of from 0 to 40 bar.
6 citations
TL;DR: In this paper, the products and mechanism of the thermal oxidative degradation at 180 °C and the photo-oxidative degradation at 40 °C of polytetrahydrofuran have been investigated using 1H NMR, 13C NMR and GPC.
Abstract: The products and mechanism of the thermal oxidative degradation at 180 °C and the photo-oxidative degradation at 40 °C of polytetrahydrofuran have been investigated using 1H NMR, 13C NMR and GPC. The NMR analysis was assisted by the use of DEPT 13C spectra, two-dimensional NMR spectroscopy (COSY, HMQC and HMBC) and chemical shift simulation software. The NMR spectra of both thermally and photolytically degraded samples were similar showing that the degradation mechanisms were similar. GPC indicated that both chain scission, leading to lower molar mass products, and chain extension, leading to higher molar mass products, occurred initially. NMR analysis of the initial soluble degraded polymers showed that chain scission resulted in formate, aldehyde, propyl ether, butyl ether and propanoyl chain ends, and in-chain ester groups were also formed. For longer periods of degradation, crosslinked gels were formed but these were not amenable to detailed structural characterisation by high-resolution NMR to determine the crosslink mechanism. Copyright © 2004 Society of Chemical Industry
6 citations
TL;DR: In this paper, a cationic ring-opening polymerization was used to prepare hydroxyl-terminated polytetrahydrofuran (PTHF) [−(CH2)4O−] having a number-average molecular weight of 20,700 ǫg mol−1, and relatively narrow molecular weight distribution.
Abstract: A cationic ring‐opening polymerization was used to prepare hydroxyl‐terminated polytetrahydrofuran (PTHF) [–(CH2)4O–] having a number‐average molecular weight of 20,700 g mol−1, and a relatively narrow molecular weight distribution. Elastomeric tetrafunctional networks were prepared by hydrolysis–condensation reactions on this polymer and on two others that had been commercially obtained. The synthesis was carried out at 60°C with 3‐isocyanatopropyltriethoxysilane as an end‐capping molecule and Sn‐octoate as a catalyst. Completeness of the end‐capping reaction was followed by infrared absorption spectroscopy, which showed gradual decreases of peaks at 2270.7 and 3475 cm−1 from the disappearances of isocyanato and hydroxyl groups, respectively, and the appearance of a peak at 3350 cm−1 from newly formed NH groups. Analysis of the kinetic data suggest that the –NCO, –OH, and –NH– peaks tend to exhibit first‐order kinetics at the beginning of the reaction and reach asymptotic values at extended time...
4 citations
Patent•
30 Dec 2004
TL;DR: In this article, the authors defined mixtures consisting of polytetrahydrofuran and stabilizers having a molecular weight of from 600 g/mol to 10000 g/m and comprising at least two phenolic groups.
Abstract: The invention relates to mixtures (1) comprising (a) polytetrahydrofuran and (b) stabilizers having a molecular weight of from 600 g/mol to 10000 g/mol and comprising at least two phenolic groups.
Patent•
19 Jun 2004
TL;DR: In this paper, a process for obtaining oligomers of polytetrahydrofuran or of tetrahydroidfuran copolymers from a methanolic crude product which contains polyto-furan and tetra-drone copolymars is described, which is obtained in the transesterification of the mono-and/or diesters of polytohexene copolymer with methanol.
Abstract: A process for obtaining oligomers of polytetrahydrofuran or of tetrahydrofuran copolymers from a methanolic crude product which contains polytetrahydrofuran or tetrahydrofuran copolymers and is obtained in the transesterification of the mono- and/or diesters of polytetrahydrofuran or tetrahydrofuran copolymers with methanol, which includes a) removing the majority of the methanol from the crude product in a first distillation stage, b) separating the resulting bottom product by distillation into a top fraction containing the oligomers of polytetrahydrofuran or of tetrahydrofuran copolymers, and polytetrahydrofuran or tetrahydrofuran copolymer, and c) condensing the oligomers of polytetrahydrofuran or of tetrahydrofuran copolymers out of the top fraction from stage b).
Patent•
06 May 2004
TL;DR: In this paper, the molecular weight distribution of polytetrahydrofuran and copolymers with alkylene oxides is narrowed down by blending the polymers with a mixture of an alicyclic compound, methanol and water at a temperature ranging from 0-40° C.
Abstract: The molecular weight distribution of polytetrahydrofuran and copolymers of tetrahydrofuran with alkylene oxides is narrowed down by blending the polymers with a mixture of an alicyclic compound, methanol and water at a temperature ranging from 0-40° C. The two phases formed are separated at 40-80° C., and polymers with low molecular weight distributions are isolated therefrom.
Patent•
26 Feb 2004
TL;DR: In this paper, a water-based polyurethane resin consisting of a high-molecular weight polyol component, a polyisocyanate compound, and a chain extender is presented.
Abstract: PROBLEM TO BE SOLVED: To provide a water-based polyurethane resin having flexibility specific to the water-based polyurethane resin, having good stability under high temperature and low temperature conditions, and having good adhesion to a plastic. SOLUTION: This water-based polyurethane resin comprises a high-molecular weight polyol component, a polyisocyanate compound, and a chain extender, wherein the high-molecular weight polyol component contains a liquid polytetrahydrofuran-based polyether polyol which is obtained by copolymerizing tetrahydrofuran with an alkylene oxide having an alkyl in its side chain or an alcohol having an alkyl in its side chain. COPYRIGHT: (C)2004,JPO
Patent•
15 Jul 2004
TL;DR: In this article, a method for the single-stage production of polytetrahydrofuran copolymers by polymerisation of tetrahedra and, optionally, at least one comonomer in the presence of a heteropoly acid is described.
Abstract: The invention relates to a method for the single-stage production of polytetrahydrofuran or tetrahydrofuran copolymers by polymerisation of tetrahydrofuran and, optionally, at least one comonomer in the presence of a heteropoly acid, characterised in that the reaction mixture comprises less than 0.5 wt. % of iron ions, based on the heteropoly acid.