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1. |
Formation and properties of poly‐L(DL)‐lysine‐copper(II) complexes |
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Die Makromolekulare Chemie,
Volume 141,
Issue 1,
1971,
Page 1-9
Masahiro Hatano,
Tsunenori Nozawa,
Sakuji Ikeda,
Takakazu Yamamoto,
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摘要:
AbstractWater‐soluble poly‐L‐lysine‐ and poly‐DL‐lysine‐copper(II) complexes were prepared in aqueous alkaline solutions.The complex‐formations of poly‐L‐lysine and poly‐DL‐lysine with cupric ions in aqueous solutions were studied with pH titration and electronic spectroscopy and measurements of optical rotatory dispersion, circular dichroism and solution viscosity. From the results it was revealed that the poly‐L‐lysine forms two kinds of complexes, being formed on the degree of neutralization α0.5, respectively. The former complex consists of a cupric ion coordinated with four amino nitrogen atoms of the side chains. Some extents of helical conformation of poly‐L‐lysine are held after the complex formation with cupric ions at a pH over 10. The results on the poly‐L‐lysine‐copper(II) complexes were compared with those on t
ISSN:0025-116X
DOI:10.1002/macp.1971.021410101
出版商:Hüthig&Wepf Verlag
年代:1971
数据来源: WILEY
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2. |
The catalytic activity of the poly‐L‐lysine‐copper(II) complex on the oxidation of 3.4‐dihydroxyphenylalanine |
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Die Makromolekulare Chemie,
Volume 141,
Issue 1,
1971,
Page 11-19
Masahiro Hatano,
Tsunenori Nozawa,
Sakuji Ikeda,
Takakazu Yamamoto,
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摘要:
AbstractThe poly‐L‐lysine‐ (PLL) and poly‐DL‐lysine‐copper(II) complexes were used as the catalysts for the oxidation of 3.4‐dihydroxyphenylalanine. The catalytic activity of poly‐L‐lysine‐copper(II) complex (PLL‐Cu(II)) was found to be larger than that of bis(ethylenediamine)‐copper(II) at both pH 6.9 and 10.5. The catalytic activity was discussed on the basis of some kinetic data. The oxidation was presumed to proceed through the formation of a reaction intermediate between the catalyst and the substrate. It was also revealed that the oxidation was catalyzed asymmetrically when the PLL‐Cu(II) was used as the catalyst at pH over 10.5. The asymmetric oxidation was presumed to be ascribed to the helical structure of PLL‐Cu(II) in the
ISSN:0025-116X
DOI:10.1002/macp.1971.021410102
出版商:Hüthig&Wepf Verlag
年代:1971
数据来源: WILEY
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3. |
The asymmetric structures of the poly‐L‐lysine‐copper(II) complex |
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Die Makromolekulare Chemie,
Volume 141,
Issue 1,
1971,
Page 21-29
Tsunenori Nozawa,
Masahiro Hatano,
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摘要:
AbstractThe asymmetric structures of poly‐L‐lysine‐copper(II) complex (PLL‐Cu(II)) were investigated and discussed in detail. The CD spectrum of PLL‐Cu(II) has four peaks, three peaks, and one peak at the wave‐length of 650–350, 350–240, and 222 mμ, respectively. These optical active transitions can be assigned to be due to d‐d transitions of cupric ions, charge transfer transitions of cupric complexes and n‐π*transition in a helical polypeptide, respectively. The first two groups of CD bands could be ascribable to the asymmetric coordination structures of ligands to cupric ions. The IR spectra of PLL‐Cu(II) showed a band around 1610 cm−1, which suggested that the peptide amide nitrogens coordinate to the cupric ions with displacements of protons. From these results, it was concluded that the asymmetries of the copper complex unit in the PLL‐Cu(II) is due to the coordination of the peptide amide nitrogens. A structure is presente
ISSN:0025-116X
DOI:10.1002/macp.1971.021410103
出版商:Hüthig&Wepf Verlag
年代:1971
数据来源: WILEY
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4. |
The mechanism in the asymmetrically selective oxidation of 3.4‐dihydroxyphenylalanine catalyzed by the poly‐L‐lysine‐copper(II) complex |
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Die Makromolekulare Chemie,
Volume 141,
Issue 1,
1971,
Page 31-41
Tsunenori Nozawa,
Masahiro Hatano,
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摘要:
AbstractIn the oxidation of 3.4‐dihydroxyphenylalanine (DOPA) the effect of the asymmetrical structure in poly‐L‐lysine‐copper(II) complex (PLL‐Cu(II)) on the asymmetrical selectivity ratio was investigated at various reaction temperatures and various preparation conditions of the catalyst, or by addition of catechol or phenylalanine. From the comparison of the asymmetric selectivity with the structure of the catalyst, the combination of two or more asymmetric cupric complex units was considered as the cause for the asymmetrically selective catalysis, where α‐helical structure may serve to hold the two or more cupric complex units in a special steric configuration. Moreover a plausible mechanism for the asymmetrically selective oxidation was discussed by the evidence from the addition effects of catechol or phenylalanine and by the asymmetrically selective interaction between PLL‐Cu(II) and DOPA. Then, the mechanism seems to be confirmed by an inspection with a m
ISSN:0025-116X
DOI:10.1002/macp.1971.021410104
出版商:Hüthig&Wepf Verlag
年代:1971
数据来源: WILEY
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5. |
Polymerisation by the chromate/arsenite system |
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Die Makromolekulare Chemie,
Volume 141,
Issue 1,
1971,
Page 43-53
Tushar K. Chatterjee,
Rajat K. Das,
Santi R. Palit,
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摘要:
AbstractThe aqueous polymerisation of methyl methacrylate initiated by the chromate/arsenite system has been studied. It is observed that the polymerisation by the above redox system is catalysed by OH⊖though the parent reaction between chromate and arsenite is catalysed by H⊕. It is also observed that traces of Cu2⊕inhibit both the polymerization reaction as also the parent reaction.From these observations it is concluded (1) intermediate valency states of chromium has no initiating power in alkali solution and (2) the redox reaction between chromate and arsenite is a chain reaction involving single electron transfer and the intermediate As4⊕thus produced is the initiating
ISSN:0025-116X
DOI:10.1002/macp.1971.021410105
出版商:Hüthig&Wepf Verlag
年代:1971
数据来源: WILEY
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6. |
Estimation of endgroups in acrylamide polymers by reverse dye partition technique |
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Die Makromolekulare Chemie,
Volume 141,
Issue 1,
1971,
Page 55-61
Sailes Mukhopadhyay,
Bhairab Chandra Mitra,
Santi R. Palit,
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摘要:
AbstractA new dye partition method, known as reverse dye partition(RDP)‐technique for estimation of carboxyl and sulfoxy endgroups in water‐soluble acrylamide polymers has been described. Detailed experimental conditions for the use of the RDP technique have been discussed and plausible theory underlying this technique has been proposed. The estimated numbers of endgroups in the polymers are in agreement with the existing free radical mechanism of initiation of polymerization. Particularly, the results support the existing idea that the termination of polymerization of acrylamide monomer occurs mainly by disproportionat
ISSN:0025-116X
DOI:10.1002/macp.1971.021410106
出版商:Hüthig&Wepf Verlag
年代:1971
数据来源: WILEY
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7. |
Die kationische polymerisation von monomerem formaldehyd in lösung. 39. Mitt. über polyoxymethylene |
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Die Makromolekulare Chemie,
Volume 141,
Issue 1,
1971,
Page 63-90
Von W. Kern,
E. Eberius,
V. Jaacks,
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摘要:
AbstractDie kationische Polymerisation (Fällungspolymerisation) von monomerem Formaldehyd wird in verschiedenen organischen Lösungsmitteln bei −78 bis −30°C untersucht; sie ist bezüglich der Initiator‐ und Monomerkonzentration jeweils erster Ordnung. Die Wirksamkeit der Initiatoren für die Polymerisation in Toluol bei −78°C nimmt in der Reihenfolge ab: SnCl4>CH3COClO4>HClO4>AlBr3>BF3ċ O(C2H5)2>TiCl4>FeCl3>SbCl5>H2SO4>Cl3CCOOH>HCOOH>Jod. Die Bruttoaktivierungsenergien betragen 1,0 bis 10 kcal/Mol. Die Polymerisationsgrade (Viskositätsmittel Pv) steigen meist etwa proportional mit der Monomerkonzentration und dem Umsatz an und erreichen Werte bis Pv∼ 15000. Bei Variation des Lösungsmittels fallen die Pv‐Werte in der Reihenfolgen‐Pentan, Toluol, Diäthyläther, Nitroäthan, Methylenchlorid, Tetrahydrofuran, Aceton stark ab, während die Polymerisationsgeschwindigkeiten in etwa dieser Reihenfolge ansteigen. In Aceton und in Tetrahydrofuran wurde starke Kettenübertragung gefunden.Zusätze von Wasser, Methanol, Ameisensäure, Aceton oder Acetanhydrid erhöhen in kleinen Konzentrationen die Polymerisationsgeschwindigkeit und wirken anscheinend als Cokatalysatoren; in höheren Konzentrationen retardieren sie hingegen.Oft tritt schon nach geringem Umsatz eine starke Abnahme der Bruttopolymerisationsgeschwindigkeit oder sogar völliger Stillstand der Reaktion ein. Durch die obengenannten polaren Zusätze, durch Verwendung stark polarer Lösungsmittel oder durch Erhöhung der Polymerisationstemperatur kann die Abnahme der Polymerisationsgeschwindigkeit vermindert oder verzögert werden.Um den Grund für die Abnahme festzustellen, wurde die Konzentration der aktiven kationischen Zentren durch Abbruch der Wachstumsreaktion mit einem großen Überschuß an Amylalkohol und analytische Bestimmung der dabei entstehenden Pentoxyl‐Endgruppen ermittelt. Die Analyse erfogte durch saure Hydrolyse des gereinigten Polymeren und gaschromatographische Bestimmung des aus den Endgruppen gebildeten Amylalkohols. Diese Methode führt in vielen Fällen zu dem Schluß, daß die Startreaktion schnell und vollständig ist, während die Wachstumsreaktion durch behinderte Diffusion des Monomeren in die feste Polymerphase in ihrem Ablauf zunehmend gehemmt wird. Hinweise auf einen ech
ISSN:0025-116X
DOI:10.1002/macp.1971.021410107
出版商:Hüthig&Wepf Verlag
年代:1971
数据来源: WILEY
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8. |
Plastic deformation of polypropylene. V. Annealing of drawn polypropylene |
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Die Makromolekulare Chemie,
Volume 141,
Issue 1,
1971,
Page 91-116
F. J. Baltá‐Calleja,
A. Peterlin,
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摘要:
AbstractIsotactic polypropylene samples drawn at 20 and 100°C to a draw ratio 6 and 10 were annealed with free and fixed ends between 40 and 155°C for periods of time between 1 and 103min. All the annealing effects proceeded farther with unclamped samples free to shrink than with clamped samples. The disorientation of crystal lattice and the shrinkage are extremely fast reaching saturation values characteristic for the temperature of annealing. At higher annealing temperature, one could observe merely the saturation values with the whole transition being completed in less than 1 min. The long period growth, the increase in density, and the intensity of small‐angle X‐ray scattering are linear functions of the logarithm of annealing time and hence persist with gradually decreasing rate long after the completion of disorientation and shrinkage. The observed effects can be well explained on the basis of the two‐stage model of plastic deformation of crystalline polymers which assumes the formation of strong well‐aligned microfibrils connected by interfibrillar tie
ISSN:0025-116X
DOI:10.1002/macp.1971.021410108
出版商:Hüthig&Wepf Verlag
年代:1971
数据来源: WILEY
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9. |
Permethylierung von polysacchariden |
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Die Makromolekulare Chemie,
Volume 141,
Issue 1,
1971,
Page 117-125
Von Gunda Keilich,
Pekka Salminen,
Elfriede Husemann,
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摘要:
AbstractDie Permethylierung von Amylose, Dextran, Pullulan und Mannan gelingt in Gegenwart von Methylsulfinylmethylcarbanion (I) mit Methyljodid in Dimethylsulfoxid (DMSO) unter N2und Feuchtigkeitsausschluß ineinem Schrittund die von Cellulose nach einer Anmethylierung mit Dimethylsulfat in Natronlauge, also inzwei Schritten; bei dieser Reaktion beträgt der Abbau 10−20%. Die Trimethyläther der genannten Polysaccharide können in guten Ausbeuten (70−90%) in einem weiten Molekulargewichtsbereich hergestellt
ISSN:0025-116X
DOI:10.1002/macp.1971.021410109
出版商:Hüthig&Wepf Verlag
年代:1971
数据来源: WILEY
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10. |
ÜBer die auswertung viskosimetrischer messungen für polymer/polymer/lösungsmittel‐systeme |
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Die Makromolekulare Chemie,
Volume 141,
Issue 1,
1971,
Page 127-144
Von Cornelia Vasile,
I. A. Schneider,
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摘要:
AbstractEs werden die in der Literatur empfohlenen Methoden für Verträglichkeitsbestimmungen in Polymergemischen aus Viskositätsmessungen an Hand des Systems PVC/PVAc/Cyclohexanon kritisch besprochen, wobei festgestellt wird, daß die besten Ergebnisse durch Vergleich der abgeleiteten Wechselwirkungsparameter erzielt werden, da optimale Mischungsverhältnisse ablesbar sind. Unter Ausdehnung der thermodynamischen Methoden auf Polymer/Polymer/Lösungsmittel‐Systeme wird gezeigt, daß die untersuchten Systeme durch weitreichende Wechselwirkungen gekennzeichnet sind, was vor allem auf Wechselwirkungen zwischen den funktionellen Gruppen der Polymeren hindeutet. Diese Schlußfolgerung bestätigt unsere frühere Annahme, daß bei Polymeren zwischen einer Verträglichkeit der Makromolekülketten und einer Pseudoverträglichkeit infolge von Wechselwirkungen der funktionellen Gruppen zu un
ISSN:0025-116X
DOI:10.1002/macp.1971.021410110
出版商:Hüthig&Wepf Verlag
年代:1971
数据来源: WILEY
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