摘要:

AbstractIn order to identify phenylhydrazone structures in the reaction products of oxidized polyisoprene or its models with phenylhydrazine, the UV,1H NMR,13C NMR and MS spectra as well as the steric exclusion chromatography parameters were determined for phenylhydrazones derived from aldehydes and ketones, selected as models of conjugated carbonyl structures, which could result from the oxidation of polyisoprene units. By comparison with possible coexistent structures, inclusively phenylhydrazones of non‐conjugated carbonyl derivatives, oxidized polyisoprene structures can be identifie

ISSN:0025-116X    

DOI:10.1002/macp.1986.021870701

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractLithium diisopropylamide(2)was found to undergo a metalation reaction with 4‐methylstyrene (1) to form 4‐vinylbenzyllithium (3), but to induce neither addition reaction nor vinyl polymerization. The equilibrium constant between2and3in THF was calculated to be 0,54 at 20°C. The 4‐vinylbenzyllithium formed initiates the polymerization of styrene derivatives to form oligomers. The resulting oligomers have a polymerizable vinyl group at the chain end quantitatively and can be regarded as a “macromonomer”. Synthesis of polystyrene, having a primary amino group at the chain end, was carried out through the reaction of polystyrene macromonomer withN‐methylethylenediamine. More than 97% of polystyrene were aminated within

ISSN:0025-116X    

DOI:10.1002/macp.1986.021870702

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractAlternating copolymers were obtained by radical copolymerization of propene (Pr) and isobutene (IB) with maleic anhydride. Both polymers (Pr and IB) do not homopolymerize under the applied reaction conditions. The copolymerization rates were determined.

ISSN:0025-116X    

DOI:10.1002/macp.1986.021870703

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe copolymerization of styrene and maleic anhydride in ethyl methyl ketone as solvent and with benzoyl peroxide as initiator at 60–80°C in the entire feed composition range was studied. The resulting copolymers appear to have negative and positive deviations from alternation as determined by use of elemental analysis. The experimental data were found to fit a three‐reactivity‐ratio copolymer composition equation from the penultimate model. The inclusion of the reactivity ratio,kSM(=kSMM/kSMS), in addition torSS(=kSSS/kSSM) andrMS(=kMSS/kMSM), allows prediction of a positive deviation from the alternation, i.e. the mole fraction of maleic anhydride in the copolymer being higher th

ISSN:0025-116X    

DOI:10.1002/macp.1986.021870704

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractAntibodies were immobilized by covalent linkage on polystyrene balls for use in solid phase enzyme‐linked immunoassays: application for detection of K 99+E. Coliin calves. The method eliminates the problem of antibody desorption noted in coventional enzyme‐linked immunosorbent assays which are based on simple adsorption on polystyrene. Further, the bond between antibodies and polystyrene balls is stable under conditions under which usually antibody — antigen complexes dissociate and permit re‐use of the immobilized antibodies for immu

ISSN:0025-116X    

DOI:10.1002/macp.1986.021870705

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractVarious acidic compounds were tested as potential initiators of the cationic polymerization ofL,L‐dilactide. Regardless of solvent and temperature only trifluoromethanesulfonic acid and methyl triflate proved to be useful initiators. With methyl triflate as initiatorL,L‐dilactide polymerizes faster than diglycolide, whereas diglycolide is more reactive when anionic or complexing initiators are used. Initiation with methyl triflate yields poly(L‐lactide) with methyl ester endgroups indicating that the chain growth proceeds via cleavage of the alkyl‐oxygen bond. At polymerization temperatures>100°C the resulting poly(L‐lactide) is 100% optically active indicating that the chain growth does not proceed via free carbenium ions, but via triflate ester endgroups. All attemps to identify cyclic dioxocarbenium ions as reaction intermediates failed, because propagation is much faster than initiation. However, in nitromethane oligomers with triflate ester endgroups were detected. For comparison the reaction of γ‐valerolactone with methyl triflate was studied by means of IR and1H NMR spectroscopy. Methylation of the exocyclic oxygen yielding a cyclic dioxocarbenium ion was found to be the

ISSN:0025-116X    

DOI:10.1002/macp.1986.021870706

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractTwo types of block copolymers,3aand3b, were synthesized from α‐hydro‐ω‐(2‐hydroxyethylthio)poly[1‐(3,3,4,4,5,5,6,6,6‐nonafluorohexyloxycarbonyl)ethylene] (1a) or α‐hydro‐ω‐(2‐aminoethylthio)poly[1‐(hexyloxycarbonyl)ethylene] (1b) and α,ω‐bis(4‐cyanatophenylthio)‐poly(1‐phenylethylene) (2), respectively, and the adhesion of blood platelets to these polymer surfaces was evaluated. Adhesion and activation of platelets were found to be effectively suppressed at the lamellar‐microdomain surface of block copolymer3a, having a surface free energy gap between microdomains of about 20 dyn/cm, whereas no such a suppression was observed for the microdomain structured surface of block copolymer3bwith a small surface free energy gap between the microdomains. Further, a random copolymer from nonafluorohexyl acrylate and styrene without microdomain structure does not suppress the adhesion and activation of platelets. From these results, it was concluded that the microdomain morphology and the surface free energy gap between microdomain is imp

ISSN:0025-116X    

DOI:10.1002/macp.1986.021870707

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe variations of diffusion constants and permeability for carbon dioxide, oxygen and nitrogen in poly(ether‐block‐amide)s were measured during the photooxidation of the polymer. The determination of these constants appears to be a sensitive criteria to characterize the photooxidative evolution of polymers. The decrease of the diffusion constant, observed in the course of photooxidation, is interpreted by the formation of chemical crosslinks and by the existence of physical interactions between primary hydroperoxidic photoproducts. Several treatments were developed which modify the nature of these oxidized groups; the evolution of diffusion constants is related to the modification of the interactions between these gro

ISSN:0025-116X    

DOI:10.1002/macp.1986.021870708

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractPotassium solutions, obtained by contacting the metal mirror with a THF solution of a crown ether were found to initiate the anionic polymerization of 4‐methyl‐2‐oxetanone (1) (β‐butyrolactone). The tacticity of the resulting polymer2was established by means of13C NMR spectroscopy. The results indicate that living polymers of1were formed, and the polymerization proceeds without abstraction of hydrogen from the monomer and no termination and transfer reactions ta

ISSN:0025-116X    

DOI:10.1002/macp.1986.021870709

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractIn contrast to the usual method of determination of the principle ratio in radical polymerization,k p2/kTe, which is based on the comparison of the rate of polymerization with the concentration of initiator, a method was used consisting in the representation of loge([M]0/[M]) versus (1 − e−kdt/2). The results obtained with styrene, vinyl acetate, acrylic acid, methacrylic acid, and 3,3,4,4,5,5,6,6,7,7,8,8,8‐tridecafluorooctyl acrylate (1) were found to be in good agreement with those already obtained by the other

ISSN:0025-116X    

DOI:10.1002/macp.1986.021870710

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY