摘要:

AbstractThe hydrolysis of Schiff's bases and hydrazones prepared by reactions of methylamine, ethylenediamine, butylamine,tert‐butylamine,sec‐butylamine, isobutylamine, octylamine, benzylamine, and isonicotino‐hydrazide with free aldehyde groups of the crosslinked macroporous copolymer divinylbenzene‐methacryl‐aldehyde, was investigated. The highest initial rate of hydrolysis was observed in the range of a high proton concentration. The initial hydrolysis rate increases and the conversion of the hydrolysis reaction decreases with increasing basicity of the amines. Comparison with the corresponding low‐molecular‐weight Schiff's bases indicated considerable polymer effects on the hydrol

ISSN:0025-116X    

DOI:10.1002/macp.1978.021790801

出版商:Hüthig&Wepf Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractBlock copolymers poly(1,2‐ and 3,4‐isoprene)‐poly(2‐vinylpyridine), poly(cis‐1,4‐isoprene)‐poly(2‐vinyl‐pyridine) and poly(cis1,4‐isoprene)‐poly(4‐vinylpyridine) were synthesized by anionic polymerization. Their structure in the dry state and in concentrated solution was studied before and after polymerization of the solvent by low angle X ray scattering and by electron microscopy. The existence of lamellar and cylindrical structures was demonstrated. The effects of the copolymer composition, the nature, the concentration and the polymerization of the solvent on the type of structure adopted by the copolymer and on its geometrical para

ISSN:0025-116X    

DOI:10.1002/macp.1978.021790802

出版商:Hüthig&Wepf Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractA series of samples of the acrylamide/acrylic acid system with various compositions was prepared by copolymerization as well as saponification, and some new results on the kinetics of both processes are given. The products were characterized by osmometry, viscometry, GPC, DTA, and elemental analysis. The results led to the conclusion that copolymerisation and saponification lead to copolymers of identical sequential distribution of the monomeric units. It was found that the intrinsic viscosity as well as the slope factorkH· [η]2—measured in 0,5 m NaBr solution—show a maximum at intermediate comonomer composition. This finding can be interpreted by chain stiffening due to intramolecular segmental intera

ISSN:0025-116X    

DOI:10.1002/macp.1978.021790803

出版商:Hüthig&Wepf Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractThe etherification of poly(oxymethylene)diol[α‐hydro‐ω‐hydroxypoly(oxymethylene)] with orthoesters in the presence of Lewis acids leads to the simultaneous formation of various types of end groups: orthoformyl [bis(alkoxy)methoxy]groups (A), formyl (oxyformyl)(B), and ether (alkoxy) groups (C). It was elucidated theoretically and experimentally that the orthoformyl end groups are intermediates of formyl end groups, and partially of ether end groups. The kinetics of the reactions was also evaluated at various tempe

ISSN:0025-116X    

DOI:10.1002/macp.1978.021790804

出版商:Hüthig&Wepf Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractA polymeric catalyst prepared from poly[1‐(4‐hydroxyphenyl)etylene] (1), and Zn(C2H5)2was found to be effective for the copolymerization of carbon dioxide and 1,2‐epoxypropane. The highest activity was observed when a mole ratio of phenolic hydrogen in1to Zn(C2H5)2equal to unity was applied in contrast to the catalysts so far reported. The structure of the catalyst after the copolymerization was determined by IR and H1NMR spectroscopy. A Zn—C2H5bond in this system was confirmed to be the active center. A possible inactivation process of the catalyst is p

ISSN:0025-116X    

DOI:10.1002/macp.1978.021790805

出版商:Hüthig&Wepf Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractThe kinetics of free radical polymerization of n‐lauryl methacrylate (dodecyl methacrylate) were studied at 60 and 80°C in bulk and in benzene solution. The analysis of the data showed the kinetic results deviated from classical behaviour and that this deviation could be explained by the chain length dependence of the diffusion controlled termination rate constant,Kt. Primary radical termination is explicitly considered and rejected as being insignificant in this work. Because of its lessened flexibility poly(n‐lauryl methacrylate) shows a greater chain length dependence forKtthan does poly(methylmethacryl

ISSN:0025-116X    

DOI:10.1002/macp.1978.021790806

出版商:Hüthig&Wepf Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractSyntheses and characterizations of polymers from the optically active vinylcarbazole derivatives (S)‐3‐sec‐butyl‐9‐vinylcarbazole (1), (S)‐9‐(2‐methylbutyl)‐2‐vinylcarbazole (2), and (S‐9‐(2‐methylbutyl)‐3‐vinyl‐carbazole)(3) are described in detail. TheN‐vinyl derivative1gives satisfactory conversions to high polymers in the presence of both radical and cationic initiators whereas theC‐vinyl derivatives2and3give better results with ionic initiators (anionic and cationic respectively). Measurement of optical rotation and circular dichroism (CD) for all the polymers as well as corresponding monomers and low molecular weight analogs indicates that the stereochemical placements of monomeric units in the macromolecules are depen

ISSN:0025-116X    

DOI:10.1002/macp.1978.021790807

出版商:Hüthig&Wepf Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractStyrene has been copolymerised with 4,4′‐divinylbiphenyl and with 4,4′‐diisopropenylbiphenyl in 15% toluene solution at 95°C. The copolymers have been analysed via UV spectroscopy, to give estimates of total crosslinker incorporated and of the number of pendant double bonds remaining. Extrapolation of the results—including viscometry—to zero conversion indicates that both crosslinkers form intramolecular linkages (rings). These rings appear to be comparable in size with those formed withp‐divinylbenzene, but to occur rather more frequently. Estimates of copolymerisation reactivity ratiosr1(styrene=1) are, for 4,4′‐divinylbiphenyl 0,77, for 4,4′‐diisopropenylbiphenyl 1,3. It is concluded that, contrary to a previous suggestion, increasing separation of reactive groups leads to more, not less, i

ISSN:0025-116X    

DOI:10.1002/macp.1978.021790808

出版商:Hüthig&Wepf Verlag    

年代:1978

数据来源: WILEY

摘要:

Abstract13C NMR spectra of isotactic and syndiotactic poly(ethyl α‐chloroacrylate)s and poly(isopropyl α‐chloroacrylate)s were measured in toluene‐d8at 25 MHz. The spectra were analyzed for triad, tetrad and pentad tacticities comparing the spectra with the results previously obtained by1H NMR spectroscopy. Tetrad tacticities of the polymers were measured from the resonance of the backbone methylene carbon and favorably compared with tetrad values obtained by1H NMR. The resonance of the carbonyl carbon showed the peaks corresponding to the tactic triad with a pentad splitting in mm resonance. The triad values obtained from the carbonyl carbon resonance were in good agreement with those calculated from the tetrad values as well as the triad tacticities obtained by1H NMR. The quaternary carbon reconances were very complicated because the chemical shift differences for the different tactic triads were of the comparable magnitude with those for the pentads, and a tentative peak assignment was made with the aid of the statistical calculation of pentad values assuming first‐order Markovian statistics for the isotactic polymer and Bernoullian statistics for the syndiotacti

ISSN:0025-116X    

DOI:10.1002/macp.1978.021790809

出版商:Hüthig&Wepf Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractComparative hydrodynamic measurements were performed for cellulose tricarbanilates (CTC) and amylose tricarbanilates (ATC)—covering the whole region from the monomer up to the highest available molecular weight of 3,6 . 106.The intrinsic viscosity vs. molecular weight relationships exhibit in both cases characteristic S‐shaped curves. In the region of oligomers the intrinsic viscosities remain almost constant; it follows then a steep increase with molecular weight which finally flattens out to constant slopes for high molecular weights. In the high molecular weight region the curves may be approximated by Kuhn‐Mark‐Houwink equations with exponents of 0,90 and 0,88 for CTC and ATC, respectively. The intrinsic viscosities are by a factor two smaller for ATC than for CTC. The S‐shaped curves are interpreted as a result of the finite cross‐section of the chains and a certain chain stiffness. Stockmayer‐Fixman plots gave strongly bent curves which is shown to be due to chain rigidity.Sedimentation coefficients and diffusion constants as functions of the molecular weight approach straight lines in a double logarithmic plot for large molecular weights; for shorter chains characteristically bent curves are obtained which are ascribed to chain stiffness and finite chain cross‐section.The origin of chain stiffness in CTC is discussed to be due to H‐bond formation between the NH‐group of the substituent in C2position of the sugar ring and a CO‐group of the substituent in C6of a neighbouring repeating unit. This interpretation is supported by the low viscosity of mannan tricarbanilate (MTC), in which the facility of H‐bond formation is lost and higher

ISSN:0025-116X    

DOI:10.1002/macp.1978.021790810

出版商:Hüthig&Wepf Verlag    

年代:1978

数据来源: WILEY