摘要:

AbstractAlkylenedioxy bridged polymeric phthalocyanines3a – dwere synthesized by the reaction of the tetracarbonitriles2a–dwith copper(II) chloride or copper in bulk. As compared with other tetracarbonitriles the reactions applying2a – d,which contain a flexible alkylene chain, run at relatively low reaction temperatures leading to good yields of polymers with a high degree of anelation of phthalocyanine rings (Pc>100). In contrast to their low swelling factors and their low surface areas, polymeric phthalocyanines, with different bridging units between the chelate rings in the solid state exhibit good absorption capacities for organic solvents, mainly from the liquid

ISSN:0025-116X    

DOI:10.1002/macp.1988.021890601

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractThe sulfur vulcanization ofcis‐1,4‐polybutadiene was studied by solid‐state13C NMR spectroscopy. Polybutadiene is cured with several different formulations including sulfur and accelerators in order to determine the network structure of the resulting vulcanizates. Polysulfidic crosslinks bound to the methylene carbons of the polybutadiene repeating unit were observed in the rubber network. Cyclic sulfide structures were detected in the network structure in addition tocis‐to‐transchain isomerization. Two different pulse sequences were used for the NMR experiments of the sulfur‐vulcanizedcis‐polybutadiene. The gated high power decoupling NMR experiment reflects the mobile regions of the vulcanizate sample while the cross polarization pulse sequence reflects the regions of the sample which are inherently more rigid. The cross polarization spectra of the samples cured with high sulfur levels showed that a considerable amount of rigidity is found in the vulcanizedcis‐polybutadiene network. It was also possible to obtain cross polarization spectra of the lightly crosslinked polybutadiene vulcanizates. This is in contrast to the NMR results of the vulcanized natural rubber systems which generally tended to have considerabl

ISSN:0025-116X    

DOI:10.1002/macp.1988.021890602

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractUltra‐high‐molecular‐weight polyethylene (UHMW‐PE) can be drawn in the melt in a limited temperature range between the melting point of lamellar crystals, appr. 135°C, and the orthorhombic → hexagonal phase transition temperature, at appr. 155°C. In this particular temperature range, referred to as region 2, drawing results in the formation of a composite structure composed of fibrous crystals as a result of strain‐induced crystallization of the high molecular weight fraction, embedded in a melt of lower molecular weight material. After cooling to room temperature, this latter fraction crystallizes using the fibrous crystals as crystallization nuclei. The resulting structure exhibits a shish‐kebab morphology. Solution‐crystallized as well as melt‐crystallized UHMW‐PE samples were studied with respect to draw efficiency and structure formation during de

ISSN:0025-116X    

DOI:10.1002/macp.1988.021890603

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractThe structure of 1‐azabicyclo[4.2.0]octane(1)was evaluated by NMR spectroscopy. It was found that the six‐membered ring has a chair conformation with the four membered ring in theN‐axial andC‐6‐equatorial position, and as a consequence, the monomer allows neither a ring inversion nor a nitrogen inversion. It possesses two centers of chirality, one at the nitrogen atom and one atC‐6. Homopolymerization was carried out in methanol at 60°C withN‐alkyl ammonium salts of1affording the polymer in high yield within a few hours. Its NMR spectra reveal that the polymer chain is preferably arranged in the biequatorial position of the six‐membered ring. As a polybase the polymer can be titrated quantitatively with acids. Its glass transition temperature is 8°C, the decompositio

ISSN:0025-116X    

DOI:10.1002/macp.1988.021890604

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractOptically active divinyl ethers, (−)‐(S)‐ and (+)‐(R)‐2,2′‐bis[2‐(2‐ vinyloxyethoxy)ethoxy]‐1,1′‐binaphthyl [(S)‐1and (R)‐1], were synthesized and polymerized with cationic catalysts. The resulting polymers are composed of only cyclic constitutional units, (S)‐ and (R)‐dinaphtho‐[2,1‐r:1,2‐t]‐1,4,7,11,14,17‐hexaoxaperhydrocyclohenicosen‐8,10‐ylene. Both (S)‐ and (R)‐polymers show nearly equal values of optical rotation, but in opposite directions. The ability of chiral recognition of the (R)‐polymer towards racemic primary alkylammonium salts was investigated with salts of 1‐phenylethylamine, valine, phenylalanine and phenylglycine, and found to be very s

ISSN:0025-116X    

DOI:10.1002/macp.1988.021890605

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractTwo different modes of interaction between 2‐chloro‐N‐dodecylpyridinium iodide (CDPI) and randomly substituted methylamylose (MA), which is mainly composed of 2,3‐O‐methylamylose or 6‐O‐methylamylose (6‐MA), are reported. The fluorescence intensity of CDPI is enhanced and its reactivity toward alkaline hydrolysis is retarded upon the addition of MA. Both cases show a saturation‐type relationship with increasing concentration in the case of MA, indicating the formation of an inclusion complex. In addition to the contribution of hydrophobic‐lipophilic interaction, the intramolecular hydrogen bonding of the host may also play an important role in stabilizing its helical conformation, as proved by the fact that the dissociation equilibrium constant,Kd, evaluated from kinetic data, increases with increasing degree of substitution of MA. This deduction is confirmed by experiments using 6‐MA as the host instead of MA. With increasing concentration of added 6‐MA, a linear relationship for the fluorescence and a bell‐type profile for the hydrolysis of CDPI are found. These results can be interpreted by the solubilization of CDPI in 6‐MA micelles. As in the case of cyclodextrin, in each turn of the amylose helix, the primary hydroxyl groups are located on one side and the secondary groups on the other side. Therefore, in the case of 6‐MA, where the primary hydroxyl groups are completely blocked, the macromolecules lose the ability to adopt a helical conformation. In conclusion, inter‐turn hydrogen bonding is an important factor contributing to the formation and stabilization of the helic

ISSN:0025-116X    

DOI:10.1002/macp.1988.021890606

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractA number of reactive styrene derivatives3a – hwas synthesized and copolymerized in suspension with styrene and divinylbenzene to produce beaded styrene‐based resins5a – h,carrying bromo, methoxy, chloromethyl, hydroxymethyl, hydroxyethyl, or α‐hydroxy‐4‐methoxybenzyl groups. The swelling behaviour of selected samples of these resins was studied in tetrahydrofuran, toluene, dichloromethane, dioxane, ethyl acetate, dimethylformamide, and methanol. Swellability data are given for resin samples having different percentages of crosslinking and for those produced in the presence of chlorobenzene as a monomer diluent (or polymerization solvent). The significance of the swellability data are briefly discussed in terms of the nature of solvent, the degree of crosslinking and the effect of the monomer diluent on the matrix structure. Details of a series of model reactions of the resin‐bound functional groups are also given, and the results are discussed on the basis of resin swellability and polymer‐substra

ISSN:0025-116X    

DOI:10.1002/macp.1988.021890607

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

Abstract(5,10,15,20‐Tetraphenylporphyrinat o)manganese acetate(2)was found to bring about the ring‐opening polymerization of 1,2‐epoxypropane(3)(R2= CH3) under mild conditions to give the polymer with a bimodal molecular weight distribution consisting of a sharp main peak and a small shoulder on the higher molecular weight side. The polymerization was found to proceed even in the presence of a protic compound such as an alcohol or a carboxylic acid to give the polymer with a unimodal very narrow molecular weight distribution. The number of the polymer molecules is in good agreement with the sum of those of2and the protic compound, demonstrating the “immortal” nature of polym

ISSN:0025-116X    

DOI:10.1002/macp.1988.021890608

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractPhenylsilane and methylphenylsilane were decomposed by anrf(radio frequency) glow discharge to investigate the effect of aromatic substitution on the reactivity of the silanes as well as on the structures and properties of the deposited films. The spectral analyses and the optical band gaps of the films indicate that the films deposited at lowrf‐powers have polysilane‐like chains with pendant phenyl groups, and that the films deposited at highrf‐powers are substantially silicon carbon alloys containing unsaturated carbon clusters. Although all the as‐deposited films are nearly insulators, the conductivities were improved by as such as six orders of magnitude by either a substitutional doping with diborane or a chemical doping with

ISSN:0025-116X    

DOI:10.1002/macp.1988.021890609

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractSeveral polycarbonate analogues with sulfur atoms replacing all or part of the oxygen atoms in the carbonate units of the polymer, were prepared by interfacial synthesis from aliphatic dithiols and phosgene or bisphenol‐A bischloroformate or bisphenol‐A polycarbonate oligomers. That way, polydithiocarbonates (containing SCOS groups)(2a – c),polythiocarbonates (containing OCOS groups)(4a – c)and block copolymers6a – c(containing OCOO groups, mainly, and OCOS groups randomly distributed along the chain) were prepared. The expected chemical structures were confirmed by1H NMR,13C NMR and FT‐IR spectroscopy. Their thermal transitions were investigated by DSC, and the effects of replacing

ISSN:0025-116X    

DOI:10.1002/macp.1988.021890610

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY