摘要:

AbstractSynthese und chemische Eigenschaften des ersten verzweigten, molekulareinheitlichen Oligoamids mit definierter Struktur werden beschrieben. N,N‐[Di‐(ϵ‐aminocaproyl)]‐ϵ‐aminocapronsäure (V), ein Oligomeres aus drei Aminocapronsäureresten mit einer Acylamidverzweigung, wurde durch Acylierung der Säureamidgruppe einer amino‐ und carboxyl‐geschützten Di‐ϵ‐aminocapronsäure mit einem N‐geschützten ϵ‐Aminocaproylchlorid und nachfolgender Abspaltung aller Schutzgruppen als Hydrochlorid bzw. Tetraphenylborat in analysenreiner Form gewonnen. In neutralem und alkalischem Medium erleidet es bereits unter mild

ISSN:0025-116X    

DOI:10.1002/macp.1965.020830101

出版商:Hüthig&Wepf Verlag    

年代:1965

数据来源: WILEY

摘要:

AbstractIn order to explain the observed rates of diffusion‐controlled macroradical bimolecular reactions, the probability of finding a polymer chain end less than a critical distance from the outer limits of the whole coiled flexible chain has been calculated. The probability that two active centres on the surfaces of the two rotating spheres come into proximity during an inelastic collision has also been calculated. When these probabilities are combined with the rate constant for diffusion‐controlled approach of macroreactants, agreement with experimental observations is found only for the soft‐sphere

ISSN:0025-116X    

DOI:10.1002/macp.1965.020830102

出版商:Hüthig&Wepf Verlag    

年代:1965

数据来源: WILEY

摘要:

AbstractThis paper presents a more detailed discussion on the kinetics of formaldehyde polymerization under gamma‐irradiation than the previous paper2. Polymerization took place in toluene and ethyl bromide and within the range of −50°∼−80°C.The overall reaction is approximately third‐order with respect to the monomer. The average molecular weight of the polyoxymethylene obtained is little dependent on the initial concentration of the monomer and on dose rate. The reaction is approximately first order with respect to dose rate. It is believed from the facts obtained here that the polymerization, in which the transfer process of growing chain to monomer is mainly responsible for governing the molecular weight, should proceed predominantly by an ionic mechanism.A study of the influence of various additives upon the polymerization shows the following results. These additives are classified in four groups with respect to their qualities, the first group having influence only upon the polymerization rate (e.g., diphenylpicrylhydrazyl), the second only upon the molecular weight (water), the third upon both of these factors (methyl formate, methyl acetate, ethyl acetoacetate, polystyrene powder, and tetrahydrofuran), and the last having no influence upon both of these factors (oxygen, carbon monoxide, nitrobenzene, and naphthalene).The apparent activation energy is estimated to be 4.15 kcal/mole from rate of polymerization, −3.50 kcal./mole from average degree of p

ISSN:0025-116X    

DOI:10.1002/macp.1965.020830103

出版商:Hüthig&Wepf Verlag    

年代:1965

数据来源: WILEY

摘要:

AbstractPolymerization of formaldehyde with “living polymer” solution was investigated and it was shown that block copolymers of formaldehyde and vinyl or diene monomers such as styrene, α‐methylstyrene, 2‐methyl‐5‐vinylpyridine, butadiene and isoprene can be synthesized.Reactions of polymeric species possessing active alcoholate anions as terminal groups with various reagents were investigated. Successful attempts were made by reacting polymeric species with acetic anhydride in toluene: the thermal stability of the obtained polymers was as good as that of polymers which were acetylated in the conventional way.In order to investigate the mechanism of the initial reaction of the polymerization of formaldehyde, the initial reaction product of formaldehyde with the sodium naphthalene complex was prepared and investigated by means of electronic and infrared spectra.From the fact that the structure of the initial product is considered to be 1,4‐ or 1,2‐ dihydronaphthalene, the initiation of the polymerization seems to be the addition reaction of formaldehyde with sodium naphthalene forming an alcoholate anion, which then is capable of polymerizing formaldehyde to high molecula

ISSN:0025-116X    

DOI:10.1002/macp.1965.020830104

出版商:Hüthig&Wepf Verlag    

年代:1965

数据来源: WILEY

摘要:

AbstractDie kationische Polymerisation von Trioxan wird durch Acetale, leicht spaltbare Äther sowie durch Ester und Anhydride übertragen. Die entstehenden Polyoxymethylene tragen Äther‐ bzw. Ester‐Endgruppen und sind daher bis über 200°C thermisch stabil. Um in guten Ausbeuten hochmolekulare thermisch stabile Polyoxymethylene zu erhalten, muß der Polymerisationsansatz schr weitgehend wasserfrei sein; dies kann durch Trocknung des Trioxans mit Isocyanaten in einer speziellen Apparatur erreicht werden.Die relative Übertragungskonstante von Dimethylformal bei 25°C beträgt 1,2, die von Methylfo

ISSN:0025-116X    

DOI:10.1002/macp.1965.020830105

出版商:Hüthig&Wepf Verlag    

年代:1965

数据来源: WILEY

摘要:

AbstractDie kationische Polymerisation von Trioxan wird durch makromolekulare Verbindungen mit reaktionsfähigen COC‐Gruppen wie Polyvinylacetat (PVA), Polyäthylenterephthalat (PET), Poly‐1,3‐dioxolan oder Polyvinylbultyral (PVB) übertragen. Dabei entstehen je nach der Art des makromolekularen Überträgers Pfropf‐Copolymere, Block‐Copolymere oder vernetzte Copolymere. Die Produkte sind überwiegend thermisch stabil.Bei der kationischen Polymerisation von Trioxan muß auch eine Übertragung an den Acetalgruppen des Polyoxymeth

ISSN:0025-116X    

DOI:10.1002/macp.1965.020830106

出版商:Hüthig&Wepf Verlag    

年代:1965

数据来源: WILEY

摘要:

AbstractThe kinetics of the polymerization of ethylene was studied in an apparatus which is described. A stable catalyst combination [Al(C2H5)2Cl/γ‐TiCl3] which does not change during the polymerization was used. Conditions are defined under which the reaction is (a) independent of mass transfer rate (b) controlled by mass transfer. After an initial period, the polymerization proceeds at constant rate until the slurry is too thick to stir adequately. The catalyst is neither occluded nor deactivated so that unlimited quantities of polymer can be made from a given amount. When the reaction is not controlled by mass transfer, the rate is linearly dependent on monomer and TiCl3concentration and is independent of Al(C2H5)2Cl. Hydrogen reduces the rate of the polymerization at a constant partial pressure of ethyle

ISSN:0025-116X    

DOI:10.1002/macp.1965.020830107

出版商:Hüthig&Wepf Verlag    

年代:1965

数据来源: WILEY

摘要:

AbstractA convenient preparation ofp‐vinylbenzoic acid from β‐haloethylbenzene with 67% overall yield was described. Monomer reactivity ratio ofp‐vinylbenzoic acid (1) to acrylonitrile (2) was determined:\documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{l} {\rm Free\ acid\:\; r}_1 = 1.8 \pm 0.05; \quad \ {\rm r}_2 = 0.076 \pm 0.001 \\ {\rm Na\ salt\:\quad r}_1 = 0.26 \pm 0.06; \quad {\rm r}_2 = 0.09 \pm 0.08\\ \end{array}$$\end{document}p‐Vinylbenzoic acid increased the affinity of acrylic fibre toward cationic dye when copolymerized with acrylonitrile, but was less effective than sulfonic acids as dye receptive site. Acid ion exchange resins based onp‐vinylbenzoic acid possessed a high selection factor of Ca2

ISSN:0025-116X    

DOI:10.1002/macp.1965.020830108

出版商:Hüthig&Wepf Verlag    

年代:1965

数据来源: WILEY

摘要:

AbstractThe molecular and crystal structure of polytetrahydrofuran has been determined by X‐ray diffraction analysis. The unit cell dimensions area= 5.48,b= 8.73,c(fiber axis) = 12.07 Å., and β = 134.2°. The space group isC2/c—C 62h. Two molecular chains pass through the unit cell. The skeleton of the molecular chain has a planar zig‐zag conformation and the zig‐zag plane is parallel to the (100)‐plane.The infrared dichroism and pleochroism were measured, and the tentative assignments for the infrared absorption bands were given

ISSN:0025-116X    

DOI:10.1002/macp.1965.020830109

出版商:Hüthig&Wepf Verlag    

年代:1965

数据来源: WILEY

摘要:

AbstractA survey is made of vinyl‐type polymers in which there appear to be links more susceptible to scission (during thermal degradation) than the normal links. The presence of such links is indicated by an examination of the change in molecular weight during the course of the reaction. A theoretical expression is used which assumes that both normal, and weak link scission, are random processes. Apart from the polymers already known to have weak links, polystyrene, polyethylene, polymethylene, and polypropylene, it appears that poly(methyl methacrylate) also contains such links. It is suggested that an alternative explanation may account for the apparent presence of weak links in so many polymer

ISSN:0025-116X    

DOI:10.1002/macp.1965.020830110

出版商:Hüthig&Wepf Verlag    

年代:1965

数据来源: WILEY