摘要:

AbstractSoluble polymeric sulfoxides were prepared by free‐radical polymerization of methyl 4‐vinylphenyl sulfoxide and methyl 4‐vinylbenzyl sulfoxide, and copolymerization of these monomers with styrene. These polymers serve as effective phase transfer catalysts for several reactions under liquid‐liquid biphase conditions. The catalytic activity of copolymers containing styrene units is generally higher than that of homopolymers. On the other hand, copolymers with acrylonitrile co‐units do not exhibit catalytic activity. It was found that polymeric sulfoxides extract all alkali metal cations examined here more efficiently than their monomeric analogs, and that the binding ability increases with increasing density of active sites, suggesting a cooperative effect of sulfoxide groups. It is reasonable therefore to assume that the catalytic activity is due to both cation binding on the polymers and activation of the anions caused by desolvation in the hydrophobic region of the

ISSN:0025-116X    

DOI:10.1002/macp.1985.021860101

出版商:Hüthig&Wepf Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractA new diblock copolymer of propene and methyl methacrylate (MMA) was prepared by adding MMA during the living coordination polymerization of propene together with the soluble catalyst V(acac)3/Al(C2H5)2Cl at −78°C and subsequently by raising the polymerization temperature up to 25°C. The homopolymerization of MMA with this catalyst exhibits the characteristics of a living polymerization at the initial stage of polymerization. From the copolymerization of MMA with styrene, it was concluded that the polymerization of MMA occurs via a radical intermediate. It is suggested that a propene‐MMA diblock copolymer is formed via the transformation of a living polypropylene end to a radica

ISSN:0025-116X    

DOI:10.1002/macp.1985.021860102

出版商:Hüthig&Wepf Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractThis work deals with the modification reaction of dextran with ethyl and butyl chloroformate using tertiary amines as catalyst/acceptor systems and the DMF/LiCl system as solvent. The structure of the resulting polymers was determined by means of IR,1H and13C NMR spectroscopy as well as by chemical analyses. The reaction rate was found to increase in the following order:N,N′‐dimethylaniline

ISSN:0025-116X    

DOI:10.1002/macp.1985.021860103

出版商:Hüthig&Wepf Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractThe copolymerization of monomethyl maleate (MMM) or monomethyl fumarate (MMF) with styrene is investigated. The dependence of the copolymerization rates on the composition of the monomer mixture and the monomer reactivity ratiosrare determined. An identical structure of the MMM and MMF polymer radicals was found, that is thek21‐values of both copolymerization systems are equal (monomer 1 ≡ styrene; monomer 2 ≡ MMM or MMF). From this knowledge the difference of the copolymerization rates between MMM and MMF can be attributed to thek12

ISSN:0025-116X    

DOI:10.1002/macp.1985.021860104

出版商:Hüthig&Wepf Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractUsing the theory of association equilibria, equations are derived for preferential and total sorption into the coil for a ternary system containing inert liquid A, self‐associating liquid B and polymer C, capable of specific interactions with component B. Due to strong interactions, the assumption of random mixing is not valid for this system. In preceding work differences between experiment and prediction based on the classical Flory‐Huggins equation were formally described by the introduction of a ternary interaction term. For this particular system the ternary term may be interpreted as a consequence of the decrease in the entropy of mixing, caused by strong association of component B. On the contrary, if this component is bound to the polymer at the same time, the ternary term decreases. The equations derived in the paper lead to a reasonable fit with experimental data of the system benzene (A)/alcohol(B)/poly(methyl methacrylate)

ISSN:0025-116X    

DOI:10.1002/macp.1985.021860105

出版商:Hüthig&Wepf Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractThe kinetics of acid hydrolysis of poly[(2,2‐dimethyl‐1,3‐dioxolane‐4‐yl)methyl methacrylate] and of its copolymers with methyl methacrylate in homogeneous phase was investigated by means of mass spectrometry using perdeuterated acetone as the internal standard. It was found that under conditions of a pseudomonomolecular reaction the homopolymer is capable of an acceleration process with respect to the splitting‐off of acetone according to the content of the syndiotactic dyads. The respective rate constantsK0andK1were calculated. Characterization of the steric situation by means of models of polymeric ketonacetals and the absence of acceleration in the case of copolymers even containing only a small amount of methyl methacrylate units lead to the conclusion that the reported phenomenon is due to steric effects combined with a neighbouring g

ISSN:0025-116X    

DOI:10.1002/macp.1985.021860106

出版商:Hüthig&Wepf Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractThe proton‐decoupled signal of methyl carbons ofO‐(2‐hydroxypropyl)cellulose (HPC) (1b,m≥ 1) was found to be split into two peaks. The results of experiments on lanthanide shift and the dependence of the relative intensities of both peaks on the molecular weight of poly(oxypropylene) [poly(propylene oxide)] (PPO) indicated that the low‐field peak results from the terminal hydroxypropyl groups and the high‐field peak from the inside oxypropylene units. From the ratio between the intensities of the two peaks and the molar substitution (MS) (average number of oxypropylene units per anhydroglucose (AHG) unit), the degree of substitution (DS) (average number of hydroxyl groups substituted per AHG unit) was calculated. This new method could be applied to samples of low‐MS to which the conventional method based on the1H NMR technique alone was inapplicable. From the analysis of13C NMR spectra of HPC samples differing in MS, an authentic structural picuture of the HPC molecule coul

ISSN:0025-116X    

DOI:10.1002/macp.1985.021860107

出版商:Hüthig&Wepf Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractThe interaction of poly(1,1‐dimethylpyrrolidinium‐3,4‐diylethylene chloride) [poly(diallyldimethylammonium chloride)] (1) with ferro‐ and ferricyanide anions was investigated by conductometric titration, viscometry, IR and Raman spectroscopy. It could be shown that the binding of ferro‐ and ferricyanide anions with1proceeds by means of an ionic mechanism and is accompanied by a spectral shift of the cyan

ISSN:0025-116X    

DOI:10.1002/macp.1985.021860108

出版商:Hüthig&Wepf Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractThe field dependence of the birefringence fraction corresponding to the well‐defined long relaxation mechanism was studied for DNA. A typical saturation curve was obtained and when analysed this phenomenon gave the parameter Δn3,sfrom which it was possible to calculate the electrical and optical polarizability anisotropies. The results were analyzed along the lines of recent theories and experimental da

ISSN:0025-116X    

DOI:10.1002/macp.1985.021860109

出版商:Hüthig&Wepf Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractThe kinetic investigation of the free radical crosslinking copolymerization of styrene withm‐orp‐divinylbenzene was performed at 60°C in benzene solution with 2,&2prime;‐azoisobutyronitrile as initiator. The mole ratio of divinylbenzene to styrene was steadily kept small. At various stages of the process the concentrations of the remaining monomers were measured by vapor phase chromatography which allowed to calculate both the conversion degrees and the instantaneous composition of the copolymers formed. The radical reactivity ratio of styrene, determined kinetically, was found to be in good agreement with the value obtained by the Kelen‐Tüdös linearization method. The branched polymers formed prior to gelation were studied by light scattering and by size exclusion chromatography. The number of pendant double bonds was determined by analytical titration. From all these results, conclusions were drawn concerning the mechanism of network formation, and more specifically on the reactivity of the pendant double bonds that are formed whenever a divinylbenzene unit is incorporated. This latter factor determines the rate of the formation of the branch points and

ISSN:0025-116X    

DOI:10.1002/macp.1985.021860110

出版商:Hüthig&Wepf Verlag    

年代:1985

数据来源: WILEY