摘要:

AbstractPolymerization mixtures before extraction and extracted polymers prepared by the anionic polymerization of 2‐pyrrolidone with various initiating systems were characterized by their content of β‐ketoamide structures (5) as a measure of side reactions of the propagation sites by condensation. WithN‐acyllactams, used as activators, the content of these structures5in poly(2‐pyrrolidone) was found to increase proportionally to the polymerization time, which may have a negative effect on the thermal stability of the

ISSN:0025-116X    

DOI:10.1002/macp.1981.021820801

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractA new method of polymerization of theN‐carboxy anhydride (NCA) of glutamic acid is presented by which poly(glutamic acid) is obtained directly from the NCA without protecting its carboxyl group. The principle underlying is that by adjusting the mole ratio of the initiator butylamine, [I], to the monomer, [A], butylamine can be used as protecting agent for the carboxyl group of the NCA so that the rest of butylamine acts as initiator in the heterogeneous polymerization in acetonitrile. Quantitative conversion was obtained for an [A]/[I]ratio of 1. In analogy to other heterogeneous polymerizations of NCAs in acetonitrile, this is due to the formation of the helix during polymerization, which was confirmed by IR absorption and X‐ray diffraction measurements. As the [A]/[I]ratio increases, the conversion, the helix content of the resultant polymer, and the amount of butylamine combined with it decrease drastically. It is suggested that “copolymerization” of the amine‐protected and unprotected NCAs occurs, giving rise to a partially helical chain, whose contents of the amine‐protected side chains and accordingly of the helix are the higher the smaller the [

ISSN:0025-116X    

DOI:10.1002/macp.1981.021820802

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractThe relationships were studied between the conformation of various poly(amino acid)s, as revealed by optical rotatory dispersion and viscosity of the solutions and polarized IR spectra of the collapsed film of their monolayers developed from the solutions, as well as the state of the aggregation of the molecules and the crystalline texture in the film, as revealed by electron microscopy. In the cases of poly(L‐alanine) and poly(L‐leucine), the α‐helical conformation in the mixed solvent of trifluoroacetic acid (TFA) and chloroform, used for the development into their monolayers, was maintained in their monolayers and collapsed films, and the rigid helical molecules were aligned perpendicularly to the direction of the applied pressure. In the case of poly(S‐methyl‐L‐cysteine), it was found that two types of β‐structure coexist, i.e., a cross‐β type (due to intramolecular hydrogen bonding) and an intermolecular β‐structure (due to intermolecular hydrogen bonding) in the solution state, whose amounts depend on the composition of the mixed solvent and polymer concentration, reflecting in the mixed structure of lamellar and fibrous crystals in the collapsed film. The aggregation of poly(S‐methyl‐L‐cysteine) molecules with the above two types of conformations seems to occur on the development of their solution onto the water surface. The same seems to apply to

ISSN:0025-116X    

DOI:10.1002/macp.1981.021820803

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractA facile synthesis ofortho‐linked novolacs was achieved by reaction of selected metal phenolates with paraformaldehyde. Both solvent and phenolate counter‐ion play a leading role in theortho‐specific methylene‐bridging of the phenolic nuclei. The combined use of highperformance liquid chromatography and13C NMR spectroscopy proved to be successful in the characterization of these

ISSN:0025-116X    

DOI:10.1002/macp.1981.021820804

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractTerpolymerizations of styrene (St)/p‐chloranil (PCA)/maleic anhydride (MAnh), St/2,3‐dichloro‐5,6‐dicyano‐p‐benzoquinone (DDQ)/MAnh, and St/DDQ/PCA systems were studied, in order to compare the reactivities as acceptor monomers among MAnh, PCA, and DDQ. These terpolymerizations were treated by the complex mechanism. The modified and real monomer reactivity ratios of the complexes in these systems were obtained asrI(KI/KII) (PCA‐St) = 1,60 andrII(KII/KI) (MAnh‐St) = 0,10,rI(PCA‐St) = 3,55 andrII(MAnh‐St) = 0,045,rI(KI/KII) (DDQ‐St) = 50 andrII(KII/KI) (MAnh‐St) = 0,01,rI(DDQ‐St) = 132 andrII(MAnh‐St) = 0,0038, andrI(KI/KII) (DDQ‐St) = 200 andrII(KII/KI) (PCA‐St) = 0,001,rI(DDQ‐St) = 238 andrII(PCA‐St) = 0,0008, respectively. The reactivity of these St complexes was concluded to be controlled primarily by th

ISSN:0025-116X    

DOI:10.1002/macp.1981.021820805

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractThe hydrochlorides ofp‐nitrophenyl 6‐aminocaproate (4a),p‐nitrophenyl 12‐aminododecanoate (4b), andp‐nitrophenyl 12‐(6‐aminocaproylamino)dodecanoate (6) were prepared and polycondensed in 1,2,4‐trichlorobenzene in the presence of tributylamine under different conditions. The polycondensation of6at 128°C gave the alternating copolyamide (PA 6, 12). The polymers were identified by D

ISSN:0025-116X    

DOI:10.1002/macp.1981.021820806

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

Abstractα‐Hydroxysuccinyl‐ω‐hydroxysuccinyloxypoly(oxyethylene)s (succinic half‐esters of poly‐(ethylene glycol)s) (2) of different molecular weights were prepared, and transformed into the corresponding benzotriazole and imidazole derivatives3and4. The benzotriazolyl or the imidazolyl residues in these polymers can easily be exchanged. This was proved with model compounds bearing hydroxyl or amino groups. Polymers of this type may be considered as potential oligomeric drug‐bin

ISSN:0025-116X    

DOI:10.1002/macp.1981.021820807

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractTrypsin was immobilized on a copolymer of methyl methacrylate and 2‐acryloylamino‐2‐methylpropanesulfinic acid. The resulting immobilized trypsin shows 25% of the soluble enzyme specific activity. The pH optimum of the immobilized trypsin is shifted to a higher value by 1,1 units. The pH stability of the immobilized trypsin is better than that of the soluble enzyme, whereas the temperature stability of the soluble and the immobilized enzyme is almost iden

ISSN:0025-116X    

DOI:10.1002/macp.1981.021820808

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractThe variation of the allophanate concentration with curing time was determined by an amine degradation method. It was concluded that the properties of polyurethane networks prepared with the same formulation differ considerably if crosslinking reactions are carried out under different conditions.

ISSN:0025-116X    

DOI:10.1002/macp.1981.021820809

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractCopolymerizations of a styrene homologue with oxygen were carried out in the presence of a Co(II) (Schiff‐base) complex having a chiral ligand. The metal complex showed a retarding effect on the rate of oxygen absorption in the reaction due to its interaction with growing radicals. Main product was almost an equimolar copolymer of monomer and oxygen, in the case of styrene and α‐methylstyrene. On the other hand,transepoxide as well as a copolymer having many ether units were formed in the reaction of β‐methylstyrene. The presence of the cobalt complex increased the yield of epoxide and induced asymmetry in the

ISSN:0025-116X    

DOI:10.1002/macp.1981.021820810

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY