摘要:

AbstractCeric perchlorate/formaldehyde (F)redox couple initiated polymerisation of the monomer methyl acrylate (MA), acrylonitrile (AN), and methyl methacrylate (MMA) in perchloric acid (25°C) was carried out. The rate of polymerisation was directly proportional to [M]2and [F] for all the systems. The rate was independent of [Ce4+] for the systems with MA or AN, but inversely proportional to [Ce4+] with MMA as the monomer. The rate of ceric disappearance was directly proportional to [Ce4+], [F], and [M]. The results were explained by a kinetic scheme involving the oxidation of the substrate by Ce4+to give the primary radical and further reaction of the latter with Ce4+to give the final product, and initiation of polymerisation both by Ce4+and the primary radical, propagation followed by termination by the metal ion. Only with MMA as the monomer, the initiation by Ce4+was found to be negligible compared to that by primary radicals. In the system with the reducing agentst‐butanol andn‐butanol, there was found to be 1:1 complex formation between the substrate and Ce4+. Otherwise the scheme is similar to that proposed for the Ce4+/HCHO/HClO4/AN (MA) sys

ISSN:0025-116X    

DOI:10.1002/macp.1968.021120101

出版商:Hüthig&Wepf Verlag    

年代:1968

数据来源: WILEY

摘要:

AbstractThe thermal degradation of polyoxymethylene has been studied in the dynamic molecular still. The energy of activation for the degradation of hydroxyl group terminated polymer increases from 5–7 kcal/mole in the early stages to 50–52 kcal/mole from about 40% volatilisation onwards. There is an inverse relationship between molecular weight and initial rate and this, together with the changes in molecular weight which occur during the course of the reaction and the fact that acetylation of the chain terminal hydroxyl groups inhibits the reaction, indicates a very close similarity between the overall reaction mechanism and that for the thermal degradation of poly(methyl methacrylate).From the shape of the rate curve obtained during the course of the reaction and the fact that the density of the residual polymer increases during the reaction it has been concluded that reaction occurs preferentially in the amorphous regions of the polymer.Molecular, free radical and ionic mechanisms have been considered in detail. An examination of minor reaction products and the effect of catalysts and inhibitors positively eliminates the possibility that a radical process is involved. In the presence of basic catalysts the reaction is undoubtedly anionic but the anionic and molecular mechanisms are virtually indistinguishable in the uncatalysed reaction although the molecular mechanism is preferred on energetic grou

ISSN:0025-116X    

DOI:10.1002/macp.1968.021120102

出版商:Hüthig&Wepf Verlag    

年代:1968

数据来源: WILEY

摘要:

AbstractUnder both 2537 Å and 3650 Å irradiationi. vac.polyoxymethylenes evolve hydrogen and carbon monoxide in a molar ratio of 3.5–4.0. Irradiation in air produces well defined changes in the hydroxyl and carbonyl regions of the infrared spectrum. 2537 Å radiation is approximately 100 times more effective than 3650 Å radiation. Carbonyl absorption has been resolved into three components at 1750, 1785, and 1815 cm−1. Under 3650 Å radiation carbonyl absorption increases autocatalytically while under 2537 Å radiation and equilibrium concentration is quickly achieved. These observations are accounted for qualitatively in terms of current theories of organic oxidation

ISSN:0025-116X    

DOI:10.1002/macp.1968.021120103

出版商:Hüthig&Wepf Verlag    

年代:1968

数据来源: WILEY

摘要:

AbstractCationic polymerization of monomeric formaldehyde has been studied at low temperature. It was found that high molecular weight polyoxymethylene with the reduced viscosity higher than 1.0 dl/g was readily obtained when the polymerization of formaldehyde was carried out in saturated hydrocarbons in the presence of LEWISacids, BRÖNSTEDacids, I2, ICl ICl3, IBr, sulfur dioxide and binary systems of sulfur dioxide with these compounds at considerably low temperature. The degree of polymerization was effected by the polymerization conditions, especially solvent, polymerization temperature and addition of chain transfer agents such as water, formic acid, methanol or methyl formate

ISSN:0025-116X    

DOI:10.1002/macp.1968.021120104

出版商:Hüthig&Wepf Verlag    

年代:1968

数据来源: WILEY

摘要:

AbstractSome polyethylenimines containing 2‐oxazolidone ring in the side chain were synthesized by (1) the MANNICHtype reaction of formaldehyde, 2‐oxazolidone, and polyethylenimine, (2) polymerization of N‐(1‐azirinomethyl)‐2‐oxazolidone, and (3) reaction of N‐hydroxy‐methyl‐2‐oxazolidone with polyethylenimine. These polymers were soluble in water, but insoluble in common organic solvents.They formed the complexes with phenol orp‐toluene sulfonic acid

ISSN:0025-116X    

DOI:10.1002/macp.1968.021120105

出版商:Hüthig&Wepf Verlag    

年代:1968

数据来源: WILEY

摘要:

AbstractPolymerization of three epoxy compounds with a trimethylsilyl group,i.e., epoxyethyltrimethylsilane (I), (3.4‐epoxybutyl) trimethylsilane (II) and (2.3‐epoxypropoxy) trimethylsilane (III) was attempted with organometallic compounds as catalyst. Polymers obtained from I by any of the catalysts examined were of low molecular weight. II and III, on the other hand, yielded high polymers and showed similar polymerizability to other alkylene oxides or glycidyl ethers. Results were discussed in relation to the effects of the trimethylsilyl group on the polymerization. Polyglycidol derived from the polymer of III by hydrolysis was of much higher molecular weight than that by direct polymerization of glycidol with an onganometallic catal

ISSN:0025-116X    

DOI:10.1002/macp.1968.021120106

出版商:Hüthig&Wepf Verlag    

年代:1968

数据来源: WILEY

摘要:

AbstractOptically active polymers could be obtained by the asymmetric polyaddition of tetramethylene dimercaptan to ethylene dimethacrylate using S‐isobutylethylenimine or its polymer as catalyst. Polymer catalysts showed an enhanced activity in the asymmetric polyadditio

ISSN:0025-116X    

DOI:10.1002/macp.1968.021120107

出版商:Hüthig&Wepf Verlag    

年代:1968

数据来源: WILEY

摘要:

AbstractThe following chelate‐polymers were synthesized and their catalytic activity was investigated: These chelate‐polymers were found to catalyse the decomposition of hydrogen peroxide. For purposes of comparison, the copper‐chelate of methyl hydroxamic acid (IV) also was synthesized; it showed no catalytic effect. The chelates (I) and (II), on the other hand, were found to have large catalytic activity for the decomposition reaction of hydrogen peroxide in aqueous solution, while their polymeric ligands alone exhibited no catalytic activity for this reaction, or, at least, less activity than the chelates themselves. In the case of the chelate (II), it was found that the catalytic activity depends on the molecular weight of the polymeric ligand.On the basis of structural analyses by means of visible and infra‐red spectroscopy, the catalytic activity of these chelate polymers is assumed to depend on the bond strength between the ligand and the cop

ISSN:0025-116X    

DOI:10.1002/macp.1968.021120108

出版商:Hüthig&Wepf Verlag    

年代:1968

数据来源: WILEY

摘要:

AbstractAn adiabatic, vacuum calorimeter has been used to measure the heat capacity of a random ethylene/propylene copolymer, containing 31 mole per cent propylene, from 80 to 320°K. An estimate has been made of heat capacity values below 80°K. Entropy, enthalpy and free energy values have been derived and are listed at ten degree intervals. The difference (1.2 cal deg−1mole repeat unit−1) between the observed entropy (15.1 ± 0.2 cal deg−1mole repeat unit−1) and that calculated from previously published data for polyethylene and polypropylene (16.3 ± 0.2 cal deg−1mole repeat unit−1) is consistent with the random nature of the arrangement of co‐monomer units along the chain, which would be expected to give rise to a residual entropy of 1.23 cal deg−1mole repeat unit−1. The entropy of polymerisation of the gaseous co‐monomers at 1 atmosphere pressure and 298.16°K to amorphous polymer, ΔS 0gc, has been calculated as −41.1 ± 0.2 cal deg−1mole repeat unit−1. The glass transition temperature of the copolymer was found to be 214 ± 2°K. The increase in heat capacity of the copolymer at the glass transition temperature, 2.6 cal deg−1bead−1See page 94., is in agreement with that expected on the basis of the hole theory of melting. An approximation is made of the number of vib

ISSN:0025-116X    

DOI:10.1002/macp.1968.021120109

出版商:Hüthig&Wepf Verlag    

年代:1968

数据来源: WILEY

摘要:

AbstractAus Copolymeren ausp‐Vinylbenzophenon, ausp‐Vinylbenzophenonanil und ausp‐Vinyl‐p′‐dimethylaminoazobenzol und Styrol entstehen mit Natrium in Tetrahydrofuran Lösungen der entsprechenden Polyradikalanionen und Polydianionen. Die makromolekularen Radikalanionen der beiden erstgenannten Copolymeren starten die Pfropfcopolymerisation von Acrylnitril und Methylmethacrylat, die entsprechenden Polydianionen darüber hinaus auch die Pfropfcopolymerisation von Styrol; mit Styrol entstehen dabei „lebende”︁ Seitenzweige. Vom Mononatriumaddukt des Copolymeren ausp‐Vinyl‐p′‐dimethylaminoazobenzol und Styrol wird nur Acrylnitril polymerisiert; die entsprechende Dinatriumverbindung bringt neben Acrylnitril noch Methylmethacrylat zur Pfropfcopolymerisation, aber nicht Styrol. Durch Lösungsversuche läßt sich zeigen, daß in den Pfropfprodukten mit Acrylnitril und Methylmethacrylat praktisch keine ungepfropften Rückgratpolymeren und ke

ISSN:0025-116X    

DOI:10.1002/macp.1968.021120110

出版商:Hüthig&Wepf Verlag    

年代:1968

数据来源: WILEY